[Cardiac alternation in pericarditis with effusion].

Alternation of the heart was revealed in 18 of 74 patients with tumorous pericarditis with effusion (24%). It was found most frequently in patients with a drastically enlarged heart and a large amount of exudate in the pericardial cavity. An electrical, mechanical and mixed character of alternation was encountered in pericarditis with effusion. Electrical alternation was caused by increased mobility of the heart in the fluid, mechanical alternation (pulsus alternans) was caused by diminished contractile function of the myocardium. In certain cases alternation of the heart is a reversible process and may disappear under the effect of treatment including irradiation, chemotherapy and pericardiocentesis.