An interventional study of Implantation of a Cardiac Resynchronisation Therapy (CRT) pacing device with or without Implanted Cardioverter Defibrillator in Heart Failure and Branch Block, Bundle, sponsored by Aarhus University Hospital. Completed at 5 sites in Denmark. Open to participants aged 40 Years and older. Per ClinicalTrials.gov, last updated 2026-05-29.
Sponsored by Aarhus University Hospital · Not applicable, Interventional, and Treatment
Heart failure is a leading cause of morbidity and mortality. Cardiac resynchronization therapy (CRT) is a well-established treatment for patients with symptomatic heart failure in spite of optimised medical treatment (OMT), reduced left ventricular pump function with left ventricular ejection fraction (LVEF) ≤ 35% and prolonged activation of the ventricles (bundle branch block: BBB). CRT is established by implanting an advanced pacemaker system with three leads in the right atrium, right ventricle, and in the coronary sinus (CS) for pacing the left ventricle (LV), and often is combined with an implantable defibrillator (ICD) function. On average, CRT treatment improves longevity, quality of life and functional class, and reduces heart failure symptoms. Thus, at present, CRT is indicated for heart failure patients on OMT with BBB or chronic right ventricular (RV) pacing.
It is, however, a significant problem that 30-40% of CRT patients do not benefit measurably - showing symptomatic improvement or improved cardiac pump function - from this therapy (socalled non-responders). LV lead placement is one of the major determinants of beneficial effect from CRT.
Observational studies and three randomised trials with small sample sizes indicate that targeted placement of the LV lead towards a late activated segment of the LV may be associated with improved outcome. Based on this literature, some physicians already search for late activation when positioning the LV lead. However, such a strategy was never tested in a controlled trial with a sample size sufficient to investigate important clinical outcomes. Detailed mapping for a late activation may increase operating times and infection risk, result in use of more electrodes and wires, thereby increasing costs, and increase radiation exposure for patient and staff. Placement of the LV lead in late activated areas close to myocardial scar may even result in higher risk of arrhythmia and death.
At present, it is completely unsettled whether targeted positioning of the LV lead to the latest electrically activated area of LV is superior to contemporary standard CRT with regard to improving prognosis for patients with heart failure and BBB.
The present study aims to test whether targeting the placement of the LV lead towards the latest electrically activated segment in the coronary sinus branches improves outcome as compared with standard LV lead implant in a patient population with heart failure and CRT indication.
Exclusion Criteria:
Implantation of a Cardiac Resynchronisation Therapy (CRT) pacing device with or without Implanted Cardioverter Defibrillator with the LV lead positioned preferentially in a posterolateral, non-apical position
Device: Implantation of a Cardiac Resynchronisation Therapy (CRT) pacing device with or without Implanted Cardioverter Defibrillator
Implantation of a Cardiac Resynchronisation Therapy (CRT) pacing device with or without Implanted Cardioverter Defibrillator with the LV lead positioned according to the latest electrical activation in the CS
Device: Implantation of a Cardiac Resynchronisation Therapy (CRT) pacing device with or without Implanted Cardioverter Defibrillator
Implantation of CRT-P/-D device
Death or first non-planned hospitalisation for heart failure
Time to death or first non-planned hospitalisation for heart failure
Time frame: All patients will be followed until the last included patient has been followed for two years
Death
Time to death
Time frame: All patients will be followed until the last included patient has been followed for two years
Non-planned hospitalisation for heart failure
Time to first non-planned hospitalisation for heart failure
Time frame: All patients will be followed until the last included patient has been followed for two years
Sudden death
Time to sudden death
Time frame: All patients will be followed until the last included patient has been followed for two years
Cardiac death
Time to cardiac death
Time frame: All patients will be followed until the last included patient has been followed for two years
Clinical response
Increase in New York Heart Association (NYHA) class (≥1 class from baseline) or improved walking distance by six-minute walk test (6MWT) (≥10% from baseline)
Time frame: Follow-up at 3, 6, 12, 24 and 48 months
Quality of Life (QoL)
Changes in score from baseline to follow-up
Time frame: Follow-up at 6, 12, 24 and 48 months
Patient Reported Outcomes (PROs)
Changes in score from baseline to follow-up
Time frame: Follow-up at 6, 12, 24 and 48 months
Echocardiographic measures of LV function
Changes from baseline to follow-up in left ventricular ejection fraction (%)
Time frame: Follow-up at 6, 12, 24 and 48 months
Time to first appropriate ICD Therapy
Time to first appropriate ICD therapy (antitachycardia pacing (ATP) or shock therapy)
Time frame: All patients will be followed until the last included patient has been followed for two years
Time to first inappropriate ICD Therapy
Time to first inappropriate ICD therapy (antitachycardia pacing (ATP) or shock therapy)
Time frame: All patients will be followed until the last included patient has been followed for two years
Numbers of appropriate ICD Therapies
Numbers of appropriate ICD therapies (antitachycardia pacing (ATP) or shock therapy)
Time frame: All patients will be followed until the last included patient has been followed for two years
Numbers of inappropriate ICD Therapies
Numbers of inappropriate ICD therapies (antitachycardia pacing (ATP) or shock therapy)
Time frame: All patients will be followed until the last included patient has been followed for two years
Ventricular tachycardia (VT)/ventricular fibrillation (VF)
Time to first episode of VT/VF
Time frame: All patients will be followed until the last included patient has been followed for two years
Persistent atrial fibrillation
Recorded by the implanted device
Time frame: All patients will be followed until the last included patient has been followed for two years
Any atrial fibrillation
\>30 seconds recorded by the implanted device
Time frame: All patients will be followed until the last included patient has been followed for two years
Implantation time
Procedure time at implantation
Time frame: 0-6 hours, assessed at completion of implantation procedure
Fluoroscopy time
Fluoroscopy time at implantation in minutes
Time frame: 0-120 minutes, assessed at completion of implantation procedure
Fluoroscopy dose
Fluoroscopy dose at implantation in mGy
Time frame: Assessed <24 hours after implantation initiation
Equipment used at implantation
Number of LV leads (0-5) used at implantation
Time frame: Assessed <24 hours after implantation initiation
Device-related outcomes
Periprocedural: lead re-operation, pneumothorax, hemothorax, pericardial bleeding/tamponade and later (30 days post implantation): LV lead re-operation, device replacement due to battery depletion, and infection requiring extraction
Time frame: All patients will be followed until the last included patient has been followed for two years
Battery replacements
Number of device replacements during the study period due to battery depletion
Time frame: All patients will be followed until the last included patient has been followed for two years
Battery longevity estimate
Measured by actual device battery longevity + estimated remaining device battery longevity as reported by the device at last study follow-up
Time frame: All patients will be followed until the last included patient has been followed for two years
QRS complex width
Changes in the ECG parameter QRS complex width during follow-up
Time frame: All patients will be followed until the last included patient has been followed for two years
QRS complex morphology
Changes in the ECG parameter QRS complex morphology during follow-up
Time frame: All patients will be followed until the last included patient has been followed for two years
Predictive value of P-wave
Predictive value of the baseline ECG parameter P-wave on clinical outcome measures in the entire cohort and between the two treatment groups
Time frame: All patients will be followed until the last included patient has been followed for two years
Predictive value of QRS complex width
Predictive value of the baseline ECG parameter QRS complex width on clinical outcome measures in the entire cohort and between the two treatment groups
Time frame: All patients will be followed until the last included patient has been followed for two years
Predictive value of QRS complex morphology
Predictive value of the baseline ECG parameter QRS complex morphology on clinical outcome measures in the entire cohort and between the two treatment groups
Time frame: All patients will be followed until the last included patient has been followed for two years
Changes in cardiac chamber dimensions
Volumes of cardiac chambers (left ventricle, left atrium, right ventricle, right atrium) measured by echocardiography and cardiac CT during follow-up in the entire cohort and between the two treatment groups
Time frame: All patients will be followed until the last included patient has been followed for two years
Changes in left ventricular ejection fraction LVEF
Changes in cardiac chamber function measured by echocardiography and cardiac CT during follow-up in the entire cohort and between the two treatment groups
Time frame: All patients will be followed until the last included patient has been followed for two years
Changes in right ventricular ejection fraction RVEF
Changes in cardiac chamber function measured by echocardiography and cardiac CT during follow-up in the entire cohort and between the two treatment groups
Time frame: All patients will be followed until the last included patient has been followed for two years
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Aarhus University Hospital