Myocardial Extracellular Volume Is Not Associated With Malignant Ventricular Arrhythmias in High-risk Hypertrophic Cardiomyopathy.
OBJECTIVE
Myocardial interstitial fibrosis, a hallmark of hypertrophic cardiomyopathy (HCM), has been proposed as an arrhythmic substrate. Fibrosis is associated with increased extracellular volume (ECV), which can be quantified by computed tomography (CT). We aimed to analyze the association between CT-determined ECV and malignant ventricular arrhythmias.


METHODS
A retrospective case-control observational study was conducted in HCM patients with implantable cardioverter-defibrillator, undergoing a CT-protocol with continuous iodine contrast infusion to determine equilibrium ECV. Left ventricular septal and lateral CT-determined ECV was compared between prespecified cases (malignant arrhythmia any time before CT scan) and controls (no prior malignant arrhythmias) and among ECV tertiles.


RESULTS
A total of 78 implantable cardioverter-defibrillator HCM patients were included; 24 were women, with a mean age of 52.1 ± 15.6 years. Mean ECV ± standard deviation in the septal left ventricular wall and was 29.8% ± 6.3% in cases (n = 24) vs 31.9% ± 8.5% in controls (n = 54); P = .282. Mean ECV in the lateral wall was 24.5% ± 6.8% in cases vs 28.2% ± 7.4% in controls; P = .043. On comparison of the entire population according to septal ECV tertiles, no significant differences were found in the number of patients receiving appropriate shocks. Conversely, we found a trend (P = .056) for a higher number of patients receiving appropriate shocks in the lateral ECV lowest tertile.


CONCLUSIONS
Extracellular volume was not increased in implantable cardioverter-defibrillator HCM patients with malignant ventricular arrhythmias vs those without arrhythmias. Our findings do not support the use of ECV (a surrogate of diffuse fibrosis) as a predictor of arrhythmias in high-risk HCM patients.
Área de Fisiopatología del Miocardio, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Instituto de Salud Carlos III, Madrid, Spain; CIBER de enfermedades CardioVasculares (CIBERCV), Spain; Departamento de Cardiología, Hospital Universitario Puerta de Hierro, Majahonda, Madrid, Spain.
Jesús G
JG
Mirelis
Área de Fisiopatología del Miocardio, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Instituto de Salud Carlos III, Madrid, Spain; Departamento de Ciencia Clínica, Philips Healthcare, Spain.
Javier
J
Sánchez-González
Departamento de Cardiología, Hospital Universitario y Politécnico La Fe, Valencia, Spain.
Esther
E
Zorio
Departamento de Cardiología, Hospital de Son Llàtzer & IdISPa, Palma de Mallorca, Spain.
Tomas
T
Ripoll-Vera
Departamento de Cardiología, Hospital Universitario 12 de Octubre, Madrid, Spain.
Rafael
R
Salguero-Bodes
Área de Fisiopatología del Miocardio, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Instituto de Salud Carlos III, Madrid, Spain; CIBER de enfermedades CardioVasculares (CIBERCV), Spain; Departamento de Cardiología, Hospital Universitario Clínico San Carlos, Madrid, Spain.
David
D
Filgueiras-Rama
Área de Fisiopatología del Miocardio, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Instituto de Salud Carlos III, Madrid, Spain; CIBER de enfermedades CardioVasculares (CIBERCV), Spain; Departamento de Cardiología, Hospital Universitario Puerta de Hierro, Majahonda, Madrid, Spain.
Esther
E
González-López
Área de Fisiopatología del Miocardio, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Instituto de Salud Carlos III, Madrid, Spain; CIBER de enfermedades CardioVasculares (CIBERCV), Spain.
María
M
Gallego-Delgado
Área de Fisiopatología del Miocardio, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Instituto de Salud Carlos III, Madrid, Spain; CIBER de enfermedades CardioVasculares (CIBERCV), Spain; Department of Cardiology, The Zena and Michael A. Wiener Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, United States.
Rodrigo
R
Fernández-Jiménez
Departamento de Cardiología, Hospital de Son Llàtzer & IdISPa, Palma de Mallorca, Spain.
María Jesús
MJ
Soleto
Departamento de Cardiología, Hospital de Son Llàtzer & IdISPa, Palma de Mallorca, Spain.
Juana
J
Núñez
Área de Fisiopatología del Miocardio, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Instituto de Salud Carlos III, Madrid, Spain; CIBER de enfermedades CardioVasculares (CIBERCV), Spain; Departamento de Cardiología, Complejo Hospitalario Ruber Juan Bravo, Universidad Europea de Madrid, Madrid, Spain.
Gonzalo
G
Pizarro
Department of Cardiology, The Zena and Michael A. Wiener Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, United States.
Javier
J
Sanz
Área de Fisiopatología del Miocardio, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Instituto de Salud Carlos III, Madrid, Spain; Department of Cardiology, The Zena and Michael A. Wiener Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, United States.
Valentín
V
Fuster
Área de Fisiopatología del Miocardio, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Instituto de Salud Carlos III, Madrid, Spain; CIBER de enfermedades CardioVasculares (CIBERCV), Spain; Departamento de Cardiología, Hospital Universitario Puerta de Hierro, Majahonda, Madrid, Spain.
Pablo
P
García-Pavía
Área de Fisiopatología del Miocardio, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Instituto de Salud Carlos III, Madrid, Spain; CIBER de enfermedades CardioVasculares (CIBERCV), Spain; Departamento de Cardiología, IIS-Hospital Fundación Jiménez Díaz, Madrid, Spain. Electronic address: bibanez@cnic.es.
Borja
B
Ibáñez
D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000473:pathology* / Q000628:therapy; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000473:pathology*; D016022:Case-Control Studies; D017147:Defibrillators, Implantable; D004719:Endomyocardial Fibrosis / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D015588:Observer Variation; D009929:Organ Size / Q000502:physiology; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed
Computed tomography; Diffuse fibrosis; Extracellular volume; Fibrosis difusa; Hypertrophic cardiomyopathy; Miocardiopatía hipertrófica; Tomografía computarizada; Volumen extracelular