Document Detail


Mechanical alternans in human idiopathic dilated cardiomyopathy is caused with impaired force-frequency relationship and enhanced poststimulation potentiation.
MedLine Citation:
PMID:  22573070     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Mechanical alternans (MA) is frequently observed in patients with heart failure, and is a predictor of cardiac events. However, there have been controversies regarding the conditions and mechanisms of MA. To clarify heart rate-dependent contractile properties related to MA, we performed incremental right atrial pacing in 17 idiopathic dilated cardiomyopathy (DCM) patients and in six control patients. The maximal increase in left ventricular dP/dt during pacing-induced tachycardia was assessed as the force gain in the force-frequency relationship (FG-FFR), and the maximal increase in left ventricular dP/dt of the first post-pacing beats was examined as the force gain in poststimulation potentiation (FG-PSP). As a result, MA was induced in 9 DCM patients (DCM MA(+)) but not in the other 8 DCM patients (DCM MA(-)), and not in any of the control patients. DCM MA(+) had significantly lower FG-FFR (34.7 ± 40.9 vs 159.4 ± 103.9 mmHg/s, P = 0.0091) and higher FG-PSP (500.0 ± 96.8 vs 321.9 ± 94.9 mmHg/s, P = 0.0017), and accordingly a wider gap between FG-PSP and FG-FFR (465.3 ± 119.4 vs 162.5 ± 123.6 mmHg/s, P = 0.0001) than DCM MA(-) patients. These characteristics of DCM MA(+) showed clear contrasts to those of the control patients. In conclusion, MA is caused with an impaired force-frequency relationship despite significant poststimulation potentiation, suggesting that MA reflects ineffective utilization of the potentiated intrinsic force during tachycardia.
Authors:
Takeshi Kashimura; Makoto Kodama; Komei Tanaka; Keiko Sonoda; Satoru Watanabe; Yukako Ohno; Makoto Tomita; Hiroaki Obata; Wataru Mitsuma; Masahiro Ito; Satoru Hirono; Haruo Hanawa; Yoshifusa Aizawa
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-5-10
Journal Detail:
Title:  Heart and vessels     Volume:  -     ISSN:  1615-2573     ISO Abbreviation:  -     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-5-10     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8511258     Medline TA:  Heart Vessels     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Division of Cardiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi, Niigata, 951-8510, Japan, kashi@med.niigata-u.ac.jp.
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