Non-complex ventricular arrhythmia associated with higher freedom from recurrent ectopy at 1-year after mitral repair surgery.

Objective The impact of mitral valve (MV) surgery on the natural history of ventricular arrhythmia (VA) in patients with arrhythmic MV prolapse (AMVP) remains unknown. We sought to evaluate the cumulative incidence of ventricular arrythmia at 1 year following surgical mitral repair. Methods A retrospective review of progressively captured data identified 204 consecutive patients that underwent elective MV repair for significant degenerative MR as a first-time cardiovascular intervention in a quaternary reference center between 01/2018 – 12/2020. A subset of 62 consecutive patients with diagnosed AMVP was further evaluated for recurrent VA following MV repair. Results The median age was 62 years (range 27-77) and 26/62 (41.9%) were females. The median time from initial MR/MVP diagnosis-to-referral was 13.8 years (IQR 5.4-25) and from VA diagnosis-to-referral was 8 years (IQR 3-10.6). Using the Löwn-Wolf classification, complex VA (Löwn grade ≥3) was identified in 36/62 patients (58%) at baseline, while 8/62 (13%) had a cardioverter/defibrillator implanted for primary (4/8) or secondary (4/8) prevention. LV myocardial scar was confirmed in 23/34 (68%) of patients scanned at baseline. The prevailing valve phenotype was bileaflet Barlow’s (59/62; 95.2%). All patients underwent surgical mitral valve repair by the same team. Surgical repair was stabilized with an annuloplasty prosthesis (median size 36mm [IQR 34-38]). Concomitant procedures included tricuspid valve repair (51/62; 82.3%), cryo-MAZE±LA appendage exclusion (14/62, 23%), and endocardial cryoablation of VA ectopy (4/62; 6.5%). The 30-day and 1-year freedom from recurrent VA were 98.4% and 75.9%, respectively. Absent VA following mitral repair was uniformly observed in patients with minor VA at baseline. Absent VA following mitral repair was uniformly observed in patients with minor VA preoperatively. Complex baseline VA was the strongest predictor of recurrent VA (HR 10.8; 95%CI: 1.4-84.2; P=0.024), irrespective of myocardial fibrosis. Conclusions In a series of 62 consecutive patients operated electively for arrhythmic mitral prolapse, ventricular arrhythmia remained undetected in 75.9% of patients at 1-year. Freedom from recurrent VA was higher among patients without complex VA preoperatively, whereas baseline Lown’s grade ≥ 3 was the strongest independent risk factor for recurrent VA at 1-year. These findings attest to the importance of early recognition and prompt referral of mitral prolapse patients with progressive ventricular arrhythmia, to specialty interdisciplinary care.