Background: The incidence of non-ST elevation myocardial infarction (NSTEMI) is increasing. Although life-threatening ventricular arrhythmias have been well-documented in patients with ST elevation MI (STEMI), their incidence and importance in NSTEMI have not been examined in similar detail. We examined the incidence, predictors, and mortality rates of ventricular arrhythmias in a cohort of NSTEMI patients undergoing an early invasive strategy.
Methods: Consecutive patients admitted with NSTEMI who underwent cardiac catheterization within 48 h of admission were identified by chart review. Presence and type of ventricular arrhythmias and 30-day mortality were recorded. Malignant arrhythmias were defined as sustained ventricular tachycardia (VT, >100 beats/min lasting >30 s) or fibrillation (VF). Clinical risk factors, laboratory values, findings on electrocardiogram, echocardiogram, cardiac catheterization, and revascularization procedure data were recorded.
Results: VT/VF occurred in 21 (7.6%) of 277 NSTEMI patients. Sixty percent of these events occurred within the first 48 h after hospital admission, with a median occurrence at 72 h. Twelve patients (4.3%) required defibrillation. Troponin levels were higher and left ventricular ejection fraction was lower in the VT/VF group. Multivariable analysis also identified the presence of left bundle branch block and need for urgent coronary artery bypass grafting as significant predictors of malignant ventricular arrhythmias. Thirty-day mortality was significantly higher in NSTEMI patients with malignant ventricular arrhythmias than without (38 vs. 3%, P<0.001).
Conclusion: Despite an early invasive strategy, malignant ventricular arrhythmias are frequent in NSTEMI patients and are associated with increased 30-day mortality.
aDepartment of Internal Medicine, Albert Einstein Medical Center
bEinstein Center for Heart and Vascular Health, Albert Einstein Medical Center and Jefferson Medical College, Philadelphia, Pennsylvania, USA
Correspondence to Vincent M. Figueredo, MD, Einstein Center for Heart and Vascular Health, Albert Einstein Medical Center, Levy Building 3232, 5401 Old York Road, Philadelphia, PA 19141, USA Tel: +1 215 456 8991; fax: +1 215 456 3533; e-mail: email@example.com
Received June 21, 2010
Accepted August 26, 2010