title: Short-term disruption in regional left ventricular electrical conduction patterns increases interstitial matrix metalloproteinase activity.
abstract: Increased matrix metalloproteinase (MMP) abundance occurs with adverse left ventricular (LV) remodeling in a number of cardiac disease states, including those induced by long-standing arrhythmias. However, whether regionally contained aberrant electrical activation of the LV, with consequent dyskinesia, alters interstitial MMP activation remained unknown. Electrical activation of the LV of pigs (n = 10, 30-35 kg) was achieved by pacing (150 beats/min) at left atrial and LV sites such that normal atrioventricular activation (60 min) was followed by regional early LV activation for 60 min within 1.5 cm of the paced site and restoration of normal atrioventricular pacing for 120 min. Regional shortening (piezoelectric crystals) and interstitial MMP activity (microdialysis with MMP fluorogenic substrate) at the LV pacing site and a remote LV site were monitored at 30-min intervals. During aberrant electrical stimulation, interstitial MMP activity at the paced site was increased (122 +/- 4%) compared with the remote region (100%, P < 0.05). Restoration of atrioventricular pacing after the 60-min period of aberrant electrical activation normalized segmental shortening (8.5 +/- 0.4%), but MMP activity remained elevated (121 +/- 6%, P < 0.05). This study demonstrates that despite the restoration of mechanical function, disturbances in electrical conduction, in and of itself, can cause acute increases in regional in vivo MMP activation and, therefore, contribute to myocardial remodeling.
authors.affiliation: Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, SC 29425, USA. mukherr@musc.edu
authors.forename: Rupak
authors.initials: R
authors.lastname: Mukherjee
authors.forename: Juozas A
authors.initials: JA
authors.lastname: Zavadzkas
authors.forename: William T
authors.initials: WT
authors.lastname: Rivers
authors.forename: Julie E
authors.initials: JE
authors.lastname: McLean
authors.forename: Eileen I
authors.initials: EI
authors.lastname: Chang
authors.forename: Shenikqua
authors.initials: S
authors.lastname: Bouges
authors.forename: Robert G
authors.initials: RG
authors.lastname: Matthews
authors.forename: Christine N
authors.initials: CN
authors.lastname: Koval
authors.forename: Robert E
authors.initials: RE
authors.lastname: Stroud
authors.forename: Francis G
authors.initials: FG
authors.lastname: Spinale
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000201:enzymology* / Q000209:etiology / Q000503:physiopathology; D001794:Blood Pressure; D002304:Cardiac Pacing, Artificial; D004195:Disease Models, Animal; D004562:Electrocardiography; D004789:Enzyme Activation; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate; D006352:Heart Ventricles / Q000201:enzymology / Q000503:physiopathology; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D020127:Recovery of Function; D013552:Swine; D013997:Time Factors; D015854:Up-Regulation; D016277:Ventricular Function, Left; D017725:Ventricular Pressure; D020257:Ventricular Remodeling
chemical_list: D020782:Matrix Metalloproteinases
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