[CRT-FORUM] 10E. Dispersion of ventricular repolarization changes. Dr. Xia

[CRT-INFO]

Dear Dr Pérez Riera

Thanks for the kind words. Your Chinese friends are also missing you
here, and welcome back to China in the near future.

I will read in detail of the two papers you mentioned. As we know, the
increased dispersion of ventricular repolarization was associated with
ventricular tachyarrhythmias. Such increase might be due to different
activation sequence, and autonomic nerval influence. But on the other
hand, theoretically the dispersion of repolarization, transmurally or
globally, might also be changed dramatically. But I have not found the
related studies on the changes of transmural dispersion in dilated
cardiomyopathy, hypertrophic cardiomyopathy, or heart failure. Do you
know any related studies under these situations?
Kind regards

Yunlong

> 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