Differentiating Murmurs of Aortic Stenosis and Mitral Regurgitation

One of the questions I was asked at the recent IBC Dubai PACES course was how would one differentiate the systolic murmurs of aortic stenosis from mitral regurgitation.
This is a good question. Most often it is very easy to make out whether it is aortic stenosis or mitral regurgitation but sometimes the features are not clear and then the differentiation can become exceedingly difficult.
The answer is not to depend on the characteristics of the murmur but to take into account all the other information gleaned on clinical examination.
To start with mitral valve disease is more likely in a female and aortic stenosis if the patient is a male (these are genralisations and not to be regarded as rules).
On general examination one may note a very pale appearance in association with aortic stenosis (Dresden doll appearance ACES for PACES page 180)
Elfin facies is associated with aortic stenosis ACES for PACES page 182
A malar flush would be in keeping with mitral valve disease and pulmonary hypertension ACES for PACES page 186
High arched palate may occur in supravalvular aortic stenosis ACES for PACES page 187
Atrial fibrillation more likely mitral valve disease ACES for PACES page 193
Low volume, slow rising pulse in aortic stenosis ACES for PACES page 193,194
Brachio-radial delay aortic stenosis ACES for PACES page 196
Displaced apex beat mitral regurgitation ACES for PACES page 202
Thrusting apex mitral regurgitation ACES for PACES page 202
Heaving apex aortic stenosis ACES for PACES page 202
Apical thrill mitral regurgitation ACES for PACES page 203
Thrill 2nd right intercostal space aortic stenosis ACES for PACES page 203
Soft 1st heart sound mitral regurgitation ACES for PACES page 205
Soft 2nd heart sound aortic stenosis ACES for PACES page 206
Pan systolic murmur radiating to the axilla inferior angle of scapula mitral regurgitation ACES for PACES page 211,213 (remember mitral regurgitation can also cause ejection systolic murmurs ACES for PACES page 211)
Ejection systolic murmur radiating to the neck aortic stenosis ACES for PACES page 210,213

This exercise in differentiating murmurs is a good illustration of the importance of following each step of the clinical examination, focussing one’s mind on the findings and analysing the findings before moving on to the next step (i.e. following the elephant’s footstep ACES for PACES preface)

History Taking, Communication and Ethics for MRCP PACES

Many candidates and unfortunately many from outside the UK do not do well in these two stations.
One of the main reasons for this is failure to ask and take into account the patient’s, or in the case of a scenario in the communication skill station, the relation or carer’s perspective.
This may be due to the fact that this has not been standard teaching or standard practice when taking histories. Indeed many clinical skills books do not give a structure or framework for asking about the patient’s perspective.
It is essential to include the patient’s perspective in standard history taking. This is the only way in which one will do this naturally rather than in an artificial way in exams.
In order to do so it is vital to have a structure of framework for doing so.
In ACES for PACES I have provided such a structure (see chapters 4 and 18)
I have also provided an acronym as an aid to memorising this structure
It is I PASSED By Employing ACES, which stands for :
Identification and Introduction
Purposefully
Analyse
Symptoms
Systems
Elicit
Details
Beliefs
Expectations
Anxieties (regarding)
Causes
Effects
Survival

Cardiovascular Examination

We had another good case at the recently concluded MRCP PACES course conducted by IBC in Dubai.
The patient was a young child who looked small.
In a small child with a cardiovascular problem one should consider congenital heart disease or rheumatic heart disease (ACES for PACES page 178)
On examination of the pulse we noted sinus rhythm approximately 80 beats per minute, no abnormality in volume or character, all pulses equal and synchronous.
No abnormality in the head or neck.
On examination of the praecordium the apex appeared displaced and was thrusting in nature.
A thrusting apex suggests mitral regurgitation, aortic regurgitation or ventricular septal defect (ACES for PACES page 202)
The fact that the pulse was of normal volume and not collapsing would make aortic regurgitation unlikely.
The fact that the pulse was in sinus rhythm would make mitral valve disease unlikely.
As we were already suspecting congenital heart disease VSD would be very likely.
On further palpation of the praecordium, we felt a systolic thrill at the left sternal edge. This would fit in with our suspicion of VSD.
Auscultation confirmed a harsh pan systolic murmur at the left sternal edge with no radiation of the murmur confirming our diagnosis of VSD.
Lungs were clear
Diagnosis
Ventricular Septal Defect
Sinus rhythm
No heart failure
No reversal of shunt

Respiratory Examination

We saw another good case at the Dubai MRCP PACES course run by IBC.
The patient was a young Asian male man who seemed of normal height and weight.
On examination of his head there was no abnormality. On examination of his hands, initial examination seemed to reveal no abnormality, but on using the method of dividing the hands into systems (see ACES for PACES) it became evident that there was a difference in size and shape of the two hands. The left hand was smaller and narrower than the right. This was a consequence of an earlier injury during childhood. It had no bearing on the diagnosis but it did reveal the importance of correct method in revealing clinical findings.
On examination of the neck we noted that the trachea was deviated to the left. This indicated either a lesion pulling from the left or pushing it from the right.
On examination of the chest we noted that there was asymmetry of the chest with some flattening of the right apex and we also noted reduced movement of the right hemithorax. This showed that the lesion was on the right hand side. A lesion pushing the trachea from the right side. As a pneumothorax was unlikely in the setting of a course, the most likely diagnosis was right sided pleural effusion.
The remainder of the examination was now much easier as it was only confirmation of the findings of right sided pleural effusion.
The findings were an increased respiratory rate, apex beat was difficult to palpate, decreased vocal fremitus and reduced respiratory movements confirmed by palpation. Stony dull percussion note at the right base and decreased breath sounds and vocal resonance. Aegophony was heard at the upper border of the effusion.
Diagnosis
Right sided pleural effusion
Probably due to tuberculosis
Impaired respiratory function

Cardiovascular examination

We saw a classic case at the recent Dubai PACES course conducted by IBC
The patient was a young man who looked fit and healthy.
His pulse rate was 80 beats per minute, regular rhythm. His JVP was not elevated, trachea midline. Apex was not displaced and normal in character. The first heart sound was loud. This was the first clue that there could be a valvular lesion and quite correctly the candidates thought that the patient may have mitral stenosis. The second hear sound was of normal intensity, suggesting that the patient had not developed pulmonary hypertension. There was a clear cut opening snap in keeping with mitral stenosis. There was the classic decrescendo mid-diastolic rumble heard just medial to the apex beat and there was pre-systolic accentuation of the murmur indicating vigorous left atrial contraction. The findings were accentuated by turning the patient to the left lateral position and by exercise.
Lungs were clear

Diagnosis
Mitral stenosis
Sinus rhythm
No heart failure or pulmonary hypertension
Most likely as a consequence of rheumatic fever