Study population and design
This retrospective, descriptive and observational registry reviewed the echocardiographic findings of patients aged 0–100 years who were presented to our outpatient cardiology clinic at a tertiary training hospital in Mogadishu, between January 1, 2019, and January 1, 2020. Overall, 6782 subjects admitted to the hospital were screened. 5642 individuals who had incomplete, unreliable data and/or those with completely normal echocardiographic findings were excluded from the analysis (Fig. 1). Accordingly, a total of 1140 patients with abnormal echocardiographic findings by age group and gender were enrolled in the study. Demographic characteristics and echocardiographic parameters including left ventricular ejection fraction (LVEF), interventricular septum thickness, left ventricular (LV) diastolic dysfunction grade, mitral valve insufficiency/stenosis, and rheumatic, and congenital heart diseases were analyzed for each participant. Echocardiographic evaluations were performed by experienced echocardiographers who were licensed in Turkey using a Toshiba Aplio™ ultrasound system (TUS-A500, Shimoishigami, Japan) in accordance with the American Society of Echocardiography guidelines [7]. Those aged 15 and under were defined as children. Age- and gender-based distributions of acquired, congenital, and rheumatic heart diseases were reported. Those with tuberculosis (active or previous) were evaluated together, regardless of whether they received treatment or not. The study was conducted according to the Helsinki Declaration. Ethical approval was obtained from the local ethics committee (date: 17.02.2021, decision no: 323). The need for informed consent was waived due to the retrospective nature of the study.
Normal echocardiography was defined as echocardiographic evaluation in which bi-ventricle (both in size and function) and valves are within normal ranges by gender and age group [8, 9].
Hypertensive heart disease (HHD) was diagnosed in the presence of signs of heart failure or criteria for concentric/eccentric LV hypertrophy (wall diameters, cavity size, and left ventricular mass index in echocardiography [10] or diagnostic electrocardiography (ECG) parameters [11]), left atrial enlargement (anteroposterior diameter, left atrial volume index measured by echocardiography or left atrial dilatation criteria on ECG), and/or presence of at least one of the following parameters; (a) severe left ventricular diastolic dysfunction (E/e’ > 14), (b) left ventricular systolic dysfunction (LVEF < 50%), (c) systolic pulmonary arterial hypertension > 60 mmHg, (d) valvular insufficiency (mitral or tricuspid) considered not to be caused by valvular heart disease (VHD) and/or acute ischemic heart disease, for known or newly diagnosed hypertensive patients (blood pressure > 140/90 mmHg).
Valvular heart disease (VHD) was defined as an obvious function and size abnormality with the calculation of velocity (m/s), gradient (mmHg), and area (cm2) for stenotic valves and with the interpretation of qualitative (valve morphology, colour flow, and holodiastolic flow reversal in descending aorta), semiquantitative (vena contracta width, pressure half time), and quantitative (regurgitant volume, effective regurgitant orifice area) measurements for valve insufficiency in at least one of the heart valves according to European Society of Cardiology guidelines for the management of valvular heart disease [12].
Rheumatic heart disease (RHD) was diagnosed in accordance with the 2012 World Heart Federation criteria for echocardiographic diagnosis of RHD [13]. Criteria include pathological (seen in two views, jet length, velocity, pan-systolic/pan-diastolic jet in at least one envelope) and morphological features (thickening, restricted leaflet motion, prolapse, coaptation defect, excessive leaflet tip motion) for valve regurgitation, and a gradient increase of ≥ 4 mmHg in mitral stenosis.
Ischemic heart disease (IHD) was diagnosed in patients with angina pectoris (current or past), previous myocardial infarction, and/or documented coronary artery disease, or an ECG feature indicating a previous myocardial infarction and/or a regional wall motion abnormality suggestive of myocardial infarction detected in echocardiography.
Dilated cardiomyopathy (DCMP); LV or biventricular systolic dysfunction and dilatation that are not explained by abnormal filling conditions, regardless of being primary or secondary. Systolic dysfunction is defined by abnormal LVEF < 45%, and LV dilatation is defined by LV end-diastolic diameters > 2 standard deviations from normal according to normograms corrected by body surface area and age [14].
Hypertrophic cardiomyopathy (HCMP) was defined as unexplained maximal wall thickness > 15 mm in any LV myocardial segment or presence of LV septal/posterior wall thickness ratio > 1.3 in normotensive patients and > 1.5 in hypertensive patients [15, 16]. Since HCMP patients in our study were adults, both thresholds were applied to all of them.
Pericardial effusion was diagnosed in the presence of an echo-free space between the visceral and the parietal pericardium. The classification was as follows: mild (< 10 mm), moderate (10-20 mm), and severe (> 20 mm).
Constrictive pericarditis was diagnosed with the help of conventional imaging methods (chest X-ray and computerized tomography-thickened, calcified, fibrotic pericardium-) and certain echocardiographic findings (including respirophasic ventricular septal shift-septal bounce-, hepatic vein diastolic flow reversal with expiration, preserved/exaggerated medial mitral annulus early diastolic (e′) velocity of ≥ 9 cm/s, at least > 25% respiratory variation of peak mitral E-wave velocity, and medial e′/lateral e′ ≥ 0.91), together with the symptoms and signs of heart failure.
Heart failure with reduced EF (HFrEF) was diagnosed in the presence of risk factors, abnormal ECG, clinical signs (e.g. elevated jugular venous pressure, hepatojugular reflux, laterally displaced apical impulse), and/or symptoms (e.g. reduced exercise tolerance, paroxysmal nocturnal dyspnea, breathlessness, orthopnoea) of heart failure, along with a reduced EF of < 50% assessed by echocardiography. Subjects with an LVEF between 41 and 49% were defined as mildly reduced LV systolic dysfunction [17].
Diastolic dysfunction, which refers to impaired LV relaxation, with or without an increase in filling pressure, was categorized into 4 grades. Grade I (mild diastolic dysfunction: E/A < 0.8, deceleration time (DT) > 200 ms, average E/e′ ≤ 8), grade II (moderate diastolic dysfunction or pseudonormal phase: E/A 0.8–1.5, DT 160–200 ms, average E/e′ 9–12), grade III (severe diastolic dysfunction or reversible restrictive filling phase: E/A ≥ 2, DT < 160 ms, average E/e′ ≥ 13), and grade IV (irreversible/fixed restrictive filling phase: as grade III with no benefit from a reduction of preload) [18].
Pulmonary arterial hypertension was defined as the presence of systolic pulmonary artery pressure (SPAP) ≥ 2.8 m/sec or ≥ 36 mmHg in echocardiography, in addition to symptoms and other findings that are associated with pulmonary hypertension [19].
Statistical analysis
Statistical analyses were performed using IBM SPSS Statistics for Windows Version 20.0 (Armonk, NY: IBM Corp.). The normality of continuous variables was assessed by analytical (Kolmogorov–Smirnov test) and visual methods (histograms and probability plots). All continuous variables were expressed as median (interquartile range [IQR]) due to the presence of abnormal distribution. Categorical variables were expressed as number (n) and percentage (%). Continuous variables were compared using the Mann–Whitney U test and categorical variables were compared using the χ2-test or Fisher’s exact test, where appropriate. A two-tailed p value of < 0.05 was considered significant throughout the study.