Bundle-Branch Block clinical trials

Acute Hemodynamic Effects of Pacing the His Bundle in Heart Failure

Cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) is indicated for patients with low ejection fraction and persistent symptoms of heart failure despite medical therapy and a wide QRS-complex, preferably with a left bundle branch block. Unfortunately, up to 40 % receiving CRT do not respond with subjective improvement or improved left ventricular ejection fraction from the treatment. There are few therapeutic alternatives in patients not responding to CRT with BVP, and the potential to improve cardiac function in these patients could make a large difference in terms of life quality and prognosis. His-bundle pacing (HBP) can be a suitable alternative, but is likely not possible in all patients with failed CRT. Furthermore, upgrading to HBP does require a surgical procedure and therefore exposes the patients to risk of complications (e.g. infection of the device). Therefore, early identification of the patients who are likely to benefit from an upgrade to HBP would be beneficial. This study aims to evaluate if patients with failed CRT treatment will benefit from hemodynamic improvement if they are treated with temporary HBP, without opening the device-pocket, and exposing the existing pacemaker-device to a risk of infection. A temporary pacemaker lead and pacing sheath will be used, and placed in the heart via a blood vessel on the right side of neck, using local anaesthesia. Acute effects on the pump function of the heart will be measured during rest and during supine bicycle test (the equivalent of moderate physical activity). Factors associated with a beneficial effect will be evaluated on a group basis. If the individual patient experiences an improvement of cardiac function during the test, he/she will be offered an upgrade to HBP and a replacement of the existing device.