Intrathoracic Far-Field Electrocardiogram Allows Continuous Monitoring of Ischemia After Total Coronary Occlusion

Continuous ST-Monitoring Function of Implantable Cardioverter Defibrillator Detects Silent Ischemia in Patients With Coronary Artery Disease

Background

Newer implantable cardioverter defibrillators can monitor intracardiac ECGs , but their ability to detect ischemia is unclear. This study investigated the usefulness of implantable cardioverter defibrillators with an ST‐monitoring function in coronary artery disease patients.

Methods and Results

We conducted a prospective study of implantable cardioverter defibrillator patients with the ST‐monitoring function. One hundred seventy‐three patients who received implantable cardioverter defibrillators for primary or secondary prevention of sudden cardiac death. All patients underwent medical examinations at least every 6 months, with standard 12‐lead ECGs and device checks that included analysis of the ST‐monitoring function. Myocardial perfusion imaging or coronary angiography was performed during the follow‐up. The mean follow‐up duration was 23.3±7.7 months. Significant ST changes occurred in 15 patients (8.7%), of whom 14 were asymptomatic. The incidence of angina pectoris was significantly higher in the ST change (+) group than that in the ST change (−) group (28.6% versus 7.2%, P=0.03). In the patients who underwent myocardial perfusion imaging, the sensitivity, specificity, and negative predictive value of the ST‐monitoring feature to detect ischemia were 75.0%, 72.5%, and 93.5%, respectively. The sensitivity, specificity, and negative predictive value of the ST‐monitoring feature to predict residual stenosis evaluated using coronary angiography were 76.9%, 83.5%, and 97.5%, respectively. The percentage of patients with a septal right ventricular lead was significantly lower in the ST change (+) group than in the ST change (−) group (13.5% versus 33.5%, P=0.01).

Conclusions

If intracardiac ECGs ST changes are detected, it is necessary to use additional modalities even in asymptomatic patients.

Clinical Trial Registration

URL: http://upload.umin.ac.jp. Unique identifier: UMIN000011824.

Remote monitoring of patients with implanted cardiac devices

Three different types of implantable cardiac devices are now commonly used in clinical medicine: pacemakers (including cardiac resynchronization systems), cardiac defibrillators, and loop recorders. Although pacing specialists and electrophysiologists have traditionally been responsible for device follow-up, the newest generation of implanted devices stores a wealth of information that can be useful to the clinical cardiologist. Important information, in addition to device function, such as incidence and type of arrhythmias, general clinical condition of the patient, and hemodynamic status can now be stored on large databases that are available via web access to all physicians caring for an individual patient. The advent of the remote monitoring capability of implanted devices has initiated a rapidly accelerating paradigm shift in device follow-up that can potentially improve patient care at lower cost.