Vasospastic Angina and Cardiac Arrest.

Vasospastic angina (VSA) is an important and potentially treatable cause of cardiac arrest (CA) and may account for approximately 2-10% of otherwise unexplained cases of out-of-hospital CA. VSA can sometimes be diagnosed by spontaneous coronary spasm during emergency coronary angiography or by transient ST-segment elevation during a spontaneous attack after resuscitation. However, because coronary spasm is transient and may not be evident during the initial evaluation, provocation testing after clinical stabilization may be required to establish the diagnosis in otherwise unexplained cases. Once VSA is diagnosed, vasodilator therapy, particularly calcium-channel blockers, is the mainstay of treatment. Nevertheless, survivors of VSA-related CA may remain at risk of recurrent lethal ventricular arrhythmias despite medical therapy. Evaluation for alternative or overlapping arrhythmogenic disorders, including cardiomyopathies and channelopathies, should therefore be considered even after a diagnosis of VSA, and implantable cardioverter-defibrillator implantation may be considered in selected patients according to the risk of recurrence and response to medical therapy. Further prospective studies, including randomized controlled trials, are needed to determine whether systematic provocation testing followed by targeted therapy reduces recurrent ventricular arrhythmias and CA and improves long-term outcomes.