Impact of obstructive sleep apnea severity on cardiac events in patients with normal or prolonged ventricular repolarization
Richards L, Pandey B, Mengesha T, et al. Impact Of Obstructive Sleep Apnea Severity On Cardiac Events In Patients With Normal Or Prolonged Ventricular Repolarization. Journal of the American College of Cardiology. 2017;69(11):463. doi:10.1016/s0735-1097(17)33852-4.
Session Title: Arrhythmias and Clinical EP: Basic 3 Location: American College of Cardiology 66th Scientific Annual Session Saturday, March 18, 2017, 9:45 a.m.-10:30 a.m. Poster Contributions Poster Hall, Hall C Abstract Category: 4. Arrhythmias and Clinical EP: Basic Presentation Number: 1191-111
BACKGROUND: Prolonged cardiac repolarization is associated with increased risk of ventricular arrhythmias which are aggravated by several triggering factors including excess catecholamine state and electrolyte abnormalities. We studied the impact of severity of obstructive sleep apnea (OSA) on ventricular tachyarrhythmias and mortality in patients with normal or prolonged ventricular repolarization as this is not well defined.
METHODS: 338 patients [59% male, mean age: 61 ± 13] undergoing polysomnography between January 2012 to June 2015 who also had a 12-lead ECG were divided into 4 groups: Group 1-no evidence of OSA, Group 2-mild, Group 3-moderate, Group 4-severe, based on apnea-hypopnea index (AHI) none<5, mild 5-14, moderate 15-29, severe >29 respectively. The differences in prevalence of non-sustained ventricular tachycardia between the 4 groups and incidence of ventricular fibrillation (VF) and overall mortality were determined using Cochran-Armitage Trend and Chi-Square. In addition, differences in VT and VF and overall mortality were determined between the 4 groups and compared to those with normal or prolonged repolarization (defined as JTc interval [JTc=QTc -QRS] >380ms for female and >360ms for male).
RESULTS: Out of 338 patients, [51% with preexisting heart failure] the prevalence of VT increased with OSA severity from 44% in Group 1 to 46%, 50%, 67% in Group 2 to 4 [p=0.004] respectively. In patients with normal repolarization, prevalence of VT increased with OSA severity from 33% in Group 1 to 50%, 60% and 84% in Group 2 to 4 [p=0.001]. However, in patients with prolonged repolarization, there was no additional impact of OSA severity on VT in Group 1 to 4: 50%, 45%, 45%, 60% [p=0.094]. The risk of VF or death increased with worsening OSA severity from Groups 1 -4: 2.7%, 5.4%, 5.8%, 9.8%, however this was not significantly significant [p=0.53].
CONCLUSIONS: In patients with underlying cardiac disease, the prevalence of VT increases with OSA severity mainly in patients with normal repolarization but have minimum effect on patients with prolonged repolarization. There is a trend toward higher risk of VF or death with worsening sleep apnea that needs to be confirmed in a larger population.