Silent Presentation of Severe Aortic Stenosis

Clinical Presentation

A normally split S2 is a reliable physical examination finding that excludes the possibility of severe aortic stenosis, according to the American Heart Association 4, 5
The American College of Cardiology recommends echocardiography as the first-line diagnostic test when evaluating abnormal heart sounds, with transthoracic echocardiography specifically recommended for initial diagnosis and assessment of suspected valvular disease 4, 5
Echocardiography is also recommended for assessment of left ventricular wall thickness, size, and function, as well as re-evaluation when symptoms or signs change 4, 5

The American Heart Association recommends follow-up echocardiography at different intervals based on severity for asymptomatic patients with suspected valvular disease, including yearly for severe aortic stenosis, every 1-2 years for moderate aortic stenosis, and every 3-5 years for mild aortic stenosis 4, 5
Exercise testing may be considered in asymptomatic patients with aortic stenosis to elicit exercise-induced symptoms and abnormal blood pressure responses (Class IIb recommendation), but should not be performed in symptomatic patients with aortic stenosis (Class III recommendation) 4, 5

During pregnancy, the increased blood volume and enhanced cardiac output can accentuate murmurs associated with stenotic heart valve lesions, according to the American College of Cardiology 6, 7
A soft grade 1-2 midsystolic murmur along the mid to upper left sternal edge is a frequent normal finding during pregnancy, and the second heart sound may widen and appear fixed during later stages of pregnancy 6, 7

Valve calcification and immobility prevent the normal rapid, forceful closure of the aortic valve leaflets, resulting in diminished or absent A2, as noted by the American College of Cardiology and the European Heart Journal 8, 9
As stenosis progresses from mild to severe, the aortic valve becomes increasingly rigid and immobile, progressively dampening the closure sound, according to the European Heart Journal 9

The disappearance of the second aortic sound is specific to severe aortic stenosis, although it is not a sensitive sign, as reported by the European Heart Journal 9
The absence or marked softening of A2, combined with other findings, establishes high pre-test probability for severe disease, as recommended by the American College of Cardiology 8, 10

Carotid pulse characteristics, such as delayed, dampened upstroke, are associated with severe aortic stenosis, as described by the American College of Cardiology 8, 10
Systolic murmur characteristics, including late-peaking, crescendo-decrescendo murmur at the right upper sternal border, are indicative of severe aortic stenosis, according to the American College of Cardiology and Circulation 8, 11
A single S2, resulting from the absence of A2, is a significant finding in severe aortic stenosis, as noted by the American College of Cardiology 8, 10

If the physical examination strongly suggests severe aortic stenosis but echocardiography shows only mild stenosis, the echocardiogram has likely underestimated disease severity, as warned by the American College of Cardiology 8, 10