Chronotropic Incompetence in Patients with an Implantable Cardioverter Defibrillator: Prevalence and Predicting Factors

Abstract

Chronotropic incompetence (CI), which has not been systematically examined in the ICD patient population, may have implications for device programming. A total of 123 ICD patients were classified into three groups: single-chamber ICD with sinus rhythm, dual-chamber ICD with sinus rhythm, and single-chamber ICD with permanent atrial fibrillation. Heart rate response, maximum oxygen uptake, and oxygen uptake at the anaerobic threshold were measured during treadmill exercise testing. In addition, clinical variables such as antiarrhythmic drug therapy, underlying heart disease, and left-ventricular (LV) ejection fraction were recorded. Of the patients studied, 38% were chronotropically incompetent (47/123). Significant predictors of CI were as follows: presence of a coronary disease (P = 0.036), prior cardiac surgery (P = 0.037), chronic drug therapy with beta-blockers (P = 0.032), administration of amiodarone (P = 0.025), and a combination of these two forms of treatment (P = 0.01). Spiroergometry revealed reduced exercise capacity (P = 0.041) and lessened VO2max (P = 0.034) among chronotropically incompetent patients. A large percentage of ICD patients demonstrates CI with subsequently reduced physical stress tolerance. In light of the DAVID study, we believe that a closer examination of rate-adaptive modes for ICD patients is warranted under enhanced conditions: (1) optimized AV interval programming; (2) utilization of new algorithms to reduce ventricular pacing in combination with rate-adaptive atrial pacing, with the goal of addressing CI while minimizing ventricular pacing; and (3) an optimized upper heart-rate limit.

Is Dual-Chamber Programming Inferior to Single-Chamber Programming in an Implantable Cardioverter-Defibrillator?

“…17 The INTRINSIC RV study accomplished this goal. Algorithms other than AVSH exist 29 to reduce ventricular pacing in dual-chamber ICDs; however, no other large randomized, prospective study has shown clinical benefits as were shown in the present study.…”

“…Rate-responsive pacing has been demonstrated to improve cardiovascular exercise response in pacemaker patients 14,15 and heart failure patients receiving cardiac resynchronization therapy. 16 A recent study reported a 38% incidence of chronotropic incompetence in ICD recipients, 17 but the utility of rate-adaptive pacing has not been studied in this population.…”

Adverse Effects of Long‐Term Right Ventricular Apical Pacing and Identification of Patients at Risk of Atrial Fibrillation and Heart Failure

“…In this context, the DAVID II trial 36 showed no differences in outcome in ICD patients who were AAI programmed versus those with VVI back‐up pacing, but it is difficult to accept AAI pacing only in ICD recipients if we consider the potential need for an extra ventricular pacing support in this population over time. SND and AV troubles characterize the clinical course of ICD patients, linked with spontaneous evolution of the disease and progression of AV conduction disturbances combined with an eventually increasing need for β‐blocking therapy or introduction of amiodarone for ventricular or supraventricular arrhythmias 41–43 …”

Design and Rationale of the Assessment of Proper Physiologic Response with Rate Adaptive Pacing Driven by Minute Ventilation or Accelerometer (APPROPRIATE) Trial

“…Depending on the definition used, CI has been identified in anywhere from 9% to 84% of patients [4][5][6][7][8][9][10] and has been associated with adverse outcomes and poor prognosis [11][12][13][14]. CI in paced patients has been associated with reduced VO 2 [9,15] while rate responsive programming in these patients has been associated with improvement in exercise tolerance [16,17].…”