Abstract 15199: Nadolol Decreases Incidence and Severity of Ventricular Arrhythmias at Exercise Compared to Metoprolol SR in Patients with Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)
Introduction: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inheritable cardiac disease predisposing to malignant ventricular arrhythmias at exercise. Beta blockers are mainstay of treatment, but not all beta blockers are equally effective. We explored the incidence and severity of exercise induced arrhythmias in CPVT patients on metoprolol SR, on nadolol medication and without medication.
Methods: In this cross over study, 9 CPVT patients were included and completed the study (age 30±15, 56% female, 8 RYR2 mutation positive). We performed 3 bicycle exercise stress tests (50W+25W increase every 2. minute until exhaustion) in each patient; 1) before start of beta blocker treatment, 2) >6 weeks on maximum tolerated dose of metoprolol SR and 3) >6 weeks on maximum tolerated dose of nadolol. We recorded resting and maximum heart rate (HR) and the most severe arrhythmia occurring. Severity of arrhythmias was scored as: no arrhythmias (0), single ventricular extra systoles (1), bigemini (2), couplets (3) and non-sustained VT (4).
Results: HR was similar on metoprolol SR and nadolol at rest (53±13bpm vs. 54±9bpm, p=0.72), while maximum HR was lower on nadolol (147±23bpm vs. 120±24bpm p=0.004). The incidence of arrhythmias was lower on nadolol compared to both metoprolol SR (5/9 (56%) vs. 9/9 (100%)) and no medication (8/9 (89%)). There was a shift towards less severe arrhythmias during exercise on nadolol compared to metoprolol SR (0.9±1.1 vs. 2.6±0.7, p=0.001) and compared to no medication (0.9±1.1 vs. 1.9±1.1, p=0.04) but not on metoprolol SR compared to no medication (2.6±0.7 vs 1.9±1.1, p=0.20)(Figure).
Conclusion: Incidence and severity of ventricular arrhythmias at exercise decreased on nadolol compared to metoprolol SR. Metoprolol SR did not change occurrence of arrhythmias compared to no medication. Our results indicate that nadolol is superior to metoprolol SR in arrhythmia control in CPVT patients.
Author Disclosures: I.S. Leren: None. E. Majid: None. T.F. Haland: None. J. Saberniak: None. T. Edvardsen: None. K.H. Haugaa: None.
- © 2014 by American Heart Association, Inc.