Patients with cardiomyopathies are a heterogeneous group of patients who experience high morbidity and mortality. Early cardiac assessment and intervention with access to genetic counselling in a multidisciplinary Cardiomyopathy Clinic may improve outcomes and prevent progression to advanced heart failure. Our prospective cohort study was conducted at a multidisciplinary Cardiomyopathy Clinic with 421 patients enrolled (42.5% female, median age 58years), including 224 patients with dilated cardiomyopathy (DCM, 42.9% female, median age 57years), 72 with hypertrophic cardiomyopathy (HCM, 43.1% female, median age 60years), 79 with infiltrative cardiomyopathy (65.8% female, median age 70years) and 46 who were stage A/at risk for genetic cardiomyopathy (54.3% female, median age 36years). Patients were seen in follow-up at a median of 18months. A pathogenic/likely pathogenic variant was identified in 28.5% of the total cohort, including 33.3% of the DCM cohort (28% TTN mutations) and 34.1% of the HCM cohort (60% MYBPC3 and 20% MYH7) who underwent genetic testing. The use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers/angiotensin receptor neprilysin inhibitor (48.3-69.5% of total cohort, P<0.001), β-blockers (58.4-72.4%, P<0.001), mineralocorticoid receptor antagonists (33.9-41.4%, P=0.0014) and sodium/glucose cotransporter-2 inhibitors (5.3-27.9%, P<0.001) all increased at follow-up. Precision-based therapies were also implemented, including tafamidis for transthyretin amyloidosis (n=21), enzyme replacement therapy for Fabry disease (n=14) and mavacamten (n=4) for HCM. Optimization of medications and devices resulted in improvements in left ventricular ejection fraction (LVEF) from 27% to 43% at follow-up for DCM patients with reduced LVEF at baseline (P<0.001) and reduction in left ventricular mass index (LVMI) from 156g/m2 to 128g/m2 at follow-up for HCM patients with abnormal LVMI at baseline (P=0.009). Optimization of therapies was associated with stable plasma biomarkers in stage B patients while lowering levels of BNP (619-517.5pg/mL, P=0.048), NT-proBNP (777.5-356ng/L, P<0.001) and hsTropT (31-22ng/L, P=0.005) at follow-up relative to baseline values for stage C patients. Despite stage B patients having overt cardiomyopathy at baseline, stage A and B patients had a similarly high probability of survival (χ2=0.204, P=0.652). The overall cardiovascular mortality rate was low at 1.7% for the cohort (0.5% for stage B and 3.3% for stage C) over a median of 34-month follow-up. Our study demonstrates that a multidisciplinary cardiomyopathy clinic can improve the clinical profiles of patients with diverse genetic cardiomyopathies.
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