Author(s)

Valérie Ndobo^1,2*, Hilary Mongo¹, Christian Ngongang Ouankou^3,4, Pierre Mintom^1,5, Jean Tinmou Bekouti¹, Nelly Ateba⁶, Guillaume Ebene Manon^1,2, Sylvie Ndongo^1,4, Jérôme Boombhi^1,7

¹Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon.
²Cardiology Unit, Central Hospital of Yaoundé, Yaoundé, Cameroon.
³Faculty of Medicine and Pharmaceutical Sciences of the University of Dschang, Dschang, Cameroon.
⁴Internal Medicine Unit, Yaoundé University Hospital Center, Yaoundé, Cameroon.
⁵Regional Hospital Annex of Ayos, Ayos, Cameroon.
⁶Faculty of Medicine and Pharmaceutical Sciences of Ebolowa, Ebolowa, Cameroon.
⁷Cardiology Unit, Yaoundé General Hospital, Yaoundé, Cameroon.

Introduction: Heart rate variability (HRV), defined as fluctuations in the time intervals between successive heartbeats, was generated by the sinoatrial node and modulated by the autonomic nervous system (ANS). HRV emerged as a prognostic marker in chronic heart failure (CHF), particularly for mortality risk assessment in Western countries. This study aimed to evaluate the utility of HRV measurement in the follow-up of CHF patients in a sub-Saharan African context. Methods: We conducted a cross-sectional, descriptive, and analytical study during six months, in the cardiology departments of the Yaoundé General Hospital (HGY) and the Yaoundé Central Hospital (HCY). Eligible participants were adults with a confirmed diagnosis of CHF based on clinical, echocardiographic and electrocardiographic criteria, who had been on treatment for at least three months and provided informed consent. Exclusion criteria included atrial disease, non-sinus rhythm (atrial fibrillation, atrial flutter), loss to follow-up, and death. Consecutive sampling was applied. HRV recordings were obtained twice at a two-month interval using a Polar H10^® heart rate monitor connected via Bluetooth to the Elite HRV application installed on an iPhone 12 Pro Max. SDNN was the standard deviation of all normal-to-normal (NN) intervals, and RMSSD was Root Mean Square of Successive Differences. HF (High Frequency, 0.15 - 0.40 Hz) corresponds to respiratory sinus arrhythmia; R-R intervals were recorded at rest for 5 minutes. Treatment adherence was assessed and its relationship to HRV was explored. Data were entered using CS Pro^® 7.0 and analyzed with SPSS^® 23. Results: Thirty-one patients were included, with a median age of 64 years; women accounted for 54.8% of the sample. The most prevalent cardiovascular risk factors were dyslipidemia (38.7%) and alcohol consumption (34.6%). The leading etiologies of CHF were hypertensive cardiomyopathy and dilated cardiomyopathy, each representing 54.8% of cases. Left ventricular failure was present in 74.2%, and 61.3% had a left ventricular ejection fraction (LVEF) < 40%. The most commonly prescribed medications were ACE inhibitors (80.6%), beta-blockers (77.4%), and loop diuretics (77.4%). Non-adherence to treatment was reported in 45.2% (14/31) of participants. Patients with good adherence demonstrated significantly higher HRV indices at both time points, including SDNN [46.7 (37.3 - 54.4) ms; p < 0.050], RMSSD [58.6 (49.5 - 78.9) ms; p < 0.010], and HF power [708.2 (417.2 - 1020.0) ms²; p = 0.040]. Factors associated with HRV impairment found a borderline association with BMI: overweight/obese patients tended to have higher odds of HRV impairment (OR = 1.7, 95% CI: 0.4 - 7.4, p = 0.052); age ≤ 60 years (OR = 0.8, 95% CI: 0.4 - 8.1, p < 0.044) and Beta-blocker (OR = 0.5, 95% CI: 0.1 - 2.5, p = 0.030) use was associated with a lower risk of HRV alteration. Treatment with good adherence showed a significant association linked to a lower risk of HRV impairment (OR = 0.2, 95% CI: 0.0 - 1.3). Conclusion: This study confirms the potential of HRV as a complementary tool for the follow-up of CHF patients. HRV indices, particularly regarding young age, good weight and combined with treatment adherence assessment, may provide a cost-effective, non-invasive method to improve CHF management in resource-limited settings.

Chronic Heart Failure, Sinus Variability, Adherence, Cameroon

Ndobo, V. , Mongo, H. , Ouankou, C. , Mintom, P. , Bekouti, J. , Ateba, N. , Manon, G. , Ndongo, S. and Boombhi, J. (2025) Exploring the Role of Heart Rate Variability: A Study on Chronic Heart Failure Follow-Up in Two Major Hospitals in Sub-Saharan Africa. World Journal of Cardiovascular Diseases, 15, 537-550. doi: 10.4236/wjcd.2025.1511047.