[CRT-FORUM] 7E. Dispersion of ventricular repolarization changes. Dr. Perez Riera

[CRT-INFO]

Dearest friend Yunlong Xia, from the beautiful Dalian, China. I’m very happy
to chat with you.  Are you fine? I miss you and the cleaver Chinese people a
lot!

Answer: Very recently, (the last Month) Dr Zhou et al (1) from  
Department of
Internal Medicine, Division of Cardiology, Second Affiliated Hospital of Sun
Yat-Sen University, Guangzhou, People's Republic of China in a canine
congestive heart failure (CHF)  model ventricular electrophysiological
characteristics correlated with abnormal autonomic nerve function may have
important effects on SCD. In the CHF dog group, significant differences from
the control group in ventricular effective refractory period, monophasic
action potential  duration, ventricular late repolarization duration, the
ratio of ventricular effective refractory period to monophasic action
potential  duration, dispersion of ventricular recovery time, and
ventricular fibrillation threshold were noted. Both baroreflex sensitivity
and the time and power domain parameters of heart rate variability were
significantly decreased in the CHF group compared with the control group,
and a significant, positive correlation between heart rate variability and
baroreflex sensitivity was identified in the CHF group. Heart rate
variability and baroreflex sensitivity were negatively and significantly
correlated with ventricular late repolarization duration and dispersion of
ventricular recovery time, and were positively correlated with ventricular
effective refractory period / monophasic action potential duration and
ventricular fibrillation threshold in the CHF canine group.
Additionally, in human explanted hearts from patients with CHF Rotigaptide
(an enhancer of gap junctional conductance drug) applied to hearts of
patients with end-stage CHF shortened refractory periods   normalized
conduction curves and increased conduction parallel to fiber direction.
However, in 50% of the hearts local slowing of conduction with
destabilization of conduction (curves) occurs at sites close to the
stimulation site, when activation is perpendicular to fiber direction.

Reference
1)    Zhou SX, Lei J, Fang C, Zhang YL, Wang JF. Ventricular
electrophysiology in congestive heart failure and its correlation with heart
rate variability and baroreflex sensitivity: a canine model study. Europace.
2009 Feb;11(2):245-251.

2)    Wiegerinck RF, de Bakker JM, Opthof T, de Jonge N, Kirkels H,
Wilms-Schopman FJ, Coronel R The effect of enhanced gap junctional
conductance on ventricular conduction in explanted hearts from patients with
heart failureBasic Res Cardiol. 2009 Jan 12. [Epub ahead of prin]

All the best
Andrés Ricardo Pérez Riera MD, chief of electrovectorcardiology sector ABC
Faculty of Medicine (FMABC), Discipline of Cardiology, Foundation of ABC
(FUABC), Santo André, São Paulo, Brazil.
Riera at uol.com.br

CRT-INFO escribió:
> Eu tenho aqui uma questão: Como ocorre a dispersão das mudanças na 
> repolarização ventricular nos pacientes com insuficiência cardíaca? 
> Como é a relação com as taquiarritmias ventriculares malignas?
>
> Atenciosamente,
>
> Dr. Yunlong Xia, PhD
> Dalian, China
>


-- 
Dr. Sergio Dubner
President of Scientific Committee

Dr. Edgardo Schapachnik
President of Steering Committee