Physical activity is associated with improved aerobic exercise capacity over time in adults with congenital heart disease

Abstract

Background: Impaired exercise capacity is common in adults with congenital heart disease (ACHD). This impairment is progressive and is associated with increased morbidity and mortality. We studied the influence of the frequency of at least moderately strenuous physical activity (PhysAct) on changes in exercise capacity of ACHD patients over time.

Methods: We studied ACHD patients ≥21 years old who had repeated maximal (RER≥1.09) cardiopulmonary exercise tests within 6 to 24 months. On the basis of data extracted from each patient's clinical records, PhysAct frequency was classified as (1) Low: minimal PhysAct, (2) Occasional: moderate PhysAct <2 times/week, or (3) Frequent: moderate PhysAct ≥2 times/week.

Results: PhysAct frequency could be classified for 146 patients. Those who participated in frequent exercise tended to have improved pVO2 (∆pVO2=+1.63±2.67 ml/kg/min) compared to those who had low or occasional activity frequency (∆pVO2=+0.06±2.13 ml/kg/min, p=0.003) over a median follow-up of 13.2 months. This difference was independent of baseline clinical characteristics, time between tests, medication changes, or weight change. Those who engaged in frequent PhysAct were more likely to have an increase of pVO2 of ≥1SD between tests as compared with sedentary patients (multivariable OR=7.4, 95%CI 1.5-35.7). Aerobic exercise capacity also increased for patients who increased activity frequency from baseline to follow-up; 27.3% of those who increased their frequency of moderately strenuous physical activity had a clinically significant (at least +1SD) increase in pVO2 compared to only 11% of those who maintained or decreased activity frequency.

Conclusions: ACHD patients who engage in frequent physical activity tend to have improved exercise capacity over time.

Keywords: Adults; Congenital heart disease; Exercise capacity and physical activity.

Figure 1. Baseline % predicted peak VO₂(A) and change in % predicted peak VO₂ between baseline and follow-up cardiopulmonary exercise tests(B) by congenital heart disease diagnostic category

While baseline pVO_2-%pred differed by diagnosis (Kruskal-Wallis, p=0.006), there was no such difference in ΔpVO_2-%pred between diagnoses (Kruskal-Wallis, p=0.96). RV=right ventricular lesion, LV=left ventricular lesion, AVCD=atrioventricular canal defect, ASD/VSD=atrial/ventricular septal defect, TOF=tetralogy of Fallot

Figure 2. Change in peak VO₂ by frequency of moderate or strenuous physical activity, <2 vs. ≥2 times per week

Panel A shows change in pVO_2-abs while panel B shows change in pVO_2-%pred between exercise tests. P values represent linear regression adjusting for baseline pVO_2-%pred.

Figure 3. Proportion of patients having >1SD(±11%) change in peak VO_2-abs between exercise tests

Most patients had stable pVO₂, independent of PA frequency. However, approximately twice as many patients in the lower exercise frequency group had a >1SD decrease in pVO₂ compared with a >1SD increase. Conversely, among those engaging in frequent PA, more than twice as many improved their pVO₂ >1SD compared to the number that had equivalently decreased pVO₂.

Figure 4. Change in peak VO₂ by change in PA frequency

(decreased=”↓”, stable=”≈”, increase=”↑”) between the baseline and follow-up CPX. Panel A shows %change pVO_2-abs. Panel B shows ΔpVO_2-%pred. P values represent linear regression adjusting for baseline pVO_2-%pred.