Table 1.
Characteristics of included studies.
| Study | Design | Patients’ information | Intervention | Measurement period | Outcome | Adverse event |
| Belardinelli et al (2006) | RCT | 15 (ICD-CRT with ET): 10 (ICD-CRT without ET) | Supervised exercise for 8 wk, 3 sessions/wk at 60% of peak VO2. Each session lasted about 1 h. | Baseline and 8 wk (the day when the completion of the training program) | Peak VO2, cardiac volumes and function, MLHFQ and LVEF | 8 controls had sustained ventricular tachycardia, while no trained patients had adverse events. |
| Conraads et al (2007) | RCT | 8 (CRT with ET): 9 (CRT without ET) | Supervised ambulatory exercise for 4 mo, 3 sessions/wk as the heart rate achieved at 90% of the ventilatory threshold during CPET, each lasting for 1 h. | Baseline, 1 mo and 5 mo after CRT implanted | Peak VO2, maximal workload, circulatory power, VO2 AT, Watt AT, LVEF, NYHA class, NT-pro BNP, and MLHFQ | |
| Patwala et al (2009) | RCT | 25 (CRT with ET): 25 (CRT without ET) | Physician-supervised exercise program for 3 mo and 3 sessions/wk at 80% of the peak heart rate for the first 4 wk, 85% for the next 4 wk, and 90% for the final 4 wk, each lasting for 30 min. | Before and 3 and 6 mo after CRT implanted | Peak VO2, NYHA functional class, exercise duration, MLHFQ, peak cardiac power output, respiratory exchange ratio, and LVEF | No patients had complications from the exercise training, and there were no cardiac arrhythmias. |
| Smolis-Bąk et al (2015) | A randomized, prospective observation | 26 (CRT with ET): 26 (CRT without ET) | Hospital-based and home-based exercise training for 8 wk plus hospital stay, 5 sessions/week at low intensity of home-based exercise training. | Prior to CRT implantation and after 3–4 and 12 mo | 0, 3–4, 12 mo: peak VO2, AT, METs, and treadmill test duration, 6-MWT, Beck Depression Inventory, and NHP. 0, 12 mo: standard echocardiography | Up to 18 mo, there were 3 cases of death (9.4%) in the CRT-Ex group and 3 cases of death in the CRT-Control group (10.3%) (P = 1.0). There were 14 (43.8%) and 15 (51.7%) hospital admissions in the CRT-Ex and CRT-Control groups, respectively (P = .5334). |
| Nobre et al (2016) | RCT | 23 (CRT with ET): 22 (CRT without ET) randomised. 14 (CRT with ET): 16 (CRT without ET) analyzed | Supervised exercise for 4 mo 3 sessions/week, each lasting for 1 h. The exercise intensity was established by heart rate levels that corresponded to anaerobic threshold up to 10% below the respiratory compensation point obtained in the CPET. | 1 mo and 5 mo after CRT implantation | Peak VO2 exercise duration, workload, and LVEF MSNA burst frequency and burst incidence, FBF and FVC Na/Ca2 exchanger relative expression and Ryanodine receptor expression | |
| Martens et al (2018) | Retrospective case–control study | 223 (CRT with ET): 432 (CRT without ET) | Supervised cardiac rehabilitation for 45 sessions, 3 session/wk, as the heart rate achieved at 90% of the ventilator threshold of the CPET, each lasting for 1 h. The intensity was increased gradually every 2 wk. | Before CRT-implant and 6 mo after CRT-implant. | NYHA-functional class, peak VO2, LVEF | During a mean follow-up of 36 ± 22 mo, 116 events occurred in the control group vs 31 events in the CR group. |
| Santa–Clara et al (2019) | RCT | 34 (CRT with HIIT): 29 (CRT without HIIT) randomized. 20 (CRT with HIIT): 17 (CRT without HIIT) analyzed. | Supervised, hospital-based, HIIT for 24 wk, 2 sessions/wk at 90–95% peak heart rate, each for 60 min. | Before and at 6 mo after CRT implantation | HRQoL (a Portuguese version of the HeartQoL), NYHA class, Peak VO2, CPET duration, Peak HR, HR recovery 1′ (bpm), LVEF, LV mass | |
| Spee et al (2019) | RCT | 12 (CRT with HIIT): 12 (CRT without HIIT) | Supervised HIIT for 3 mo, 3 sessions/wk with a workload corresponding to 85–95% of peak VO2, each lasting for about 40 min. | Before and at 3 and 6 mo after CRT implantation | HRQoL (MLHFQ), LVEF, peak VO2, and peak workload | No adverse cardiovascular events occurred during exercise testing and high intensity interval training sessions. |
6-MWT = six-minute walk test, AT = anaerobic threshold, CHF = chronic heart failure, CPET = cardiopulmonary exercise testing, CR = cardiac rehabilitation, CRT = cardiac resynchronization therapy, ET = = exercise training, FBF = forearm blood flow, FVC = forearm vascular conductance, HIIT = high-intensity interval training, HRQoL = health related quality of life, ICD = implantable cardioverter defibrillators, LVEF = left ventricular ejection fraction, METs = metabolic equivalents, MLHFQ = Minnesota living with heart failure questionnaire, MSNA = muscle sympathetic nerve activity, NT-proBNP = NT-pro brain natriuretic peptide, NYHA = New York Heart Association.