Presence of diastolic dysfunction after biphasic synchronized transthoracic shocks in a porcine model evaluated with CMR
© Nadeshalingam et al.; licensee BioMed Central Ltd. 2014
Published: 16 January 2014
Defibrillation and cardioversion are often used as life-saving measures in cases of cardiac arrest and arrhythmias. Previous studies in humans with cardioversion of arrhythmias, found a decrease in ejection fraction but no significant changes in preload, afterload and heart rate. However, it is not clear whether the underlying cardiac condition may have contributed to these findings. This study aimed to observe the effects of biphasic synchronized shocks on left-ventricular function parameters over a 5-hour period in a porcine model.
Ten pigs received five consecutive biphasic synchronized shocks of 200J. Six pigs served as healthy controls and underwent the identical anesthesia and imaging protocol. Images were acquired with a clinical 3T MRI scanner (Siemens Magnetom Skyra). Routine functional cine imaging was completed for all pigs at baseline by acquiring a short-axis stack (7-10 slices) of the left ventricle. This imaging protocol was repeated hourly for 5 hours. All MR images were analyzed for cardiac function parameters (cardiac output, stroke volume, ejection fraction, end-diastolic and end-systolic volume) and in addition to assess left ventricular motion abnormalities. T2 maps were acquired at each time point to evaluate the presence of myocardial edema following the shock series.
Biphasic synchronized shocks of cumulative 1000J in a porcine model lead to a significant decrease in EDV and CO. Shock-induced myocardial edema may be an explanation of our findings indicating diastolic dysfunction with preserved ejection fraction.
Funding is provided by the Montreal Heart Institute Foundation and the Canadian Foundation for Innovation.
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