Cardiac Performance Evaluation in Patients with Muscular Dystrophy

Ventriculoarterial coupling (VAC), the ratio of arterial elastance (Ea) to LV end-systolic elastance (Ees), measures the relationship between ventricular performance and arterial stiffness. We hypothesized that VAC is abnormal in muscular dystrophy (MD) patients and worsens with disease progression. MD patients < 21 years were included. Demographics, MD phenotype, medications, medical history, and clinical status were collected. Initial and last follow up echocardiograms were reviewed to determine Ea, Ees, and VAC and compared between MD and age-matched males and between the initial and last follow up studies in the MD patients. Univariable and multivariable regression analyses was performed to determine factors independently associated with VAC. Forty-six MD patients, median age at diagnosis 9.8 years (IQR 7 -12.2), followed for a median of 4.1 years (IQR 3-6) were included for study. 41% patients were wheelchair-bound, 67% were on steroids, and 65% on afterload reducing medications. Ejection Fraction (EF) < 55% was found in 28% of patients at diagnosis and in 44% at the last follow-up. EF and Ees were significantly lower and VAC ratio was significantly higher (worse) in the MD patients compared to controls & showed significant worsening from diagnosis to last follow up. Ambulation status was independently associated with EF and Ees at last follow up. Cardiac performance, as measured by VAC ratio, is impaired in patients with MD compared with a control population and worsens with longitudinal follow-up. Ambulation status is independently associated with this impairment, offering mechanistic insight into the development and progression of cardiac dysfunction.