Document Detail


Mechanical dispersion assessed by myocardial strain in patients after myocardial infarction for risk prediction of ventricular arrhythmia.
MedLine Citation:
PMID:  20223421     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVES: The aim of this study was to investigate whether myocardial strain echocardiography can predict ventricular arrhythmias in patients after myocardial infarction (MI). BACKGROUND: Left ventricular (LV) ejection fraction (EF) is insufficient for selecting patients for implantable cardioverter-defibrillator (ICD) therapy after MI. Electrical dispersion in infarcted myocardium facilitates malignant arrhythmia. Myocardial strain by echocardiography can quantify detailed regional and global myocardial function and timing. We hypothesized that electrical abnormalities in patients after MI will lead to LV mechanical dispersion, which can be measured as regional heterogeneity of contraction by myocardial strain. METHODS: We prospectively included 85 post-MI patients, 44 meeting primary and 41 meeting secondary ICD prevention criteria. After 2.3 years (range 0.6 to 5.5 years) of follow-up, 47 patients had no and 38 patients had 1 or more recorded arrhythmias requiring appropriate ICD therapy. Longitudinal strain was measured by speckle tracking echocardiography. The SD of time to maximum myocardial shortening in a 16-segment LV model was calculated as a parameter of mechanical dispersion. Global strain was calculated as average strain in a 16-segment LV model. RESULTS: The EF did not differ between ICD patients with and without arrhythmias occurring during follow-up (34 +/- 11% vs. 35 +/- 9%, p = 0.70). Mechanical dispersion was greater in ICD patients with recorded ventricular arrhythmias compared with those without (85 +/- 29 ms vs. 56 +/- 13 ms, p < 0.001). By Cox regression, mechanical dispersion was a strong and independent predictor of arrhythmias requiring ICD therapy (hazard ratio: 1.25 per 10-ms increase, 95% confidence interval: 1.1 to 1.4, p < 0.001). In patients with an EF >35%, global strain showed better LV function in those without recorded arrhythmias (-14.0% +/- 4.0% vs. -12.0 +/- 3.0%, p = 0.05), whereas the EF did not differ (44 +/- 8% vs. 41 +/- 5%, p = 0.23). CONCLUSIONS: Mechanical dispersion was more pronounced in post-MI patients with recurrent arrhythmias. Global strain was a marker of arrhythmias in post-MI patients with relatively preserved ventricular function. These novel parameters assessed by myocardial strain may add important information about susceptibility for ventricular arrhythmias after MI.
Authors:
Kristina H Haugaa; Marit Kristine Smedsrud; Torkel Steen; Erik Kongsgaard; Jan P?l Loennechen; Terje Skjaerpe; Jens-Uwe Voigt; Rik Willems; Gunnar Smith; Otto A Smiseth; Jan P Amlie; Thor Edvardsen
Publication Detail:
Type:  Journal Article; Multicenter Study; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  JACC. Cardiovascular imaging     Volume:  3     ISSN:  1876-7591     ISO Abbreviation:  JACC Cardiovasc Imaging     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-03-12     Completed Date:  2010-06-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101467978     Medline TA:  JACC Cardiovasc Imaging     Country:  United States    
Other Details:
Languages:  eng     Pagination:  247-56     Citation Subset:  IM    
Copyright Information:
Copyright 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
Affiliation:
Department of Cardiology, Rikshospitalet University Hospital and University of Oslo, Oslo, Norway.
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MeSH Terms
Descriptor/Qualifier:
Aged
Arrhythmias, Cardiac / etiology,  physiopathology,  prevention & control,  ultrasonography*
Belgium
Case-Control Studies
Defibrillators, Implantable
Echocardiography*
Electric Countershock / instrumentation
Electrocardiography
Female
Humans
Kaplan-Meiers Estimate
Male
Middle Aged
Myocardial Contraction*
Myocardial Infarction / complications,  physiopathology,  ultrasonography*
Norway
Predictive Value of Tests
Primary Prevention
Proportional Hazards Models
Prospective Studies
Recurrence
Risk Assessment
Risk Factors
Secondary Prevention
Ventricular Function, Left*
Comments/Corrections
Comment In:
JACC Cardiovasc Imaging. 2010 Mar;3(3):330-1   [PMID:  20223434 ]

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