Cardiovascular Journal of Africa: Vol 24 No 2 (March 2013)

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CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 2, March 2013 AFRICA 7
patients less than 65 years of age, and without structural cardiac
abnormalities. Patients who had not completed 12 months since
the index AF event at the six-month follow up were classified
as having ‘incomplete follow up’ for the purposes of our study.
We used the CHADS2 scoring system9 to stratify patients for
prediction of thrombo-embolic (TE) and stroke risk. This scheme
has been validated, although not in African patients, to provide a
predictive value of TE risk. A score of ≥ 2 predicts a significant
TE risk, warranting anticoagulation, while a score of 0 or 1
predicts moderate risk, favouring anticoagulation over aspirin.
A comprehensive two-dimensional transthoracic
echocardiography with pulsed- and continuous-wave Doppler
and colour-flow velocity spectral imaging was performed to
determine the severity of valvular heart disease in only patients
with clinical signs suggestive of valvular heart disease. Patients
with echocardiographic moderate to severe mitral or aortic
stenosis, or moderate to severe aortic and mitral regurgitation
were classified as having valvular heart disease. Patients with
either mitral stenosis, or combined mitral stenosis and aortic
regurgitation were labelled as having rheumatic heart disease
(RHD).
All continuous variables are expressed as mean ± standard
deviation. Categorical variables are expressed as percentages.
Results
In this survey, 162 patients from 22 144 general hospital
medical admissions were recruited over a 36-month period.
Their baseline characteristics are given in Table 1. Ninety-five
per cent of the patients recruited had AF, with the rest having
AFL. The mean age at presentation was 67 years, with incidence
increasing with age and peaking at the age bracket 70–100 years,
as described in Table 1.
In terms of haemodynamics at presentation, 5% presented
with hypotension (systolic blood pressure: SBP ≤ 90 mmHg),
and 46% with a rapid heart rate (resting heart rate ≥ 90 beats/
min). Thirty-two per cent of the patients presented to hospital
due to symptoms related to their rapid heart rate (palpitations,
dizziness, syncope and fatigue), 17% had congestive heart
failure, 15% thrombo-embolic events (transient ischaemic attack,
cerebrovascular accident, other embolic events), 8.3% for other
surgical indications, and 1.9% due to acute coronary syndrome
and major bleeding, respectively.
Hypertension (68%), heart failure (38%), diabetes mellitus
(33%) and coronary artery disease (19%) were the commoner
underlying predisposing factors; valvular heart disease (12%),
chronic obstructive airway disease (7%), excess alcohol
intake (5%) and hyperthyroidism (3%) accounted for the
other predisposing risk factors of atrial fibrillation. Only six
(32%) of the 19 patients who had valvular heart disease had
echocardiographic evidence of rheumatic heart disease.
Rate control was the more preferred strategy for management
of arrhythmia (78.4%), while the remainder were managed with
a rhythm-control approach. The choice of both rate- and rhythm-
control agents is summarised in Table 2. Amiodarone was the
only agent used for chemical cardioversion, while direct-current
cardioversion was opted for in 37.1% of the patients in the rhythm
strategy. AF ablation was not performed in any of the patients, as
this modality of rhythm control is not locally available.
For stroke risk categorisation, 18.6, 16.7 and 64.7% of the
patients had a CHADS2 score of 0, 1 and ≥ 2, respectively. Of
the patients with a CHADS2 score ≥ 2, 21.2% did not receive
any form of anticoagulation, with the majority being on aspirin.
Of the patients with a CHADS2 score between 0 and 1, 36.4%
TABLE 1. BASELINE CHARACTERISTICS
Mean age (years) 67.8 ± 17.1
Incidence by age bracket (years )
18–30 (%) 3.1
31–50 (%) 13.0
51–70 (%) 26.9
71–100 (%) 57.0
Race
Native Africans 46.8
Asians 30.7
Caucasians 22.5
AF:AFL 19:1
Male: female 1.27:1
SBP at diagnosis (mmHg) 131 ± 28
DBP at diagnosis (mmHg) 78 ± 16
Heart rate at diagnosis 95 ± 35
BMI 27.2 ± 5.8
AF subtype
Paroxysmal (%) 40
Persistent (%) 13.5
Permanent (%) 40
Incomplete follow up (%) 6.5
Reason for presentation
AF/AFL (%) 32.1
Heart failure (%) 17.3
TE event (%) 15.5
Sepsis (%) 13.6
Other (%) 21.5
Risk factors
Hypertension (%) 68
Heart failure (%) 38
Diabetes mellitus (%) 33
Coronary artery disease (%) 19
Valvular heart disease (%) 12
SBP: systolic blood pressure, DBP: diastolic blood pressure, TE: throm-
bo-embolic event.
TABLE 2. RHYTHM MANAGEMENT STRATEGY
Management strategy
Rate control (%)
(n = 127/162)
Rhythm control (%)
(n = 35/162)
Digoxin alone 38 (29.9) –
BB alone 36 (28.3) –
BB + digoxin 32 (25.2) –
CCB 10 (7.8) –
Amiodarone alone 3 (2.3) 9 (25.8)
BB + amiodarone 4 (3.1) –
BB + CCB 2 (1.7) –
CCB + digoxin 2 (1.7) –
Spontaneous cardioversion – 13 (37.1)
DC cardioversion – 13 (37.1)
BB: beta-blockade, CCB: non-dihydropyridine calcium channel blockers,
DC: direct current.