The Defibrillation Conundrum: New Insights into the Mechanisms of Shock-Related Myocardial Injury Sustained from a Life-Saving Therapy

Implantable cardiac defibrillators (ICDs) are recommended to prevent the risk of sudden cardiac death. However, shocks are associated with an increased mortality with a dose response effect, and a strategy of reducing electrical therapy burden improves the prognosis of implanted patients. We review the mechanisms of defibrillation and its consequences, including cell damage, metabolic remodeling, calcium metabolism anomalies, and inflammatory and pro-fibrotic remodeling. Electrical shocks do save lives, but also promote myocardial stunning, heart failure, and pro-arrhythmic effects as seen in electrical storms. Limiting unnecessary implantations and therapies and proposing new methods of defibrillation in the future are recommended.

Tako-tsubo Syndrome in Men: Rare, but With Poor Prognosis

INTRODUCTION AND OBJECTIVES

Tako-tsubo syndrome is a potentially serious disease during the acute phase. It mimics myocardial infarction, but with no potentially causative coronary lesions. The aim of this study was to analyze the clinical course and outcome of patients with tako-tsubo syndrome by sex.

METHODS

We analyzed the characteristics of patients included in the RETAKO registry from 2003 to 2015, a multicenter registry with participation of 32 Spanish hospitals.

RESULTS

Of 562 patients included, 493 (87.7%) were women. Chest pain was less frequent as an initial symptom in men than in women (43 [66.2%] vs 390 [82.8%]; P < .01). The prognosis was worse in men, with higher in-hospital mortality (3 [4.4%] vs 1 [0.2%]; P < .01), longer intensive care stay (4.2 ± 3.7 vs 3.2 ± 3.2 days; P = .03) and a higher frequency of severe heart failure (22 [33.3%] vs 95 [20.3%]; P = .02). However, dynamic obstruction at the left-ventricular outflow tract occurred exclusively in women (39 [7.9%] vs 0 [0.0%]; P = .02). The incidence of functional mitral regurgitation was also higher in women (52 [10.6%] vs 2 [2.9%]; P = .04).

CONCLUSIONS

Tako-tsubo syndrome shows wide differences by sex in terms of its incidence, presentation, and outcomes. Prognosis is worse in men.