Question 27

Clinical examination of a 35 year old man who is short of breath reveals a pansystolic murmur. Outline the salient clinical features and investigations which will help you distinguish between mitral regurgitation, tricuspid regurgitation and a ventricular septal defect in this setting.

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College Answer

This question lends itself to answering with table. An example of the sort of information that could
be provided is included in the following example table:

	MR	TR	VSD
Symptoms	Paroxysmal Nocturnal Dyspnoea, orthopnea, palpitations, Chest Pain	Pedal oedema, Chest Pain, Short Of Breath	Chest Pain, Short Of Breath
Pulse	Commonly AF	May be AF	Usually Sinus Rhythm
JVP	May be raised	V waves	Prominent a waves because of pulmonary hypertension
Precordium	Systolic Thrill +/- Parasternal lift +/-	Systolic Thrill +/- Parasternal lift +/-	Systolic Thrill +/- Parasternal lift +/-
Murmur	Apical to axilla	Left Sternal Border, increases with inspiration	Left Sternal Border, occasionally concomitant Atrial Regurgitation


Other systemic signs	Basal crepitations	Pulsatile liver	Other congenital abnormalities +/-
Chest X-Ray	Straight Left heart border, pulmonary oedema	Enlarged Right Atrium	Nil specific
Echocardiogram	Classic features	Classic features	Classic features
Pulmonary Artery Catheter	Pulmonary hypertension	Pulmonary hypertension, V waves on Central Venous Pressure	Step up in O2 saturation at ventricular level

Discussion

To answer this, I have referred again to my own tabulated summary of heart murmurs.

One can do little to improve on the table presented in the college answer.

The MR and TR are easy to tell apart. TR gets louder on inspiration, and causes a pulsatile liver.

MR gets louder on expiration, and causes pulmonary oedema.

The VSD is a little more tricky, and apart from occasionally causing pulmonary hypertension its murmur is difficult to distinguish from the others.

Both VSD and MR will be loudest on expiration, but VSD will be most audible at the left sternal border, whereas the MR is best heard near the apex.

References

Clinical Examination of the Critically Ill Patient, 3rd edition by L.I.G. Worthley - which can be ordered from our college here.

Clinical Examination: whatever edition, by Talley and O'Connor. Can be acquired anywhere.

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