Arrhythmias and conduction defects in patients with mitral valve prolapse: a study based on ambulatory monitoring and electrophysiologic studies.

Twenty consecutive symptomatic patients of mitral valve prolapse (MVP) and 20 normal age, sex and symptom matched controls were studied. Ambulatory monitoring studies revealed the presence of atrial premature beats (APC) in 16 subjects in each group. Isolated ventricular premature beats (VPC) were observed in 12 patients with MVP and 15 subjects in control group (p = ns). Complex VPCs (Lown IVa, IVb) were recorded in 4 patients of MVP vs 3 controls (p = ns). There was no correlation between the occurrence of arrhythmias with the degree of MVP or the degree of mitral regurgitation. Likewise, MVP patients with prolonged QTc interval did not show higher incidence of spontaneous arrhythmias when compared to those with normal QTc interval. Nineteen patients underwent electrophysiological studies. Two patients showed evidence of abnormal sinus node function. Both these patients in addition had AV nodal abnormalities, manifested by prolonged AH interval. Programmed stimulation studies induced AV nodal tachycardia in one and non-sustained ventricular tachycardia in two (polymorphic in one and monomorphic in the other). Ambulatory monitoring in both these patients did not show any evidence of complex VPCs or VT, indicating poor correlation between inducibility and presence of spontaneous complex VPCs. Patients with MVP do not have a higher prevalence of spontaneous atrial or ventricular arrhythmias when compared to matched normal controls with similar symptomatology. The presence of mitral regurgitation, severity of MVP and associated prolonged QTc interval is not associated with higher prevalence of arrhythmias. The correlation between spontaneous and inducible arrhythmias is poor.(ABSTRACT TRUNCATED AT 250 WORDS)