Characterization of the Electrophysiological Substrate in Patients with
Barlow's Disease
Abstract
BACKGROUND. Myxomatous mitral valve prolapse (MVP) and mitral-annular
disjunction (Barlow disease) are at-risk for ventricular arrhythmias
(VA). Fibrosis involving the papillary muscles and/or the infero-basal
left ventricular (LV) wall was reported at autopsy in sudden cardiac
death (SCD) patients with MVP. METHODS AND RESULTS: Twenty-three
patients with VA were enrolled, including five with syncope and four
with a history of SCD. Electrophysiological parameters were correlated
with VA patterns, ECG inferior negative T wave (nTW), and late
gadolinium enhancement (LGE) assessed by cardiac magnetic resonance.
Premature ventricular complex (PVC) burden was 12061.9±12994.6 /24 hours
with a papillary-muscle type (PM-PVC) in 18 patients (68%). Twelve-lead
ECG showed nTW in 12 patients (43.5%). A large Uni<8.3mV area
(62.4+/- 45.5 cm2) was detected in the basal infero-lateral LV region in
12 (73%) patients, and in the papillary muscles (2.2+/-2.9 cm2) in 5
(30%) of 15 patients undergoing EAM. A concomitant Bi<1.5 mV
area (5.0±1.0 cm2) was identified in 2 patients. A history of SCD, and
the presence of nTW, and LGE were associated with a greater
Uni<8.3mV extension: (32.8+/-3.1 cm2 vs. 9.2+/-8.7 cm2), nTW
(20.1+/-11.0vs.4.1+/-3.8cm2), and LGE (19.2 ± 11.7 cm2 vs. 1.0 ± 2.0
cm2, p=0.013), respectively. All patients with PM-PVC had a
Uni<8.3mV area. CONCLUSIONS: Low unipolar low voltage areas
can be identified with EAM in the basal infero-lateral LV region and in
the papillary muscles as a potential electrophysiological substrate for
VA and SCD in patients with MVP and Barlow disease phenotype