CARDIOVASCULAR JOURNAL OF AFRICA • Volume 35, No 2, May – August 2024 90 AFRICA Ethical Principles for Medical Research Involving Human Subjects (http://www.wma.net/en/30publications/10policies/b3/index. html.pdf Accessed 08/02/2014) (revised October 2013). Ethics approval and clearance was obtained from the University of the Witwatersrand human research ethics committee, clearance certificate number: M180811. All patients above 18 years of age with native MVD formed part of the study. Patients with previous mitral valve (MV) repair were included. Patients with prosthetic mitral valves, congenital VHD, non-dominant MVD and functional lesions were excluded. Demographic information, co-morbidities and relevant past cardiovascular symptoms and systemic enquiries for all enrolled patients were retrieved from the patient file records on the day of their routine clinic visit, as the files are kept with the patients and not at the cardiac clinic. Echocardiographic and electrocardiographic (ECG) data were also collected from patient files. In cases where information was insufficient, patients were interviewed prospectively. Examination not done routinely in the clinic, such as weight and height, were done prospectively after obtaining the patient’s consent. Transthoracic echocardiography was performed on all patients in the left lateral position by trained technicians using a S5-1 transducer on a Philips iE33 system (Amsterdam, The Netherlands) during routine clinic visits. All images and echocardiographic measurements were interpreted and reported by the attending cardiologist as per standardised guidelines on chamber quantification and VHD assessment and quantification of severity.10-12 As per the current heart failure (HF) guidelines, preserved left ventricular ejection fraction (LVEF) was described as an EF above 50%. Severe LV systolic dysfunction was stipulated as an EF below 40%. An EF between 40 and 49% was defined as mid-range.13 For MR, a LVEF of ≤ 60% was considered significant as per VHD guidelines.14 Pulmonary artery systolic pressure (PASP) was estimated from the peak velocity of the tricuspid regurgitation jet plus the estimated right atrial pressure. Patients with PASP ≥ 30 mmHg were classified as mild (< 50 mmHg), moderate was 50–79 mmHg and severe was ≥ 80 mmHg pulmonary hypertension.15 The MV was considered of rheumatic aetiology when there was a previous history of ARF and echocardiographic evidence of chordal thickening, thickened anterior mitral leaflet, calcification and excessive leaflet motion in systole as per the World Heart Federation criteria.10 ARF was diagnosed on the basis of clinical manifestations (carditis, arthritis, chorea, erythaema marginatum, subcutaneous nodules) supported by laboratory tests (for a preceding group A streptococcal infection) and echocardiography as per the revised Duckett Jones 2015 recommendations for a moderate- to highrisk population.16 A standard 12-lead ECG recording or a single-lead ECG tracing of ≥ 30 seconds showing heart rhythm with no discernible repeating Pwaves and irregular RR intervals (when atrioventricular conduction is not impaired) is diagnostic of clinical AF. ECG documentation is required to establish the diagnosis of AF.17 Surgical intervention included previous percutaneous mitral balloon valvotomy patients (where the Wilkins score was favourable). Patients with previous MV repair were also included. Prosthetic MV patients were excluded from this study. Statistical analyses Statistical analyses were performed with Statistica version 13 series 0414 for Windows. Descriptive statistics were used in the data analysis. Continuous variables are shown as mean ± standard deviation for data that was normally distributed. The median analyses were used for non-parametric distributions. Categorical variables are demonstrated as frequencies and percentages. Results Ninety-six per cent of the patients were of African ancestry. The group of patients with MVD were older and had numerous co-morbidities. The majority of patients were overweight and 36% were obese with a body mass index > 30 kg/m2. All retroviral disease (RVD)-positive patients were on appropriate antiretroviral treatment regimens. Only 11% of patients were on penicillin prophylaxis for rheumatic fever. Most patients were on medical therapy for HF and heart rate control. Thirty-one per cent of patients were on an anticoagulation for AF (Table 1). Table 1. Demographic and clinical characteristics of patients with MVD Characteristics Study patients (n = 134) Age (years), mean ± SD 50 ± 13.3 Gender, n (%) Female 103 (77) Male 31 (23) Body mass index (kg/m2), mean ± SD 29 ± 3 Heart rate (bpm), mean ± SD 75 ± 17 Systolic blood pressure (mmHg), mean ± SD 127 ± 21 Diastolic blood pressure (mmHg), mean ± SD 77 ± 12 Race, n (%) African 128 (96) Mixed ancestry 3 (2) Indian 3 (2) Clinical indices NYHA functional class, n (%) I 58 (43) II 71 (54) III 5 (3) IV 0 (0) Heart failure hospitalisation, n (%) 1 admission 104 (78) 2 admissions 17 (12) 3 or more admissions 13 (10) Co-morbidities, n (%) Hypertension 40 (30) Type 2 diabetes mellitus 6 (4) Graves/hyper-/hypothyroidism 6 (4) HIV 16 (12) Cerebrovascular accident/TIA 10 (7) Arrhythmias 3 (2) Medication, n (%) HAART 16 (12) Penicillin prophylaxis 14 (11) Furosemide 126 (94) Aldosterone receptor antagonist 64 (47) Angiotensin converting enzyme inhibitor 85 (63) Carvedilol or atenolol 75 (55) Amlodipine 51 (38) Warfarin 41 (31) Digoxin 55 (41)
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