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Reduced Anisotropy of Action Potential Conduction in Left Ventricular Hypertrophy
Author(s) -
CAREY PETER A.,
TURNER MARK,
FRY CHRISTOPHER H.,
SHERIDAN DESMOND J.
Publication year - 2001
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1046/j.1540-8167.2001.00830.x
Subject(s) - nerve conduction velocity , medicine , left ventricular hypertrophy , cardiology , muscle hypertrophy , blood pressure
Conduction and Left Ventricular Hypertrophy.Introduction: The aim of this study was to determine if anisotropic action potential conduction was altered during development of left ventricular hypertrophy (LVH). Methods and Results: Isolated guinea pig left ventricular preparations from hearts that had developed LVH were used to measure conduction velocity in longitudinal and transverse orientations to the fiber direction. A variable degree of LVH was induced by placing a ring around the ascending aorta for 50 to 250 days. Results were compared with an age‐matched control group that underwent a similar operation but with no ring placement. LVH was measured as the heart‐to‐body‐weight ratio (HBR), which correlated with an increase of mean myocyte cross‐sectional area. Longitudinal conduction velocity (LCV) declined progressively as HBR increased (mean ± SD: sham vs LVH: HBR 3.74 ± 0.30 g/kg vs 4.53 ± 0.52 g/kg; LCV 72.8 ± 15.5 vs 63.6 ± 11.1 cm/sec). Mean transverse conduction velocity (TCV) was greater in LVH compared with control (20.5 ± 4.7 cm/sec vs 25.4 ± 8.1 cm/sec), but there was no significance in the trend as a function of HBR. The anisotropic ratio (LCV/TCV) significantly declined as HBR increased. The time constant of the foot of the action potential was smaller in the transverse compared with the longitudinal dimension. There was no influence of hypertrophy. Conclusion: The decrease of LCV and reduction of the anisotropic conduction ratio suggest remodeling of the tissue in LVH. The consequences for the generation of arrhythmias are discussed.