Question
A 68-year-old man visits his doctor with a long history of ankle swelling and now reports breathlessness on mild exertion. He has known Chronic Obstructive Pulmonary Disease, coronary artery disease, and type 2 diabetes. He quit smoking after decades of use.
On examination, there is a pansystolic murmur best heard along the lower left sternal border, bilateral pitting oedema, and clear lung fields. He is stable at rest.
What is the most likely underlying cause of this murmur?
a. Congenital connective tissue abnormality
b. Increased cardiac output state
c. Persistent fetal vascular connection
d. Elevated pressure in pulmonary circulation
e. Post-infarction septal defect
Answer
Elevated pressure in pulmonary circulation (Pulmonary hypertension)
Detailed Explanation
This is a classic case of functional tricuspid regurgitation (TR) secondary to pulmonary hypertension, most likely due to underlying COPD.
Key reasoning:
- Pansystolic murmur at left sternal edge → think tricuspid regurgitation
- Peripheral oedema + clear chest → right-sided heart failure
- Background of COPD → chronic hypoxia → pulmonary vasoconstriction → pulmonary hypertension
👉 This leads to:
- Right ventricular dilatation
- Tricuspid annular dilatation
- Functional TR
Why not the other options?
- Connective tissue disorder → causes MR/AR (e.g. Marfan), not isolated TR
- Hyperdynamic circulation → causes flow murmurs, not pansystolic TR
- Patent ductus arteriosus → continuous “machinery” murmur
- Ventricular septal rupture → acute post-MI complication with shock
Cheat Sheet for Exams
Tricuspid Regurgitation (TR)
- Murmur: Pansystolic, left lower sternal edge
- Increases with inspiration (Carvallo sign)
- Signs:
- Raised JVP with prominent V waves
- Pulsatile hepatomegaly
- Peripheral oedema
Common Causes
- Pulmonary hypertension (MOST COMMON)
- Right ventricular infarction
- Infective endocarditis (IV drug users)
- Rheumatic disease
- Carcinoid syndrome
Flashcards
Q1: Most common cause of tricuspid regurgitation?
A: Pulmonary hypertension causing functional annular dilatation
Q2: Murmur of tricuspid regurgitation location?
A: Left lower sternal edge
Q3: What happens to TR murmur during inspiration?
A: It increases (Carvallo sign)
Q4: Key JVP finding in TR?
A: Prominent V waves
Q5: COPD leads to TR via what mechanism?
A: Hypoxia → pulmonary hypertension → RV dilatation
MCQs
1. A pansystolic murmur at the left sternal edge that increases with inspiration is most likely due to:
a. Mitral regurgitation
b. Aortic stenosis
c. Tricuspid regurgitation
d. Pulmonary stenosis
Answer: c
Explanation: TR murmur increases with inspiration (Carvallo sign), unlike MR.
2. Which of the following is FALSE regarding tricuspid regurgitation?
a. Causes prominent V waves in JVP
b. Best heard at apex
c. Associated with pulsatile hepatomegaly
d. Often secondary to pulmonary hypertension
Answer: b
Explanation: TR is heard at the left lower sternal edge, not apex.
3. A patient with COPD develops right heart failure. What is the mechanism?
a. Left ventricular hypertrophy
b. Increased systemic vascular resistance
c. Pulmonary hypertension due to hypoxia
d. Coronary artery thrombosis
Answer: c
Explanation: Chronic hypoxia → pulmonary vasoconstriction → pulmonary hypertension.
4. Which murmur is continuous rather than pansystolic?
a. Tricuspid regurgitation
b. Ventricular septal defect
c. Patent ductus arteriosus
d. Mitral regurgitation
Answer: c
Explanation: PDA produces a continuous “machinery” murmur.
5. Ventricular septal rupture typically presents:
a. Gradually over years
b. Immediately after birth
c. 2–8 days post myocardial infarction with shock
d. Only during exercise
Answer: c
Explanation: It is an acute mechanical complication of MI.
Summary for Quick Exam Revision
Functional tricuspid regurgitation is most commonly caused by pulmonary hypertension, especially in patients with chronic lung disease such as COPD. Chronic hypoxia leads to pulmonary vasoconstriction and increased pulmonary arterial pressure, resulting in right ventricular dilatation and subsequent tricuspid annular dilatation. This produces a pansystolic murmur best heard at the left lower sternal edge, which increases with inspiration (Carvallo sign). Clinically, patients present with features of right heart failure, including raised JVP with prominent V waves, peripheral oedema, and pulsatile hepatomegaly, often with a clear chest. Differentiating this from other causes of pansystolic murmurs is crucial: mitral regurgitation is heard at the apex, ventricular septal rupture is acute and post-MI, and patent ductus arteriosus produces a continuous murmur. In exam settings, always associate COPD with pulmonary hypertension and secondary tricuspid regurgitation unless proven otherwise.