Concepts and questions in programming cardiac resynchronization devices

Group Purchasing Organizations: Optimizing Cardiac Device Selection, Therapy Delivery, and Fiscal Responsibility

Group purchasing organizations (GPOs) have played a major role in supporting health care delivery in recent years as the healthcare industry has faced stronger economic pressures. Consequently, a position statement was drafted to act as a guideline for a GPO in creating a fiscally responsible, yet unrestricted environment for physicians to select the most appropriate cardiac device for their patients. This cardiac device selection guideline is to be implemented in hundreds of member hospitals but may be of use in non-member hospitals as well. The guideline will only be effective when the physicians or cardiac device caregivers have the knowledge and skills to optimally program and match device therapies and algorithms to individual patient needs.

Blanked Atrial Flutter in Patients with Cardiac Resynchronization Therapy: Clinical Significance and Implications for Device Programming

BACKGROUND

Atrial arrhythmias are frequently observed in patients with heart failure and may be a primary cause for decompensation during cardiac resynchronization therapy (CRT). The accurate detection of organized atrial tachyarrhythmias poses a challenge to the function of mode-switching biventricular pacemakers/defibrillators.

METHODS

The purpose of the study was to determine retrospectively the incidence of blanked atrial flutter and mode switch failure (2:1 lock-in), and to look for factors predisposing to this problem. A total number of 65 patients with CRT devices has been followed regularly over 18 +/- 12 months. Five patients were excluded because of chronic atrial fibrillation and reprogramming to VVIR mode.

RESULTS

Seven out of 60 patients (12%) were diagnosed with blanked atrial flutter at unscheduled device interrogation. Sustained biventricular pacing at a median rate of 125/min-mimicking sinus tachycardia-resulted in rapid deterioration of heart failure and hospitalization. Mode switch failure occurred due to coincidence of every second flutter wave with atrial blanking. The group with 2:1 lock-in was programmed to longer atrial blanking times (143 +/- 34 ms vs 105 +/- 32 ms; P = 0.026) and AV intervals (126 +/- 8 ms vs 107 +/- 29; P = 0.001) than the group without lock-in. Other clinical characteristics examined did not differ between the two groups apart from a previous history of atrial fibrillation (P = 0.032).

CONCLUSION

Blanked atrial flutter with rapid ventricular pacing is a clinically important problem in heart failure patients treated with CRT devices. Efforts should be made to avoid this complication by atrial lead implantation without ventricular farfield oversensing, by programming short PVAB and AV intervals, and by implementation of dedicated device algorithms.