CRT (Cardiac Resynchronization Therapy)

Cardiac Resynchronization Therapy (CRT)

Cardiac Resynchronization Therapy (CRT), also known as biventricular pacing, is a specialized treatment for heart failure patients whose heart's lower chambers (ventricles) do not beat in sync. In a healthy heart, both ventricles contract simultaneously; however, in many heart failure patients, a delay in the electrical system causes one ventricle to beat after the other, leading to poor blood flow. By using a sophisticated pacemaker to send timed electrical pulses to both ventricles, CRT restores their coordinated pumping action and improves overall efficiency.

When You Should Consider CRT

• Moderate to severe heart failure symptoms (NYHA Class II, III, or ambulatory IV) that persist despite optimal medication.

• Low Ejection Fraction, where the heart's pumping capacity is 35% or less.

• Evidence of an electrical delay, such as a wide "QRS complex" on an ECG (usually >120–150ms).

• Documented Left Bundle Branch Block (LBBB) indicating uncoordinated ventricular contractions.

• Evidence of significant heart enlargement or heart overload caused by inefficient pumping.

Methods of CRT Therapy

• Biventricular Pacing: The core mechanism of sending timed electrical signals to both ventricles to resynchronize their "closing fist" contraction.

• CRT-P (Pacemaker): A device that focuses solely on resynchronization and treating slow heart rates.

• CRT-D (Defibrillator): A combination device providing resynchronization plus the life-saving shock functions of an ICD to stop dangerously fast rhythms.

• Coronary Sinus Lead Placement: A specialized technique to reach and pace the left ventricle's lateral wall through the heart's venous system.

• Real-time Fluoroscopy: High-definition X-ray guidance used to navigate the complex placement of three separate heart leads.

How CRT Is Performed

• Surgical Access: A small incision is made below the collarbone to create a "pocket" for the pulse generator.

• Right-Side Lead Placement: Two leads are threaded through veins into the right atrium and right ventricle to monitor and pace those chambers.

• Left-Side Lead Placement: A third lead is guided through the coronary sinus vein to reach the outside wall of the left ventricle.

• Device Deployment: The three leads are plugged into the pulse generator, which is then tucked into the skin pocket.

• Monitoring: Real-time imaging ensures all three leads are perfectly positioned to coordinate the heart's rhythm before finishing.

Pre-Procedure Preparation

• Fasting for 8–12 hours before the surgery, which is performed under local anesthesia and sedation.

• Blood tests, ECG, and chest X-rays to assess overall cardiac health and anatomy.

• Adjusting current heart medications as directed by the electrophysiology team.

• Discussing any allergies, particularly to nickel used in devices or the contrast dye used during navigation.

• Arranging for post-operative care and a support person for the recovery period.

Tests Before CRT Implantation

• Echocardiogram (TTE) to measure Ejection Fraction and determine the size and location of ventricular dyssyncrony.

• Cardiac Catheterization to evaluate heart and lung pressures and map the coronary sinus anatomy.

• ECG to document the wide QRS complex and identify Left Bundle Branch Block.

• Cardiac MRI or CT scan for detailed 3D mapping of the heart muscle and venous structure.

• Pulse oximetry to evaluate oxygen saturation levels in the blood.

Life After CRT Implantation

• Short hospital stay, usually requiring one night for monitoring and device checks.

• Avoid strenuous activity, driving, and heavy lifting for approximately one week to one month post-procedure.

• Immediate improvement in breathing, energy levels, and physical stamina for approximately 70% of responders.

• Regular follow-up visits with a cardiologist or electrophysiologist to monitor device function and battery life.

• Long-term protection against heart failure-related hospitalizations.

Benefits of CRT Therapy

• Restores normal, coordinated blood flow and prevents oxygen-rich blood from being pumped inefficiently.

• Significantly improves exercise capacity and the ability to perform daily activities.

• Protects the heart and lungs from further damage caused by chronic, uncoordinated pumping.

• Reduces the risk of heart failure progression and enlargement of the heart's chambers.

• Provides a durable, long-term solution that improves quality of life and survival rates.