Cardiovascular Journal of Africa: Vol 29 No 5 (September/October 2018)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 5, September/October 2018 270 AFRICA
The reasons for seeking medical attention at the time of
diagnosis varied. These included palpitations (71%) (n = 30),
dizziness (64%) (n = 27), dyspnoea (45%) (n = 19), near blackouts
(40%) (n = 17), chest pain (21%) ( n = 9) and fatigue (21%) (n =
9). The mean duration of symptoms prior to presentation was
7.7 years.
Triggers included exertion 26% (n = 11) and alcohol
consumption (17%) (n = 7). Other triggers such as stimulant use,
caffeine, postprandial states and sleep were not well elucidated
on history in the medical records.
Complications of lone AF included stroke (10%) (n = 4) and
tachycardia-related cardiomyopathy (17%) (n = 7). No deaths
were recorded.
Therapy instituted included atrioventricular nodal blocking
agents, such as beta-blockers (60%) (n = 25), digoxin (29%)
(n = 12) and verapamil (14%) (n = 6). Often a combination of
beta-blockers and digoxin was used. Twenty one per cent of
patients (n = 9) required amiodarone. Twelve per cent (n = 5) had
radiofrequency ablation of the concomitant AF and one patient
had radiofrequency ablation of the atrial ectopic foci arising
from the pulmonary veins. Ten per cent of patients (n = 4) went
on to have an atrioventricular nodal ablation and permanent
pacemaker insertion because of inadequate rate control with
drugs. One patient was put onto flecainide and another onto
propafenone. Cardioversion was attempted at least once in 29%
(n = 12) of the patients.
Eighty per cent of patients ( n = 34) were on anticoagulant
therapy. Sixty-seven per cent (n = 28) of our subjects were on
warfarin and 26% (n = 11) were on aspirin. Eleven per cent (n =
3) had bleeding complications while on anticoagulation therapy
with warfarin. There was a 12% (n = 5) crossover between the
anticoagulants. Indications for warfarin included age over 75 years
(n = 2); age between 60 and 75 years (n = 8); tachycardia-related
cardiomyopathy (CHADS2 score 1) (n = 3); post stroke (CHADS2
score 2) (n = 3); possible or probable hypertension that developed
during follow up (CHADS2 score 1) (n = 6); and myocardial
infarction with heart failure (CHADS2 score 1) (n = 1) during
follow up. Two patients had no clear indication for warfarin.
Indications for aspirin included age over 75 years and
patient reluctance to be on warfarin (n = 1); tachycardia-related
cardiomyopathy (n = 1) (could not tolerate warfarin); and
possible or probable hypertension that developed over time (n =
1). Three patients who had bleeding complications on warfarin
were placed on aspirin. Two were placed on aspirin for less-
robust indications, such as dilated left atria. Three patients had
no clear indications for aspirin
Discussion
Fifteen per cent of the patients with AF presenting to the
Cardiac Clinic at GSH over a 15-year period had lone AF. This
finding is similar to other studies in which lone AF accounted for
three to 20% of cases of AF.2,3
As opposed to most studies, our study included patients
with lone AF over the age of 60 years at the time of diagnosis,
as this is more reflective of what we see in our clinical practice.
The male-to-female ratio of 1.3:1 was lower than that reported
in most studies. Those studies did not however include patients
over 60 years.2,4,9 If we excluded patients over the age of 60 years,
males comprised 70% (n = 24) and females 30% (n = 10). The
higher male-to-female ratio of 2.3:1 in patients under 60 years is
in keeping with that found in other studies. 2,4,9
If we excluded patients over the age of 60 years, the mean
age for male patients at diagnosis was 46 years, and 45 years for
females. The mean age for all patients under 60 years at diagnosis
was 45.5 years, which is comparable to the mean age of 44 years
found at the Mayo Clinic.2
This study is unique in that it included patients of various
racial backgrounds. Fifty per cent (n = 21) were white, 36% (n =
15) were of mixed race and 7% (n = 3) were black. Seven per cent
( n = 3) did not have their race specified. The differences mirror
access to tertiary healthcare afforded to the various racial groups.
Forty-three per cent (n = 18) of the patients were of normal
weight (body mass index < 25 kg/m2), 36% were overweight
(body mass index > 25 kg/m2) and 21% did not have their weight
specified. This is of interest as there are epidemiological studies
linking atrial fibrillation to obesity. 20-22 Postulated mechanisms
include the inflammatory state associated with the metabolic
syndrome, neurohormonal activation, autonomic dysfunction
associated with sleep apnoea, and increased left atrial size.10,11,16,20,21
It is intriguing to speculate that weight reduction may lower the
risk of atrial fibrillation in this group of patients.
As found in other studies, the majority of patients (50%)
( n = 21) had paroxysmal AF and 29% (n = 12) had permanent
AF. Twelve per cent (n = 5) progressed from paroxysmal to
permanent AF, which is slightly higher than the 7.8% reported
in the study by Patton et al.25
We also report on a subset of patients with lone AF and
concomitant atrial flutter. Seventeen per cent of these patients
(four males and three females) had one or more episodes of
documented atrial flutter at diagnosis or during follow up. This
is comparable to the 19.7% reported in the study by Patton et al.25
There was another subset of patients with structurally normal
hearts, AF and associated SSS (SSS/AF) or the bradycardia–
tachycardia syndrome. Twenty one per cent (n = 9) of our patients
had SSS/AF in comparison to the 6% reported in the study by
Patton et al.25 Seven of the nine patients had a permanent
pacemaker inserted. Five patients were female, of whom three
were older than 60 years. Interestingly, all three patients suffered
a thromboembolic event. Four patients were males, all younger
than 60 years.
Traditionally, the bradycardia–tachycardia syndrome (SSS/
AF) is considered to be a degenerative, age-related disorder.
Interestingly, it has recently been shown that AF and conduction-
system disorders tend to run in families and mutations in both
the lamin A/C and the ankyrin 2 genes have been associated with
this condition, 26 therefore prioritising these genes to be potential
candidates for further investigation into the likely aetiology of
this subtype of AF.
Triggers for symptoms of AF in our cohort included exertion
(27%) and alcohol consumption (17%). Our figures are lower
than that reported in the study by Paton et al.25 where patients
reported their episodes to be triggered by adrenergic states such
as alcohol consumption (34%) and exercise (36%).
Seventeen per cent (n = 7) of patients developed a tachycardia-
related cardiomyopathy. This is comparable with the 18% reported
in the study by Jahingir et al.4 Four of these patients presented
with symptoms and signs of heart failure, rapid AF (otherwise
normal ECG), left ventricular dilatation (otherwise normal echo),
and normal metabolic screen. Their symptoms and signs resolved