My doctor said I need a biventricular pacemaker or defibrillator. What is that?

The main pumping chamber of the heart is the left ventricle. However, the effectiveness of that pump is compromised if the sides of the left ventricle don’t squeeze simultaneously. This lack of synchronization affects the heart’s output and can lead to progressive weakening and enlargement of the heart. When that lack of synchronization is caused by a delay in the electrical signal directing the heartbeat, it can be corrected by a special pacemaker known as a biventricular pacemaker. This is also referred to as cardiac resynchronization therapy. This pacing technique can be applied to both pacemakers and implantable defibrillators.