Long-term observation of cardiac arrhythmias during and after cardiac surgery. II. Congenital heart disease.

Twelve arrhythmias that occurred in conjunction with surgery for congenital heart disease were studied in a group of 38 randomly selected patients. Halothane was used for anaesthesia and procaine-magnesium-aspartate solution for cardiac arrest. Registration and analysis of rhythm disturbances were carried out at 10 different time points, spaced narrowly in the intra- and early postoperative phases, then more widely up to the 96th hour of observation. Arrhythmic incidence per case and occurrence per case and phase are given, thereby also allowing an account of transient arrhythmias. The peak occurrence of intra-operative rhythm disturbances was found at about the time of aortic cross-clamping and release (ischaemia and halothane effect). A decline in arrhythmic incidence in the 1st-6th post-bypass hours was followed by a 2nd peak in the 6th-23rd postoperative hours (electrolyte and acid-base disturbances and/or a digitalis effect). All 12 arrhythmia types of the cardiopulmonary bypass group, as well as the separately considered ventricular arrhythmias of the first "arrhythmia peak", did not reveal any significant relation to: patients' age, total anaesthesia time, total surgery time and total bypass time. It is recognized that any comparative evaluation of operative arrhythmias, and especially a study of the causes and development of "surgically induced" A-V block, is problematic.