PMID- 19815540 OWN - NLM STAT- MEDLINE DCOM- 20100107 LR - 20151119 IS - 1532-2092 (Electronic) IS - 1099-5129 (Linking) VI - 11 IP - 11 DP - 2009 Nov TI - Adrenergic stimulation increases repolarization dispersion and reduces activation-repolarization coupling along the RV endocardium of patients with cardiomyopathy. PG - 1529-35 LID - 10.1093/europace/eup295 [doi] AB - AIMS: Dispersion of repolarization (DOR) in the human heart is minimized by activation-repolarization coupling. Adrenergic stimulation can be proarrhythmic in patients with impaired left-ventricular function and its effect on repolarization dispersion has not been systematically investigated. Our objective was to study the effect of dobutamine on repolarization dispersion and activation-repolarization coupling in patients with cardiomyopathy. METHODS AND RESULTS: Activation recovery intervals (ARI) and activation times (AT) were measured from unipolar electrograms at 10 sites along the apicobasal right ventricle (RV) in 14 patients with cardiomyopathy (LVEF < 40%). These measurements were made during control, dobutamine 2.5-5.0 microg/kg/min, and a recontrol phase while maintaining constant heart rates with atrial pacing. Dispersion of repolarization was calculated from the total recovery time (TRT, AT+ARI). Activation-repolarization coupling was assessed by linear regression of ARI and AT. Dispersion of repolarization across all 10 sites and between adjacent sites increased with dobutamine compared with control (whole DOR: range 15 +/- 2 vs. 12 +/- 2 ms, P = 0.06 and standard deviation 5.5 +/- 0.9 vs. 4.3 +/- 0.9 ms, P = 0.04; adjacent DOR: 5.9 +/- 0.8 vs. 4.5 +/- 0.6 ms, P = 0.04). This was associated with shallower ARI/AT slopes (-0.3 +/- 0.2 vs. -0.8 +/- 0.2, P = 0.05) and a decrease in ARI-AT correlation (R(2) 0.4 +/- 0.1 vs. 0.6 +/- 0.1, P = 0.05) with dobutamine compared with control. CONCLUSION: Adrenergic stimulation increases apicobasal RV DOR and reduces coupling between activation and repolarization in patients with cardiomyopathy. This may provide a mechanism for the proarrhythmic potential of heightened adrenergic states in these patients. FAU - Selvaraj, Raja J AU - Selvaraj RJ AD - Division of Cardiology, University Health Network, Toronto, Canada. FAU - Suszko, Adrian M AU - Suszko AM FAU - Subramanian, Anandaraja AU - Subramanian A FAU - Nanthakumar, Kumaraswamy AU - Nanthakumar K FAU - Chauhan, Vijay S AU - Chauhan VS LA - eng PT - Controlled Clinical Trial PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20091007 PL - England TA - Europace JT - Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology JID - 100883649 RN - 0 (Adrenergic beta-Agonists) RN - 3S12J47372 (Dobutamine) SB - IM MH - Adrenergic beta-Agonists/administration & dosage MH - Aged MH - Cardiomyopathies/complications/*diagnosis/*physiopathology MH - Dobutamine/*administration & dosage MH - Endocardium/drug effects/physiopathology MH - Female MH - Heart Conduction System/drug effects/*physiopathology MH - Heart Ventricles/drug effects/*physiopathology MH - Humans MH - Male MH - Ventricular Dysfunction, Right/complications/diagnosis/physiopathology EDAT- 2009/10/10 06:00 MHDA- 2010/01/08 06:00 CRDT- 2009/10/10 06:00 PHST- 2009/10/10 06:00 [entrez] PHST- 2009/10/10 06:00 [pubmed] PHST- 2010/01/08 06:00 [medline] AID - eup295 [pii] AID - 10.1093/europace/eup295 [doi] PST - ppublish SO - Europace. 2009 Nov;11(11):1529-35. doi: 10.1093/europace/eup295. Epub 2009 Oct 7.