ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices) developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons

What evidence do we have to replace in-hospital implantable cardioverter defibrillator follow-up?

INTRODUCTION

Due to the increasing number of patients with an implantable cardioverter defibrillator (ICD), new options for ICD patient follow-up management are required.

METHODS

Patients with ICD indication according to the guidelines received an ICD with Home Monitoring technology. The devices enabled the transmission of the relevant episode, therapy, and system integrity data. Patients were followed for 12 months with routine controls every 3 months. The physician analyzed the Home Monitoring data before the routine follow-up visit (FU) and gave a forecast on the necessity of the pending FU, which was compared with the evaluation after the FU. Based on the derived forecast reliability, a patient management scheme was developed and its impact on patient safety was assessed retrospectively.

RESULTS

A total of 271 patients were enrolled (40 f, mean age 62+/-12 years, mean LVEF 39+/-15%, 65% ischemic heart disease, 20% cardiomyopathy) and followed for 339+/-109 days. Of 908 pairs of Home Monitoring data and FU data evaluation, 129 there were false negative results for 92 patients. Safety concerns from false negative forecasts can be minimized with a patient management scheme containing the following elements: 1) never skip the first routine FU; 2) never skip a routine FU for a patient having already shown pacing threshold problems; 3) perform FU following hospitalizations; 4) perform FU following episode detection by the ICD; and 5) perform a routine FU if the patient reports symptoms. The retrospective analysis showed, that if the patients had been managed using this scheme, 503 of 1079 routine FU could have been skipped with only one safety concern, a three month delay in the detection of silent paroxysmal atrial fibrillation in one patient.

CONCLUSIONS

Home Monitoring in ICD therapy over 12 months is feasible. The data transmitted relevantly contribute to a remarkable reduction of follow-up burden and enable the individualization of routine follow-up.

Heart rate turbulence: a new predictor for risk of sudden cardiac death

Initial acceleration and a subsequent deceleration of sinus rhythm following a ventricular ectopic beat with a compensatory pause has been termed heart rate turbulence (HRT). The changes in sinus rhythm are thought to be mediated by a baroreflex response to the lower stroke volume of the ectopic beat. HRT is vagally mediated and abolished by atropine, whereas beta-blockers have no effect. HRT has been shown to be an independent and powerful predictor of mortality after myocardial infarction. In patients on beta-blockers, it scores better than left ventricular ejection fraction (LVEF) in its predictive value. Two common measures of HRT are turbulence onset and turbulence slope. When both these measures are abnormal, it is as powerful a predictor of mortality as LVEF. HRT correlates with other indices of cardiac autonomic functions like baroreflex sensitivity and heart rate variability. A composite autonomic index including all these three has been shown to be a powerful predictor of mortality. In patients undergoing direct percutaneous intervention for myocardial infarction, HRT improves in those attaining successful reperfusion. Abnormal values for HRT have been noted in patients with dilated cardiomyopathy and Chagas disease. Diabetic and elderly individuals are more likely to have blunted HRT. HRT cannot be measured in patients lacking ventricular ectopic beats and in patients presenting with atrial fibrillation.