A survey on the treatment of atrial fibrillation in South Africa.

BACKGROUND: The burden of cardiovascular disease is expected to escalate in developing countries. However, studies and guidelines concerning atrial fibrillation (AF) are restricted to the developed world. OBJECTIVES: To assess the treatment modalities of AF in South Africa. METHODS: A cross-sectional, observational, multicentre, national registry of the treatment of 302 patients with AF was conducted from February 2010 to March 2011. Specific drug use for rate or rhythm control, as well as drug use for stroke prevention, was surveyed. Events during the 12 months prior to the survey were also characterised, including non-drug treatments, resource utilisation and complications. RESULTS: The single most prevalent clinical characteristic was hypertension (65.9%). Rhythm control was being pursued in 109 patients (36.1%) with class Ic and class III antiarrhythmic agents, while rate control, mainly with beta-blockers, was pursued in the remainder of the patients. Concomitant use of other cardiovascular drugs was high, and 75.2% of patients were on warfarin for stroke prevention. There was a high burden of AF-related morbidity during the preceding year, with 32.5% reporting a history of heart failure, 8.3% a stroke and 5.3% a transient ischaemic attack. Therapeutic success, as defined by either the presence of sinus rhythm or rate-controlled AF, was achieved in 86.8% as judged clinically by the treating physician, but in only 70.2% according to the electrocardiogram criterion of heart rate ≤80 bpm. CONCLUSION: There were no striking differences from previously reported registries worldwide. The lack of application of strict rate control criteria is highlighted.

Mitral valve billow and prolapse: a brief review at 45 years - with reference to : mitral valve billowing and prolapse : perspective at 25 years.

Barlow's syndrome has become a regular, often-used and very often misused diagnosis. Its description followed extensive, prolonged and detailed clinical observation by JB Barlow and his co-workers. This major research effort was necessary because of the protean manifestations of the condition. The differentiation of Barlow's syndrome from other conditions with similar and sometimes identical symptoms requires clear and unambiguous criteria. These criteria were identified by penetrative clinical research. Consequently, it became possible to diagnose Barlow's syndrome with a high degree of specificity. Almost equally important were the gains made in understanding various conditions with similar symptoms but totally different management. An example of which, understanding some of the electrocardiographic patterns that emerge on effort in patients with ischaemic heart disease. Similarly, understanding mitral valve billow led to a greater knowledge of the entire pathophysiology of the mitral valve closure and important aspects of mitral regurgitation. Primary mitral valve billow, Barlow's syndrome, resulted from clinical research of the highest quality and has had a major application in clinical medicine.

The haemodynamic correlations of the cardiopulmonary flow index, a relatively non-invasive technique for diagnosis of myocardial pump insufficiency.

The cardiopulmonary flow index (CPFI) is the ratio of cardiopulmonary blood volume to stroke volume. OBJECTIVE. To compare the CPFI derived from a first-pass radiocardiogram and electrocardiogram with the usual haemodynamic measurements obtained by bedside catheterisation. DESIGN. Sixty-one patients in a coronary care unit who had flow-directed pulmonary artery catheterisation for clinical indications had a CPFI recorded together with the usual haemodynamic measurements and calculations. RESULTS. In patients with myocardial pump failure without significant pulmonary disease, linear regression analysis indicated that the best fit for the CPFI could be obtained with a model that used the inverse of stroke index and pulmonary capillary wedge pressure as independent variables. Ninety-six per cent of the variation in CPFI can be explained by variations in pulmonary capillary wedge pressure and stroke index. The CPFI correlated less well with these variables in patients with concomitant lung disease. CONCLUSION. The CPFI is a potentially useful and relatively non-invasive index of haemodynamic function in acutely ill patients without significant pulmonary disease.

Efficacy of oral sotalol in reentrant ventricular tachycardia.

Oral sotalol was given to 64 patients (78% postinfarction) with recurrent, reentrant ventricular tachycardia (VT) during an average follow-up period of 19.7 months. Fifty-nine (92%) patients had previously experienced recurrent ventricular tachycardia, in spite of having received an average of three conventional antiarrhythmic drugs (13 had previously failed on other Class III drugs). The nature and mechanism of the VT was proved with electrophysiologic testing (EPS), and the chronic sotalol dosage was determined by repeated EPS at 3- to 4-day intervals until the VT was no longer inducible. Sotalol failed in five patients and was discontinued in six patients because of severe side effects (three proarrhythmic effects, including two with torsades de pointes)--a total of 18%. Sotalol was successful alone in 42 patients (65%) and in combination with another antiarrhythmic drug in 11 patients (18%). The average dose of sotalol required for success was 589 mg; 658 mg was the mean daily dose when given alone and 486 mg when given in combination. Side effects were common and were due mainly to the beta-blocking effects of sotalol. Dual chamber pacing was required by 11 patients because of poorly tolerated bradycardia, and 14 patients remained symptomatic from worsening of the cardiac failure in spite of pacing, increased diuretics, or vasodilator therapy. The average drug dosage was the same for symptomatic (680 mg) and asymptomatic (627 mg) patients. Sotalol is a valuable antiarrhythmic drug for reentrant ventricular tachycardia. High doses are needed, and at these doses the beta-blocking activity is responsible for most of the side effects.

Atrial pacing and the risk for AV block: is there a time for change in attitude?

A literature survey was performed to establish the prevalence of second and third degree AV block among patients with permanent atrial pacemakers because of sinus node disease. This study reviews data from 28 different studies on atrial pacing with a median follow-up of 36 months. The collected data shows a median annual incidence of second and third degree AV block of 0.6%, range 0%-4.5% with a total prevalence of 2.1%, range 0%-11.9%. There was no significant difference in follow-up time between studies that showed a low, compared with a high incidence of AV-block. Patients with sinus node disease treated with atrial pacing have a low risk of developing clinically important conduction disturbances.

Flecainide acetate in the treatment of resistant supraventricular arrhythmias.

Thirty-one patients with a variety of supraventricular tachyarrhythmias resistant to conventional anti-arrhythmic therapy were treated with flecainide acetate, a new class Ic antiarrhythmic drug. The mean follow-up period was 7 months. Control was attained in 19 patients (62%) initially, and the long-term success rate was 39%. In 7 of the 19 controlled patients the drug was subsequently discontinued because of major side-effects, which included negative inotropism and pro-arrhythmia. The mechanisms and implications of these side-effects are reviewed.

Late potentials, ventricular stimulation and ventricular tachycardia.

Late potentials are depolarizations which arise from areas of delayed ventricular activation and may indicate a propensity for ventricular tachycardia. Sixty-four subjects were assessed by non-invasive measurement. Late potentials were not present in 20 subjects with normal hearts nor in 6 patients with cardiac disease but with no evidence of ventricular tachycardia (VT). Seventeen of 20 patients with recurrent sustained ventricular tachycardia (RSVT) and 2 of 10 patients with unsustained VT had late potentials. None of the 6 patients with automatic VT or the 2 patients with torsades de pointe had late potentials. In a subgroup of 28 symptomatic patients in whom programmed ventricular stimulation was performed, late potentials correlated with inducibility of sustained VT (P less than 0.05). Late potentials may therefore serve as a useful marker of RSVT and confirm a re-entrant mechanism of VT.

Intravenous acebutolol raises serum potassium in acute myocardial infarction.

Hypokalaemia commonly occurs in acute myocardial infarction (AMI) and may be caused by elevated serum levels of adrenaline, allegedly by beta 2-adrenergic mediated influx of potassium (K) into cells. We investigated the effect on serum K of intravenous acebutolol (a relatively beta 1-selective agent) in 50 patients with AMI. Serum K was measured before and 1 hour after drug administration. The same measurements were made in a comparable control group of 30 patients who did not receive the drug. Mean serum K rose from 3.58 to 3.81 mEq/l (P less than 0.005) in the treated group. No significant change occurred in the control group. The rise in serum K could not be correlated with prior beta-blocker therapy, zone of infarction, prior diuretic therapy, or gender of the patient. We conclude that the administration of intravenous acebutolol after AMI raises serum K, despite the fact that this beta receptor blocking agent is relatively beta 1-selective. Since hypokalaemia is associated with an increased risk of ventricular fibrillation, it should no longer be assumed from acute intervention trials with beta-blockers in AMI which had mortality or arrhythmias as end-points, that beneficial effects were necessarily due to limitation of infarct size or to a direct anti-arrhythmic action of the drugs. Future trials should take the effect on serum K levels into consideration.

Some aspects of neurological presentation of patients with important cardiac arrhythmias requiring pacemaker therapy: a preliminary report.

We report the short- and long-term effects of pacing on 82 patients presenting with significant bradyarrhythmias and neurological symptoms. The 3 categories of neurological symptoms were dizziness alone, syncope with or without dizziness and focal neurological symptoms with a history of dizziness or syncope.

Atrial trigeminy induced by a normally functioning DVI pacemaker.

Atrial trigeminy was seen in a patient with a normally functioning DVI pacemaker (Byrel-5992). Atrial competition resulted from coincidence of sinus and atrial escape rates together with late ventricular sensing. This resulted in atrial output stimuli occurring within the QRS complex. Alternate impulses occurred late enough to conduct to the ventricle after recovery of the AV node. Reprogramming the pacemaker to either a faster DVI rate or to VVI abolished the arrhythmia.