Correlation of the standard electrocardiogram and continuous ambulatory monitoring in the detection of ventricular arrhythmias in coronary patients

Ventricular arrhythmias during exercise testing and 24-hour ECG tape recording in patients with ischaemic heart disease and in normal individuals

The occurrence of ventricular arrhythmias (VA) during resting ECG, maximal bicycle exercise testing and 24-hour ECG tape recording (24-ETR) was studied in 24 patients and 24 matched normal persons. The patients were on treatment with beta-receptor blocking agents or verapamil for ischaemic heart disease (IHD), verified by coronary angiography. The matched persons showed no signs of heart disease. VA did not occur in any of those studied on a 60-second resting ECG. During exercise testing, one patient and six normal subjects had VA. During 24-ETR, VA were found in 16 patients and 11 normal persons. The maximum heart rate during exercise and the average heart rate during ETR did not differ significantly between individuals with and without VA in the groups of patients and normal subjects, respectively. It is concluded that in IHD patients receiving beta-blocking agents or verapamil, 24-ETR is a more reliable indicator of VA than exercise ECG testing. In normal individuals the two methods are of similar value.

Predictive value of continuous ambulatory electrocardiographic monitoring in elderly people

OBJECTIVE

To determine the predictive value of findings on continuous ambulatory electrocardiographic monitoring in elderly subjects.

DESIGN

Retrospective cohort study. Ten year follow up of randomly selected elderly subjects who participated in ambulatory electrocardiography study in 1982. Mortality data derived from official registers.

SETTING

Turku, Finland.

SUBJECTS

480 people aged 65 or older in 1982 who were living in the community, of whom 72% agreed to participate.

MAIN OUTCOME MEASURES

Mortality from cardiac and non-cardiac causes during 10 year follow up.

RESULTS

In the univariate analysis adjusted for age, risk of death from cardiac causes was increased among those with ventricular ectopy of more than 100 beats during the day (odds ratio 2.6; 99% confidence interval 1.4 to 6.1) or at night (3.3; 1.1 to 9.8) and in those with multifocal ventricular ectopic beats during the day (2.3; 1.0 to 5.0) or night (3.0; 1.3 to 7.1) compared with those with no ventricular ectopy. Sinoatrial pauses exceeding 1.5 seconds during the day (4.5; 1.8 to 11.1) were also associated with excess mortality from cardiac causes. None of the findings on ambulatory electrocardiography predicted death from non-cardiac causes. A further study of explanatory variables in the stepwise logistic regression analysis showed that sinoatrial pauses exceeding 1.5 seconds (4.0; 95% confidence interval 1.8 to 8.9) and night time multifocal ventricular ectopy (2.7; 1.2 to 5.9) predicted excess mortality from cardiac causes independently of age or clinically evident heart disease.

CONCLUSION

Daytime sinoatrial pauses exceeding 1.5 seconds and night time multifocal ventricular ectopy in the ambulatory electrocardiogram predict increased mortality from cardiac causes independently of clinically evident cardiac diseases in unselected elderly subjects.

Effects of supplemental oxygen on cardiac rhythm during upper gastrointestinal endoscopy: a randomised controlled double blind trial

To investigate the effects of supplemental oxygen on cardiac rhythm during gastroscopy, 103 patients aged over 60 were randomised to receive either supplemental oxygen or air at 2 litres/minute during the procedure. Pulse rate, blood pressure, oxygen saturation, and a Holter cardiac trace were monitored before, during, and for one hour after the gastroscopy. A wide range of electrocardiographic abnormalities were recorded in both oxygen and air groups, of which ventricular and supraventricular ectopic beats were the most common. There were no significant differences in the rate of occurrence of any clinically important cardiac abnormality either between the oxygen and air groups or between the three monitored periods before, during, and after gastroscopy. There were significantly fewer patients, however, with supraventricular extra systoles when oxygen was given during gastroscopy (p < 0.05). Although supplemental oxygen during gastroscopy significantly improved oxygen saturation (p < 0.001; 95% confidence intervals for the difference between the means: 2.9 to 4.7), there was no correlation between oxygen saturation and any electrocardiographic changes. It is concluded that electrocardiographic abnormalities are common in patients over 60, but this study found no evidence that they are induced by gastroscopy. Supplemental oxygen increases oxygen saturation but does not reduce the incidence of clinically important cardiac arrhythmias.

Asymptomatic telephone ECG transmissions as an outpatient surveillance system of ventricular arrhythmias: relationship to quantitative ambulatory ECG recordings

Although ambulatory ECG recordings provide quantitative information in the follow-up of patients with ventricular arrhythmias, they are performed infrequently, potentially missing serious arrhythmias in the unmonitored periods. Telephone ECG systems offer "real-time" ECG information, theoretically functioning as an arrhythmia surveillance system. Thus we incorporated frequent telephone ECG transmissions in two antiarrhythmic drug protocols. The first investigation was designed to show the relationship of telephone and ambulatory ECGs in patients with frequent ventricular tachycardia (VT). The second protocol selected patients with "nonlife-threatening" frequent premature ventricular complexes (PVCs) in whom a second placebo period was instituted to simulate the clinical situation of asymptomatic arrhythmia increase. In both drug trials there was a strong linear relationship between the log-transformed PVC counts of telephone ECG and concomitant PVC, couplet, and VT frequencies on ambulatory ECG. In the VT population, greater than or equal to 1 PVC on telephone ECG reflected the presence of VT on ambulatory ECG (sensitivity 87%; specificity 77%). In the second study, telephone ECG transmissions with PVCs on three consecutive transmissions reflected the change from less than or equal to 10 PVCs/hour to greater than or equal to 40 PVCs/hour on ambulatory ECG within 48 hours. These data support the concept that daily surveillance by means of telephone ECG provides arrhythmia information of qualitative clinical relevance.

Standard ECG versus 24-hour Holter monitoring in the detection of ventricular arrhythmias

A total of 386 corresponding registrations of standard ECG and 24-h Holter monitoring were compared in order to elucidate the information obtainable from a 60-s standard ECG with regard to ventricular arrhythmias. Ventricular ectopic beats (VEB) were present on 17% of the standard ECG against 90% of the monitorings (p less than 0.001). The corresponding figures for complicated VEB (multiform, repetitive, R on T) were 2% and 41%, respectively (p less than 0.001). The presence of VEB on the standard ECG was associated with a significantly increased incidence of all types of ventricular arrhythmias during Holter monitoring performed within the same day. The number of VEBs on the standard ECG did not predict the number during monitoring, but to some extent did predict the occurrence of complicated types. In 52 patients free from VEB on four consecutive standard ECGs, Holter monitoring showed complicated ectopic activity in 32 (62%). Thus standard ECG is an insensitive method for the detection of ventricular arrhythmias.

Cardiac risk factors in patients undergoing noncardiac surgery

Cardiac risks of noncardiac surgery are associated with some noncardiac risk factors but are primarily a function of the patient's underlying cardiac disease. Elective surgery should only be performed when the patient is in optimal condition--i.e., with no evidence of heart failure, at least 6 months after a previous myocardial infarction, and so forth. Careful monitoring of fluid status should lead to reduced cardiac morbidity and mortality after surgery in these patients.

Effect of coronary arterial bypass surgery on exercise-induced ventricular arrhythmias. Long-term follow-up of a prospective randomized study

The effect of coronary arterial bypass surgery on exercise-induced ventricular arrhythmias and their relation to sudden death was examined in 102 patients with stable angina pectoris randomly assigned to medical and surgical therapy (54 and 48 patients, respectively). Symptom-limited treadmill tests were performed at entry and at 1 and 5 years. The surgical group demonstrated significant improvement in exercise performance at 1 year compared with the medical group, and at 5 years exercise-induced ischemia as evidenced by S-T depression and exertional angina remained substantially decreased in the surgical group with little change in the medical group. However, the frequency and severity of exercise-induced ventricular arrhythmias in each group remained unchanged at 1 and 5 years from those at entry. Similar results were obtained from an evaluation of ventricular arrhythmias in the electrocardiogram at rest. With the exception of exercise-induced ventricular tachycardia and fibrillation, no relation was found between ventricular arrhythmias and sudden death. Coronary bypass grafting does not decrease the frequency or severity of exercise-induced or resting ventricular arrhythmias. In patients with stable angina pectoris, with the exception of ventricular tachycardia and fibrillation, exercise-induced ventricular arrhythmias are poor predictors of sudden death. The data suggest that exercise-induced ventricular arrhythmias may not be related to ischemia but to other effects of exercise such as cardiac stimulation by catecholamines or other factors.