The correlation of the computer quantitated treadmill exercise electrocardiogram with cinearteriographic assessment of coronary artery disease.

One hundred and twenty-five consecutive patients being submitted for coronary cinearteriography were subjected to preliminary graded exercise testing using a Quinton treadmill and ECG data computer. Patients with disease of the left main coronary artery are at particular risk during coronary arteriography and it was hoped that exercise testing might identify these patients. This hope was not realised. A satisfactory end point to the exercise test was either the attainment of 85% of the maximal heart rate assessed for age, or ST segment depression greater than 2 mm. Exercise induced angina also formed an end point to the test and was considered a positive result. Results were determined by McHenry's discriminant analysis. The sensitivity of the exercise test was 66, 88 and 92% for one, two and three vessel disease respectively. Specificity was at least 83%. Exercise induced ST segment elevation occurred in four patients all of whom had previous extensive anterior wall infarction. Exercise testing is without risk in patients with ischaemic heart disease provided well defined precautions are taken.

The prevalence of disturbance of cardiac rhythm in healthy New Zealand Adults: a pilot study.

Continuous portable 24-hour tape recorded monitoring of the electrocardiogram in 189 healthy adults was used to provide data about dysrhythmia during normal daily activity. The age of the subjects ranged from 20 to 70 years and the mean age was 44. One hundred and forty-eight were less than 50 years of age. Dysrhythmia, mainly asymptomatic, occurred in 71 subjects (37 percent). In 31 (16 percent) it was ventricular, in 20 (10.5 percent) it was supraventricular and in a further 20 (10.5 percent) it was combined. In 12 (6.3 percent) ventricular ectopy was considered potentially serious. It was not more prevalent in smokers. This study shows a lesser number of normal subjects with dysrhythmia than in most other reported studies.

Rheumatic fever and streptococci: the Wairoa College study.

The decline in incidence of rheumatic fever seen in many countries is not evident in New Zealand. Wairoa county has the highest hospital admission rate within New Zealand, 232 per 100 000 per year, five times the national average, 43 per 100 000. Studies in Wairoa included a cross-sectional survey of the local secondary school. Throat swabbing yielded 13.6% of subjects positive for beta-haemolytic streptococcus group A. Boys had a higher rate than girls, and girls aged 14 and over had a lower rate than younger girls. Discriminant analysis failed to identify ethnic, social or geographic factors as contributing to positivity. Sibling concordance was not significant. ASO titres were high in comparison with another New Zealand study (Rotorua Lakes). There was an association between high ASO titre and throat swab positive for group A and group C streptococci. The prevalence of definite rheumatic fever and rheumatic heart disease was established as 11/715 (1.5%). A wide range of residential geographic, climatic and socioeconomic factors failed to discriminate between cases and noncases. Ethnicity alone was a significant discriminator, the cases being more Maori than noncases.