CaMKII Inhibition

Abstract

Electrical storm (ES), a medical emergency, is the frequent occurrence of ventricular tachycardia or fibrillation, defined as 3 or more episodes in a 24-hour period. Although ES can occur in a variety of settings, including ischemia, heart failure, and channelopathies, general incidence and awareness of this condition have dramatically risen since the advent of automatic internal cardiac defibrillators (ICDs). Approximately half of the patients who receive an ICD for secondary prevention of sudden cardiac death will receive an appropriate shock to abort a life-threatening ventricular arrhythmia within the first 2 years of device implantation, and 10% to 20% will experience ES.1 Although this number is lower (≈4%) in patients who receive an ICD for primary prevention, the absolute number is still very high given the large number of devices implanted for this indication (≈152 000 ICDs per year as of 2007). ES has serious prognostic implications, because patients who have had ES have a higher death rate than ICD patients who never experience ES, mostly because of worsening heart failure. The relentless progression of heart failure in many patients with structural heart disease highlights the fact that conventional ICD therapy does not favorably affect the pathways responsible for myocardial dysfunction. In addition to being a marker for early death, ES can be a terrifying experience in conscious patients. Clearly, improved ES therapies are necessary and desirable, but lack of understanding of the underlying mechanisms causing ES has led to limitations in successfully treating or preventing ES. Article see p 2192 Whereas multiple models have been described to study ventricular arrhythmias, there has been a paucity of animal models to study ES, which presents a unique set of challenges and complexities. In the current issue of Circulation , Tsuji et al2 developed a new rabbit model of ES by …