It must be noted that there are a number of standard treadmill protocols that can be tailored for patients to reach the endpoint of 85% to 100% maximum predicted heart rate
while the Bruce protocol is most widely used and popular.
Our study defined normal sinus function as that the heart rate during the treadmill testing should exceed 85% maximum predicted heart rate (85% x [220 − age]).
Exercise endpoint was when patients felt uncomfortable or ran out of strength or when the exercise sinus rate exceeded 85% maximum predicted heart rate.
Pacemakers of all the eligible patients were programmed to have: (1) A lower rate limit of 60 beats/min; (2) a maximum sensor rate equal to the maximum predicted heart rate (220−age); and (3) DDDR therapy mode; (4) dynamic atrioventricular delay mode was programmed ON, providing a shorter atrioventricular delay at faster heart rate; (5) recording method was programmed to high resolution at which setting the ventricular rate was averaged and recorded every 16 s and the ACC and MV raw sensor data were collected; (6) the sensor response factors were programmed passive during the treadmill testing and converted to the default settings of ACC = 8, MV = 3 when analyzing the SIR data; (7) the baseline sensor rate was set accordingly with the sinus rate at rest.
Among 200 subjects 42 (21%) achieved 100% maximum predicted heart rate
and 31 (16%) achieved less than 85% of maximum predicted heart rate
and 127 (63%) achieved
Light aerobic exercise- walking, swimming or stationary cycling keeping intensity of 70% maximum predicted heart rate
, no resistance training (weight lifting).
Patients underwent either exercise stress testing using the standard Bruce protocol achieving 85% of maximum predicted heart rate
, or received an adenosine infusion of 0.