Association of myocardial fibrosis, electrocardiography and ventricular tachyarrhythmia in hypertrophic cardiomyopathy: a delayed contrast enhanced MRI study.
BACKGROUND
Patients with hypertrophic cardiomyopathy (HCM) are predisposed to ventricular tachyarrhythmia (VT); likely due to myocardial fibrosis or disarray. Delayed hyperenhancement magnetic resonance imaging (DHE-MRI) accurately detects myocardial fibrosis (scar). We sought to determine the association between septal thickness, myocardial scar and VT.


METHODS
Sixty-eight patients (mean age 44 years, 69% males) with documented HCM underwent cine MRI (Siemens Sonata or Avanto 1.5 T scanner, Erlangen, Germany) in short axis, 2, 3 and 4-chamber views and maximal interventricular septal thickness was recorded at end-diastole. Corresponding DHE-MR images (8-10 mm thick) were obtained, approximately 20 min after injection of 0.2 mmol/kg of Gadolinium. Scar was determined semi-automatically (as % of total myocardium) using VPT software (Siemens) and defined as intensity >2 SD above viable myocardium in a 12 segment short-axis model at apex, mid LV and base. Presence of VT (documented on ambulatory ECG monitoring) and history of sudden death were recorded.


RESULTS
One patient had a history of sudden death and 9 (13%) had VT on ambulatory ECG monitoring. On DHE-MRI, 39 (57%) patients had myocardial scar. Patients with VT had significantly higher scar %, compared to those without: 14% [6, 19] vs. 6% [0, 10], P = 0.01. On logistic regression, only the size of the scar was a significant predictor of VT (P = 0.03).


CONCLUSIONS
HCM subjects with VT have a higher % of myocardial scarring noted on DHE-MRI, independent of septal thickness or beta-blocker use.
Kwon
Deborah H
DH
Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA.
Setser
Randolph M
RM
Popović
Zoran B
ZB
Thamilarasan
Maran
M
Sola
Srikanth
S
Schoenhagen
Paul
P
Garcia
Mario J
MJ
Flamm
Scott D
SD
Lever
Harry M
HM
Desai
Milind Y
MY
D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000473:pathology*; D003287:Contrast Media; D003645:Death, Sudden / Q000209:etiology; D015716:Electrocardiography, Ambulatory; D005260:Female; D005355:Fibrosis; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D016015:Logistic Models; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology
D003287:Contrast Media; D019786:Gadolinium DTPA