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65 Cards in this Set
- Front
- Back
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what does S1 represent?
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marks the beginning of ventricular SYSTOLE. S1 is the closing of the mitral (M1) and tricsupid (T1) valves, normally separated by an interval of .02-.03 seconds (T1 is more distinct and snappier during inspiration)
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when does S1 have wide splitting?
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incomplete and complete Right Bundle Branch Block (RBBB)
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what 4 things contribute to S1 intensity?
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mobility of cusps, rate of ventricular contraction, position of cusps at onset of systole, adequacy of atrioventricular cusps to halt regurgitant flow
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S1 is accentuated in...
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shortened PR interval, mild mitral stenosis, high cardiac output states (anemia, exercise, thyrotoxicosis, anxiety)
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S1 is diminished in...
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lengthened PR interval and 1st degree atrioventricular block, mitral regurgitation, severe mitral stenosis, noncompliant (stiff) left ventricle
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what does S2 represent?
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marks the beginning of ventricular DIASTOLE. S2 is related to the closure of the semilunar valves.
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where do you hear S1 best?
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tricuspid area (left lower sternal border), best heard w/diaphragm
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where do you hear S2 best?
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pulmonic area (2nd-3rd left interspace), best heard w/diaphragm. listening to S2 in the pulmonic area is the KEY TO CARDIAC AUSCULTATION
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explain the mechanism for the physiological splitting of S2
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inspiration results in decreased intrathoracic pressure --> increased systemic venous return to the right atrium --> increased RV EDV --> greater volume of blood ejected into the artery and longer RV ejection time --> delayed closure of the pulmonary valve (P2); there's also decreased diastolic back pressure on pulmonary valve (delays P2) and an interventricular septal shift that results in shorter LV ejection time (earlier A2)
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what causes widened splitting of S2? (A2 and P2 split on both expiration and inspiration, but especially on inspiration)
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right bundle branch block; pulmonary stenosis
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what causes fixed splitting of S2 (A2 and P2 are the same distance apart on expiration as inspiration)
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atrial septal defect
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when does S2 splitting normally occur?
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on inspiration
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what causes paradoxical splitting of S2 (P2 comes before A2 on expiration, come at ~same time on inspiration)
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left bundle branch block; advanced aortic stenosis
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where best do you hear an aortic ejection click? is there respiratory variation?
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heard best with the diaphragm at the mitral area, is widely transmitted. no respiratory variation. (aortic ejection click comes shortly after S1.)
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what causes an aortic ejection click?
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congenital aortic valve disease; dilatation of the aortic root.
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where best do you hear a pulmonic ejection click? is there respiratory variation?
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heard best with the diaphragm at the pulmonary area, is well localized. pulmonic ejection click is decreased in intensity on inspiration, frequently disappearing entirely. (pulmonic ejection click comes shortly after S1 on expiration)
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what causes a pulmonic ejection click?
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congenital pulmonary valve stenosis; idiopathic dilatation of the pulmonary artery
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where do you best hear S3 (ventricular gallop)?
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heard best with the bell (low frequency) at the mitral area (in the case of early LV filling) or the tricuspid area (in the case of early RV filling, increased on inspiration). (S3 comes a little after S2)
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what are the causes of a ventricular gallop?
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can be physiological (a normal finding in children and young adults); can be pathological in left or right ventricular volume overload
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how do you listen for S4 (atrial gallop)?
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with the bell (low frequency), S4 comes shortly before S1. can also palpate the apex impulse in the lateral decubitus position (pre-systolic outward movement --> large A-wave)
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what causes S4 (atrial gallop)?
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abnormally forceful atrial contraction resulting in increased rate of late diastolic filling and distension of a stiffened (less compliant) ventricle. caused by ventricular hypertrophy; ischemic myocardial injury. S4 is always PATHOLOGICAL.
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is S4 a sign of ventricular volume overload? heart failure?
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no and no. S4 is always diagnostic of a stiffened ventricle w/decreased compliance.
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how do you classify systolic murmurs?
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timing! midsystolic (ejection), pansystolic or holosystolic (regurgitant), mid-to-late systolic (regurgitant)
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what's the physiology behind a midsystolic murmur?
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caused by flow across a partial obstruction, increased flow through normal structures, or ejection of blood into a dilated chamber
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what causes a midsystolic murmur?
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can be innocent, can also be caused by aortic stenosis or pulmonary stenosis
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what causes a pansystolic murmur?
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mitral regurgitation, tricuspid regurgitation, ventricular septal defect; pansystolic murmurs are always pathological
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what causes a late systolic murmur?
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mitral valve prolapse
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what's the physiology behind a pansystolic murmur?
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caused by flow across an incompetent (regurgitant) AV valve or abnormal shunting of blood from relatively high pressure vascular chamber to lower pressure chamber
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what's the physiology behind a mid-to-late systolic murmur?
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results from mild mitral regurgitation due to mitral valve prolapse --> these murmurs are commonly, but not always, preceded by a mid-systolic click. as w/other AV valve regurg, these murmurs continue up to or through S2.
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how can you hear mitral valve prolapse?
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listen for mid-to-late systolic murmur. having patient lie, squat, and stand can help (should be loudest on standing and softest on sitting due to increased venous return)
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what view is best for viewing the size of the heart?
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PA image (CXR)
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what makes up the right border of the heart on x-ray?
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right atrium
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what makes up the front border of the heart on x-ray?
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right ventricle
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what makes up the left border of the heart on x-ray (frontal view)
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left atrium at the top, left ventricle at the bottom
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what does a normal heart look like on cxr?
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cardiothoracic ration <50% (>50% --> enlarged heart)
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when do you see dilatation of the heart?
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in chronic disease processes. mitral stenosis --> left atrial dilatation, right ventricle and right atrial enlargement
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what are pulmonary manifestations of heart disease?
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increased pulmonary venous pressure may be a result of left heart failure --> you see increased pulmonary markings, redistribution of blood flow from bases to apices of lung, pulm edema, and pleural effusions
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why do we use the pulmonary artery wedge pressure in cardiac catheterization?
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closely matches the left atrial pressure, used to estimate left ventricular diastolic pressure (ventricular preload). elevated PCWP --> left-sided heart failure, mitral stenosis or mitral regurg
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how do you calculate pulmonary vascular resistance?
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PVR = 80 x [(mean pulm artery pressure - left atrial pressure)/cardiac output]
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how do you calculate systemic vascular resistance?
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SVR = 80 x [(mean arterial pressure - right atrial pressure)/cardiac output]
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differential for left axis deviation
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inferior wall myocardial infarction, left anterior fascicular block, left ventricular hypertrophy (sometimes)
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PR interval (normal)
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.12-0.20 sec (3-5 small boxes)
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normal QRS interval
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less than or equal to 0.10 sec (<2 1/2 small boxes)
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normal QT interval
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corrected QT < or = 0.44 seconds (< 1/2 of R-R interval)
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when is the PR interval decreased?
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preexcitation syndrome, junctional rhythm
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when is the PR interval increased?
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1st degree AV block
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when is the QRS interval increased?
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bundle branch blocks, ventricular ectopic beat, toxic drug effect (e.g., antiarrhythmics), severe hyperkalemia
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when is the QT interval decreased?
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hypercalcemia, tachycardia
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when is the QT interval increased?
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hypocalcemia, hypokalemia (increased QU interval b/c of increased U wave), hypomagnasemia, myocardial ischemia, congenital prolongation of QT, toxic drug effect (e.g., antiarrhythmics)
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you see a big P wave on lead II and a P wave that begins positive and ends negative on lead V1. what causes this?
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RA enlargement (P height >2.5 mm in lead II)
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you see a wide P wave in lead II and a mostly negative P wave in lead V1. what causes this?
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left atrial enlargement (negative P in V1 >1mm wide and >1mm deep)
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EKG criteria for right ventricular hypertrophy
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R>S in lead V1 and Right axis deviation
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EKG criteria for left ventricular hypertrophy
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1 of these: S in V1 + R in V5 or V6 > 35mm; R in aVL >11mm; R in lead I >15mm
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what do you see on EKG in right bundle branch block?
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widened QRS, RSR' in V1 (rabbit ears), prominent S in V6
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what do you see on EKG in left bundle branch block?
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widened QRS, broad notched R in V6, absent R and prominent S in V1 (upside down bunny ears)
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what do you see on EKG in left anterior fascicular block?
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left axis deviation, small Q in leads aVL and I, small R in inferior leads (II, III, aVF)
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what does ST segment elevation indicate?
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full thickness/transmural MI --> baseline shifted downward
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when do you see a delta wave? (short PR and long QRS)
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Wolff Parksinson White syndrome --> accessory pathway with ventricular preexcitation
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what does ST segment non-elevation indicate?
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not full thickness MI --> baseline shifted upward
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describe the typical EKG findings for digoxin therapy
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ST scooped depression, mild PR prolongation
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describe the typical hyperkalemia EKG findings
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tall peaked T wave
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describe the typical EKG findings for severe hyperkalemia
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flattened P, widened QRS
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describe the typical EKG findings for hypokalemia
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ST depression, flattened T, prominent U wave
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describe the typical EKG findings for hypercalcemia
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shortened QT interval
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describe the typical EKG findings for hypocalcemia
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prolonged QT interval
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