Can exercise-based cardiac rehabilitation increase physical activity in patients who have undergone total thoracoscopic ablation?

¹ Division of Sports Medicine, Department of Orthopedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, 06351 Seoul, Republic of Korea

² Department of School of Global Sports Studies, Social Physical Education, Korea University, 30019 Sejong, Republic of Korea

³ Division of Cardiology, Department of Internal Medicine, Cardiac Center, Heart Stroke & Vascular Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, 06351 Seoul, Republic of Korea

⁴ Department of Thoracic and Cardiovascular Surgery, Cardiovascular Imaging Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, 06351 Seoul, Republic of Korea

^*Correspondence: cabg.jeong@samsung.com (Dong-Seop Jeong)
Academic Editor: Kazuhiro P. Izawa

Rev. Cardiovasc. Med. 2021, 22(4), 1595–1601; https://doi.org/10.31083/j.rcm2204165

Submitted: 15 August 2021 | Revised: 14 September 2021 | Accepted: 15 September 2021 | Published: 22 December 2021

(This article belongs to the Special Issue Cardiac rehabilitation)

This is an open access article under the CC BY 4.0 license (https://creativecommons.org/licenses/by/4.0/).

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Abstract

Evidence of the effect of exercise therapy in patients who have undergone total thoracoscopic ablation is lacking. This study aimed to evaluate the effects of eight weeks exercise-based cardiac rehabilitation on cardiopulmonary fitness and adherence to exercise in patients who underwent total thoracoscopic ablation and followed a regimen of exercise therapy. Twenty-four patients were involved in the study and were divided into two groups. The exercise group underwent exercise therapy, which included aerobic and resistance exercises, twice a week as part of an eight weeks hospital-based outpatient cardiac rehabilitation program. Cardiopulmonary exercise test was used to evaluate exercise capacity and the International Physical Activity Questionnaire was utilized to identify the amount of physical activity and confirm adherence to exercise at six months postoperatively. There were significant differences between the groups in moderate activity level (p = 0.004) and extent of total physical activity (p = 0.0001). Complications such as recurrent atrial fibrillation did not occur during the exercise training. Exercise-based cardiac rehabilitation was beneficial in maintaining the activity level at six months postoperatively. Early exercise intervention at four weeks post-surgical ablation is a safe and effective therapy that can increase physical activity. Further studies are needed to verify the effect of exercise intervention in a larger sample size of patients who have undergone total thoracoscopic ablation.

Keywords

Exercise therapy

Atrial fibrillation

Adherence to exercise

1. Introduction

Atrial fibrillation (AF) is a condition of abnormal atrial rhythms, with irregular and often rapid heart rates [1]. Prevalence of AF is estimated to be about 0.4% in the general population: women show a two-fold increased risk, whereas men show a 1.5-fold increased risk [2]. Patients with AF have a three- to five-fold higher risk of strokes, so early interventions are critical for reducing risk of strokes and other related complications [3].

Initial treatment of AF is focused on antiarrhythmic medication although pharmacological treatment has been reported to be unsatisfactory [4]. Total thoracoscopic ablation, a minimally invasive surgical technique, has been performed to ablate the epicardial site and is superior to catheter ablation in terms of restoration of sinus rhythm following arrhythmias [5, 6].

The exercise capacity of patients with AF is 20% lower than that of the age-matched normal population [7]. Cardiopulmonary fitness is an important factor in reduction of mortality and improvement of survival rates in these patients [8, 9]. Exercise therapy can improve exercise capacity, daily activity level, and quality of life in patients with AF [10, 11]. Improvement of exercise capacity after cardioversion has been shown to be delayed [12]. Several studies [13, 14] have reported that surgical intervention can improve clinical outcomes, including cardiopulmonary fitness and quality of life, but reports on the effect of exercise intervention after thoracoscopic ablation are limited.

Adherence to a home-based exercise regimen after exercise therapy is crucial for maintaining the effect of exercise intervention. Several factors including self-motivation, self-efficacy, social support, and previous adherence to exercise-related behavior are related to compliance to home-based physical activity [15]. Interventions that aid in adherence to the exercise regimen including an activity monitor and feedback system, written exercise instructions, and behavioral exercise programs have been employed before [16]. Among these interventions, the monitoring and feedback approach has showed more positive outcomes on adherence to exercise [17]. This study was performed to confirm the effect of exercise therapy on the exercise capacity and compliance to exercise at home after center-based cardiac rehabilitation (CR) in patients recovering from total thoracoscopic ablation (TTA).

2. Methods

2.1 Study designs

Twenty-four patients who underwent TTA (Fig. 1) were included and were allocated to two groups: exercise group (n = 12) aged 58.4 $\pm$ 6.5 years, and control group (n = 12) aged 59.5 $\pm$ 6.1 years based on their willingness to participate in the program. The exclusion criteria were the following: patients with recurrent AF after surgery, those with musculoskeletal problems, and those who disagreed to participate in this study. A cardiopulmonary exercise test was performed on the patients, and cardiopulmonary function-related parameters were recorded using 12-lead electrocardiography. A questionnaire for assessment of extent of physical activity was also used. Prior to conduct of the study informed consent was obtained from all subjects and all methods were carried out in accordance to relevant guidelines and regulations. The study protocol was approved by the Samsung Medical Center Institutional Review Board (IRB No: 2018-04-060-001) and complied with the 1964 Helsinki declaration and its subsequent amendments. This study was registered in ClinicalTrials.gov and has the clinical trial registration number NCT04500184.

Fig. 1.

Surgical intervention using total thoracoscopic ablation. (a) Intervention site for ablation. (b) Roof line ablation. (c) Ganglionated plexi ablation. (d) Superior vena cava circular ablation.

2.2 Cardiopulmonary exercise test

The patients underwent a symptom-limited, incremental treadmill ergometer test with continuous respiratory gas exchange analysis (Parvo Medics, East Sandy, UT, USA), wherein clinical variables such as electrocardiography results and VO ${}_{2}$ peak were measured preoperatively and three months postoperatively. Exercise responses, including heart rate, blood pressure, and respiratory exchange ratio, were also measured. General procedures for the present test were performed according to the American College of Sports Medicine guidelines [18].

2.3 Physical activity level

The self-administered International Physical Activity Questionnaire short form, consisting of four generic items, was also used in this study [19]. Patients chose the questionnaire items according to their activity level; walking (3.3 Metabolic equivalents: METs) and moderate (4.4 METs) and vigorous (8.0 METs) activities. The questionnaire score was calculated, where a higher score indicated increased activity. Subjects were instructed to check the questionnaire before and six months after the surgery.

2.4 Exercise program

The exercise regimen was started one month postoperatively. The exercise program was prescribed according to frequency, intensity, time, and type of exercise and was conducted twice a week for eight weeks (16 sessions). Each training session was conducted for 1 hour, and warm-up and cool-down were performed for 5 min each. The exercise regimen consisted of aerobic exercise and resistance training. The initial exercise intensity for aerobic exercise was 40%–50% of the heart rate reserve [(maximal heart rate-resting heart rate) $\times$ 40%–50% + resting heart rate] and was progressively increased to reach 75% during a 2-month period. The initial duration of aerobic exercise was 10 min in 3 sessions, and it was progressively increased to 30 min per session during the study period. Patients were instructed to undergo resistance training after 2 weeks of aerobic exercise. Patients’ electrocardiograms were monitored during the exercise using Quinton Q-Tel RMS 3.1 (Quinton, Bothell, WA, USA). Patients were encouraged to be physically active during the training period by performing supplementary treadmill and stationary bike exercises at the Samsung Sports Medicine Center (Seoul, Republic of Korea). A similar exercise program has been reported previously [10].

2.5 Statistical analysis

Descriptive statistics were used to determine the mean and standard deviation. To compare the differences in repeated measures of continuous data between groups, we used repeated measures analysis of variance (ANOVA). Paired t-tests were used to identify the effects of exercise in each group when the interactions between time and group were confirmed in repeated measures ANOVA. All statistical analyses were performed using SPSS version 21 (IBM Corp., Armonk, NY, USA). A p-value $<$ 0.05 was considered statistically significant.

3. Results

3.1 Study description

Sixty patients treated at Samsung Medical Hospital (Seoul, Republic of Korea) with TTA were enrolled for this study. We excluded subjects with recurrent AF (n = 3) and musculoskeletal problems (n = 2); we also excluded patients for other reasons (n = 5). Other reasons for exclusion included self-reported reasons for non-participation in clinical trial due to lack of interest (n = 10), long distances to the center from home (n = 11), and inability to exercise due to disease (n = 5). Twenty-four patients consented to this study and all patients completed this eight weeks intervention (Fig. 2). Persistent AF was the superior type between the groups (67%), followed by the paroxysmal type (33%). The rate of previous cardioversion treatment was 50% in the intervention group and 42% in the control group and that of advanced intervention as cardioversion was 17% and 8%, respectively (Table 1).

Fig. 2.

Flowchart for study process related to the subject’s selection and follow-up period.

Table 1.Characteristics of subjects at baseline.

Parameters		Exercise group (n = 12)	Non-exercise group (n = 12)
Age (years)		58.4 $\pm$ 6.5	59.5 $\pm$ 6.1
Number of male subjects		10	10
Number of female subjects		2	2
Weight (kg)		73.8 $\pm$ 9.6	72.5 $\pm$ 9.5
BMI (kg/m ${}^{2}$ )		26.1 $\pm$ 3.6	25.5 $\pm$ 3.1
Atrial fibrillation (type)
	Paroxysmal, n	4	4
	Persistent, n	8	8
Duration (months)		34.5	84
Treatment
	Previous ablation, n	2	1
	Previous cardioversion, n	6	5
CHA ${}_{2}$ DS ${}_{2}$ VASc score
	0, n	5	4
	1, n	2	4
	$\geq$ 2, n	5	4
BMI, body mass index; CHA ${}_{2}$ DS ${}_{2}$ VASc, Congestive heart failure Hypertension Age ${}_{2}$ Diabetes mellitus Stroke ${}_{2}$ Vascular disease Age Sex category of female.

3.2 Cardiopulmonary function

Between the groups, differences in improvement in cardiopulmonary fitness (F = 4.119, p = 0.055) was marginally significant. VO ${}_{2}$ peak after the exercise intervention improved by 9% from 26.1 $\pm$ 3.6 mL/kg/min to 28.9 $\pm$ 7.6 mL/kg/min in the exercise group. However, other parameters obtained from the cardiopulmonary exercise test were not significantly different between the groups (Table 2).

Table 2.The results of cardiopulmonary exercise test preoperatively and 3 months postoperatively.

Variables	Exercise group		Non-exercise group		F	p
Variables	Baseline	Post 3 M	Baseline	Post 3 M	F	p
VO ${}_{2}$ peak (mL/kg/min)	26.07 $\pm$ 3.64	28.89 $\pm$ 7.62	28.30 $\pm$ 7.44	26.85 $\pm$ 6.23	4.119	0.055
AT (%)	60.16 $\pm$ 6.37	61.42 $\pm$ 7.11	56.4.2 $\pm$ 1.54	56.33 $\pm$ 11.27	0.065	0.127
RPP (mmHg·bpm)	23896.25 $\pm$ 6023.47	19906.92 $\pm$ 4158.98	23103.16 $\pm$ 4311.78	18893.92 $\pm$ 3712.45	0.011	0.918
Exercise time (min)	11.58 $\pm$ 2.54	11.78 $\pm$ 2.69	12.45 $\pm$ 2.23	12.15 $\pm$ 2.40	0.539	0.470
RER	1.10 $\pm$ 0.13	1.11 $\pm$ 0.08	1.07 $\pm$ 0.12	1.12 $\pm$ 0.11	0.307	0.585
Data are means $\pm$ standard deviation. VO ${}_{2}$ peak, peak oxygen uptake; AT, anaerobic threshold; RPP, rate pressure product; RER, respiratory exchange ratio; M, month. F-value and p-value of means of interaction between group and time from two-way repeated ANOVA.

3.3 Physical activity level

At the low physical activity level, there were no significant differences between groups, although the level of activity increased from 668.3 $\pm$ 665.0 MET-min/week to 915.8 $\pm$ 776.2 MET-min/week in the exercise group. At the moderate physical activity level, the interaction between group and time was revealed to have a significant difference (F = 10.614, p = 0.004). Change to moderate activity exerted a positive effect in the intervention group from 340.4 $\pm$ 725.0 MET-min/week to 510.0 $\pm$ 712.9 MET-min/week, whereas the control group showed a negative effect from 1032.5 $\pm$ 1013.5 MET-min/week to 510.0 $\pm$ 1056.3 MET-min/week. On the basis of the results, total physical activity showed a significant difference in interaction between group and time (F = 17.871, p = 0.0001). In the exercise group, the eight weeks exercise intervention improved the total physical activity (PA) at six months postoperatively (Table 3). Recurrent arrhythmias or other exercise-related complications did not occur during the intervention period.

Table 3.The results of physical activity level preoperatively and 6 months postoperatively.

Physical activity level	Exercise group		Non-exercise group		F	p
Physical activity level	Baseline	Post 6 M	Baseline	Post 6 M	F	p
Low	668.25 $\pm$ 664.95	915.75 $\pm$ 776.23	692.83 $\pm$ 783.08	478.50 $\pm$ 294.99	2.304	0.143
Moderate	340.42 $\pm$ 724.99	510.0 $\pm$ 712.92 ${}^{†}$	1032.50 $\pm$ 1013.52	510.00 $\pm$ 1056.25	10.614	0.004 ${}^{*}$
Vigorous	52.25 $\pm$ 144.50	1100.00 $\pm$ 1750.09	220.00 $\pm$ 573.98	660.75 $\pm$ 1770.51	0.903	0.352
Total PA	1060.50 $\pm$ 979.77	2426.75 $\pm$ 164.98 ${}^{†}$	1863.00 $\pm$ 1653.18	1648.50 $\pm$ 1716.21	17.871	0.000 ${}^{***}$
Data are means $\pm$ standard deviation. PA, physical activity; M, month. F-value and p-value of means of interaction between group and time from two-way repeated ANOVA. ${}^{\textdagger{}}$ It means that a significant difference within group confirmed by paired t-test. p $<$ 0.05, p $<$* 0.001***.

4. Discussion

This study demonstrated that exercise therapy is beneficial in increasing PA and improving marginal exercise capacity in patients undergoing TTA. It also revealed that early enrollment in exercise-based CR was safe and effective. This study was valuable in identifying the effect of exercise therapy in patients treated with thoracoscopic ablation.

Cardiopulmonary fitness in patients with AF has been reported to be 20% lower than the age-matched general population [7]. Subjects of this study had lower exercise capacity than their age-matched normal population pre-intervention. Exercise therapy can improve VO ${}_{2}$ peak and can reduce mortality by 20% in patients treated for AF [8]. In this study, although VO ${}_{2}$ peak increased after the intervention, the statistical significance was marginal. Exercise intervention for patients with surgical thoracoscopic ablation has not been reported. Hence, findings of this study on improvement of exercise capacity could not be compared with other studies. Several factors including the small sample size and short-term intervention used in this study also need to be considered. According to a systematic review, the effects of exercise training in individuals with permanent AF remain controversial [20]. Different testing equipment could affect the measurement of these factors, as cycle ergometer testing estimated a VO ${}_{2}$ peak 5% lower than that for treadmill ergometer testing [21]. Therefore, further studies of patients who have undergone TTA with longer exercise duration and frequency, are needed to identify improvement of parameters about tolerance as well as VO ${}_{2}$ peak.

Improvement in PA level is associated with improvement in exercise capacity and is influenced by a higher socioeconomic status, less comorbidity, better physical abilities, and fewer depressive symptoms, resulting in a reduction in the incidence of cardiovascular diseases [22, 23]. In the present study, preoperative and six months postoperative PA levels were checked using a questionnaire. The activity level was different for the two groups in this study; the exercise group had more participants with a low activity level, whereas the control group had more participants with moderate activity level. At six months postoperative, scores for all categories of activity level improved in the exercise intervention group. The self-efficacy of patients was strongly related to the increase in habitual PA, and encouragement has been shown to motivate increased habitual PA [24]. On the basis of the results, improvement in PA level was found to be associated with encouragement for enrollment in CR and regular attendance at a facility.

Exercise maintenance in this study was evaluated using a questionnaire at six months postoperatively. From previous studies, adherence was defined as attendance to the exercise program with a prescribed number of sessions, intensity, frequency, and duration of aerobic exercise [25]. At the three months follow-up period, exercise group maintained total PA at postoperative six months. Improvement in patient’s self-efficacy and motivation to exercise were helpful in increasing and maintaining PA or exercise level [26]. Social support can help improve perceived behavioral control, resulting in improvement in exercise adherence [27]. Among other studies, the results of this study were associated with face-to-face education in center-based program, although effects of cognitive training for behavioral change were not evaluated.

Assessment of arrhythmia recurrence after surgery is required to understand the success of intervention. Postoperative recurrence rate of atrial arrhythmia was 16% six months after surgery [28]. The risk factors of recurrent AF are old age, hypertension, left atrial volumes [28]. Physical exertion in hospitalization is associated with developing paroxysmal AF [29]. Therefore, recommendation for initial time of exercise can be explained as an important consideration for prevention of recurrent AF. In this study, patients were instructed to participate in moderate-intensity exercise therapy at one month post-operation, if they did not exhibit recurrent AF or any other complications. The observed results support the fact that early participation in exercise is a safe and effective intervention for patients with TTA. However, exercise intensity needs to be considered when starting the intervention early in the postoperative period.

This clinical study has few limitations. First, 24 patients participated in this study, which is a small number. The sample size was too small to verify the effects of exercise therapy. Therefore, further studies with larger sample sizes are necessary to confirm the effect of exercise therapy. Second, the present study used a PA questionnaire, which is a patient-reported outcome, for checking the subject’s activity level and adherence to exercise after intervention. This questionnaire had three categories: low, moderate, and vigorous activity levels, and was capable of reflecting the PA level of the last 7 days only. It was insufficient to obtain the total PA data for three months and could not identify the start time of exercise. To overcome this, further studies that use other measurement tools are needed.

5. Conclusions

Exercise-based CR of eight weeks was associated with an increase in PA and exercise maintenance in patients that have undergone TTA surgery. Early exercise training is a safe and effective intervention without side effects and is recommended for these patients. Future studies with long-term follow-up are needed to determine the effect of exercise-based CR in patients who have undergone TTA.

Author contributions

YGS and DSJ designed the study and YGS performed the study and recorded the data. YGS and JS analyzed the data and prepared the table and figures. YGS, DSJ, and MKK interpreted the results. YGS wrote manuscript. All authors critically revised the manuscript and approved the final manuscript.

Ethics approval and consent to participate

The study protocol was approved by the Samsung Medical Center Institutional Review Board (IRB No, 2018-04-060-001) and complies with the 1964 Helsinki declaration and its later amendments.

Acknowledgment

The authors would like to thank the cardiac rehabilitation team at Samsung Medical Center.

Funding

This research received no external funding.

Conflict of interest

The authors declare no conflict of interest.

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