Heart conditions can significantly affect the heart’s ability to pump blood effectively throughout the body. When the heart’s pumping chambers do not work in a coordinated manner, it can lead to symptoms such as shortness of breath and fatigue. For certain individuals experiencing specific heart rhythm issues in conjunction with heart failure, specialized medical interventions become necessary. One such advanced treatment option is Cardiac Resynchronization Therapy, often referred to as CRT. This therapy aims to improve heart efficiency and alleviate symptoms for selected patients.
Understanding Cardiac Resynchronization Therapy
Cardiac Resynchronization Therapy (CRT) is a specialized pacemaker therapy designed to enhance the heart’s pumping function. It addresses a problem where the heart’s lower chambers, the ventricles, do not contract in sync. When out of sync, the heart struggles to pump blood efficiently, worsening heart failure symptoms. CRT helps these ventricles beat in a more synchronized and effective manner. This therapy is also known as biventricular pacing.
How CRT Works
A CRT system consists of two primary components: a pulse generator and thin, insulated wires called leads. The pulse generator, a small device, contains a computer and battery, sealed within a titanium case. These leads deliver tiny electrical impulses to specific areas of the heart. Typically, one lead is placed in the right atrium, another in the right ventricle, and a third in a vein on the left ventricle’s surface.
The strategic placement of these leads allows the device to send electrical signals to both the right and left ventricles simultaneously or nearly simultaneously. This coordinated electrical stimulation helps to resynchronize the contractions of the ventricles, ensuring they pump together more effectively. By restoring this synchronized contraction, CRT improves the heart’s ability to pump blood and enhances overall cardiac efficiency.
Who Benefits from CRT
Cardiac Resynchronization Therapy is indicated for a specific group of patients with symptomatic chronic heart failure. These individuals typically have a reduced left ventricular ejection fraction, which is a measure of the heart’s pumping ability, usually 35% or less. A key criterion for CRT is the presence of an electrical delay within the heart, often characterized by a Left Bundle Branch Block (LBBB) on an electrocardiogram (ECG).
The duration of the QRS complex on the ECG, which reflects ventricular electrical activity, is also an important factor. Candidates typically have a QRS duration of 120 milliseconds or longer, with stronger evidence of benefit for those with 150 milliseconds or longer. Patients considered for CRT usually experience moderate to severe heart failure symptoms despite receiving optimal medical therapy.
The CRT Procedure and What to Expect
Implanting a CRT device is a minor surgical procedure and does not involve open-heart surgery. It is typically performed under local anesthesia with sedation. A small incision is usually made in the upper chest, near the collarbone, where the device is placed beneath the skin.
Flexible leads are guided through a vein and positioned within the heart chambers using X-ray imaging for precise placement. Once in position, leads connect to the pulse generator, and the device is tested for proper function.
Following the procedure, patients typically have a short hospital stay for monitoring. Patients limit activities involving the arm on the implant side, such as heavy lifting, for several weeks. Wound care involves keeping the incision site clean and dry and monitoring for infection. Regular follow-up appointments, often every six months to a year, check the device’s function and allow for setting adjustments. Most individuals gradually resume normal daily activities after recovery.