Author + information
- Received March 1, 2013
- Accepted March 21, 2013
- Published online August 1, 2013.
- Kristina H. Haugaa, MD, PhD∗,†,
- Bjørnar L. Grenne, MD, PhD‡,
- Christian H. Eek, MD, PhD∗,
- Mads Ersbøll, MD§,
- Nana Valeur, MD, PhD⋮,
- Jesper H. Svendsen, MD, PhD§,¶,
- Anca Florian, MD#,
- Benthe Sjøli, MD, PhD‡,
- Harald Brunvand, MD, PhD‡,
- Lars Køber, MD, PhD§,
- Jens-Uwe Voigt, MD, PhD#,
- Walter Desmet, MD, PhD#,
- Otto A. Smiseth, MD, PhD∗,† and
- Thor Edvardsen, MD, PhD∗,†∗ ()
- ∗Department of Cardiology, Institute for Surgical Research and Center for Cardiological Innovation, Oslo University Hospital, Rikshospitalet Oslo, Norway
- †University of Oslo, Oslo, Norway
- ‡Sørlandet Hospital, Arendal, Norway
- §Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
- ⋮Department of Cardiology, Gentofte Hospital, Gentofte, Denmark
- ¶The Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark
- #Department of Cardiology, University Hospital Gasthuisberg, Catholic University Leuven, Belgium
- ↵∗Reprint requests and correspondence:
Dr. Thor Edvardsen, Department of Cardiology, Oslo University Hospital, Rikshospitalet, N-0027 Oslo, Norway.
Objectives The aim of this study was to test the hypothesis that strain echocardiography might improve arrhythmic risk stratification in patients after myocardial infarction (MI).
Background Prediction of ventricular arrhythmias after MI is challenging. Left ventricular ejection fraction (LVEF) <35% is the main parameter for selecting patients for implantable cardioverter-defibrillator therapy.
Methods In this prospective, multicenter study, 569 patients >40 days after acute MI were included, 268 of whom had ST-segment elevation MIs and 301 non–ST-segment elevation MIs. By echocardiography, global strain was assessed as average peak longitudinal systolic strain from 16 left ventricular segments. Time from the electrocardiographic R-wave to peak negative strain was assessed in each segment. Mechanical dispersion was defined as the standard deviation from these 16 time intervals, reflecting contraction heterogeneity.
Results Ventricular arrhythmias, defined as sustained ventricular tachycardia or sudden death during a median 30 months (interquartile range: 18 months) of follow-up, occurred in 15 patients (3%). LVEFs were reduced (48 ± 17% vs. 55 ± 11%, p < 0.01), global strain was markedly reduced (−14.8 ± 4.7% vs. −18.2 ± 3.7%, p = 0.001), and mechanical dispersion was increased (63 ± 25 ms vs. 42 ± 17 ms, p < 0.001) in patients with arrhythmias compared with those without. Mechanical dispersion was an independent predictor of arrhythmic events (per 10-ms increase, hazard ratio: 1.7; 95% confidence interval: 1.2 to 2.5; p < 0.01). Mechanical dispersion and global strain were markers of arrhythmias in patients with non–ST-segment elevation MIs (p < 0.05 for both) and in those with LVEFs >35% (p < 0.05 for both), whereas LVEF was not (p = 0.33). A combination of mechanical dispersion and global strain showed the best positive predictive value for arrhythmic events (21%; 95% confidence interval: 6% to 46%).
Conclusions Mechanical dispersion by strain echocardiography predicted arrhythmic events independently of LVEF in this prospective, multicenter study of patients after MI. A combination of mechanical dispersion and global strain may improve the selection of patients after MI for implantable cardioverter-defibrillator therapy, particularly in patients with LVEFs >35% who did not fulfill current implantable cardioverter-defibrillator indications.
This study was funded by Inger and John Fredriksen's foundation, the South-Eastern Norway Regional Health Authority, and The Research Council of Norway. Oslo University Hospital, Rikshospitalet, has filed patent application 61/306,678 regarding the method of mechanical dispersion; Drs. Haugaa and Edvardsen are patent applicants. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received March 1, 2013.
- Accepted March 21, 2013.
- American College of Cardiology Foundation