Usefulness of bifocal pacing in patients with heart failure and intraventricular conduction delay.
BACKGROUND
Bifocal pacing (BFP) has been proposed as a feasible alternative to cardiac resynchronization therapy.


OBJECTIVE
To evaluate BFP in patients with severe heart failure and significant intraventricular conduction delay and to compare it with biventricular pacing (BVP).


METHODS
Echocardiographic examination including TDI and invasive measurement of haemodynamics was performed under basal conditions, during BFP and during BVP.


RESULTS
Fifty patients were included: 29 with ischaemic heart disease (IHD), 21 with idiopathic dilated cardiomyopathy (IDCM). LV dp/dt(max) increased during BFP compared to the basal state (13.4%, 95% CI 9.2-17.6%, p<0.0001) and a further increase was achieved during BVP (29.5%, 95% CI 23.7-35.4%, p<0.0001). A significant correlation was found between the distance of the right ventricular apical and outflow tract leads and percentage of dp/dt(max) increase in IDCM patients (r=0.72), but not in IHD patients. Interventricular mechanical delay (IVMD) decreased in BFP (43+/-22 ms vs. 53+/-31 ms, p=0.006), but BVP produced even shorter IVMD (22+/-19 ms, p<0.0001). In all patients, regional systolic contraction times were significantly shortened, corresponding with prolongation of the respective regional diastolic filling times during both BFP (p<0.05 for all segments) and BVP (p<0.001 for all segments).


CONCLUSIONS
BFP improves LV haemodynamics by decreasing the inter- and intraventricular conduction delays. The leads in the right ventricle should be placed at the longest achievable distance. BVP is superior to BFP.
Bulava
Alan
A
1st Department of Internal Medicine, University Hospital and Faculty of Medicine, Palacky University, Olomouc, Czech Republic. alanbulava@seznam.cz <alanbulava@seznam.cz>
Lukl
Jan
J
D000368:Aged; D000369:Aged, 80 and over; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects / Q000379:methods*; D002311:Cardiomyopathy, Dilated / Q000503:physiopathology / Q000628:therapy*; D015150:Echocardiography, Doppler / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000503:physiopathology / Q000628:therapy*; D015203:Reproducibility of Results; D013997:Time Factors