title: Exercise chronotropy in patients with normal and impaired sinus node function after cardiac transplantation.
abstract: The chronotropic response during graded, symptom limited exercise was investigated in 32 cardiac transplant recipients a mean of 49 +/- 18 days after transplantation. All patients had systematic evaluation of postoperative donor sinus node (SN) function and the cardioacceleratory response was compared according to the SN function. Twenty-one patients had normal postoperative SN studies (corrected SN recovery time < 520 msec, group I) while the SN function was impaired postoperatively in the remainder (n = 11, group II; corrected SN recovery time 4,149 +/- 6,283 msec in 5 patients, junctional escape rhythm in 6 patients). All patients had regained sinus rhythm at time of the exercise test. Patients in group II had lower basal sinus rates at the beginning of exercise (91.5 +/- 11 vs 101.4 +/- 7 beats/min, P < 0.02). This lower chronotropy was maintained over every incremental step (F rate between groups = 30, P = 0.0001, F rate vs workload = 15, P = 0.0001 by two-way ANOVA) and resulted in a significantly lower heart rate at individual peak exercise (108.3 +/- 20 vs 124.2 +/- 13 beats/min, P < 0.02). A total of 14/16 patients in group I but only 2/16 patients in group II accomplished a peak heart rate > or = 120 beats/min (P = 0.009). The workload achieved did not differ between the groups (107 +/- 29 vs 102 +/- 32 watts, P > 0.5). These data show a lower SN chronotropy during rest and at peak exercise in cardiac transplant recipients with postoperative SN deficiency and apparent normalization of SN function.
authors.affiliation: Department of Internal Medicine II, University of Vienna, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Heinz
authors.forename: S
authors.initials: S
authors.lastname: Radosztics
authors.forename: C
authors.initials: C
authors.lastname: Kratochwill
authors.forename: G
authors.initials: G
authors.lastname: Kreiner
authors.forename: P
authors.initials: P
authors.lastname: Buxbaum
authors.forename: M
authors.initials: M
authors.lastname: Grimm
authors.forename: G
authors.initials: G
authors.lastname: Sunder-Plassmann
authors.forename: G
authors.initials: G
authors.lastname: Laufer
authors.forename: A
authors.initials: A
authors.lastname: Laczkovics
authors.forename: H
authors.initials: H
authors.lastname: Gössinger
mesh_terms: D000328:Adult; D001146:Arrhythmia, Sinus / Q000209:etiology / Q000503:physiopathology*; D005080:Exercise Test; D006339:Heart Rate; D016027:Heart Transplantation / Q000009:adverse effects*; D006801:Humans; D008875:Middle Aged