Long-term observations of cardiac arrhythmias during and after cardiac surgery. I. Acquired heart disease.

Twelve arrhythmias that occurred during and following surgery for acquired heart disease were studied in a group of 52 randomly selected patients. In cases of aortic and mitral valve replacement, Björk-Shiley prosthetic valves were used, and procain-magnesium-aspartate solution was applied for cardiac arrest. Registration and analysis of rhythm disturbances were carried out at 10 different time intervals, spaced narrowly in the intra-and early postoperative phases, then more widely up to the 96th hour of observation. Arrhythmic incidence and occurrence per case and phase are given, thereby allowing an account of transient arrhythmias as well. The peak occurrence of serious rhythm disturbance was found, intraoperatively, at about the time of aortic cross-clamping and release (ischaemic effect) with the exception of the mitral-commissurotomy group. The 1st-6th postbypass hours showed an arrhythmia trough, followed by a 2nd peak (9th-96th postoperative hour) made up of less serious arrhythmias (electrolyte- and acid-base disturbances; digitalis effects). All 12 arrhythmia types, as well as the five separately considered ventricular arrhythmias of the "first arrhythmia peak", did not reveal any significant relation to: patients' age, N.Y.H.A. criteria, pre-operative PAm or the duration of anaesthesia, surgery and bypass time.