Abstract 17579: Pericellular Fibrosis is Associated With Cardiac Events and Reduced Septal Contraction in Patients With Obstructive Hypertrophic Cardiomyopathy.
Purpose: Myocardial fibrosis is associated with increased risk of malignant arrhythmias in patients with hypertrophic cardiomyopathy (HCM) and is frequently located in the hypertrophied inter ventricular septum. The aim of this study was to explore the impact of regional septal contraction by strain echocardiography and extent of septal fibrosis (pericellular and/or replacement-type fibrosis) on serious events in obstructive HCM-patients undergoing basal septal reduction with surgical myectomy.
Methods: Of 24 HCM-patients included (54% men; mean age 58±10 years), 5 experienced a serious event (cardiac arrest, non sustained VT, unexplained syncope), while 19 had no events. Myocardial strains by speckle tracking technique were averaged from 4 septal segments (basal and mid septal segments from apical long axis and 4-chamber views) as a measure of septal contraction. Degree of pericellular and replacement type fibrosis was determined in percentage of total specimen, by histopathology of surgical specimen.
Results: Maximal septal thickness was 1.9±0.3 cm, left ventricular outflow peak gradient by Doppler was 65±21 mmHg and NYHA classification was 2.9±0.4. In patients with events the median percentage area of pericellular fibrosis was higher (30%, range 17–62) than in patients without events (8%, range 0–60), p=0.009 (Figure). Mean septal strain was reduced in patients with events (−11.2 ±4.2%) vs. no events (−15.9 ±3.8%), p=0.03 (Figure). There was a weak but significant correlation between area of pericellular fibrosis and septal strain (R=0.27, p=0.01). Replacement type fibrosis was not associated with events.
Conclusion: Increased area of pericellular fibrosis and reduced septal contraction were interrelated and associated with serious events in patients with obstructive HCM. These findings indicate that septal pericellular fibrosis may serve as an arrhythmic substrate and cause reduced septal contraction.
- © 2010 by American Heart Association, Inc.