NMS Q&A Family Medicine

Cardiology 43Examination Answers1. The answer is C. Treponin, for which lab study is mostsensitive for picking up a 7-day-old MI. Treponin levelpeaks in 12 hours and lasts 15 days. Myoglobin peaks in4–5 hours, lasts 7 hours; CK-MB fraction peaks in 8 hours,lasts 2–3 days; AST, known best as an indicator of hepatocellulardamage, does rise in MI but is not specific enoughfor clinical application in cardiology.2. The answer is D. The stress testing protocol that wouldbe best for the described patient (atypical chest pain andresting bradycardia in a patient with symptomatic arthritisinvolving the knees) is D. Dobutamine, radionuclideangiography. It functions by causing vasodilatation, whichis scanned by radioisotope. The injured portion of myocardiumwill not show the vasodilatation in response todobutamine, and ischemic areas will fail to dilate and thuswill not take up the radioactive tracer. One of dobutamine’seffects is an increase in heart rate and it also increases BP.The phased treadmill exercise stress test is impracticalbecause the arthritic patient will not likely be able to challengecardiac output through the physical activity of thetreadmill. Likewise, thallium sestamibi scintigraphy (scanfor ischemia before and after programmed exercise) is notsuitable for the same reasons. Adenosine chemical stresstesting would be a reasonable choice if the baseline bradycardiawere not present. Adenosine may reduce heart rateand especially in the face of second-degree heart block(Mobitz type 2) may cause complete arrest for varyingblocks of time. Stress echo test normally involves physicalexercise and thus is disqualified in patients who cannotexert normally on a treadmill.3. The answer is B. Auscultation, while the patient issquatting during inspiration, is the maneuver that woulddo the most to differentiate the murmur of hypertrophicIHSS. In congenital HISS, the murmur is enhanced by anyforce that reduces venous return through the venae cavae,due to the hypertrophic aortic outflow tract that canprogress under certain conditions to critical degrees, thatis, choking off the cardiac output. Conversely, in situationsthat increase venous return, the outflow tract opensand turbulence is reduced. In the case presented, thisresults in a decreased intensity or disappearance of themurmur.4. The answer is A. The answer to which maneuverenhances the auscultatory finding of mitral insufficiencyis inspiration, squatting. This maneuver enhancesvenous return and thus increases mitral regurgitationwhen present. Expiration, standing erect, decreasesvenous return and effects an increase in the prominenceof a mitral click. Valsalva phase 3, the release phase, producesa rapid decline in arterial BP but in a normallyfunctioning heart has no affect on a mitral murmur. Valsalvaphase 4, the rebound phase, produces a rise in arterialBP and bradycardia through its affect on the carotidsinus. Handgrip produces a rise in SVR, heart rate, andcardiac output.5. The answer is C. The blood study that would be mosthelpful in delineating heart failure is serum pro-BNP level(pro-brain natriuretic peptide). BNP and ANP (atrialnatriuretic peptide) are renin-angiotensin antagonistsand serve as homeostatic responses to congestive heartfailure (CHF). BNP has a tendency to rise with the severityof CHF. Thus, BNP is a sensitive indicator of CHF witha high negative predictive value. A recommended cutpointfor elevation is 125 pg/mL for patients under 75 yearsof age. On average, females’ BNPs are about 15% higherthan that of males (38 vs. 31 pg/mL)and people over75 years of age roughly 10 times that of the populationunder 75 years (354 vs. 35 pg/mL). But even given such awide spread, CHF results in a roughly 10-fold elevationfor those under 75 years and close to 50% elevation in theover 75 population with CHF. Serum aldosterone rises inlong-standing CHF, especially when there is a strong rightheart failure component with great amounts of fluidretention. However, it is affected also by other fluid retentionstates, such as liver cirrhosis and other causes ofanasarca. Serum cortisol has virtually no meaningful relationshipwith cardiac compensation. Digoxin, a positiveinotrope, is used now most often in controlling certainsupraventricular dysrhythmias. Serum creatinine level is ameasure of renal function and will rise late in prerenalazotemia (long after urea nitrogen), of which CHF may beone cause.6. The answer is B. This patient depicts diastolic heartfailure (DHF). The name refers to the fact that the ventricularwall is stiff and does not fully relax during diastole.Ejection fraction is not compromised and is generally50%, although the stroke volume is below normal. Themost common causes of this type of failure are age anduncontrolled hypertension. Distended neck veins aremore likely to occur with systolic heart failure, whereinthe ventricles are flabby and whose contractions areweaker. Likewise, pulmonary passive congestion, althoughnot absent in DHF, is more likely in systolic failure and itsreduced ejection fraction. Both S 3 and S 4 gallops are foundin a strong minority of DHF cases but are found in amajority of systolic failure cases. Hepatomegaly may befound in 15% of cases of either type of failure.