Fast non-sustained ventricular tachycardias predict life threatening ventricular arrhythmias in patients with mitral valve prolapse monitored by implantable loop recorder
J Bergh, C Bugge, E W Aabel, E Hopp, N E Hasselberg, J P E Kvitting, C K Five, K H HaugaaAbstract
Background
A subset of patients with mitral valve prolapse (MVP) have ventricular arrhythmias originating from papillary muscles and the mitral ring and are defined as arrhythmic MVP (AMVP). Non-sustained ventricular tachycardia (NSVT) during follow-up is found to be predictive of severe ventricular arrhythmias (VA); however, the impact of NSVT rate is less documented. Prospective studies using continuous rhythm monitoring in AMVP patients with LGE data are scarce.
Purpose
We aimed to evaluate the presence of fast NSVTs and LGE on cardiac magnetic resonance (CMR) as prognostic factors for severe VA in patients with AMVP continuously rhythm monitored with an implantable loop recorder (ILR).
Methods
We included AMVP patients without previous severe VA for prospective VA monitoring with ILR implanted at inclusion. NSVT was defined as ≥ 3 consecutive beats with heart rate > 100 beats per minute (bpm). We recorded the number of NSVTs below and above rate of 180 bpm with fast NSVT defined as rate > 180 bpm. Life threatening VA was defined as aborted cardiac arrest, appropriate treatment by primary preventive implantable cardioverter-defibrillator, sustained ventricular tachycardia or NSVT with hemodynamic instability. CMR with LGE was performed within 18 months after inclusion.
Results
52 patients (71 % female, mean age 48 ±16 years) were monitored with ILR for a mean duration of 36 ± 6 months. Severe VA occurred in six patients during follow-up. Five of six patients (83%) with severe VA had fast NSVT during follow-up, and fast NSVT predicted severe VA with OR 15.91 (95% CI 1.67-151.15, P=0.02). Also, a higher number of fast NSVTs predicted risk of severe VA (OR 1.63, [95% CI 1.08-2.46], P=0.02.) Presence of NSVT < 180 bpm and the number of NSVTs < 180 bpm were not associated with severe VA (P>0.05). 41 patients underwent CMR with LGE present in 7 (17%) patients. Of the 6 patients with severe VA, 5 underwent LGE-evaluation, and 3/5 (60%) had LGE present on CMR with an association between presence of LGE and severe VA with an OR of 12.00 (95% CI 1.52-95.03, P=0.02). Patients with LGE had a higher number of NSVTs > 180 bpm compared to those without (incidence rate ratio 3.89, [95% CI 1.02-14.83], P=0.048).
Conclusion
Fast NSVT with rate > 180 bpm predicted severe VA in AMVP patients prospectively monitored with ILR while NSVT with rate < 180 bpm did not. Presence of LGE was associated with severe VA and a higher number of fast NSVTs. These results support NSVT > 180 bpm as an important risk marker in patients with AMVP.