Changes in the rhythm of the heart during resection of the pericardium in chronic constrictive pericarditis, as recorded electrocardiographically

1. 1. Electrocardiograms which were taken before, and at intervals during, resection of the pericardium in six cases of chronic constrictive pericarditis have been described. 2. 2. Two patients who had auricular fibrillation developed both right and left ventricular premature contractions and short runs of ventricular paroxysmal tachycardia. In one case of normal sinus rhythm, auricular premature contractions which had been present beforehand increased in frequency. Moreover, paroxysms of auricular fibrillation, auricular flutter, and auricular paroxysmal tachycardia were recorded. Two patients with normal sinus rhythm and one with auricular fibrillation developed neither premature contractions nor other changes in rhythm. In only one case did the electrocardiograms which were taken before and after operation show appreciable changes in the amplitude and form of the T waves. 3. 3. These observations demonstrate the remarkable amount of manipulation and mechanical stimulation of its surface that the heart can tolerate without the occurrence of prolonged abnormalities of rhythm and without embarrassment of its function. These observations should give assurance to surgeons who undertake the surgical treatment of chronic constrictive pericarditis.