Continuous Ambulatory Monitoring Research Articles

Limitations of continuous ambulatory ECG monitoring for detecting coronary artery disease in patients with chest pain and normal resting ECGs

Limitations of continuous ambulatory ECG monitoring for detecting coronary artery disease in patients with chest pain and normal resting ECGs

New approaches to resolving diagnostic problems in patients with angina pectoris.

Several new noninvasive techniques are now available to evaluate the patient with chest pain to determine if myocardial ischemia is present. Continuous ambulatory ECG monitoring can detect myocardial ischemia in some patients who have normal ECG responses to graded exercise tests. Defects in myocardial perfusion can be visualized by radionuclide imaging at rest and after exercise. Also, abnormal left ventricular wall motion due to myocardial ischemia can be detected by gated blood pool scanning at the same time. Other techniques can olso be valuable in evaluating wall motion. Standard M-mode echocardiography can detect anteroseptal and posteroinferior wall motion abnormalities with remarkable anatomic detail, and newer echo techniques are promising for delineating the motion of other parts of the left ventricle. Finally, abnormal contractile areas can be assessed by videotracking the fluoroscopic cardiac silhouette and by a new noninvasive technique, the displacement cardiograph, which does not involve radiation exposure. Although none of these tests are both highly sensitive and highly specific for myocardial ischemia, their combined application in a symptomatic patient may provide considerable useful information which will help to determine who should be subjected to the risk and expense of coronary arteriography.

Continuous Ambulatory Electrocardiographic Monitoring: Use in Cardiac Exercise Programs

In order to evaluate cardiac rate and rhythm in 20 patients with coronary atherosclerotic disease who were engaged in a medically supervised exercise program, continuous ambulatory electrocardiographic monitoring was performed during an exercise training class and the subsequent 24 hours, which included activities at work and home. Sixty-five percent (13) of the 20 patients had abnormal findings on recordings. Of the 20 patients studied, 40 percent (eight) had arrhythmias detected by ambulatory recording that had not been detected either by resting or exercise electrocardiograms. Three patients with ventricular ectopis (multiform premature ventricular beats, couplets, and begeminy) had exercise activities temporarily curtailed and therapy with antiarrhythmic drugs begun, with subsequent resolution or improvement. Two other patients (with recorded heart rates of 160 beats per minute) were instructed to carefully monitor their heart rate in order to not exceed the target maximum. We conclude that 24-hour continuous electrocardiographic monitoring is beneficial in evaluating patients in cardiac exercise programs and frequently influences the management of such patients.

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

To evaluate the efficacy of ventricular arrhythmia detection in ambulatory patients with stable coronary artery disease, 101 coronary patients documented by arteriography or remote myocardial infarction underwent concurrent evaluation by 10-hour portable ambulatory ECG monitoring and standard 12-lead electrocardiograms (ECGs) obtained serially over 24 months. Portable ECG recorded premature ventricular contractions (PVCs) in 77 patients: 50% serious PVCs (multifocal, paired, >5/minute, R on T) and 9% patients with ventricular tachycardia. Standard ECG was insensitive (p<.001) in arrhythmia detection both by one tracing (PVC prevalence 17%) obtained within 12 hours of portable ECG or by four serial standard ECGs during the subsequent two weeks (PVC prevalence 18%). Although a total of 1,414 standard ECGs during 24 months recorded PVCs in 49% of patients, serious PVCs were limited (p<.001) to 25% and ventricular tachycardia to 1% of patients. However, ventricular ectopy present by any standard ECG (10 per patient) within three months of ambulatory monitoring was associated with high prevalence of hazardous ectopics by portable ECG (p<.05): serious PVC 92%; ventricular tachycardia 17% patients. Even in patients free of ventricular ectopy by 24-month serial standard ECG, portable ECG detected serious PVCs in 62% and ventricular tachycardia in 6% of patients. Thus stable coronary patients manifested frequent ventricular ectopics by portable ECG which were usually undetected by even multiple serial standard ECGs. Importantly, presence of PVCs by standard ECG was related to increased risk of hazardous ventricular arrhythmias by portable ECG.

The systolic click-murmur syndrome: Clinical recognition and management

The midsystolic click-late systolic murmur syndrome is a complex entity with variable manifestations that involves a primary process causing myxomatous degeneration of the mitral valve leaflet(s) and subsequent systolic mitral valve leaflet prolapse. Other cardiac diseases may cause mitral valve prolapse and regurgitation associated with a midsystolic click that mimics this primary syndrome. The prolapsing mitral valve leaflet(s) syndrome occasionally may be familial. Most patients are asymptomatic but some complain of chest pain, palpitation, dyspnea or fatigue. Prolapsing mitral valve leaflet(s) can be distinguished from other causes of systolic clicks and mitral regurgitation murmurs by the characteristic movement of the clikmurmur complex in systole with various hemodynamic interventions. The clinical diagnosis usually can be confirmed by echocardiography, which demonstrates the abnormally prolapsdrome usually is minimal but can be progressive and lead to the need for prosthetic valve replacement. Most symptomatic patients can be managed medically but some require cardiac catheterization to evaluate the possibility of coexistent coronary artery disease, to assess the degree of mitral regurgitation and to evaluate other associated cardiac lesions. All patients with this syndrome should receive antibiotic prophylaxis prior to any surgical or dental procedures. Those patients suspected of having arrhythmias should be evaluated by continuous ambulatory ECG monitoring and dangerous arrhythmias probably should be treated. The prognosis usually is excellent, but sudden death and rapidly progressive mitral regurgitation due to ruptured chordae tendineae have been reported. Although more than a decade has elapsed since the midsystolic click-late systolic murmur syndrome was first recognized, much remains to be learned about this common but complex clinical entity.

Pacemaker Implantation Based on Ambulatory ECG Monitoring in Patients with Cerebral Symptoms

Continuous ambulatory ECG monitoring was performed in 110 patients because of a history of dizziness, alleged syncope of vague cerebral manifestations. The resting ECG failed to provide an explanation for symptoms in any of the patients. In 12 patients the monitoring revealed a variety of arrhythmic mechanisms which required pacemaker implantation. Five of these patients had sick sinus syndrome with episodes of prolonged sinus arrest, while in the others various degrees of A-V block were detected. Implantation of a pacemaker relieved the symptoms in all. It is concluded that ambulatory ECG monitoring is essential in evaluating cases of unexplained cerebral symptoms.