Spontaneous ventricular fibrillation occurring immediately after institution of cardiopulmonary bypass: possible...

Twenty-four patients developed spontaneous ventricular fibrillation (SVF), for no apparent reasons, immediately after the institution of cardiopulmonary bypass (CPB) and prior to aortic cross-clamping and cardioplegic arrest. These were compared to 76 similar patients who remained in normal sinus rhythm (NSR). The following observations were made: (1) SVF occurred more frequently in patients undergoing urgent coronary bypass and having unstable or crescendo angina with severe triple coronary artery disease and/or left main coronary artery stenosis; (2) in nonvented hearts the mean left atrial pressure increased to levels above 28 mm Hg during SVF and prior to cardioplegic arrest; (3) at the end of CPB, arrhythmias and episodes of ventricular fibrillation were common (48% SVF versus 8% NSR); (4) the overall myocardial infarction rate was 37% SVF versus 4% NSR; and (5) the mortality rates were 25% SVF versus 1.3% NSR. It is postulated that the occurrence of SVF at the start of CPB may be indicative of serious derangements in myocardial cellular metabolism and/or function and may have clinical and prognostic implications.