Final answer:
CRT, or cardiac resynchronization therapy, is a treatment for heart failure and certain types of irregular heartbeat. It involves implanting a biventricular pacemaker to improve heart function.
Step-by-step explanation:
CRT, or cardiac resynchronization therapy, is indicated for certain patients with heart failure and certain types of irregular heartbeat (arrhythmias). It is used when the patient is not responding to ACE inhibitors and diuretics, and when other treatments have failed to relieve symptoms. CRT involves implanting a device called a biventricular pacemaker, which delivers synchronized electrical impulses to the heart chambers, helping them contract more efficiently and improve overall heart function.