Overview

Left bundle branch block (LBBB) exists in about 25% of patients with congestive heart failure and is associated with worsened prognosis. Cardiac resynchronization therapy (CRT) has been one of the most important advancements in the past two decades for patients with LBBB heart failure. However, 30-40% of patients receiving a CRT do not benefit from it. In this study, the investigators will test a noninvasive device to evaluate acute effect of CRT during implantation and at follow-up CRT controls. In addition, echocardiography will be performed during CRT turned ON and OFF to visualize the changes in intraventricular flow and functional parameters of the heart.

Eligibility

Inclusion Criteria:

• Patients referred for CRT implantation or postoperative control at Oslo University Hospital based on the European Society of Cardiology (ESC) guidelines (2021), and criteria below:
  1. Sinus rhythm.
  2. New York Heart Association class II / III heart failure on diagnosis and on optimal medical therapy.
  3. Left bundle branch block.
  4. QRS duration ≥ 130 ms.
  5. Left ventricular ejection fraction ≤ 40%.
  6. Patients must have echocardiography examination before implantation
  7. Informed consent obtained from the patient.

Exclusion Criteria:

1. Age < 18 years and > 80 years;
2. Ongoing atrial fibrillation;
3. Complete atrioventricular block