ISSN 2996-8215
International Journal of Cardiology | Vol. 15, No. 4, April 2024 | pp. 25–32
DOI: 10.46882/2024/IJC/000180
Original Research Article
Prevalence and Prognostic Impact of Speckle-Tracking Derived Right Ventricular Free-Wall Longitudinal Strain in Left Ventricular HCM
Hiroshi Yamamoto¹, Takashi Sato¹, Kenji Nakamura²
¹Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
²Division of Cardiology, Tokyo Medical and Dental University, Tokyo, Japan
Abstract:
Hypertrophic cardiomyopathy (HCM) is predominantly characterized by left ventricular hypertrophy and diastolic impairment, but the right ventricle (RV) can also be involved. Because conventional RV parameters like fractional area change (FAC) are often insensitive to early mechanical alterations, subclinical RV impairment may go undetected. This study evaluated the prevalence of subclinical RV dysfunction using speckle-tracking derived longitudinal strain and investigated its association with clinical worsening. We prospectively evaluated 150 stable patients with confirmed left ventricular HCM and preserved conventional right ventricular function (FAC greater than or equal to 40%). Off-line speckle-tracking deformation imaging determined right ventricular free-wall longitudinal strain (RV-FWS). Clinical worsening was defined as a 36-month composite endpoint of heart failure hospitalization, sustained ventricular arrhythmia, or all-cause mortality. Subclinical RV dysfunction, defined as an absolute baseline RV-FWS less than 18.0%, was identified in 36 patients (24.0%) despite a normal mean FAC (44.6% ± 3.2%). Over a median follow-up of 34 months, the composite endpoint occurred in 28 patients (18.7%). Kaplan-Meier analysis revealed significantly lower event-free survival rates in patients with impaired absolute RV-FWS (log-rank p = 0.002). Multivariable Cox proportional hazards regression confirmed that an absolute RV-FWS less than 18.0% was an independent predictor of long-term clinical worsening (hazard ratio: 2.15, 95% CI: 1.28–3.62, p = 0.004). Subclinical right ventricular dysfunction is present in nearly a quarter of hypertrophic cardiomyopathy patients with normal conventional RV metrics and serves as a powerful, independent predictor of long-term clinical progression.
Keywords: Hypertrophic cardiomyopathy, Right ventricular dysfunction, Speckle-tracking echocardiography, Longitudinal strain, Prevalence, Prognosis
Received: January 12, 2024; Revised: February 24, 2024; Accepted: March 15, 2024; Published: April 25, 2024