Correct Answer: A. Presystolic accentuation is a hallmark feature
The patient presents with classic features of mitral stenosis with atrial fibrillation (AF)—a 6-month history of paroxysmal nocturnal dyspnea, palpitations, irregularly irregular pulse, elevated JVP, tender hepatomegaly, and a mid-diastolic murmur at the apex. The key discriminator is that presystolic accentuation is NOT a hallmark feature of this condition. Presystolic accentuation (a brief increase in murmur intensity just before systole) occurs in mitral stenosis only when the patient is in sinus rhythm, because atrial contraction forcefully propels blood across the stenosed mitral valve. However, this patient has atrial fibrillation, which abolishes organized atrial contraction. Without effective atrial systole, there is no presystolic accentuation—the murmur remains uniformly low-pitched throughout diastole. This is a critical clinical pearl: AF in mitral stenosis eliminates the presystolic accentuation that would otherwise be present. The other features (absent 'a' wave in AF, increased stroke risk, right heart failure signs) are all true and expected findings in this scenario.
Why the other options are wrong
B. The 'a' wave is absent in the JVP — This is TRUE and a hallmark of atrial fibrillation. The 'a' wave represents atrial contraction; in AF, there is no organized atrial systole, so the 'a' wave disappears from the JVP tracing. The JVP shows only 'c' and 'v' waves. This is a classic finding and a correct statement, making it an incorrect answer to the 'false' question. C. This patient has an increased risk of stroke — This is TRUE. Mitral stenosis with AF carries a very high thromboembolic risk (up to 17% annually without anticoagulation). The combination of reduced cardiac output, blood stasis in the dilated left atrium, and AF creates ideal conditions for thrombus formation. Indian guidelines (RNTCP-aligned cardiology practice) mandate anticoagulation in all such patients. This is a correct statement, not the false one. D. This patient shows features of right heart failure — This is TRUE. The elevated JVP, tender hepatomegaly, and heaving apex beat (from RV hypertrophy) are classic signs of right heart failure secondary to chronic mitral stenosis. Pulmonary hypertension develops from chronic pulmonary congestion, leading to RV strain and eventual RV failure. These findings are expected and correctly described in the clinical presentation.
High-Yield Facts
- Presystolic accentuation occurs in mitral stenosis only in sinus rhythm; it is abolished by atrial fibrillation due to loss of organized atrial contraction.
- 'a' wave is absent in atrial fibrillation because there is no effective atrial systole; JVP shows only 'c' and 'v' waves.
- Mitral stenosis + AF = thromboembolic risk up to 17% annually; anticoagulation is mandatory per Indian cardiology guidelines.
- Mid-diastolic murmur at the apex in mitral stenosis is best heard with the patient in the left lateral decubitus position using the bell of the stethoscope.
- Rheumatic heart disease remains the leading cause of mitral stenosis in India; acute rheumatic fever is the predisposing factor in >90% of cases.
Mnemonics
MS in AF = No Presystolic Mitral Stenosis + Atrial Fibrillation = No presystolic accentuation (because no atrial kick). Remember: presystolic accentuation needs a beating atrium. JVP in AF: CAV waves In Atrial Fibrillation, the 'a' wave is absent from JVP. You see only 'c' and 'v' waves. Mnemonic: 'a' = atrial contraction (gone in AF).
NBE Trap
NBE pairs presystolic accentuation with mitral stenosis (which is true in sinus rhythm) to trap students who forget that AF abolishes this finding. The question tests whether candidates understand that the rhythm determines the presence or absence of presystolic accentuation, not just the valve lesion itself.
Clinical Pearl
In Indian practice, rheumatic mitral stenosis with AF is common in middle-aged women. The loss of presystolic accentuation when AF develops is a bedside clue that the rhythm has changed—if you previously heard presystolic accentuation and it disappears, suspect new-onset AF and check an ECG. Always anticoagulate such patients to prevent stroke.
_Reference: Harrison Ch. 282 (Valvular Heart Disease); Robbins Ch. 12 (Cardiovascular Pathology); KD Tripathi Ch. 8 (Cardiac Arrhythmias)_