Clinical research: interventional cardiology
Myocardial infarction after percutaneous transluminal septal myocardial ablation in hypertrophic obstructive cardiomyopathy: evaluation by contrast-enhanced magnetic resonance imaging

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Abstract

Objectives

The aim of this study was to evaluate myocardial infarction induced by percutaneous transluminal septal myocardial ablation (PTSMA) in symptomatic patients with hypertrophic obstructive cardiomyopathy using contrast-enhanced (CE) magnetic resonance imaging (MRI).

Background

Contrast-enhanced MRI delineates the extent of myocardial infarction in coronary artery disease, but its role in ethanol-induced infarction has not been established.

Methods

Cine and CE MRI were performed before and one month after PTSMA in 24 patients. Size and location of the induced infarction were related to left ventricular (LV) mass reduction, enzyme release, volume of ethanol administered, LV outflow tract gradient reduction, and coronary ablation site.

Results

One month after PTSMA, regional hyperenhancement was visualized in the basal interventricular septum in all patients. Mean infarction size was 20 ± 9 g, corresponding to 10 ± 5% and 31 ± 16% of total LV and septal mass, respectively. Total LV mass decreased from 219 ± 64 to 205 ± 64 g (p < 0.01), and septal mass from 76 ± 25 to 68 ± 22 g (p < 0.01). Total LV mass reduction exceeded septal mass reduction (p < 0.01). Infarction size correlated with peak creatine phosphokinase-MB (β = 0.67, p < 0.01), volume of ethanol administered (β = 0.47, p = 0.02), total LV and septal mass reduction (β = 0.50, p = 0.02; β = 0.73, p < 0.01), and gradient reduction (β = 0.63, p < 0.01). Seven patients with exclusively right-sided septal infarction had smaller infarction size and less gradient reduction than remaining patients with left-sided or transmural infarction (p < 0.01). In five of these, PTSMA was performed distal in the target artery.

Conclusions

Contrast-enhanced MRI allowed detailed evaluation of size and location of septal myocardial infarction induced by PTSMA. Infarction size correlated well with clinical indexes of infarct size.

Abbreviations

CE
contrast-enhanced
CK
creatine phosphokinase
HOCM
hypertrophic obstructive cardiomyopathy
IVS
interventricular septum
LV
left ventricle/ventricular
LVOT
left ventricular outflow tract
MRI
magnetic resonance imaging
NYHA
New York Heart Association
PTSMA
percutaneous transluminal septal myocardial ablation

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Supported by the Netherlands Heart Foundation (grant 99.203) and the Interuniversity Cardiology Institute of the Netherlands.