Forty nine patients with sick sinus syndrome seen at the University Hospital, Kuala Lumpur are reviewed. The ages of patients ranged from 17 to 85 years. There were 21 males and 28 females. The diagnostic criteria were sinus bradycardia in 8 patients (Group I), sinus arrest or sinoatrial block in 24 patients. (Group Il), and bradycardia tachycardia syndrome in 17 patiens (Group Ill). The aetiology was unknown in the majority of patients. Ischaemic heart disease was the commonest known aetiological factor. Patients with symptomatic sinus bradycardia and sinus arrest were initially treated with oral isoprenaline, and if this failed, they were paced. Temporary transvenous pacing was necessary in 27 patients and subsequent permanent pacing performed on 23 patients.
A retrospective study of the indications for temporary transvenous pacing in the University Hospital, Kuala Lumpur, from 1971 to 1979 is reviewed. There were 111 patients. The main indications for temporary transvenous pacing were, namely,complete heart block (57%), sick sinus syndrome (24%), Mobitz type 11 block (5%) and bifascicularblock (3%).
A prospective study to correlate clinical digoxin toxicity with serum digoxin levels was carried out in 67 patients of whom 24 were clinically toxic and 43 were asymptomatic. The patients were clinically diagnosed to be toxic based on typical cardiac arrhythmias (n = 11) or non-cardiac symptoms (n = 13). Blood samples were collected at least six hours after the last digoxin dose and the sera assayed for digoxin using a radioimmunoassay method. The mean serum digoxin level in the toxic group (x1 = 2.09 +/- 1.28 ng/ml) was significantly higher than in the non-toxic group (x2 = 1.20 +/- 0.75 ng/ml), p less than 0.01. All the non-toxic patients had serum digoxin levels below 3 ng/ml. However, there was a considerable overlap of serum digoxin levels between the two groups of patients. Serum level cannot be the sole criterion in diagnosing digoxin toxicity. Nevertheless, raised serum digoxin levels especially above 3 ng/ml, in the presence of suggestive clinical features is strongly suggestive of toxicity.