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187 Cards in this Set
- Front
- Back
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Atrial Systole
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Contraction of atria that causes an increase in volume to the ventricles (atrial kick)
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Cardiac Index
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- cardiac output divided by patient's body surface area (BSA)
CI = CO / BSA Normal values = 2.5-3.5 L/min/m |
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Cardiac Output
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- amount of blood ejected by left ventricle per minute
CO = HR x SV (stroke volume) |
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Diastole
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Relaxation of heart muscle, begins when aortic valve closes
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Ejection Fraction
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- percent of L ventricular end diastolic volume that's ejected during systole
- normal = 60-70% EF = SV/EDV |
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Gradient
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Difference in pressures (across valves or stenotic areas)
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Mean Arterial Pressure
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The time-averaged pressure throughout each cycle of heart beat
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Stroke Volume
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Amount of blood ejected by L ventricle w/ each beat
SV = EDV - ESV |
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Systemic Vascular Resistance
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- resistance the LV must pump against to eject its volume (opposition to blood flow offered by blood vessels)
- normal = 800-1200 dynes/sec/cm |
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As SVR increases, cardiac output (CO)....
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Decreases
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Causes of increased SVR
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Vasoconstriction, hypertension, cardiogenic shock, cardiac tamponade
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Causes of decreased SVR
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Vasodilation (& therapy), septic shock (hyperdynamic)
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Systole
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Phase of cardiac cycle in which heart is contractin
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Ventricular Filling
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Passive flow of blood from atria to ventricles
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SA Node
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- where electrical system's activity begins
- located = superior R atria - normal = 60-100 bpm |
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AV Node
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- 2nd electrical stop
- takes over electrical impulses if SA node fails - normal = 40-60 bpm |
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Ventricles (electrics)
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- destination point of electric signal
- can still create electrical signal w/o AV & SA nodes, very inefficient - normal = 20-40 bpm |
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Cardiac Cycle - Isoelectric Line
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- no electrical activity
- all deviation from this represent electrical impulse |
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Depolarization
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Contraction of muscle
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Repolarization
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Relaxation of muscle (filling of chambers)
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EKG/ECG Complex - P Wave
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- atrial depolarization
- atria are contracting forcing blood into venticles |
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EKG/ECG Complex - PR Segment
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- no electrical impulse generated; short segment along isoelectric baseline
- clinically significant |
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EKG/ECG Complex - PR Interval (PRI)
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- delay @ AV node ("gatekeeper" effect it has to make sure ventricles don't get overworked)
- represents time from impulse generation at SA node through AV node and into ventricles (indirect assessment of AV node function) |
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EKG/ECG Complex - QRS Complex
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- ventricular depolarization
- ventricular contraction (increases pressure in chamber until pulm. & aortic valves open letting blood into pulm trunk & into aorta [respectively]) - ventricles continue to squeeze until fully contracted, then pressure rapidly falls as muscle relaxes |
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EKG/ECG Complex - T Wave
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- ventricular repolarization
- ventricular relaxation & filling |
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EKG/ECG Complex - QT Interval
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-measured from beginning of QRS complex to end of T wave
- prolonged QT interval could be suspect of ventricular arrhythmias |
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EKG/ECG Complex - U Wave
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- repolarization of interventricular septum
- not often seen on normal ECG complex - if prominently seen, may be related to underlying hypokalemia (K+ def.) or hypocalcemia (Ca+ def.) |
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What does the Wiggers' Diagram show?
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Relationships of electrical activity to mechanical (hemodynamic) activity
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Isovolumetric
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No valves in heart open
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Wiggers' Diagram - part A
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- mitral valve open
- filling phase; final increase in pressure due to atrial contraction (P wave) |
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Wiggers' Diagram - part B
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- QRS complex begins (electrical activity occurring in ventricle)
- pressure from L ventricle rises until it exceeds L atria pressure, mitral valve closes - when isovolumetric contraction occurs |
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Wiggers' Diagram - part C
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- pressure in ventricle = pressure of fluid in aorta
- aortic valve opens - aortic wave form & ventricular wave form identical from C to E b/c aortic valve open & pressure is equalized - ejection phase (from C to E) |
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Wiggers' Diagram - part D
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- ventricle finished completely contracting, enters relaxation phase
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Wiggers' Diagram - part E
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- pressure in aorta > pressure in ventricle
- aortic valve closes - can see notch formed in aortic pressure waveform (artifact from aortic valve closing ["dicrotic notch"]) - from E to F = isovolumetric relaxatio |
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Wiggers' Diagram - part F
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- pressure in L ventricle < pressure L atrium
- mitral valve opens to allow ventricle to fill |
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How long is a typical rhythm strip?
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6 seconds long (30 large boxes)
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How long is each small box?
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0.04 seconds
5 small make up 1 "large box" (0.20 seconds) |
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Amplitude of Small Box
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0.1 mV
Large box = 0.5 mV |
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Things to Evaluate when reading ECG/EKG strips
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Regularity, rate, P wave, PRI, & QRS
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Regularity
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- how regular beats are
- measured from 1 type of wave to next occurrence of same wave type (Ex. from P to P wave) |
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Rate
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- how quickly heart is beating (bpm)
- on 6 sec strip, can quickly guesstimate rate by counting # of complete cycles on strip and multiply by 10 |
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P Wave
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- look for: uniform P waves, is there 1 for every QRS complex, do they occur consistently
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PRI
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- distance from beginning of P wave to beginning of Q wave
- should be measured to help decipher underlying rhythm (to measure, count small boxes) |
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QRS
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- should occur 1 to 1 w/ P waves
- can be measured to evaluate delays within ventricles during conduction |
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Bipolar EKG Leads
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- has 1 positive & 1 negative pole
- limb leads are bipolar |
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Unipolar EKG Leads
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- 2 pole; negative pole is made up of other electrodes
- in 12-lead, all other electrodes besides limb leads are unipolar |
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Leads I, II, III
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I = LA - RA
II = LL - RA III = LL - LA |
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Analyzing Rhythms - Sinus Rhythm ("Normal")
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- 16-18 boxes btw. each R peak (8 R waves, indicated 80 BPM)
- A & V equal; 60-100 BPM - PRI = 0.12-0.20 sec, QRS < 0.12 sec |
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Analyzing Rhythms - Sinus Brachycardia
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- R-R intervals constant, rhythm regular
- A & V equal; < 60 BPM - PRI & QRS same as normal |
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Analyzing Rhythms - Sinus Tachycardia
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- R-R intervals constant, rhythm regular
- A & V equal: > 100 BPM - same PRI & QRS as normal |
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Analyzing Rhythms - Sinus Arrhythmia
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- R-R interval varies (rate changes w/ respirations)
- A & V equal, usually normal range - PRI & QRS same as normal |
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Analyzing Rhythms - Atrial Flutter
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- A & V reg if AV node conducts consistently (A = 250-350 BPM, V rate depends on ratio conducted to ventricles)
- sawtoothed P waves - PRI hard to measure QRS < 0.12 sec |
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Analyzing Rhythms - Atrial Fibrillation
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- A rhythm immeasurable; V rhythm irregular (no impulse to follow)
- if V < 100 BPM, it's "controlled"; if V > 100 BPM, "rapid ventricular response" - no P wave, no PRI, QRS < 0.12 sec |
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Analyzing Rhythms - 1st Degree Heart Block
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- P wave upright & uniform
- PRI constant, always > 0.20 sec - rate & regularity depends on underlying rhythm |
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Analyzing Rhythms - 2nd Degree Heart Block
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- R-R consistent if conduction rate consistent
- rate normal (A impulse are blocked, V will be bradycardic) - more P waves than QRS complexes - PRI may be longer than normal |
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Analyzing Rhythms - 3rd Degree Heart Block (i.e. Complete Heart Block)
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- P-P & R-R are regular
- A normal, V slower - more P waves than QRS complexes - no impulses conducted through AV node to ventricles (i.e. NO PRI) - QRS < 0.12 sec if junctional origin, QRS > 0.12 sec if ventricular focus |
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Analyzing Rhythms - ST Segment Elevation
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- QRS complex widened
- comes from ventricle prematurely repolarizing (before it's done squeezing) - indicative of MI |
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Analyzing Rhythms - Premature Ventricular Contractions (PVCs)
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- don't count each PVC
- underlying rhythm irregular - no P wave before ectopic QRS complex (no PRI) - somewhere along the way, a point inside the ventricle decides to fire w/o provocation |
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Analyzing Rhythms - Ventricular Tachycardia (VT)
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- increased ventricular rate; V rate = 150-250 BPM
- no QRS complex; see dissociated P waves - if you let VT go w/o treatment, turns into VFib - QRS > 0.12 sec |
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Analyzing Rhythms - Ventricular Fibrillation (VFib)
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- no waves or complexes to analyze regularly
- coarse, rough waves (no discernible P wave, QRS complex, shockable rhythm) - fine waves (some activity, barely moving, shockable [harder to come back from]) |
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Analyzing Rhythms - Asystole
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- i.e. dead
- no regularity or rhythm, flat line |
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Atrial pressures have ____ "markers"
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2; "a" wave & "v" wave
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Ventricular pressures have _____ "markers"
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3; peak systole, begin diastole, end diastole
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Arterial pressures have ____ "markers"
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3; Peak systole, diastole, dicrotic notch
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Waveform Similarities
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- LA, RA, & PW (pulmonary wedge) look similar
- PA & AO look similar - RV & LV waveforms look similar |
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Where are sine waves seen?
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Atrial hemodynamics
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Where are square waves seen?
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Ventricular hemodynamics
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Where are triangular waves seen?
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Great vessels (pulmonary arteries & aortic hemodynamics)
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Pressures are usually greater on the _________ (left/right) side of heart
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Left
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What scale are RA/RV/PA/LA measured on?
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50-scale
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What scale are LV/AO measured on?
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200-scale
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When in the respiratory cycle should pressure readings be measured?
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End of expiration
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Atria "Markers"
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- a waves follow P waves in RA
- a waves follow QRS complexes in PAW - v wave = increase in pressure when atria fills against closed AV valves (follows T wave) - 'x' & 'y' descents represent relaxation phase |
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Wedge
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- PW or PAW or PCW is pulmonary artery or capillary wedges
- measured by allowing a catheter to "wedge" in lung bed - cuts off PA flow & end hole lumen measure pressures "through" capillary bed to LA - PAW = LA & L ventricular EDV |
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Systolic Pressure
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- occurs shortly after QRS ventricular squeeze from electrical waveform
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Diastolic Pressure
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- occurs right before or in conjunction w/ QRS complex b/c this is greatest point of relaxation within arterial system
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Pullback Pressures - Venous Side (25 or 50 mm Hg scale)
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- PW to PA (sine to triangular wave)
- PA to RV (triangular to square wave) - RV to RA (square to sine wave) |
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Pullback Pressures - Arterial Side (200 mm Hg scale)
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- LV to AO (square to triangular wave)
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Stroke Volume Index
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- SV as it relates to body surface area
SVI = SV/BSA (body surface area) Normal = 25-45 mL/m^2 |
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Causes of decreased CO or CI
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MI, shock, decreased HR & SV, increased vascular resistance, cardiac tamponade, hypovolemia, valvular heart disease, high PEEP
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Cardiac Tamponade
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Hole in heart that's allowing blood to exist heart (gets caught in pericardial sac; as sac fills, squeezes heart, decreases CO)
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Causes of increased CO or CI
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Decreased vascular resistance, pulmonary edema, increased metabolic state, positive inotropes
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Pulmonary Vascular Resistance
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- resistance RV must pump against to eject its volume (created by pulm. A & arterioles)
- normal = 100-250 dynes/sec/cm - represents RV afterload |
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Causes of increased PVR
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- pulmonary vessel constriction (increased PaCO2, decreased PaO2)
- pulmonary embolus |
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Preload
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- volume of blood in ventricle @ end of diastole
- Frank-Starling's Law (the more a myocardial fiber is stretched during filling, the more it shortens during systole & the greater the force of contraction) - increased by fluid admin, decreased by diuresis |
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Clinical significance of Preload
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- represents fluid returning to heart
- "filling pressure" - increased preload = increased MVO2 |
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What is LV preload measured as?
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PAW (LV-edp)
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What is RV preload measured as?
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RA (central venous pressure)
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Afterload
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- amount of pressure ventricle must work against during systole to open
- LV afterload = systemic vascular resistance - RV afterload = pulmonary vascular resistance |
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Clinical significance of Afterload
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With increased afterload, it increases work of heart & increases MVO2 demand
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Factors that increase Afterload
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- vasoconstriction, valvular stenosis, increased BV
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Contractility
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- heart's contractile force or muscle strength
- increases when preload isn't changed yet heart contracts more forcefully - Influencing factors: Starling's Law, SNS, pharmacologic agents |
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What's the most important regulatory fact for myocardial contractility?
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Sympathetic Nervous System (SNS)
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Inotropes
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- ino = strength, tropy = enhancing
- positive --> stronger contraction (vis versa) |
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Positive Inotropes
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Epinephrine, dopamine (intropin), dobutamine (dobutrex)
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Negative Inotropes
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Lopressor, amiodarone (Cordarone), diltiazem (Cardizem)
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Normal range of RA & PAW (Preload)
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RA = 0.8 mm Hg
PAW = 1-12 mm Hg |
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Normal range of SVR & MAP (Afterload)
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SVR = 800-1200 dynes/sec/cm
MAP = 70-105 mm Hg |
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Where does the R atrium receive blood from
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SVC, IVC, coronary sinus
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Tricuspid Valve
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- R atrioventricular valve (inlet)
- prevents backflow into aorta |
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Bicuspid Valve
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- mitral, L atrioventricular valve (inlet)
- 2 crescent shaped leaflefts - prevents backflow into aorta |
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Pulmonary Semilunar Valve
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- between RV & pulmonary trunk
- R, L, anterior cusps |
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Aortic Semilunar Valve
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- between LV & aorta
- 3 cusps (R, L, posterior) - 2nd most common cause of aortic valve disease requiring surgery = genetic condition of only having 2 cusps |
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Left Dominant Heart
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- circumflex supplies PDA/PLA
- 15% of population |
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Right Dominant Heart
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- RCA supplies PDA/PLA
- 60% of population |
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Co-Dominant Heart
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- supply to PDA/PLA is shared
- 25% of population |
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Single Coronary Artery Anomaly (CAA)
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- RCA absent, left system compensates
- rare, asymptomatic; can be life threatening if osteum & prox. portions of artery pass btw. origins of aorta & pulmonary trunk |
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Left Heart Cath (LHC)
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- looks @ LCA & RCA; can also look @ LV (aortic & mitral valves)
- arterial access procedure |
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Right Heart Cath (RHC)
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- used to determine pathologies within chambers of heart
- identifies gradients across valves - venous access procedure |
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Cardiac Cath Indications
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CAD, angina, positive stress test, silent ischemia, pericardial constriction, cardiomyopathy, prior to heart transplant, doc wants to check heart's functionality prior to major surgery
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Cardiac Cath Contraindications - Stabilized
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CHF, arrhythmias, electrolyte imbalance, anemia, med intox
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Cardiac Cath Contraindications - Non-Stabilized
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Recent MI, recent CVA (< 1 month), fever w/ unknown origin, poor LV function
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Cardiac Cath - Pre-Procedure Care
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Explanation of procedure, obtaining informed consent, premedication, baseline measurements
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Cardiac Cath - Intra-Procedure Care
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Modified seldinger technique, continuous EKG, BP, pulse ox, response to adverse situations
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Cardiac Cath - Intra-Procedure Care (Adverse Situations & Responses)
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- bradycardia/hypotension (atropine or epinephrine)
- contrast media rxn (Benadryl, atropine, crash cart) - chest pain (vasodilator, nifedipine) - PVC/VT/VF (lidocaine, shock) |
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Catheters - Judkins (JL, JR)
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- L & R
- number sizing variations relate to amount of curvature distance |
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Catheters - Amplatz (AL, AR)
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- different shape than Judkins, same function (across R & L systems)
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Catheters - Multipurpose (MP)
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- used for cardiac arteries
- used for locating other things (ex. 4 vessel studies) |
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Catheters - Bypass
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- R & L coronary bypass graft tips used to access certain types of bypass grafts
- IMA - used to access L internal mammary artery |
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Patient Positioning - RAO
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- image intensifier (II) on right anterior surface of patient (think like a bucky)
- catheter & spine found on LEFT side of image - RAO caudal = no diaphragmatic shadow |
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Patient Positioning - LAO
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- II on left anterior surface of patient
- spine is on RIGHT side of image |
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Cranial vs. Caudal
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- tube is below patient, cranial causes II to move towards head
- for PA & cranial angulation, catheter & spine in center, there is a diaphragmatic shadow |
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Left System Views - 45 degrees LAO
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Used to see body of circumflex
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Left System Views - 30-45 degrees LAO cranial
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Used to see left main, bifurcation of LAD & circumflex
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Left System Views - 30 degrees RAO cranial
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Used to see distal 2/3 of LAD, origin of diagonals
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Left System Views - 30 degrees RAO
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Entire circumflex, OMs, distal LAD
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Left System Views - 20 RAO caudal
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Straightened out circumflex & OM
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Left System Views - PA caudal
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Circumflex, proximal LAD
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Left System Views - PA
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Only used to see left main
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Left System Views - LAO caudal
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- "spider view"
- shows LM, bifurcation of LAD & circumflex |
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Right System Views - 30 degrees RAO
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Shows RCA, R ventricular branch, PDA
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Right System Views - 30-45 degrees LAO
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Shows RCA ("AP" view), R ventricular branch, PDA, PLA
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Right System Views - LAO cranial
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Removes superimposition of vessels for clear view of PDA/PLA bifurcation
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Left Ventriculogram
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- determines ejection fraction (i.e. heart's efficiency)
- measured by calculating volume of fluid within heart during diastole, then measuring volume of fluid that remains @ end of systole - pigtail catheter used |
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Cardiac studies are recorded at _______ frames/sec frame rate
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15-30 (higher the FR, more radiation)
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Lesion-type Masking Pathology
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- complex or multifocal lesions can mask pathology
- even when using multiple views |
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Intravascular Ultrasound (IVUS)
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- mechanical transducers & electronic multi-element phased-array transducers
- catheters = 2.9F & 3.2F - has allowed for pre-interventional lesion imaging & imaging lesions more distally - takes raw radiofrequency data & converts into color coded images |
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What's measured during a RHC?
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- O2 Saturation (evaluate possible atrioseptal & ventriculoseptal defects / sufficient O2/CO2 transfer in lungs)
- Cardiac Output (avg = 4-6L/min of blood pumped through heart) - Hemodynamic Pressure Tracings (variations in pressure btw chambers [can indicate valve stenosis, hypertension]) |
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RHC Procedure
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SVC (O2 sat meas.) / IVC (same) / RA (same) / RA pressure / RV pressure / PW pressure / PW to PA pullback pressure / PA pressure / PA (O2 sat meas.)
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Post-Procedure Care
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Bed rest, groin check (every 15 min for 2-4 hrs, every 30 min next 2-4 hrs), fluid consumption (help flush contrast), BP, resume diet, self-observation
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Valvular Regurgitation
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- part of valve prolapses, fluid goes opposite way
- most often seen in mitral valve |
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Patent Ductus Arteriosus (PDA)
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Connection between aorta & pulmonary artery
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Complications of Cardiac Cath
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MI, arrhythmias, vascular damage, cardiac tamponade, contrast rxn/renal failure, infection, vaso-vagal rxn, hemorrhage, death
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Allergy Meds - Steroids
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- anti-inflammatory; helps mitigate histamines from causing issues
- ex. Prednisone, Methylprednisolone, Hydrocortisone |
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Allergy Meds - Antihistamines (H1 Blockers)
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- anti-inflammatory; different mechanism of action
- ex. Benadryl (diphenhydramine), Vistaril (hydroxyzine), Claratin (ranitidine), Allegra (fexofenadine) |
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Allergy Meds - Antihistamines (H2 Blockers)
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- works through reduction of stomach acid
- helps control n/v associated w/ contrast media rxns - ex. Pepcid (famotidine), Tagamet (cimetidine), Zantac (ranitidine) |
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Infection Prophylaxis Meds
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- given when there's a skin incision involved or when infection is likely (i.e. compromised immune system)
- ex. Cephalosporin (Ancef, Keflex, Duracef), Fluoroguinolene (Levaquin), Glycopeptides (Vancomycin) |
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Anxiolysis Meds
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- given to reduce apprehension prior to procedure or when patient is agitated
- ex. Valium/Atavan (benzodiazepines) |
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Renal Insufficiency/Failure Meds
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- pre-procedure lab work is critical
- multiple items in combo can be given to protect kidneys - ex. Mucomyst (n-acetylcystine [antioxidant]), Sodium Bicarbonate (increase O2 levels), Saline (increases BV) |
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Conscious Sedation (Intra-procedural Meds)
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- minimizes pain/discomfort; in control of their own breathing; brief amnesia
- ex. benzodiazepines, narcotics (Fentanyl, morphine), oxygen, Benadryl |
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What medication is used to reverse benzodiazeprines?
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Flumazenil (Romazicon)
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What medication is used to reverse narcotics?
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Naloxone (Narcan)
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Antiemetic Meds
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- assists w/ mitigating n/v; oral tablet or liquid IV form
- ex. Zofran, Phenergan, Inapsine, Compazine |
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Platelet Inhibitor Meds
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- used w/ caution
- stopped prior to most procedures (b/c of decreased ability to clot) - ex. Plavix (clopidogrel), Aspirin |
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Fibrinolytics/Thrombolytics Meds
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- used to "bust" (lyse) clots
- tPA (Activase) - tissue plasminogen activator - ex. Reteplase (retavase), Urokinase (abbokinase) |
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Vasodilator Meds
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- dilate diameter of vessels
- ex. Nitroglycerine, Verapamil, Nicardipine |
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Antihypertensive Meds
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- similar action to vasodilators
- ex. Clonidine (catapres), Nitro |
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Vasopressor Meds
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- cause vasoconstriction (increases BP)
- ex. Dopamine, Dobutamine, Norepinephrine |
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Post-Procedural Meds
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- pain meds, antibiotis, antiemetic, anticoagulants/platelet inhibitors
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Cardiac devices are designed to...
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Restore or maintain a rhythm & rate sufficient to meet metabolic needs
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Diagnostic Device Operation Info
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Lead impedances, pacing thresholds, P & R wave sensing trends, battery voltage & impedance
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Diagnostic Patient Info
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AF burden, activity levels, % ventricular pacing, HR variability, fluid accumulation (some devices)
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Pacemakers/Implantable Pulse Generators (IPG)
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- provide rate to support metabolic needs & various diagnostics
- single & dual chambered (dual = R atrium & RV) - longevity = 8-10 years |
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Implantable Cardioverter Defibrillators (ICDs)
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- restores sinus rhythm in presence of tachycardia
- longevity = 6-9 years - provide rate to support metabolic needs & various diagnostics |
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ICD Past (~10-12 years ago)
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- major surgery (abdominal implants, median sternotomy)
- nonprogrammable, high-energy shock only - indicated for patients who survived cardiac arrest TWICE - 1.5 year longevity; used on < 1000 cases a year |
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ICDs Today
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- similar to pacemaker implant; single incision (pectoral implant, overnight stay)
- local anesthesia/conscious sedation - single, dual, & triple chamber - 9 years longevity |
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Cardiac Resynchronization Therapy (CRT)
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- restore ventricular synchrony in presence of HF by pacing both ventricles
- standard pacemaker used for RV, special lead navigated via coronary sinus to LV - CRT pacing combined w/ ICD ("high-power CRT") |
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Implantable Loop Recorders (ILR)
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- provide rate-based monitoring for patients experiencing transient recurrent syncope
- provides EGM during triggered events (intracardiac electrogram) - longevity = 14 months |
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Indications for Pacemaker Implantation
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- patients w/ symptomatic bradycardia, refractory to treatment, sick sinus syndrome, complete heart bock, vaso-vagal syndrome
- most often used = dual chambered |
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Single-chamber pacemaker used for...
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Ventricular --> Patients w/ chronic AF w/ slow ventricular response
Atrial --> patients w/ sinus node disease, no evident AV block |
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Primary Prevention for SCA (Sudden Cardiac Arrest)
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- patient who have not experienced SCA/VA, but are at risk
- studies --> MADIT II, SCD-HeFT (demonstrated use of ICDs in patients) |
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Secondary Prevention for SCA
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- patients who have experienced previous SCA or ventricular arrhythmia (VA)
- studies --> AVID, CIDS, CASH support use of ICDs in these patients |
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Indications for ICDs
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- cardiac arrest (due to VT or VF)
- syncope (sustained VT or VF induced during EP) - nonsustained VT w/...(coronary disease or prior MI & LV dysfunction) |
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Indications for CRT Therapy
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- NYHA Class III or IV heart failure
- wide QRS complex (> 120ms wide); EF < 35% - most get ICD w/ CRT b/c of risk of SCD |
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Indications for Loop Recorders
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- transient, infrequent but recurrent syncope
- many also diagnosed w/ seizure disorder - monitored w/ Holter monitor |
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What is one way to identify the type of pacemaker a patient has?
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If they don't have their ID card, use CXR to determine how many chambers (i.e. how many leads coming off of pacemaker)
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Pacing Therapy (I.e. how a pacemaker works)
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- senses underlying HR
- delivers low energy electrical pulses when HR falls below programmed limit - Dual chamber IPGs provide A-V synchrony |
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What does an ICD offer that a pacemaker does not?
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2 things --> defibrillation & ventricular ATP (anti tachy-pacing)
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High-Voltage Therapy
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- cardioversion (timed in synchrony w/ QRS) & difib delivered in biphasic waves
- device must detect, charge, confirm, deliver shock - common vector = from can + SVC coil to RV coil, back to can + SVC coil |
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How big is a typical ICD therapy lead?
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7F diameter lead
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"Active Fixation" Lead (dual coil ICD lead)
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Fixation mechanism on tip of lead is small helix (screw)
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"Passive Fixation" Lead (dual coil ICD lead)
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Fixation mechanism on tip of lead resembles small grappling hook (made from silicone)
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CRT Therapy
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- by pacing from both R & L ventricles, this can improve EF & reduce patient symptoms
- mitral regurgitation |
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When were the first pacemakers implanted?
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early 1960s (single chamber, non-programmable, 2 year longevity)
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Pacing Codes - Code Positions
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I - chamber(s) paced
II - chamber(s) sensed III - response to sensed event IV - programmability features V - anti-achyarrhythmia function |
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Pacing Code - Code Letters (I-IV)
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V = ventricle / A = atrium / D = A & V / O = none / T = trigger pacing / I = inhibit pacing / P = programmability / M = multi-programmability / C = communicating / R = rate modulation
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Pacing Code - Code Letters (V)
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P = pacing
S = shock D = dual (P & S) O = none |
