Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
37 Cards in this Set
- Front
- Back
blood supply to SA node
|
RCA (55%)
Left circumflex (45%) |
|
blood supply to the AV node
|
RCA ( 90%)
left circumflex (10%) |
|
Coronary vascular territory
|
Anatomic Region of Heart-------Coronary Artery (most likely associated)
Inferior-------Right coronary Anteroseptal--------Left anterior descending Anteroapical------Left anterior descending (distal)Anterolateral-----Circumflex Posterior--------------Right coronary artery |
|
DDX considerations for bradycardia
|
Electolyte disorders
drugs (digitalis, B-Blockers, amiodarone, propofol) Infection (typhoid, leigonaire's, malaria, dengue) Infarction |
|
Tx for bradydysrhytmias
|
Atropine (0.5-1mg q 3-5 minutes- max 3mg)
Glucagon (for B-Blocer/CaChannel blocker toxicity) Dopamine (2-10 mcg/minute infusion) Artificial Pacing (Transcutaneous, transvenous, transthoracic) |
|
Major mechanisms for brady- and tachydysrhythmias
|
disorders of impulse formation
disturbance of conduction |
|
sinus bradycardia
|
sinus rhythm <60 bpm
|
|
sick sinus syndrome
|
spectrum of conditions includingsevere sinus bradycardiaSA blocksinus arrest bradycardia-tachycardia syndrome (intermittent brady and tachydysrhytmias- inc. a.fib/flutter, PVST- in the same patient)
|
|
AV Juntional Rhythms
|
-intrinsic rate approx 45-60 bpm
-occur in the abscence of sinus stimulus or with rapid juntional foci firing -typical QRS morphology is similar to pt's sinus beats -retrograde P waves -junctional escape beat typically occurs after an interval longer than the dominant cycle |
|
ventricular escape rhythm- rate?
|
-rate = <50 bmp
-drugs that may abolish ventricular rhythm may cause asystole and are contraindicated !(i.e Lidocaine, amiodarone) |
|
1st degree AV Block
|
PR interval > 200ms
-all p-waves conducted -constant P-R, and R-R intervals -can be associated with electrolyte disturbances, digitalis, Ca+ Chanel blockers, AMI (esp inferior MI) |
|
Mobitz tple I 2nd degree AV Block (Wenchebach)
|
-usually results from conduction delay in the AV node (but may ;be seen with lower conduction tissue block)
-usually normal duration ORS -progressive prolongation of the PR interval, then dropped QRS -usually transient, asymptomatic and carries a good prognosis |
|
Mobitz Type II 2nd degree AV block
|
-constant PR interval with intermittent dropped beats
-site of block is usually within the His-Purkinje system -typically seen with a BBB, wide QRS complex -often symptomatic, high rate of progression to 3rd degree AVB -requires permenent cardiac pacing |
|
3rd degree AV block
|
-no atrial impulses reach the ventricles
-block site may be AVN/His-Purkinjee/Bundles -requires perment pacemaker placement -consider atropine/emergent pacer if symptomatic |
|
Indications for temporary pacemaker
|
-Any hemodynamically unstable bradydysrhymia refractory to pharmacologic therapy
-Acute MI and -1st degree ACB + new onset BBB -Tyle II 2nd degree AVB -3rd degree AVB -RBBB + LAFB or LPFB -LBBB and Swan Ganz placement (b/c risk of iatrogenic RBBB) |
|
Pacer settings
|
-Maximal output setting until capture is acheived,
then decrease as tolerated -typical initial rate = 80-100 bpm -asynchronous mode--> cardiac arrest -synchronous mode--> bradydysrhytmias |
|
complication from central line/swan in pt with LBBB
|
complete heart block (moderater band with RBB disruption)
|
|
chronotrope
|
effects heart rate
|
|
ionotrope
|
effects strength of myocardial contraction
|
|
dysrhythmias due to pressors
|
due to beta on stimulations-highest incidence with dopamine
|
|
PSVT
|
includes AVNRT
- duel pathways in he AV node-most common AVRT -requires an accessory path-ex. WPW |
|
management steps for tachycardia
|
1. be prepared for cardiac arrest
2. determine stability 3. determine rate 4. determine QRS width(>.12=wide)narrow- always supraventricular 5. assess regularity of RR intervals 6.determine presence or absence of a p wave |
|
tachycardia
narrow, regular, with p waves |
sinus tachycardia(most common)
PAT (rare) |
|
tachycardia- ddx---
narrow regular no p waves |
AVNRT
AVRT atrial flutter with block |
|
PSVT treatment
|
vagal maneuvers - valsalva, carotid massage, ice water immersion
pharmacotherapy -adenoside-1st line-verapamil or diltizem ( if not contraindicated ) -esmolol (less effective) |
|
dig effect on EKG
|
PR prolongation plus ST segment scooping
|
|
two mechanisms for tachydysrhymias
|
re-entry and enhanced automaticity
|
|
;Atrial flutter treatment
|
extremely electrosensitive (cardioversion!)
-amiodarone can be used for chemical cardioversion **careful with drugs that speed up AV nodal conduction (ex. procainamide), these can increase conduction of flutter waves! |
|
Tachycardaia-
Ddx Narrow, irregular, P waves present |
MAT-most common in chronic lung disease patients
|
|
tachycardia
Ddx narrow, irregular, no P waves |
Atrial fibrillation
a flutter with variable block |
|
treatment for A.fib
|
rate control
Diltiazem (5-10mgIV over 2 min, q5min, max total 50-60mgiver 30 minutes, then gtt@ 5-15 mg/h) alternatives- verapamil, B-Blockers, digoxin, magnesium) cardioversion- hemodynamic instability electrical chemical-amiodarone anticoagulation **may require pacemaker if spontaneous slow ventricular repsonse |
|
tachycardia-ddx
wide, regular , no p waves |
monomorphic V tach
PSVT with aberrancy (BBB)antiodromic WPW ***For treatment purposes, safest to treat as VT |
|
Ventricular tachycardia-treatment
|
Unstable- synchronized electrical cardioversion, then antiarrythmic infusion (below)
Stable- Amiodarone (150mg IV over 10 minutes, the gtt at 1mg/min OR Procainaminde (17 mg/kg bolus, max rate 50mg/min) Lidocaine (100mg IV bolus)Magnesium ( 2-4g IV over 5 minutes, then 1 g/hour) |
|
tachycardia-DDX
Wide,; irregular,no p waves |
AF with BBB
AF with WPW polymorphic VT (including TdP) VF |
|
Wide comlex A.fib- treatment considerations
|
due to BBB
- tx similar to narrow a. fib agents that slow condution through AV note are CONTRAINDICATED (i.e diltiazem, BBlockers, digitalis; theses will increase conduction through a bypass tract best treated with electrical cardioversion, then amiodarone/procainamide to prevent recurrence --due to WPW |
|
Torsades de Pointes
-causes, treatment |
-drugs! (antiarrythmics, phenocthiazines)
-electrolyte disturbances(hypocalcemia, hypokalemia) Treatment -magnesium (2-4g over 5-10 minutes) -replete K -avoid QT prolonging agents (including amiodarone!) |
|
Ventricular fibrillation
|
defibrillation
Biphasic 100J-200J Monophasic 200J-360J After sucessful defibrillation, start IV amiodarone, lidocaine or procainamide gtt to prevent further arrythmia |