5 Aortic stenosis
Salient features
History
• Asymptomatic (many patients do not have symptoms)
• Angina (in ~70% of adults; average survival after onset of angina is 5 years)
• Syncope (in 25% of patients, during or immediately after exercise; average survival after onset of syncope is 3 years)
• Dyspnoea: common presenting symptom (suggests left ventricular dysfunction; heart failure reduces life expectancy to <2 years).
Examination
Pulse
• Low volume pulse, with a delayed upstroke (pulsus parvus et tardus). This is caused by a reduction in systolic pressure and a gradual decline in diastolic pressure.
• Normal pulse in mild aortic stenosis when the gradient is <50 mmHg.
• Slow rise with diminished ‘volume’, sometimes with notch on the upstroke (‘anacrotic’): indicating severe aortic stenosis with associated aortic regurgitation, double pulse may be felt (‘bisferious’) (Fig. 5.1).
Heart
• Apex beat is heaving in nature but is not displaced. (A displaced apex beat indicates left ventricular dilatation and severe disease.)
• Palpable systolic vibrations over the primary aortic area, with the patient in the sitting position during full expiration (often correlates with a gradient of >40 mmHg)
• Systolic thrill over the aortic area and the carotids
• Ejection click heard 0.1 s after first heart sound, along the left sternal border (indicates valvular stenosis). An ejection sound that moves with respiration is not aortic in origin (Fig. 5.2)
• An atrial (S4) sound may be heard
• Ejection systolic murmur at the base of the heart conducted to the carotids and the right clavicle (Fig. 5.2). (Listen carefully for an early diastolic murmur as mild aortic regurgitation often accompanies aortic stenosis.) Remember Valsalva decreases duration of murmur of aortic stenosis and increases the murmur of hypertrophic cardiomyopathy
• Third heart sound: in patients with aortic stenosis, third heart sounds are uncommon but usually indicate the presence of systolic dysfunction and raised filling pressures.
Questions
What does the second heart sound tell us in this condition?
• A soft second heart sound indicates valvular stenosis (except in calcific stenosis of the elderly, where the margins of the leaflets usually maintain their mobility).
• A single second heart sound may be seen when there is fibrosis and fusion of the valve leaflets.
• Reversed splitting of the second sound indicates mechanical or electrical prolongation of ventricular systole.
• A perfectly normal second heart sound (i.e. normal splitting with A2 of normal intensity) is strong evidence against the presence of critical aortic stenosis.
