Cardiology

Step 1: Recall ECG components.
An ECG wave typically consists of the P wave, QRS complex, and T wave.
- P wave: Atrial depolarization.
- QRS complex: Ventricular depolarization (Q = initial downward deflection, R = tall upward deflection, S = downward deflection following R).
- T wave: Ventricular repolarization.
Step 2: Analyze the given ECG figure.
The figure shows a prominent upward spike (R wave), a downward deflection after it (S wave), and a rounded wave after that (T wave).
The initial small wave before QRS complex (P wave) is missing.
Step 3: Exclude wrong options.
- (A) R wave: Already visible in the figure.
- (B) S wave: Present after the R wave.
- (C) Q wave: Usually a small downward deflection before R, but here the P wave is entirely absent.
- (D) P wave: Missing wave; correct answer.
Step 4: Conclusion.
Thus, the missing wave in the ECG trace is the P wave.

Step 1: Recall pathogenesis of Rheumatic heart disease.
Rheumatic heart disease is a chronic consequence of rheumatic fever, which follows untreated group A beta-hemolytic streptococcal throat infections. The immune system cross-reacts with cardiac tissue, causing pancarditis and chronic valvular deformities.
Step 2: Which valve is most commonly affected?
The mitral valve is the most frequently involved, in up to 70–80% of cases. It shows leaflet thickening, commissural fusion, and chordae tendineae shortening, leading to mitral stenosis or regurgitation.
The aortic valve is the second most commonly affected, often along with the mitral valve. Tricuspid and pulmonary valves are rarely involved.
Step 3: Analyze the options.
- (A) Mitral: Correct. Most frequently deformed valve.
- (B) Aortic: Less commonly affected, usually in association with mitral involvement.
- (C) Tricuspid: Rare, except in severe or advanced cases.
- (D) Pulmonary: Extremely rare in rheumatic heart disease.
Step 4: Conclusion.
Therefore, in Rheumatic heart disease, the mitral valve has the highest probability of deformation.