Left ventricular function after repeated episodes of ventricular fibrillation and defibrillation assessed by transoesophageal echocardiography

BACKGROUND: Investigators studying the effects of cardioverter-defibrillators on left ventricular systolic function have given only minor attention to the diastolic effects. OBJECTIVES: The purpose of this study was to investigate the impact of repeated episodes of ventricular fibrillation and defibrillation on systolic function and diastolic filling of the left ventricle during non-thoracotomy implantation of a cardioverter-defibrillator. METHODS: Systolic function and diastolic filling of the left ventricle were assessed peri-operatively on a beat-by-beat basis using a transoesophageal echo-Doppler technique in 12 patients during > or = 4 episodes of ventricular fibrillation and defibrillation. Systolic function was assessed from the fractional area change and diastolic filling from the E/A ratio. Arterial blood pressure and the ECG were recorded continuously. RESULTS: Blood pressure and heart rate did not change significantly throughout the procedure. The systolic function, similarly, was not significantly affected; the only changes were seen in the first two beats after defibrillation when the mean fractional area increased from 0.2 +/- 0.01 to 0.4 +/- 0.02 and 0.3 +/- 0.02, respectively (P < 0.001). Diastolic filling was, however, impaired as reflected by a decrease in the E/A ratio from 2.6 +/- 0.5 before to 1.6 +/- 0.4 (P < 0.01) after repeated threshold tests. CONCLUSIONS: While the combined ischaemic and electrical trauma caused by repeated episodes of ventricular fibrillation and defibrillation during the implantation of a cardioverter-defibrillator did not cause any systolic dysfunction, diastolic filling was significantly impaired.