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Parasympathetic effects on cardiac electrophysiology during exercise and recovery in patients with left ventricular dysfunction.
Chicos, Alexandru B; Kannankeril, Prince J; Kadish, Alan H; Goldberger, Jeffrey J.
Afiliação
  • Chicos AB; Division of Cardiology, Bluhm Cardiovascular Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA.
Am J Physiol Heart Circ Physiol ; 297(2): H743-9, 2009 Aug.
Article em En | MEDLINE | ID: mdl-19525382
ABSTRACT
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.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Sistema Nervoso Parassimpático / Parassimpatolíticos / Atropina / Exercício Físico / Disfunção Ventricular Esquerda Tipo de estudo: Diagnostic_studies Limite: Aged / Female / Humans / Male / Middle aged Idioma: En Ano de publicação: 2009 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Sistema Nervoso Parassimpático / Parassimpatolíticos / Atropina / Exercício Físico / Disfunção Ventricular Esquerda Tipo de estudo: Diagnostic_studies Limite: Aged / Female / Humans / Male / Middle aged Idioma: En Ano de publicação: 2009 Tipo de documento: Article