Correct Answer: D. Tricuspid stenosis
Tricuspid stenosis (TS) presents with a diastolic murmur at the left lower sternal border that increases with inspiration (Carvallo's sign). The key discriminating feature here is the prominent a-waves in JVP. In tricuspid stenosis, the stenotic tricuspid valve prevents normal atrial emptying during ventricular diastole, causing blood to back up into the right atrium. This generates forceful atrial contraction against the narrowed valve orifice, producing exaggerated a-waves on the JVP tracing. The a-wave represents atrial contraction; when the tricuspid valve is stenotic, this contraction becomes more vigorous and prominent. Tricuspid stenosis is most commonly rheumatic in origin in India, often coexisting with mitral valve disease. The combination of a diastolic murmur (from blood flowing across the stenotic valve during ventricular filling) and prominent a-waves (from forceful right atrial contraction against obstruction) is pathognomonic for tricuspid stenosis. This distinguishes it from tricuspid regurgitation, which produces systolic murmurs and prominent v-waves, not a-waves.
Why the other options are wrong
A. Mitral regurgitation — Mitral regurgitation produces a holosystolic (pansystolic) murmur, not a diastolic murmur. MR causes prominent v-waves (or cv-waves) in the JVP due to blood regurgitating back into the left atrium during systole, not prominent a-waves. The murmur is heard best at the apex with radiation to the axilla. B. Mitral stenosis — While mitral stenosis does produce a diastolic murmur, it causes prominent a-waves in the pulmonary venous pressure (not JVP), and the JVP typically shows normal or diminished a-waves. MS is associated with an opening snap and a low-pitched rumbling murmur at the apex. The JVP findings do not match this diagnosis. C. Tricuspid regurgitation — Tricuspid regurgitation produces a holosystolic murmur at the left lower sternal border, not a diastolic murmur. TR causes prominent v-waves (or cv-waves) in the JVP due to systolic backflow into the right atrium, not prominent a-waves. The murmur increases with inspiration (Carvallo's sign), but the timing and JVP pattern are systolic, not diastolic.
High-Yield Facts
- Tricuspid stenosis produces a diastolic murmur at the left lower sternal border that increases with inspiration.
- Prominent a-waves in JVP are the hallmark of tricuspid stenosis, reflecting forceful right atrial contraction against a narrowed valve.
- Rheumatic heart disease is the most common cause of tricuspid stenosis in India, usually coexisting with mitral valve involvement.
- Tricuspid regurgitation (not stenosis) produces systolic murmurs and prominent v-waves, not a-waves.
- Mitral stenosis produces diastolic murmurs but affects pulmonary venous pressure, not JVP a-waves.
Mnemonics
TS vs TR Murmur Timing TS = Diastolic (valve opens, blood flows across narrowed orifice during filling). TR = Systolic (valve leaks during contraction). Remember: Stenosis = Slow filling = Diastolic; Regurgitation = Reverse flow = Systolic. JVP Waves in Right-Sided Lesions TS → a-waves (prominent, forceful atrial contraction). TR → v-waves (systolic backflow). a = atrial contraction, v = venous filling. Stenosis blocks outflow → exaggerated a. Regurgitation allows backflow → exaggerated v.
NBE Trap
NBE pairs diastolic murmurs with mitral stenosis to lure students into choosing MS without carefully analyzing the JVP findings. The prominent a-waves are the discriminating feature that separates tricuspid stenosis from mitral stenosis, which would show normal or diminished a-waves.
Clinical Pearl
In Indian rheumatic heart disease clinics, tricuspid stenosis is rarely seen in isolation—it almost always coexists with mitral valve disease. The prominent a-waves on JVP examination are a bedside clue that should immediately prompt you to look for tricuspid involvement rather than assuming all diastolic murmurs are mitral stenosis.
_Reference: Harrison's Principles of Internal Medicine, Ch. 236 (Valvular Heart Disease); Robbins and Cotran Pathologic Basis of Disease, Ch. 12 (Heart)_