Initial heart rate score predicts new-onset atrial tachyarrhythmias in pacemaker patients.

Aims: Heart rate score (HRSc), the per cent of atrial paced and sensed event in the largest 10 b.p.m.

Lower rate limit for pacing by cardiac resynchronization defibrillators: Should lower rate programming be reconsidered?

Background: No real-world large database associates lower rate limit (LRL) programming and survival of subjects with cardiac resynchronization therapy-defibrillators (CRT-Ds).

Objective: The purpose of this study was to test the hypothesis that lower LRL programming is independently associated with survival, and that LRL and heart rate score (HrSc) are associated.

Methods: All dual-chamber CRT-D devices in the Remote Patient Monitoring (RPM) ALTITUDE database (2006-2011) were queried.

Heart rate score, a measure related to chronotropic incompetence in pacemaker patients.

Background: Heart rate score (HrSc) ≥70% in cardiac resynchronization therapy defibrillator and implantable cardioverter-defibrillator subjects predicts 5-year mortality risk. A high HrSc suggests few sensed cardiac cycles above the programmed lower rate.

Objective: To determine if HrSc is related to chronotropic incompetence (CI) in pacemaker (PM) subjects.

Novel Low-Voltage MultiPulse Therapy to Terminate Atrial Fibrillation.

Objectives: This first-in-human feasibility study was undertaken to translate the novel low-voltage MultiPulse Therapy (MPT) (Cardialen, Inc., Minneapolis, Minnesota), which was previously been shown to be effective in preclinical studies in terminating atrial fibrillation (AF), into clinical use.

Background: Current treatment options for AF, the most common arrhythmia in clinical practice, have limited success.

Heart rate score predicts mortality independent of shocks in ICD and CRT-D patients.

Background: Heart Rate Score (HrSc), a novel index found to predict mortality in patients with implantable defibrillator (ICD) and cardiac resynchronization defibrillator (CRT-D) devices, is associated with mortality in ICD and CRT-D recipients when HrSc is ≥ 70%. Implantable defibrillator shocks have also been associated with increased mortality in ICD and CRT-D recipients. The objective of this study was to evaluate the relationships between HrSc, shocks, and mortality in ICD and CRT-D patients.

Addition of minute ventilation to rate-response pacing improves heart rate score more than accelerometer alone.

Background: Heart rate score (HRSc) ≥70%, a novel parameter, predicts risk of mortality in patients with implantable cardioverter-defibrillators and identifies patients who have survival benefit with DDDR vs DDD pacing.

Objective: The purpose of this study was to determine if DDDR pacing lowers HRSc, and a blended sensor with minute ventilation (MV) and accelerometer (XL) improves HRSc more than accelerometer (XL) alone in patients requiring pacemakers (PMs).

Methods: HRSc, the percentage of all beats in the tallest 10-beat/min device histogram bin, was calculated.

Effect of pacing for soft indications on mortality and heart failure in the dual chamber and VVI implantable defibrillator (DAVID) trial.

Background: The dual chamber and VVI implantable defibrillator (DAVID) trial demonstrated that dual chamber (DDDR) pacing in defibrillator candidates with impaired ventricular function and no established indication for pacing resulted in worsened congestive heart failure (CHF) or death. Many patients had abnormalities for which pacing is often advocated to improve the management of ventricular dysfunction.

Objectives: Evaluate the impact and interaction of nonessential but potentially justifiable reasons to pace ("soft indications"), together with pacing mode, on outcome.

Abnormal conduction increases risk of adverse outcomes from right ventricular pacing.

Objectives: The purpose of this study was to determine whether QRS duration or morphology increased the risk of adverse outcome in the DAVID (Dual Chamber and VVI Implantable Defibrillator) trial.

Background: The DAVID trial found an increased risk of the combined end point of death and new or worsening congestive heart failure (CHF) in defibrillator recipients who were paced DDDR-70 versus VVI-40.

Methods: We analyzed the combined end point in patients with abnormal QRS duration (AbQRS) (> or =110 ms) compared with those with normal QRS duration (NQRS) (<110 ms).

Percent right ventricular pacing predicts outcomes in the DAVID trial.

Background: The Dual-Chamber and VVI Implantable Defibrillator (DAVID) trial demonstrated a worse outcome in patients with implantable cardioverter-defibrillators (ICDs) programmed to DDDR at 70 bpm compared with patients who had ICDs programmed to VVI backup pacing at 40 bpm. Pacing was more frequent in the DDDR group.

Objectives: The purpose of this study was to determine whether right ventricular pacing (RV) is an independent predictor of outcome in the DAVID trial.

Hybrid therapy with right atrial catheter ablation and previously ineffective antiarrhythmic drugs for the management of atrial fibrillation.

Background: Many patients with paroxysmal atrial fibrillation (AF) become refractory to antiarrhythmic drugs (AADs). Early studies suggested that linear catheter ablation in the right atrium may provide sufficient substrate modification to reestablish therapeutic efficacy of previously ineffective AADs.

Methods: This prospective before-after multicenter trial evaluated the safety and effectiveness of hybrid therapy that included right atrial catheter ablation coupled with a regimen of previously ineffective AADs on AF episode frequency and symptoms in drug refractory patients with paroxysmal AF.

Shock on T versus direct current voltage for induction of ventricular fibrillation: a randomized prospective comparison.

VF is induced during ICD implantation to determine efficacy of therapy. Establishing the best clinical method of induction of VF would potentially be beneficial in reducing the number of induction attempts and reducing the frequency of inadvertent induction of VT. Commonly used methods to induce VF include shock in the T wave vulnerable period (T shock) and high frequency stimulation.