Improvement in cardiac adrenergic function post biventricular pacing for heart failure.
OBJECTIVE
We investigated whether biventricular (BiV) pacing favourably affects cardiac sympathetic activity in heart failure (HF).


RESULTS
In 10 HF patients treated with BiV pacing, we assessed cardiac sympathetic activity by metaiodobenzylguanidine ((123)I-MIBG) imaging. Patients were randomized in a double-blinded crossover fashion, for two weeks of either inactivation of BiV pacing or BiV pacing, with crossover to the alternate group for a further two weeks. After randomization blocks, cardiac (123)I-MIBG imaging and a 6 min walk test were performed. BiV pacing was associated with significant improvements in cardiac (123)I-MIBG uptake reflected by increases in early (BiV 1.71 +/- 0.09 vs. non-BiV 1.63 +/- 0.06, P = 0.03) and late (at 4 h) heart to mediastinal ratio of uptake (BiV 1.54 +/- 0.08 vs. non-BiV 1.45 +/- 0.06, P = 0.03). Additionally, pulmonary (123)I-MIBG uptake, measured as lung to mediastinal ratio, significantly improved (P = 0.009). Six-minute walk and systolic blood pressure tended to improve with BiV vs. non-BiV pacing (P = 0.09).


CONCLUSIONS
In patients with stable HF, BiV pacing is associated with long-term improvements in cardiac sympathetic nerve activity, as reflected by improvements in cardiac (123)I-MIBG uptake. This is a potential mechanism for morbidity and mortality benefits observed in larger studies.
Gould
Paul A
PA
Wynn Department of Metabolic Cardiology, Baker Heart Research Institute, Central, Melbourne VIC, Australia.
Kong
Grace
G
Kalff
Victor
V
Duffy
Stephen J
SJ
Taylor
Andrew J
AJ
Kelly
Michael J
MJ
Kaye
David M
DM
D019797:3-Iodobenzylguanidine / Q000494:pharmacology; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging* / Q000294:innervation / Q000502:physiology; D006333:Heart Failure / Q000628:therapy; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D011941:Receptors, Adrenergic / Q000378:metabolism*; D013564:Sympathetic Nervous System / Q000000981:diagnostic imaging* / Q000502:physiology
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D011941:Receptors, Adrenergic; D019797:3-Iodobenzylguanidine