Abstract 15341: Clinical Implication of Tissue Fibrosis and Physiological Parameters for Adverse Cardiac Events in Hypertrophic Cardiomyopathy
Natural history of hypertrophic cardiomyopathy (HCM) patients is various from an asymptomatic benign course to poor prognosis due to heart failure or sudden arrhythmic death. We hypothesized that myocardial fibrosis in HCM has an critical role in major adverse events such as ventricular tachyarrhythmias (VT/VF) or heart failure.
Methods. Of 494 consecutive HCM patients, 216 patients histologically diagnosed were enrolled (55±14 years old). The amount of fibrosis (%area) were quantified in tissue sample from RV biopsy and hemodynamic, echocardiographic and electrophysiologic parameters were evaluated. Patients were followed up and the primary endpoint was adverse cardiac events: heart failure or lethal ventricular arrhythmias, and secondary endpoint was death by any causes.
Results. During 3±1 years follow up, 93 (43%) patients had adverse cardiac events. Family history of HCM, higher brain natriuretic peptide level (BNP>360mg/dl), history of VT/VF, higher left ventricular end-diastolic pressure (LVEDP>15mmHg), pulmonary capillary wedge pressure (PCWP>10mmHg), mean pulmonary artery pressure (mean PAP>17 mmHg) and positive late potential by signal averaged ECG (SAECG) were the independent predictors for adverse cardiac events (p<0.05). However, history of atrial fibrillation, LV wall thickness, LV ejection fraction (LVEF)and LA diameter were not correlate to the cardiac events. Degree of fibrosis in tissue from RV biopsy were mildly correlate to LVEDP (r2=0.15, p<0.001) but not independently predict the following cardiac events. Multivariate Cox regression analysis revealed that longer QRS duration of SAECG had a greater risk of adverse cardiac events with a hazard ratio:1.13 /10-ms (95%CI=1.01-1.24; p<0.05). On the other hand, lower LVEF (p=0.008) and history of VT/VF (p=0.02) were the independent predictor for any cause of death.
Conclusion: Myocardial fibrosis in tissue sample from RV biopsy are not directly correlated to clinical prognosis, but higher LVEDP-related fibrotic change in HCM patients may contribute to the abnormal conduction delay as well as lower LVEF or spontaneous VT/VF, leading to poor prognosis.
- © 2012 by American Heart Association, Inc.