Detrimental ventricular remodeling in patients with congenital complete heart block and chronic right ventricular apical pacing.
BACKGROUND
Although dual-chamber pacing improves cardiac function in patients with complete congenital atrioventricular block (CCAVB) by restoring physiological heart rate and atrioventricular synchronization, the long-term detrimental effect of asynchronous electromechanical activation induced by apical right ventricular pacing (RVP) has not been well clarified.


RESULTS
Twenty-three CCAVB adults (24+/-3 years) with a DDD transvenous pacemaker underwent conventional echocardiography before implantation and, after at least 5 years of RVP, an exercise test and echocardiography coupled with tissue Doppler imaging and tissue tracking. They were compared with 30 matched healthy control subjects. After 10+/-3 years of RVP, CCAVB adults had significantly higher values versus controls in terms of intra-left ventricular (LV) asynchrony (respectively, 59+/-18 versus 19+/-9 ms, P<0.001), extent of LV myocardium displaying delayed longitudinal contraction (39+/-15% versus 10+/-7%, P<0.01), and septal-to-posterior wall-motion delay (84+/-26 versus 18+/-9 ms, P<0.01). The ratio of late-activated posterior to early-activated septal wall thickness was higher after long-term RVP than before (1.3+/-0.2 vs 1+/-0.1, P=0.05) and was higher than in controls (1+/-0.1, P<0.05). The percentage of patients with increased LV end-diastolic diameter was higher after long-term RVP than before implantation and was higher than in controls (57% versus 13%, P<0.05, and 57% versus 0%, P<0.01, respectively). CCAVB patients with long-term RVP had a lower cardiac output than controls (3.8+/-0.6 versus 4.9+/-0.8 L/min, P<0.05) and lower exercise performance (123+/-24 versus 185+/-39 W, P<0.001).


CONCLUSIONS
Prolonged ventricular dyssynchrony induced by long-term endovenous RVP is associated with deleterious LV remodeling, LV dilatation, LV asymmetrical hypertrophy, and low exercise capacity. These new data highlight the importance of the ventricular activation sequence in all patients with chronic ventricular pacing.
Thambo
Jean-Benoît
JB
Hôpital Cardiologique du Haut Lévèque, 19 avenue de Magellan, Pessac Cedex 33604 France. jean-benoit.thambo@chu-bordeaux.fr
Bordachar
Pierre
P
Garrigue
Stephane
S
Lafitte
Stephane
S
Sanders
Prashanthan
P
Reuter
Sylvain
S
Girardot
Romain
R
Crepin
David
D
Reant
Patricia
P
Roudaut
Raymond
R
Jaïs
Pierre
P
Haïssaguerre
Michel
M
Clementy
Jacques
J
Jimenez
Maria
M
D000328:Adult; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects*; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D005500:Follow-Up Studies; D006327:Heart Block / Q000151:congenital* / Q000628:therapy; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D018487:Ventricular Dysfunction, Left / Q000209:etiology* / Q000503:physiopathology; D020257:Ventricular Remodeling