Related Experiment Video
Updated: May 13, 2026
Calculating Heart Rate Variability from ECG Data from Youth with Cerebral Palsy During Active Video Game Sessions
Published on: June 5, 2019
[Heart rate variability: analysis of time-domain indices in patients with chronic Chagas disease before and after an
Marcus Vinicius Amaral da Silva Souza1, Carla Cristiane Santos Soares, Juliana Rega de Oliveira
1Instituto Nacional de Cardiologia, Setor de Reabilitação Cardíaca, Rio de Janeiro, Brasil. souza.mv@globo.com
Insights
Cardiac rehabilitation did not significantly improve heart rate variability in Chagas cardiomyopathy patients. Further research is needed to understand exercise benefits for Chagas disease (CD) and chronic Chagas cardiomyopathy (CCC).
Area of Science:
- Cardiology
- Infectious Diseases
- Physiology
Context:
- Chagas disease (CD), caused by Trypanosoma cruzi, leads to chronic Chagas cardiomyopathy (CCC) affecting myocardial fibers.
- Dysautonomia is common in CCC, impacting heart rate variability (HRV).
- Exercise has shown benefits in congestive heart failure (CHF), potentially improving autonomic tone.
Purpose:
- To assess autonomic function in CCC patients with dysautonomia after a cardiac rehabilitation program.
- To determine if rehabilitation reduces daytime SDNN and increases daytime/nighttime pNN50 and rMSSD levels.
- To evaluate HRV parameters before and after a six-month supervised exercise intervention.
Summary:
- A six-month supervised exercise program was implemented for 18 CCC patients with dysautonomia.
- Time-domain HRV indices (SDNN, pNN50, rMSSD) were analyzed via 24-h Holter monitoring before and after the program.
- No statistically significant changes in HRV parameters were observed post-rehabilitation.
Impact:
- The study found no significant HRV improvements in CCC patients after a six-month cardiac rehabilitation program.
- Potential factors for non-significant results include large standard deviations, poor adherence, low socioeconomic status, small sample size, and short program duration.
- Further investigation is warranted to optimize exercise protocols for managing autonomic dysfunction in chronic Chagas cardiomyopathy.
Unlabelled:
Chagas disease (CD) is an infection caused by the protozoan flagellate Trypanosoma cruzi, and transmitted by insects of the genera Triatoma, Rhodnius and Panstrongylus. The heart is affected to varying degrees by inflammatory and destructive lesions in atrial and ventricular myocardial fibers. Several studies have demonstrated the benefits of exercise in patients with congestive heart failure (CHF), including reduced sympathetic tone and increased parasympathetic tone, the result of reduced epinephrine and norepinephrine levels, both at rest and during exercise, including at submaximal levels. It has been hypothesized that the increase in sympathetic arousal during exercise improves peripheral muscle metabolism.
Objectives:
The objectives of this study were to select patients with chronic Chagas cardiomyopathy (CCC) with dysautonomia on 24-h Holter monitoring, assess autonomic function after rehabilitation, and determine whether it resulted in reduced daytime levels of SDNN and increased daytime and nighttime levels of pNN50 and rMSSD.
Methods:
We analyzed time-domain indices of heart rate variability through 24-h Holter monitoring before and after a supervised exercise program. We studied 18 CCC patients (five men), mean age 57.33±9.73 years, followed at the CD outpatient clinic of the National Institute of Cardiology and IPEC/Fiocruz in Rio de Janeiro, Brazil, between April 2009 and November 2010. The following tests were used to assess the severity of CCC: clinical examination, functional evaluation by cardiopulmonary stress testing, electrocardiogram and conventional Doppler echocardiography. The exams were performed within a month of the start and end of the exercise program, which consisted of 60-min sessions of aerobic exercise on a treadmill and resistance training three times a week for six months. The goal was to reach the patients' heart rate target zone during training, and their rating of perceived exertion was assessed by the modified Borg scale.
Results:
There were no statistically significant differences (p>0.05) in SDNN, pNN50 and rMSSD, probably due to the large standard deviation observed, patients' poor adherence to the program and their low socioeconomic status, resulting in a small sample, and the short duration of the program.
Conclusion:
Heart rate variability parameters in patients with CCC did not undergo statistically significant changes after a six-month cardiac rehabilitation program.
More Related Videos
Related Concept Videos
01:30Factors Influencing Heart Rate
Let us explore the significant factors affecting heart rate, including age, body temperature, posture, acute pain, chemical influences,...
01:30Acute Coronary Syndrome III: Diagnostic Studies
01:19Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart rate...
01:26Exercise Stress Test
Exercise stress testing, commonly known as a treadmill test, is a noninvasive procedure used to evaluate cardiovascular function and diagnose heart conditions.
Definition
An exercise stress test measures the heart's response to exertion using a treadmill or stationary bicycle. Chest electrodes record the heart's electrical activity through an ECG, and blood pressure is monitored regularly.
Purposes
01:26Heart Failure III: Clinical Manifestations
01:25Correlation between ECG and Cardiac Cycle
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...