Abstract
Abnormal ventricular wall motion is a strong clinical predictor of sudden, arrhythmic, cardiac death. Dispersion in repolarization is a prerequisite for the initiation of re-entrant arrhythmia. We hypothesize that regionally decreased wall motion is associated with heterogeneity of repolarization. We measured local activation times, activation-recovery intervals (ARIs, surrogate for action potential duration), and repolarization times using a multielectrode grid at nine segments on the left ventricular epicardium in 23 patients undergoing coronary artery surgery. Regional wall motion was simultaneously assessed using intraoperative transesophageal echocardiography. Three groups were discriminated: (1) Patients with normal wall motion (n = 11), (2) Patients with one or more hypokinetic segments (n = 6), (3) Patients with one or more akinetic or dyskinetic segments (n = 6). The average ARI was similar in all groups (251 ± 3.7 ms, ±SEM). Dispersion of ARIs between the nine segments was significantly increased in the hypokinetic (84 ± 7.4 ms, p < 0.005) and akinetic/dyskinetic group (94 ± 3.5 ms, p < 0.0005) compared with the normal group (49 ± 5.1 ms), independent from the presence of myocardial infarction. Repolarization heterogeneity occurred primarily in the normally contracting regions of the hearts with abnormal wall motion. An almost maximal increased dispersion of repolarization was observed when there was only a single hypokinetic segment. We conclude that inhomogeneous wall motion abnormality of even moderate severity is associated with increased repolarization inhomogeneity, independent from the presence of infarction.
Highlights
Abnormal ventricular wall motion abnormality (WMA) is one of the strongest clinical predictors of sudden cardiac death due to arrhythmia in patients with heart disease (Tracy et al, 1987; Trappe et al, 1989; Nath et al, 1993; Kober et al, 1997; Camm and Katritsis, 2000; Kohl et al, 2005)
Patients without myocardial infarction (MI) are depicted by thin lines between their minimum and maximum ARIs and patients with MI are marked by bold lines
We have shown in the human heart that wall motion abnormalities are associated with increased dispersion of ARIs and RTs, independent from the presence of MI, and without effect on activation time (AT)
Summary
Abnormal ventricular wall motion abnormality (WMA) is one of the strongest clinical predictors of sudden cardiac death due to arrhythmia in patients with heart disease (Tracy et al, 1987; Trappe et al, 1989; Nath et al, 1993; Kober et al, 1997; Camm and Katritsis, 2000; Kohl et al, 2005). In the Strong Heart Study, a large population-based study in patients without clinically recognizable cardiovascular disease, wall motion abnormalities were associated with an about 2.5 times higher risk of both cardiovascular events and death during an 8-years follow-up (Cicala et al, 2007). In human atria, both in silico (Kuijpers et al, 2011) and in vivo (Coronel et al, 2010a) dilatation has been shown to underlie conduction abnormalities and/or increased dispersion in refractoriness. It has been reported that the timing of stretch in relation with the phase of the action potential is important for the effect (Zabel et al, 1996)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
