An accessory left ventricular apical-basal muscle bundle was identified by CMR in 63% of HCM patients and 60% of genotype-positive/phenotype-negative family members, compared to 10% of controls (P<0.01).
Observational (n=386)
What is the prevalence and clinical significance of a left ventricular apical-basal muscle bundle identified by CMR in patients with hypertrophic cardiomyopathy and their family members?
Apical-basal muscle bundles are a common morphological feature in HCM patients and genotype-positive/phenotype-negative family members, potentially serving as an early marker of the disease.
Absolute Event Rate: 63% vs 10%
p-value: p=<0.01
AIMS: Cardiovascular magnetic resonance (CMR) has improved diagnostic and management strategies in hypertrophic cardiomyopathy (HCM) by expanding our appreciation for the diverse phenotypic expression. We sought to characterize the prevalence and clinical significance of a recently identified accessory left ventricular (LV) muscle bundle extending from the apex to the basal septum or anterior wall (i.e. apical-basal). METHODS AND RESULTS: CMR was performed in 230 genotyped HCM patients (48 ± 15 years, 69% male), 30 genotype-positive/phenotype-negative (G+/P-) family members (32 ± 15 years, 30% male), and 126 controls. Left ventricular apical-basal muscle bundle was identified in 145 of 230 (63%) HCM patients, 18 of 30 (60%) G+/P- family members, and 12 of 126 (10%) controls (G+/P- vs. controls; P < 0.01). In HCM patients, the prevalence of an apical-basal muscle bundle was similar among those with disease-causing sarcomere mutations compared with patients without mutation (64 vs. 62%; P = 0.88). The presence of an LV apical-basal muscle bundle was not associated with LV outflow tract obstruction (P = 0.61). In follow-up, 33 patients underwent surgical myectomy of whom 22 (67%) were identified to have an accessory LV apical-basal muscle bundle, which was resected in all patients. CONCLUSION: Apical-basal muscle bundles are a unique myocardial structure commonly present in HCM patients as well as in G+/P- family members and may represent an additional morphologic marker for HCM diagnosis in genotype-positive status.
Gruner et al. (Thu,) conducted a observational in Hypertrophic cardiomyopathy (n=386). Cardiovascular magnetic resonance imaging vs. Controls was evaluated on Prevalence of left ventricular apical-basal muscle bundle (p=<0.01). An accessory left ventricular apical-basal muscle bundle was identified by CMR in 63% of HCM patients and 60% of genotype-positive/phenotype-negative family members, compared to 10% of controls (P<0.01).