Ventricular arrhythmias in arrhythmic mitral valve syndrome-a prospective continuous long-term cardiac monitoring study

Abstract

Aims: Arrhythmic mitral valve syndrome is linked to life-threatening ventricular arrhythmias. The incidence, morphology and methods for risk stratification are not well known. This prospective study aimed to describe the incidence and the morphology of ventricular arrhythmia and propose risk stratification in patients with arrhythmic mitral valve syndrome.

Methods: Arrhythmic mitral valve syndrome patients were monitored for ventricular tachyarrhythmias by implantable loop recorders (ILR) and secondary preventive implantable cardioverter-defibrillators (ICD). Severe ventricular arrhythmias included ventricular fibrillation, appropriate or aborted ICD therapy, sustained ventricular tachycardia and non-sustained ventricular tachycardia with symptoms of hemodynamic instability.

Results: During 3.1 years of follow-up, severe ventricular arrhythmia was recorded in seven (12%) of 60 patients implanted with ILR [first event incidence rate 4% per person-year, 95% confidence interval (CI) 2-9] and in four (20%) of 20 patients with ICD (re-event incidence rate 8% per person-year, 95% CI 3-21). In the ILR group, severe ventricular arrhythmia was associated with frequent premature ventricular complexes, more non-sustained ventricular tachycardias, greater left ventricular diameter and greater posterolateral mitral annular disjunction distance (all P < 0.02).

Conclusions: The yearly incidence of ventricular arrhythmia was high in arrhythmic mitral valve syndrome patients without previous severe arrhythmias using continuous heart rhythm monitoring. The incidence was even higher in patients with secondary preventive ICD. Frequent premature ventricular complexes, non-sustained ventricular tachycardias, greater left ventricular diameter and greater posterolateral mitral annular disjunction distance were predictors of first severe arrhythmic event.

Keywords: Cardiomyopathy; Implantable loop recorder; Mitral annular disjunction; Mitral valve prolapse; Sudden cardiac death; Ventricular tachycardia.

Graphical Abstract

We included 80 patients with arrhythmic mitral valve syndrome followed for 3.1 years; 60 were implanted with a loop recorder (ILR) and 20 had prior implantable cardioverter defibrillator (ICD). Severe ventricular arrhythmia occurred in seven patients (12%) in the ILR-group and four (20%) in the ICD-group. Servier Medical Art. LV = left ventricle, MR = mitral regurgitation, MVP = mitral valve prolapse, NSVT = non-sustained ventricular tachycardia, PVC = premature ventricular complex, VT = ventricular tachycardia.

Figure 1

Study flow chart. We included 80 patients with arrhythmic mitral valve syndrome followed for 3.1 years; 60 were ILR and 20 had prior ICD. Severe ventricular arrhythmia occurred in 7 patients (12%) in the ILR-group and 4 (20%) in the ICD-group. One patient with ILR-detected arrhythmia leading to ICD implantation later experienced appropriate ICD shock.

Figure 2

Recordings of the severe ventricular arrhythmias in seven patients with implantable loop recorder at baseline. During follow-up, seven patients had severe ventricular arrhythmias. Patient ILR #1 was implanted with ICD due to frequent NSVTs and syncope at wakeful rest, and experienced appropriate ICD therapy for ventricular fibrillation during mild activity. Patient ILR #2 had polymorphic VT degenerating into VF, which was associated in time with a mitral valve chordal rupture. Patient ILR #3 had monomorphic NSVT causing syncope while standing. Patient ILR #4 had polymorphic sustained VT during exercise with subsequent traumatic head injury. Patient ILR #5 had monomorphic NSVT with presyncope while sitting and carrying a conversation. Patient ILR #6 had monomorphic VT with presyncope while standing. Patient ILR #7 had monomorphic VT with presyncope during wakeful rest.

Figure 3

Markers of greater NSVT burden detected by implantable loop recorder in 60 patients with arrhythmic mitral valve syndrome. NSVT occurred in 24 (40%) patients during 3.2 years (interquartile range 3.0–3.5). NSVT burden was greater in patients with posteromedial papillary muscle LGE, bileaflet prolapse, moderate/severe mitral regurgitation or premature ventricular complexes with right bundle branch block and superior axis. Absence of any of these markers was related to low arrhythmic risk. RBBB = right bundle branch block, VA = ventricular arrhythmia.

Figure 4

Suggested follow-up in patients with arrhythmic mitral valve syndrome. Patients with arrhythmic mitral valve syndrome should undergo 24 h Holter monitoring, stress ECG, echocardiography and cardiac magnetic resonance for risk stratification. Patients without any of the NSVT risk markers reassuringly seemed at low arrhythmic risk. The presence of NSVT risk markers and dilated left ventricle, frequent PVCs or NSVT could help guide selection of patients for prolonged arrhythmia monitoring by implantable loop recorder.