TY - JOUR
T1 - Parasympathetic effects on cardiac electrophysiology during exercise and recovery in patients with left ventricular dysfunction
AU - Chicos, Alexandru B.
AU - Kannankeril, Prince J.
AU - Kadish, Alan H.
AU - Goldberger, Jeffrey J.
N1 - Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2009/8
Y1 - 2009/8
N2 - Depressed parasympathetic activity has been proposed to be associated with an increased risk of sudden death. Parasympathetic effects (PE) on cardiac electrophysiology during exercise and recovery have not been studied in patients with left ventricular dysfunction. We performed noninvasive electrophysiological studies (NI-EPS) and characterized the electrophysiological properties of the sinus node, atrioventricular (AV) node, and ventricle in subjects with depressed left ventricular ejection fraction and dual-chamber defibrillators. NI-EPS were performed during rest, exercise, and recovery at baseline and after parasympathetic blockade with atropine to assess PE (the difference between parameter values in the 2 conditions). Ten subjects (9 men: age, 60 ± 9 yr; and left ventricular ejection fraction, 29 ± 8%) completed the study. All NI-EPS parameters decreased during exercise and trended toward rest values during recovery. PE at rest, during exercise, and during recovery, respectively, were on sinus cycle length, 320 ± 71 (P = 0.0001), 105 ± 60 (P = 0.0003), and 155 ± 82 ms (P = 0.0002); on AV block cycle length, 137 ± 136 (P = 0.09), 37 ± 19 (P = 0.002), and 61 ± 39 ms (P = 0.006); on AV interval, 58 ± 32 (P = 0.035), 22 ± 13 (P = 0.002), and 36 ± 20 ms (P = 0.001); on ventricular effective refractory period, 15.8 ± 11.3 (P = 0.02), 4.7 ± 15.2 (P = 0.38), and 6.8 ± 15.5 ms (P = 0.20); and on QT interval, 13 ± 12 (P = 0.13), 3 ± 17 (P = 0.6), and 20 ± 23 (P = 0.04). In conclusion, we describe for the first time the changes in cardiac electrophysiology and PE during rest, exercise, and recovery in subjects with left ventricular dysfunction. PEs are preserved in these patients. Thus the role of autonomic changes in the pathophysiology of sudden death requires further exploration.
AB - Depressed parasympathetic activity has been proposed to be associated with an increased risk of sudden death. Parasympathetic effects (PE) on cardiac electrophysiology during exercise and recovery have not been studied in patients with left ventricular dysfunction. We performed noninvasive electrophysiological studies (NI-EPS) and characterized the electrophysiological properties of the sinus node, atrioventricular (AV) node, and ventricle in subjects with depressed left ventricular ejection fraction and dual-chamber defibrillators. NI-EPS were performed during rest, exercise, and recovery at baseline and after parasympathetic blockade with atropine to assess PE (the difference between parameter values in the 2 conditions). Ten subjects (9 men: age, 60 ± 9 yr; and left ventricular ejection fraction, 29 ± 8%) completed the study. All NI-EPS parameters decreased during exercise and trended toward rest values during recovery. PE at rest, during exercise, and during recovery, respectively, were on sinus cycle length, 320 ± 71 (P = 0.0001), 105 ± 60 (P = 0.0003), and 155 ± 82 ms (P = 0.0002); on AV block cycle length, 137 ± 136 (P = 0.09), 37 ± 19 (P = 0.002), and 61 ± 39 ms (P = 0.006); on AV interval, 58 ± 32 (P = 0.035), 22 ± 13 (P = 0.002), and 36 ± 20 ms (P = 0.001); on ventricular effective refractory period, 15.8 ± 11.3 (P = 0.02), 4.7 ± 15.2 (P = 0.38), and 6.8 ± 15.5 ms (P = 0.20); and on QT interval, 13 ± 12 (P = 0.13), 3 ± 17 (P = 0.6), and 20 ± 23 (P = 0.04). In conclusion, we describe for the first time the changes in cardiac electrophysiology and PE during rest, exercise, and recovery in subjects with left ventricular dysfunction. PEs are preserved in these patients. Thus the role of autonomic changes in the pathophysiology of sudden death requires further exploration.
KW - Autonomic
KW - Heart failure
KW - Nervous system
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U2 - 10.1152/ajpheart.00193.2009
DO - 10.1152/ajpheart.00193.2009
M3 - Article
C2 - 19525382
AN - SCOPUS:68049110614
VL - 297
SP - H743-H749
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
SN - 0363-6143
IS - 2
ER -