Unmasking Hypokinetic Non-Dilated Cardiomyopathy in sub-Saharan Africa: a Study of Ethnic Black African Population

Background: Hypokinetic non-dilated cardiomyopathy (HnDCM) is a less recognized cardiomyopathy phenotype characterized by global left ventricular (LV) systolic dysfunction without significant chamber enlargement. Sub-Saharan Africa lacks substantial data on this specific cardiomyopathy phenotype. To address this knowledge gap, a study was conducted to investigate the clinical, echocardiographic, electrocardiographic, and roentgenographic characteristics of 16 consecutive patients diagnosed with HnDCM in Sub-Saharan Africa. Methods: This prospective study included 16 patients with hypokinetic non-dilated cardiomyopathy (HnDCM) recruited over a 38-month period in Sokoto, Nigeria. Patients underwent clinical assessment, echocardiography, electrocardiography, and chest X-ray. Diagnosis was based on European Society of Cardiology (ESC) working group diagnostic criteria, which include left ventricular (LV) or biventricular global systolic dysfunction (defined as LV ejection fraction <45%) without LV dilatation, and absence of abnormal loading conditions such as (hypertension, valvular heart disease) or coronary artery disease (CAD). Results: The cohort was predominantly middle-aged (mean age 47.8 ± 16.25 years), with a slight female majority (56.25%). All patients presented with heart failure and reduced ejection fraction (<45%), with the majority (56.25%) presenting with left-sided heart failure. A significant proportion exhibited mild to moderate systolic dysfunction (93.75%) and diastolic dysfunction (62.5%). Structural abnormalities were common, including abnormal left ventricular mass index (LVMI) (62.5%) and geometry (68.75%). Significant valvular regurgitation was infrequent, and all patients had normal left ventricular end-diastolic diameter. Electrocardiographic abnormalities were prevalent, including sinus tachycardia (68.75%), ST segment depression (87.50%), T wave inversion (87.50%), prolonged QT (62.50%), and a QRS (RV6/R in I or II or III) voltage ratio of ≤ 3 (93.75%). Chest X-ray revealed cardiomegaly in 56.25% of patients and cardiogenic pulmonary edema in all patients. Conclusions: Hypokinetic non-dilated cardiomyopathy (HnDCM) is a significant cause of heart failure in SubSaharan Africa, often overlooked. Increased awareness and targeted research are needed to improve outcomes.