Abstract 13056: Risk Stratification of Hypertrophic Cardiomyopathy Subjects, with Presence of LV Fibrosis, but No Significant Coronary Arterial Stenosis, Using Number of Morphological Types of Ventricular Premature Beats
Purpose: To perform risk stratification of hypertrophic cardiomyopathy (HCM) subjects with left ventricular (LV) fibrosis, and without obstructed coronary arteries as diagnosed by 320 slice CT, using the number of morphological types of ventricular premature beats (VPB) detected by 12-lead Holter ECG.
Methods: This was a retrospective analysis of 48 consecutive HCM patients (36 males, 61 ± 13 yrs) who underwent 320 slice CT and 12-lead Holter ECG within 12 months. Subjects had no significant coronary stenosis (≥ 50%) on CT and were followed for a median of 47.5 months. On CT, if contrast defect in LV myocardium was observed in the early phase, late phase acquisition was added and if there was an abnormal enhancement in the corresponding site, we regarded this as fibrosis.
Results: LV fibrosis was detected in 28 patients and the number of morphological types of VPBs in all patients was 7.4 ± 8.3. Major adverse cardiac events (MACE) occurred in 6 subjects. Kaplan Meier analysis revealed a significant difference in incidence of MACE between HCM subjects, with and without LV fibrosis (P = 0.019). According to a receiver operating characteristic (ROC) curve, the best cutoff value for number of morphological types of VPB to distinguish subjects with and without MACE, was 12 (sensitivity 66.7%, specificity 92.9% and area under the curve 0.730). We then divided subjects into 3 groups; Group 1: presence of LV fibrosis and number of morphological types of VPBs ≥ 12, Group 2: presence of LV fibrosis with number of morphological types of VPBs ≤ 12 and Group 3: absence of LV fibrosis. Kaplan Meier analysis revealed a significant difference in incidence of MACE between Group 1 and Group 3 (P ≤ 0.001) and Group 1 and Group 2 (P = 0.001).
Conclusion: Presence of LV fibrosis on CT may predict poor prognosis in HCM subjects without obstructed coronary arteries. Furthermore, if these patients had ≥ 12 morphological types of VPB, they had a significantly worse prognosis than those with ≤ 12 morphological types of VPB.
- © 2013 by American Heart Association, Inc.