Electrocardiographic Features in a Patient with the Coexistence of Long QT Syndrome and Coronary Vasospasm

A Case of Ventricular Fibrillation in Masked Long-QT Syndrome Coexisting with Coronary Vasospasm

Although long-QT syndrome (LQTS) with a normal range QT interval at rest leads to fatal ventricular arrhythmias, it is difficult to diagnose. In this article, we present a rare case of a patient who suffered a cardiac arrest and was recently diagnosed with LQTS and coronary vasospasm. A 62-year-old man with no syncopal episodes had a cardiopulmonary arrest while running. During coronary angiography, vasospasm was induced and we prescribed coronary vasodilators, including calcium channel blockers. An exercise stress test was performed to evaluate the effect of medications and accidentally unveiled exercise-induced QT prolongation. He was diagnosed with LQTS based on diagnostic criteria. Pharmacotherapy and an implantable cardioverter defibrillator were used for his medical management. It is extremely rare for LQTS and coronary vasospasm to coexist. In cases of exercise-induced arrhythmic events, the exercise stress test might be helpful to diagnose underlying disease.

Symptomatic Long QT Syndrome Coexisting with Asymptomatic Acetylcholine-induced Vasospasm

We herein report a rare case of long QT syndrome (LQTS) coexisting with acetylcholine (Ach)-induced vasospasm. A 31-year-old woman experienced cardiopulmonary arrest during running. LQTS was diagnosed by an electrocardiogram, and the coexistence of Ach-induced vasospam was determined by an Ach provocation test on coronary angiography. Although an implantable cardioverter defibrillator was placed, a beta-blocker was not prescribed for two reasons: first, the patient showed Ach-induced vasospasm alone with no symptoms and no ST change by Ach injection, and second, the use of beta-blockers alone in such patients carries a risk of vasospasm-induced ventricular fibrillation.

Endocardial arrhythmogenic mechanisms of torsades de pointes in patients with the congenital long QT syndrome

We injected acetylcholine (Ach) into the coronary artery to ascertain whether coronary vasospasm contributed to the syncopal events or chest oppression suffered by 3 patients with long QT syndrome (LQTS). During the test, a quadripolar electrode catheter was placed in the right ventricle and the activation-recovery interval was reanalyzed from the stored data. Intracoronary Ach transiently prolonged the QT intervals in all 3 patients without inducing coronary vasospasm. The Ach-induced QT prolongation was associated with enhanced spatial and temporal dispersion of intra-ventricular repolarization. The electrophysiological abnormalities were consistent with the putative arrhythmogenic mechanisms identified in experimental studies of LQTS.