A presystolic impulse together with a sustained apical impulse may be felt in a patient with left ventricular hypertrophy. The presystolic component is the palpable equivalent of an audible fourth heart sound. It reflects augmented left atrial systole from the work of having to fill the hypertrophied, non compliant left ventricle. The sustained systolic component reflects left ventricular hypertrophy. In the accompanying video and graphic, the cotton swab over the carotid identifies systole. Note that the other cotton swab over the apical impulse, identifies a presystolic component well before the carotid pulse and the sustained systolic component begins just before the carotid pulse.