Circulation, Vol 80, 106-111, Copyright © 1989 by American Heart Association
Exercise response before and after termination of atrial tachycardia after congenital heart disease surgery
HU Wessel, DW Benson Jr, EA Braunlin, A Dunnigan and MH Paul
Children's Memorial Hospital, Willis J. Potts Children's Heart Center, McGaw Medical Center, Northwestern University, Chicago, Illinois 60614.
We studied exercise performance before and after conversion of atrial
tachycardia to sinus rhythm, atrial bradycardia, or junctional rhythm in 10
patients 9-25 years of age 8-20 years after congenital heart disease
surgery (complete transposition of the great arteries, seven of 10
patients). The same maximal cycle (five of 10 patients) or treadmill (five
of 10 patients) exercise protocol was performed in atrial tachycardia and
sinus rhythm 1-232 days after atrial tachycardia (mean, 34 days).
Electrocardiogram, heart rate, and pulmonary gas exchange were recorded.
Sinus rhythm exercise increased peak VO2 (mean, 28.7 [sinus rhythm] vs.
24.7 [atrial tachycardia], p less than 0.01), exercise time (p less than
0.01), and O2 pulse at rest (p less than 0.01) and at peak exercise (NS).
Mean resting heart rate decreased from 109 to 70 beats/min (p less than
0.01). In atrial tachycardia, peak exercise heart rate was low (80-163
beats/min) because of fixed conduction (six of 10 patients) or high as
conduction approached 1:1 (176-252 beats/min) (four of 10 patients). In
sinus rhythm, rest to peak exercise heart rate increased in six of 10
patients (p less than 0.05). The data show improved exercise performance in
sinus rhythm primarily because of improved heart rate adaptation to
exercise, by either permitting increased heart rate response or eliminating
excessively high heart rate with inadequate diastolic filling.