Abstract P112: Precordial Thump Ineffective in Terminating Ventricular Fibrillation but May Have a Role in Asystole

Abstract

BACKGROUND. The efficacy of the chest thump in cardiac arrest is controversial. In an animal model of cardiac arrest we assess the efficacy of precordial thump in ventricular fibrillation (VF) and asystole. METHODS. Under general anesthesia, 10 swine were induced to VF using a RV pacing lead and an AC fibrillator. In random order, animals received chest thumps with a 30 or 40 mph lacrosse ball or a chest thump with a fist. If VF continued after 3 thumps, animals were externally defibrillated. All animals underwent 6 VF inductions and received a total of 18 chest thumps; 2 sets of 3 thumps each with a fist, 30 mph, and 40 mph lacrosse balls. If asystole followed defibrillation, chest thumps with a fist were given to induce premature ventricular contractions (PVCs) until resumption of sinus rhythm. LV pressures of all thumps were recorded. RESULTS. None of the 180 chest thumps terminated VF. The LV pressure generated by thumps during VF was 263 ± 52 mmHg for manual thumps, 392 ± 179 mmHg for 30 mph thumps, and 616 ± 182 mmHg for 40 mph thumps (p<0.001). All VF episodes were terminated by a 200J shock. Defibrillation was followed by asystole after 46/60 (77%) of VF inductions. During asystole, 1533/1856 (83%) chest thumps induced PVCs. LV pressure was higher for thumps that induced PVCs than those that did not (113 ± 27 vs 75 ± 23 mmHg, p<0.001). For each 10 mmHg rise in LV pressure, the OR of inducing a PVC was 1.9 (95% CI 1.8 –2.1; Figure ). CONCLUSIONS. Despite achieving high LV pressures, precordial thumps were not effective in terminating VF, but did produce PVCs in asystole. Based on this data, a precordial thump cannot be recommended for VF, but its use in asystole should be further explored.