Background - Pacemaker treatment gives asynchronous activation of the heart that often results in decreased heart function and clinical heart failure. New pacemaker types that stimulates both left and right ventricle ( biventricular pacemakers ) is introduced to the treatment of patients with heart failure, decreased left ventricular function and ECG signs with left bundle branch block.
Hypothesis - Ventricular pacing results in remodelling of the left ventricle and decreased left ventricular function. Biventricular pacing do not do this. Ventricular pacing results in heart failure and increased wall stress with decreased 6 minutes walk test and increased BNP in blood samples. This is not seen by biventricular pacing.
Materials and methods - 3 studies. All patients are examined by echocardiography 2-dimensional, M-mode, 3-dimensional and with tissue harmonic imaging. Study 1) Patients with AV-conduction disorder that needs pacemaker treatment are randomized to DDD-pacemaker or biventricular pacemaker. Study 2) Patients with sick sinus syndrome included in DANPACE are randomized to AAI- or DDD-pacemaker. Study 3 ) Acute study to examine the changes in patients AV-block before DDD-pacemaker implantation and after implantation.