Optimal medications and appropriate implantable cardioverter-defibrillator shocks in aborted sudden cardiac death due to coronary spasm

Abstract

Objective Life-threatening ventricular arrhythmias are recognized in patients with coronary spastic angina. Implantable cardioverter-defibrillators (ICDs) are effective in patients with structural heart disease and ventricular fibrillation. However, the optimal medication for patients with aborted sudden cardiac death (SCD) due to coronary artery spasm after the implantation of ICD remains controversial. Methods We investigated the medications and the numbers of appropriate ICD shocks in 137 patients with a history of aborted SCD due to coronary spasm. Results Appropriate ICD shocks were observed in 24.1% (33/137) of patients with aborted SCD due to coronary spasm during 41 months of follow-up. Only 15 (15.6%) of the 96 patients with ICDs received aggressive medical therapy, including two or three calcium-channel antagonists. The rate of appropriate ICD shocks was significantly higher in Western countries than in Asian countries (42.9% vs. 19.3%, p<0.01), whereas the medications did not differ between the two regions. Appropriate ICD shocks successfully resuscitated 33 patients. Three patients died due to second serious fatal arrhythmias. Conclusion Appropriate ICD shocks were recognized in a quarter of patients with aborted SCD due to coronary spasm and ICD implantation was effective for suppressing the next serious fatal arrhythmia in these patients. We should reconsider prescribing more medications after ICD implantation in patients with aborted SCD due to coronary artery spasm.