Rubs, Gallops, and Continuous Murmurs

     You are now listening to a typical example of a friction rub. It is caused by the beating of the heart against an inflamed pericardium or lung pleura, which itself has a wide variety of etiologies. This sound is usually continuous, and heard diffusely over the chest. It typically has three components, one systolic and two diastolic. The systolic occurs with ventricular contraction, and the diastolic occurs during both rapid ventricular filling and atrial contraction. It is accentuated when the patient sits up and leans forward, and may be accentuated during inspiration. If the rub completely disappears when the patient holds his breath it is more likely due to pleural, not pericardial, origin.