Palpation across the chest may reveal an abnormal pulsation, due for example, to an aneurysm of the left ventricle or, more rarely, of the ascending aorta (figure 47a,b). A very rare anomaly is right/left transposition of the viscera (situs inversus), where the heart and apex beat, project to the right side.
A tapping apex beat is suggestive of mitral stenosis. A dyskinetic impulse may be due to transmission of a powerful atrial contraction and this typically occurs in hypertrophic obstructive cardiomyopathy (HOCM) and in systemic hypertension. A dyskinetic impulse may also result from a left ventricular aneurysm.
When your hand is placed firmly over the chest, just lateral to the sternum on the left, abnormal impulses from the right ventricle may be felt, as for example in right ventricular hypertrophy due to pulmonary hypertension. If the pulmonary artery is dilated, an impulse may be felt in the second left intercostal space during expiration.
An arterial impulse in the suprasternal notch may indicate an unfolded aorta and abnormal arterial pulses in the neck may result from the tortuosity and hardening of the carotid arteries. A prominent pulsation just above the right sternoclavicular joint, is usually due to hardening, lengthening and rotation of the bifurcation of the brachiocephalic artery, rather than an aneurysm. The subject is hypertensive, with some wasting of the overlying sternomastoid muscle. In thin patients, especially if affected by chronic airways obstruction, it is not unusual for a pulsation to be detected in the epigastrium.
The presence of a palpable thrill almost always indicates an organic lesion (figure 48a–c).It indicates turbulent flow, usually through a small orifice, such as a narrowed valve or a ventricular septal defect. Thrills are usually systolic, i.e. coincident with the apex beat, but may occur in diastole. In order to detect a thrill, it may be necessary to lean the patient forward during expiration and apply the palm of your hand to the base of the heart (central sternum). The pulmonary component of the second sound may also be palpable. In this position also palpate for thrills over the apex.