Related Experiment Video
Updated: Aug 17, 2026
Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
[Combined cardiac resynchronization and implantable cardioversion defibrillation]
Quan Fang1, Tao Guo, K Jackson
1Department of Cardiology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100730, China.
Insights
Implantation of combined cardiac resynchronization therapy (CRT) and implantable cardioverter-defibrillator (ICD) devices is safe in elderly patients. Further studies are needed to observe the long-term clinical efficacy of these combined devices.
Area of Science:
- Cardiology
- Medical Devices
- Electrophysiology
Background:
- Patients with heart failure often require advanced therapies like cardiac resynchronization therapy (CRT) and implantable cardioverter-defibrillators (ICD) to manage arrhythmias and improve cardiac function.
- Combined CRT-ICD devices offer a potential solution for patients needing both therapies, simplifying management and potentially improving outcomes.
Purpose of the Study:
- To evaluate the safety and efficacy of implanting a novel device with combined CRT and ICD capabilities.
- To assess the procedural success and early outcomes of this combined device implantation in a patient cohort.
Main Methods:
- Eleven patients (48-80 years old) with heart failure (LVEF ≤35%, QRS duration ≥120ms) and high risk for sudden cardiac death received a combined CRT-ICD device.
- Left ventricular leads were placed in the coronary sinus branches under general anesthesia, with AV interval optimization post-procedure using echocardiography.
- Device parameters, including lead thresholds and defibrillation thresholds (DFT), were assessed post-implantation.
Main Results:
- All procedures were completed successfully without major complications.
- Lead parameters (amplitude, resistance, threshold) were within acceptable ranges for atrial, right ventricular, and left ventricular leads.
- Successful defibrillation thresholds were achieved in most patients, with two requiring external defibrillation or experiencing ECG abnormalities during DFT testing. Improvement in mitral regurgitation was observed post-AV optimization.
Conclusions:
- Implantation of combined CRT-ICD devices is a safe procedure, even in an aging patient population.
- The study demonstrates the feasibility of implanting these devices, with initial results suggesting safety and potential benefits.
- Long-term clinical efficacy and outcomes of this combined device require further investigation.
Objective:
To examine the efficacy and safety of implantation of the device with combined cardiac resynchronization therapy (CRT) and implantable cardioversion defibrillation (ICD) capabilities.
Methods:
Eleven patients aged 48 - 80 (71.6 +/- 9.5) years, 7 male and 4 female, were included in the study. All patients had either a history of aborted sudden cardiac death, ventricular tachyarrhythmia, or induced ventricular tachycardia during cardiac electrophysiological study, whose left ventricular ejection fractions were 35% or less and QRS durations were 120 or longer. The patients were implanted a Medtronic INSYNC II MARQUIS(TH) 7289. All left ventricular leads were implanted in left lateral or left posterior lateral side-branches of coronary sinus. The procedures were performed in general anesthesia status. The AV interval was optimized guided by ECHO in all the patients in the day after the procedure.
Results:
All procedures were successfully completed without major complications. The fluoroscopy time was 19 - 73 (44.7 +/- 19.9) min. Atrial lead amplitude, resistance and threshold were 0.5 - 3.5 (2.47 +/- 0.77) mV, 410 - 749 (590 +/- 126) Omega and 0.9 - 3.0 (1.37 +/- 0.71) V respectively. Right ventricular septal lead amplitude, resistance and threshold were 6.8 - 15.8 (11.00 +/- 3.48) mV, 387 - 750 (586 +/- 116) Omega and 0.4 - 1.0 (0.69 +/- 0.21) V respectively. The amplitude, resistance and threshold of left ventricular leads were 1.2 - 25 (15.37 +/- 5.15) mV, 423 - 812 (602 +/- 125) Omega and 0.3 - 5.0 (1.62 +/- 1.59) V respectively. The defibrillation thresholds (DFT) of 20 J were obtained in 3 patients, 6 J in 3 patients, and 15 J, 12 J and 3 J in one patient respectively. One of the 11 patients with failed old device did not obtain successful DFT after lead and device replacement and was defibrillated externally during DFT test. The another one did not obtain successful DFT because of abnormal ST-T changes in ECG. All devices were programmed to maximum of 30 J and discharged from the hospital in 48 hours except the one who failed to obtain DFT. The patients with mitral regurgitation improved after the AV optimization.
Conclusions:
Implantation of device with CRT and ICD features is safe even in aging patients. The long time outcomes of the clinical efficacy of this combined device remain to be observed.
Related Concept Videos
01:29Cardiomyopathy V: Interprofessional Care
01:23Cardiopulmonary Resuscitation III: AED Use
01:30Cardiomyopathy II: Dilated Cardiomyopathy
01:25ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
01:25Dysrhythmias VI: Management of Dysrhythmias
01:22Heart Failure VI: Adjunct Therapies