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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 3, May/June 2018
140
AFRICA
Keywords:
valvular, atrial fibrillation, heart failure, sub-Saharan
Africa
Submitted 16/9/16, accepted 19/11/17
Cardiovasc J Afr
2018;
29
: 139–145
www.cvja.co.zaDOI: 10.5830/CVJA-2017-051
Rheumatic heart disease (RHD) remains an important cause of
heart failure in sub-Saharan Africa (SSA),
1,2
and RHD associated
with valvular atrial fibrillation (AF) is also common on the
continent.
3
Among the regions enrolled in the Randomised
Evaluation of Long-Term Anticoagulation Therapy in Atrial
Fibrillation (RE-LY-AF), a global prospective registry that
enrolled patients presenting to an emergency department with
AF, RHD was present in 22% of African patients compared with
2% of North American patients.
3
The risk of AF increases multiple-fold in the presence of heart
failure (HF) and valvular disease.
4
The prognostic influence of
the presence of AF in HF remains controversial, with some
studies illustrating an independent adverse effect on mortality
rate.
5,6
In a recent meta-analysis of 16 studies comprising more
than 50 000 patients with chronic HF, Mamas and colleagues
showed that AF was associated with an adverse effect on total
mortality rate.
7
From a cohort of 1 006 African patients admitted with acute
heart failure (AHF) and enrolled in the sub-Saharan Africa
Survey of Heart Failure (THESUS-HF) registry, we analysed
the burden, clinical characteristics and outcomes of AF in
general and valvular AF in particular among acute HF patients
in sub-Saharan Africa.
Methods
THESUS-HF was a prospective, multicentre, international
observational survey of acute HF in 12 cardiology centres
from nine countries in sub-Saharan Africa.
2
All participating
centres had a physician trained in clinical cardiology and
echocardiography.
Patients, who were older than 12 years, admitted with
dyspnoea as the main complaint, and diagnosed with acute
HF based on symptoms and signs that were confirmed by
echocardiography (
de novo
or decompensation of previously
diagnosed HF), were enrolled consecutively. Patients excluded
were those with acute ST-elevation myocardial infarction, severe
known renal failure (patients undergoing dialysis or with a
creatinine level of
>
4 mg/dl), nephrotic syndrome, hepatic failure
or another cause of hypoalbuminaemia.
Written informed consent was obtained from each subject
who was enrolled into the study. Ethical approval was obtained
from the ethical review boards of the participating institutions,
and the study conformed to the principles outlined in the
Declaration of Helsinki.
Details of data collection have been previously described.
2
In brief, we collected demographic data, detailed medical
history, vital signs (blood pressure, heart rate, respiratory rate
and temperature), and signs and symptoms of HF (oxygen
saturation, intensity of oedema and rales, body weight and levels
of orthopnoea). Assessments were done at admission and on
days one, two and seven (or discharge if earlier).
Electrocardiograms were done and read using standard
reference ranges. All ECGs were read centrally at the Momentum
Research Inc by one cardiologist and reviewed by a second
cardiologist. ECGs were analysed for conduction or rhythm
disturbances, evidence of myocardial ischaemia/infarction or
hypertrophy. AF was defined as either a history of documented
AF or a finding of AF on the admission ECG. The information
obtained was entered in the database registry together with other
clinical data.
A detailed echocardiographic assessment of ventricular
contractility, valvular structure and function, as well as regional
wall abnormalities was performed. All echocardiographic
procedures were undertaken by trained physicians, and
measurements were made according to the American Society of
Echocardiography Guidelines.
8
The probable primary cause of
HF was provided by the investigators, based on the European
Society of Cardiology (ESC) guidelines
9
as recently applied in
the chronic HF cohort of the Heart of Soweto Study.
10
RHD
was defined based on clinical and echocardiographic criteria.
11,12
Information on readmissions and death, with respective reasons
and cause, was collected over the six-month follow up. Outcomes
of interest were readmission or death within 60 days, and death
within 180 days.
Laboratory evaluations provided by the local institutions and
intravenous and oral medications were recorded at admission,
and on days one, two and seven (or discharge if earlier).
Vital signs (blood pressure, heart rate, respiratory rate and
temperature), and signs and symptoms of HF (including oxygen
saturation, intensity of oedema and rales, body weight, levels of
orthopnoea) were assessed at the same time points. Changes in
dyspnoea and well-being relative to admission were assessed on
days one, two and seven (or discharge if earlier).
Subjects who were discharged after admission were evaluated
at one and six months’ follow up. At these time points, patients
were evaluated for signs and symptoms of HF, laboratory
evaluations were performed, and oral medications recorded.
Readmissions and death, with respective reasons and cause, over
the six months of follow up were collected.
Statistical analyses
All data were processed at the central coordinating centre at
MomentumResearch, Durham, North Carolina, USA. Data were
analysed with the use of SAS version 9.3 (SAS Institute, Cary,
North Carolina). Summary statistics (mean, SD, median, and
25th and 75th percentiles) are provided for continuous variables
and frequencies for categorical variables. Unless otherwise stated,
a chi-squared test was used for categorical variables, the Cochran–
Mantel–Haenszel test for ordinal variables, and Wilcoxon test for
continuous variables to examine comparisons between groups.
AF classification was based on subjects either having a
history of AF or the presence of AF on an ECG taken at
admission. Baseline characteristics by AF status are presented,
as well as characteristics between patients with valvular
and non-valvular AF. Comparisons between valvular and
non-valvular AF patients are presented to examine differences
in the following outcomes: length of index hospitalisation, time
to first rehospitalisation within 60 days, all-cause mortality
within 180 days, and the composite endpoint of time to all-cause
mortality or rehospitalisation within 60 days.