Treatment of post resuscitation myocardial dysfunction: aortic counterpulsation versus dobutamine

Abstract

Background: Post resuscitation myocardial stunning is well described and recognized as a significant contributor to poor long-term outcome following cardiac arrest. Optimal strategies for treatment have not been determined. Methods: Ten domestic swine (49±3 kg) underwent 15 min of untreated ventricular fibrillation before being successfully resuscitated. Left ventricular systolic and diastolic function was measured at pre-arrest baseline, at 30 min and at 6 h post resuscitation. Five animals were treated immediately after resuscitation with intra-aortic balloon counterpulsation (IABP) and five were given dobutamine (5 mcg/kg per min). Results: No baseline differences were found. At 30 min post resuscitation pulmonary capillary wedge pressure and LVEDP were significantly higher (16±3 vs. 7±1 and 20±2 vs. 11±1 mmHg) while LV isovolumic relaxation (‘Tau’) was significantly longer (34±2 vs. 20±2 ms) in the IABP treated versus the dobutamine treated animals. Likewise, at 6 h post resuscitation LV ejection fraction was significantly less (21±6 vs. 39±4%), and LVEDP significantly higher (18 vs. 10 mmHg) in the IABP group. Heart rate was not different between the groups at any time post resuscitation. Conclusion: Dobutamine was superior to IABP for treatment of post resuscitation left ventricular systolic and diastolic dysfunction. The hypothesized advantage of IABP for treatment of post resuscitation myocardial stunning without excessively raising the heart rate like dobutamine was not realized.