Malignant Arrhythmias During Induction of Target Temperature Management After Cardiac Arrest

Abstract

The aim of this study was to evaluate the incidence and determinants of malignant arrhythmias (MA) in patients with shock following out-of-hospital cardiac arrest (OHCA) treated with targeted temperature management. Risk factors for the development of MA were prospectively analyzed in patients after OHCA. MA were defined as ventricular tachycardia or fibrillation with a duration >30 seconds, which had to be terminated by defibrillation. All patients were treated with therapeutic hypothermia for 24 hours. Demographics, OHCA details, interventions, and intensive care unit (ICU) treatment were recorded. A total of 55 patients were included, 11 (20%) of whom developed MA during the ICU stay. All MA occurred within the first 18 hours after admission. Patients who developed MA showed a stronger decrease in body temperature (D-2.4°C-0.8°C vs. D-1.3°C-1.3°C; p = 0.016) and in serum potassium levels (D-0.9-1 mmol/L vs. D-0.3-0.6 mmol/L; p = 0.037) during the cooling period compared with patients without MA. In the multivariable analysis, fast temperature decline as well as lower potassium levels were associated with MA. In addition, higher number of shocks during resuscitation and higher ICU epinephrine use were independent predictors of MA in patients with OHCA. The use of epinephrine as well as hypokalemia in context with intense cooling may increase the incidence of MA in patients with shock after cardiac arrest. Therefore, these therapeutic strategies should be applied with caution in this vulnerable group of patients.

A review of Adverse Effects of Targeted Temperature Management for Post-Cardiac Arrest Patients

“…The rate of MA did not vary with target temperature but was correlated with more aggressive decrease in body temperature in the first 6 hours of treatment [24]. This follows other studies which have suggested rate of temperature decline, and thus strength of heat homeostasis, as a possible predictor of mortality and outcome [24,26].…”

“…Similar to the changes observed in VEB prevalence, the number of defibrillations was significantly higher in patients who developed MA [24]. Additionally, patients with MA had longer time to ROSC, which has also been shown as a predictor of outcome [24,26].…”

“…Copy@ Leonard Ranasinghe MA (defined as ventricular fibrillation, sustained ventricular tachycardia, torsades de pointes) is a dangerous complication of cardiac arrest, regardless of use of TTM, and is associated with significant mortality for post cardiac arrest patients [24,25].…”

An Overview of Therapy Guidelines for Cardiac Arrest and the Potential Benefits of Hemoglobin-Based Oxygen Carriers

“…This therapy also helps to improve neurologic outcomes by reducing neuron metabolism and ROS generation [31]. However, it is important to note that therapeutic hypothermia is known to be arrhythmogenic and malignant arrhythmia is an unfortunate complication of this therapy [32]. Hypothermia prolongs the action potential duration and increases the heterogeneity of ventricular repolarization to predispose the myocardium to arrhythmia [33].…”

“…Hypothermia prolongs the action potential duration and increases the heterogeneity of ventricular repolarization to predispose the myocardium to arrhythmia [33]. This has been explained by potassium shifts that occur during hypothermia resulting in systemic hypokalemia, which is linked to the development of polymorphic ventricular tachycardia [32]. It is interesting to contrast these studies with those investigating hypothermia as an adjunct to cardioplegia during cardiac surgery.…”