Abstract 2124: Acquired Long QT from Stress Cardiomyopathy is Associated with a Risk of Torsades de Pointes
BACKGROUND: Stress cardiomyopathy (SCM) or Takotsubo is a recently recognized syndrome of transient ventricular dysfunction triggered by severe emotional or physical stress, and is believed to result from catecholamine-mediated myocardial toxicity. Repolarization abnormalities associated with hyperadrenergic states can result in QT prolongation and lethal arrhythmia including torsades de pointes (TdP). Most patients with SCM develop diffuse T wave inversions and QT prolongation; however, there remains little in the literature regarding the risk of life-threatening ventricular arrhythmias in SCM. We examine the prevalence of TdP in a cohort of patients with SCM.
METHODS: Data from a prospectively maintained registry of consecutive patients with SCM from 2 institutions was reviewed. Patients having experienced TdP were identified and clinical characteristics were analyzed.
RESULTS: Out of 78 patients with SCM, 5 (6.4%) experienced TdP (mean age 72 ± 11 yr). All TdP patients developed diffuse T wave inversions and QT prolongation within 2 days of presentation. The mean QTc at the time of TdP was 576 ± 72 ms and the mean serum K+ and Mg++ levels were 3.4 ± 0.8 and 2.0 ± 0.2 meq/l (Table⇓). The mean QTc at discharge was 469 ± 26 ms and at follow up further decreased to 401 ± 6 ms (n = 3). All patients showed the typical apical ballooning pattern. Initial ejection fraction was 39 ± 10% and improved to 54 ± 3% at discharge or follow up (n = 4). All patients survived. Two patients required defibrillation, 1 having suffered an out of hospital arrest. Two patients required temporary transvenous pacing. Two patients were treated with permanent implantable devices, 1 with a PPM and 1 with an ICD.
CONCLUSIONS: SCM should be recognized among the causes of acquired long QT syndrome and can be associated with a risk of TdP in 5–10% of patients. All patients with SCM who develop repolarization abnormalities, including severe QT prolongation, should be monitored in a cardiac unit for several days.