Impaired recovery of cardiac output and mean arterial pressure after successful defibrillation in patients with low left ventricular ejection fraction.
BACKGROUND
Early defibrillation clearly improves survival from malignant arrhythmia. However, in some cases the cause of death will only be altered from arrhythmic to nonarrhythmic. We evaluated the impact of left ventricular ejection fraction (LVEF) on trend and recovery profile of beat-to-beat cardiac output (CO) and mean arterial blood pressure (MAP) after successful defibrillation.


METHODS
We investigated 63 NYHA class I-III patients undergoing threshold testing in the course of insertion of an implantable cardioverter defibrillator (ICD) in monitored anaesthesia care. Preoperatively, LVEF was classified as either normal (>50%), moderately (30-50%) or severely impaired (<30%). CO and MAP were measured continuously throughout the implantation procedure.


RESULTS
Arrest time and body mass index were not different between groups. CO in patients with severely and moderately reduced LVEF dropped 21% and 13% below baseline (P<0.05), respectively. MAP also decreased by 26% and 17%, respectively. In contrast, 45% of patients with LVEF>50% showed sympathetic activation that resulted in a 12% and 2% increase in mean values for CO and MAP, respectively. In relation to patients with LVEF<50%, CO and MAP values were significantly higher after defibrillation (P<0.05). Additionally, recovery of CO was prolonged in the groups with ventricular dysfunction (P<0.05). Temporary post-shock pacing was observed in 40% of patients.


CONCLUSIONS
A large number of ICD patients with restricted LVEF appears to lack the ability to quickly restore CO and MAP after successful defibrillation. Organ reperfusion may thus still be compromised.
Skhirtladze
Keso
K
Division of Cardiothoracic and Vascular Anaesthesia and Intensive Care Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria.
Mora
Bruno
B
Moritz
Andrea
A
Birkenberg
Beatrice
B
Ankersmit
Hendrik Jan
HJ
Dworschak
Martin
M
D000328:Adult; D000368:Aged; D001794:Blood Pressure; D002302:Cardiac Output; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000295:instrumentation; D006801:Humans; D008875:Middle Aged; D020127:Recovery of Function; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology* / Q000628:therapy*