The role of cardiac MRI in risk stratification for sudden cardiac death in patients with hypertrophic cardiomyopathy

Abstract

Hypertrophic cardiomyopathy (HCM) is a prevalent genetic heart disease with a worldwide prevalence. Its estimated incidence in young individuals is approximately 1 case per 500 population. HCM in adults can be clinically diagnosed through visualization, either via 2D echocardiography or cardiac magnetic resonance (CMR) imaging, where the maximum thickness of any left ventricular (LV) segment, measured in end-diastolic phase, is 15 mm in the absence of other hypertrophy causes. Aim. To demonstrate the role and diagnostic capabilities of CMR as a powerful diagnostic tool for detecting and evaluating sudden cardiac death (SCD) risk factors in patients with HCM. Materials and methods. From January 2022 to September 2023, 236 CMR examinations were conducted and analyzed at the Diagnostic Radiology Department of Amosov National Institute of Cardiovascular Surgery in patients with suspected HCM. All examinations were performed on a magnetic resonance tomograph “Toshiba Vantage Titan 1.5T” until May 2023, and “Canon Vantage Orian 1.5T” from May to September 2023, with ECG and respiratory synchronization as well as intravenous injection of gadolinium-based contrast agent (Gadovist 1.0) at a dose of 0.1 mL/kg body weight. Statistical and mathematical data processing was performed by using the Statistica 6.0 (StatSoft Inc., USA) application package. Results. The mean age of the examined patients was 41 ± 28 years, there were 142 male (60 %) and 94 (40 %) female patients. Symmetric non-obstructive HCM was identified in 39 patients (16.5 %) and 184 patients (78.0 %) had asymmetric obstructive HCM. Apical HCM was diagnosed in 4 patients (1.5 %), and midventricular HCM – in 9 patients (4.0 %) including one patient with a combination of midventricular and apical forms. Risk factors for SCD were identified in 60 patients (25.4 %) with myocardial thickness exceeding 30 mm, 8 patients (3.3 %) with apical aneurysm, 4 patients (1.6 %) with reduced LV systolic function (LV ejection fraction <50 %), and 164 patients (69.4 %) with pathological late gadolinium enhancement. Conclusions. CMR is a modern, high-precision and powerful diagnostic method that plays a key role in identifying and assessing SCD risk factors in patients with HCM. CMR helps to identify HCM patients at high SCD risk who may benefit from preventive measures such as implantable cardioverter-defibrillator therapy.

Keywords

• hypertrophic cardiomyopathy
• left ventricular hypertrophy
• arrhythmia
• imaging modalities
• septal myectomy
• cardioverter-defibrillator implantation