Document Detail

Relationship of mechanical dyssynchrony to QT interval prolongation in hypertrophic cardiomyopathy.
MedLine Citation:
PMID:  22185753     Owner:  NLM     Status:  Publisher    
AIMS: Hypertrophic cardiomyopathy (HCM) is usually associated with electrocardiographic (ECG) abnormalities. QT interval and its dispersion can be clinical markers of electrophysiological instability and ventricular arrhythmias. We aimed to clarify the relation of QT variables to mechanical dyssynchrony and myocardial function in HCM. METHODS AND RESULTS: The study population comprised 82 HCM patients, 28 healthy subjects as control. We assessed regional deformation indexes using vector velocity imaging in 12 myocardial segments. Peak systolic strain (ε(sys)), strain rate (SR(sys)), and post-systolic strain (PSS) were measured. Contraction time (CT) was measured from regional strain curves for each segment, as the time from the beginning of the Q-wave to the time-to-peak ε(sys) (TPS), mechanical dyssynchrony was estimated as TPS-SD. From 12-lead surface ECG, QT interval, QT dispersion, and its corrected values were measured. According to QT(c) (QT(c) ≥ 440 or <440 ms), patients were categorized into two groups: long QT and normal QT HCM. In the long QT group, QT(cd) and CT in all left ventricular (LV) segments were significantly prolonged; ε(sys) and SR(sys) were markedly attenuated compared with the other two groups (P<0.001). LV dyssynchrony was significantly greater (P<0.001) and PSS was more frequent in long QT HCM compared with the other two groups (P<0.001). TPS-SD was correlated positively with QT(c) (r=0.38, P<0.01) and QT(cd) (r=0.45, P<0.001). QT(c) ≥ 440 ms identified LV mechanical dyssynchrony with 70% sensitivity, 100% specificity, and positive predictive value. CONCLUSION: QT interval prolongation on surface ECG shows significant association with mechanical dyssynchrony and LV dysfunction in HCM. This may add pathophysiological insight into understanding ECG changes in such myocardial disease.
Hala Mahfouz Badran; Mohamed Fahmy Elnoamany; Ghada Soltan; Mohamed Ezat; Mohamed Elsedi; Raed Ahmed Abdelfatah; Magdi Yacoub
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-12-20
Journal Detail:
Title:  European journal of echocardiography : the journal of the Working Group on Echocardiography of the European Society of Cardiology     Volume:  -     ISSN:  1532-2114     ISO Abbreviation:  -     Publication Date:  2011 Dec 
Date Detail:
Created Date:  2011-12-21     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100890618     Medline TA:  Eur J Echocardiogr     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Cardiology Department, Menoufiya University, 60 Said Street, PO Box 34, Tanta, Gharbia 0350, Egypt.
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