Ventricular activation patterns during different pacing modes. An insight from electroanatomical mapping.
BACKGROUND
Biventricular pacing (BiV) is employed as the current standard for cardiac resynchronisation therapy. Other pacing modalities have been proposed as alternatives; however, data on changes in electrical activation sequence caused by pacing from various sites are limited.


OBJECTIVE
To describe changes in activation patterns during different ventricular pacing modes in patients with chronic heart failure.


METHODS
A total number of 20 patients (mean age 59.6+/-8 years) with chronic heart failure, intraventricular conduction abnormality (QRS >130 ms) or complete AV block were studied. Endocardial activation maps of both ventricles (CARTOTM, Biosense-Webster) were obtained during spontaneous rhythm and biventricular (BiV, n=9), right ventricular bifocal (BiF, n=7) and single-site left ventricular (LV, n=4) pacing. The following parameters were assessed: activation pattern, total LV endocardial activation time (LVAT) and electrical interventricular delay (IVD).


RESULTS
Right ventricular apical pacing was associated with the longest LVAT (145+/-24 ms). On the contrary, both BiV and BiF pacing shortened LVAT with BiV being superior in the degree of LVAT reduction (89+/-13 vs 103+/-10 ms, p<0.05). BiV pacing also significantly shortened IVD and modified the LV activation sequence in a complex manner. Such changes were not observed during BiF pacing. In the presence of fusion with spontaneous activation, single-site LV pacing was comparable to BiV pacing.


CONCLUSIONS
Among the different pacing modes, BiV pacing and single-site LV pacing with fusion resulted in the most pronounced changes in ventricular activation that appear to be a prerequisite for successful resynchronization of both ventricles.
Peichl
Petr
P
Department of Cardiology, Institute for Clinical and Experimental Medicine, Vídenská 1958/9, 14021 Praha 4, Czech Republic. petr.peichl@medicon.cz
Kautzner
Josef
J
Cihak
Robert
R
Riedlbauchova
Lucie
L
Bytesnik
Jan
J
D000328:Adult; D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000601:surgery*; D006346:Heart Septum / Q000503:physiopathology; D006352:Heart Ventricles / Q000033:anatomy & histology* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018497:Ventricular Dysfunction, Right / Q000150:complications / Q000503:physiopathology