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.