Cardiac resynchronization therapy

Cardiac resynchronization therapy
Intervention
Three leads can be seen in this example of a cardiac resynchronization device: a right atrial lead (solid black arrow), a right ventricular lead (dashed black arrow), and a coronary sinus lead (red arrow). The coronary sinus lead wraps around the outside of the left ventricle, enabling pacing of the left ventricle. Note that the right ventricular lead in this case has 2 thickened aspects that represent conduction coils and that the generator is larger than typical pacemaker generators, demonstrating that this device is both a pacemaker and a cardioverter-defibrillator, capable of delivering electrical shocks for dangerously fast abnormal ventricular rhythms (see separate knol on Implantable Cardioverter-Defibrillators (ICDs).
ICD-9-CM	00.51, 00.54
MeSH	D058409
eMedicine	1839506-devices

An implanted cardiac resynchronization device is a medical device used in cardiac resynchronization therapy (CRT). It resynchronizes the contractions of the heart’s ventricles by sending tiny electrical impulses to the heart muscle, which can help the heart pump blood throughout the body more efficiently. CRT defibrillators (CRT-D) also incorporate the additional function of an implantable cardioverter-defibrillator, to quickly terminate an abnormally fast, life-threatening heart rhythm. CRT and CRT-D have become increasingly important therapeutic options for patients with moderate and severe heart failure.

Cardiac resynchronization therapy in heart failure

Cardiac resynchronization therapy (CRT) is an effective therapy in patients with heart failure and dyssynchrony identified as a prolonged QRS duration. Benefits include improved exercise tolerance, reduced remodeling (reduction in LV chamber size and measures of mitral regurgitation), reduced mortality, and need for hospitalization in patients in sinus rhythm.