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Updated: May 2, 2026
Primary Outcome Assessment in a Pig Model of Acute Myocardial Infarction
Published on: October 14, 2016
Left ventricular function after repeated episodes of ventricular fibrillation and defibrillation assessed by
M Runsiö1, L Bergfeldt, L A Brodin
1Department of Thoracic Surgery, Karolinska Institute at Karolinska Hospital, Stockholm, Sweden.
Insights
Repeated cardioverter-defibrillator shocks did not impair systolic function but significantly worsened diastolic filling of the left ventricle in patients undergoing implantation.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Surgery
Background:
- Limited research exists on the diastolic effects of cardioverter-defibrillators.
- Previous studies focused primarily on systolic function impacts.
Purpose of the Study:
- To evaluate the effects of repeated ventricular fibrillation and defibrillation on left ventricular systolic function and diastolic filling.
- To assess these impacts during non-thoracotomy cardioverter-defibrillator implantation.
Main Methods:
- Transesophageal echo-Doppler assessed systolic function (fractional area change) and diastolic filling (E/A ratio) in 12 patients.
- Measurements were taken beat-by-beat during at least 4 episodes of ventricular fibrillation and defibrillation.
- Continuous monitoring of arterial blood pressure and ECG was performed.
Main Results:
- No significant changes in blood pressure or heart rate were observed.
- Systolic function remained largely unaffected, with transient increases in fractional area post-defibrillation.
- Diastolic filling was significantly impaired, indicated by a decreased E/A ratio post-procedure.
Conclusions:
- Repeated ventricular fibrillation and defibrillation during cardioverter-defibrillator implantation did not induce systolic dysfunction.
- Significant impairment of left ventricular diastolic filling was observed, highlighting potential long-term implications.
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.
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