# The effects of different physical activities on atrial fibrillation in patients with hypertension and chronic kidney disease PMID: 28904878 Journal: Kidney Research and Clinical Practice Published: 2017 Sep Authors: Kiuchi MG, Chen S, Hoye NA ## Question To evaluate the effects of HIIT versus moderate exercise on atrial fibrillation occurrence measured by implantable cardiac monitor, renal function, ambulatory blood pressure, and echocardiographic parameters in patients with chronic kidney disease and hypertension over 3 years. ## Summary This 3-year clinical intervention compared a high-intensity interval training group with a progressive moderate exercise group in sedentary patients with chronic kidney disease and controlled hypertension. Atrial fibrillation onset was substantially higher in the HIIT group than in the moderate exercise group, while renal function and selected echocardiographic measures improved more with moderate exercise. The study is relevant mainly as a safety and clinical-boundary signal because the exact HIIT regimen actually prescribed is not fully described. ## Population - Sedentary patients with chronic kidney disease and controlled hypertension, structurally normal hearts, no prior AF symptoms, and implantable cardiac monitoring. - Sample size: 50 - Age: Eligibility 18-75 years; HIIT 52 +/- 10 years, ModEx 63 +/- 9 years. - Sex: HIIT 18 male/7 female; ModEx 15 male/10 female. - Fitness level: Sedentary - Health status: Chronic kidney disease with controlled hypertension; eGFR <60 mL/min/1.73 m2. ## Methodology - Prospective longitudinal two-group intervention study with 3-year follow-up; the manuscript states patients were randomly divided 1:1 but later describes the study as unblinded and non-randomized. - 3 years - Hospital e Clinica Sao Goncalo, Rio de Janeiro, Brazil, with CardioStim Arrhythmias and Artificial Cardiac Pacing Service Research - Controlled study design. ## Protocol - HIIT. - Intensity: Nearly maximum intensity hard portions with approximately 50% recovery intensity in generic definition; exact study prescription not reported. - Program length: 3 years. - ModEx. - Modality: Walking on treadmill and cycling on stationary or transport bicycle. - Work intervals: Continuous aerobic exercise. - Intensity: 55% HRmax first 6 months, 65% HRmax months 6-12, 75% HRmax months 12-18, 85% HRmax from month 19 onward. - Session duration: 30 min first 6 months, 45 min months 6-12, 60 min months 12-18 and from month 19 onward. - Frequency: 5 sessions per week. - Program length: 3 years. - Progression: Progressive increases in session duration and heart-rate target across the first 19 months. ## Outcomes ### Atrial fibrillation onset Status: worse/safety concern AF onset was higher in CKD patients who engaged in HIIT (72%) than ModEx (24%). HR 3.847; 95% CI 1.694-8.740; P = 0.0013 by log-rank test. ### Systolic 24-hour ABPM Status: improved Both groups had significant intragroup changes in mean systolic 24-hour ABPM, with significant between-group differences at the same timepoints favoring ModEx. Table 2 reports P <0.05 or P <0.001 versus baseline and between-group footnotes at 12, 24, and 36 months. ### Renal function Status: mixed Renal markers improved more in ModEx than HIIT; ModEx creatinine decreased from 1.74 +/- 0.09 to 1.40 +/- 0.09 mg/dL and eGFR increased from 41.2 +/- 5.5 to 53.3 +/- 4.0 mL/min/1.73 m2 by 36 months. ModEx changes at later timepoints frequently P <0.001 versus baseline; HIIT changes were smaller. ### Indexed left atrial volume Status: worse/safety concern HIIT indexed LA volume increased from 30.5 +/- 2.1 to 34.2 +/- 1.3 mL/m2 by 36 months, while ModEx decreased from 31.0 +/- 1.7 to 27.8 +/- 1.4 mL/m2. HIIT 24 and 36 months P <0.0001 versus baseline; ModEx 24 and 36 months P <0.0001 versus baseline. ### LV mass index Status: improved LV mass index decreased in both groups, with larger decrease in ModEx by 36 months. HIIT from 95.9 +/- 14.6 to 77.4 +/- 11.5 g/m2, P <0.0001 at 36 months; ModEx from 100.2 +/- 18.3 to 66.0 +/- 9.3 g/m2, P <0.0001 at 36 months. ## Practical Insights - This paper is more useful for safety boundaries than for HIIT workout design because the actual HIIT protocol is unclear. - For CKD patients with hypertension, moderate progressive aerobic exercise may be a safer evidence-aligned recommendation than vigorous interval training. - Clinical populations with kidney disease and cardiovascular risk should not be treated as equivalent to healthy users in HIIT programming. ## Limitations - Small sample size. - Article is internally inconsistent about randomization and later describes the design as unblinded non-randomized. - Exact HIIT modality, work intervals, recovery intervals, frequency, session duration, progression, adherence, and actual intensity are not reported. - Cardiac MRI was not used because of gadolinium risk in CKD. - Preliminary findings require validation in a large randomized trial with treatment concealment. ## Safety And Adherence - AF onset was higher in HIIT than ModEx over 3 years. - The authors note vigorous activity can cause acute catecholamine fluxes, autonomic tone changes, and atrial stretching, all potentially contributing to AF risk. - Participants were clinically screened and monitored with implantable cardiac monitors. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/28904878/) (pubmed) - [DOI](https://doi.org/10.23876/j.krcp.2017.36.3.264) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5592894/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.