Cardiac electrophysiology is a specialized field within cardiology focused on the heart’s electrical system. This discipline investigates heart rhythm disorders, known as arrhythmias, which occur when electrical signals do not fire or travel correctly. Electrophysiologists use advanced diagnostic techniques to map these faulty electrical pathways. The goal is to understand these disturbances and provide targeted treatment to restore a normal heart rhythm.
The Heart’s Electrical Wiring System
The heart’s ability to pump blood relies on a precisely timed electrical impulse that coordinates the contraction of its four chambers. This process begins in the sinoatrial (SA) node, located in the upper right chamber, which acts as the heart’s natural pacemaker. The SA node generates a signal that spreads across the upper chambers (atria), causing them to contract and push blood into the ventricles.
The impulse then travels to the atrioventricular (AV) node, situated between the atria and the ventricles. The AV node briefly delays the signal. This delay ensures the ventricles have time to fill completely with blood before they contract, which is fundamental to efficient blood circulation.
From the AV node, the electrical current moves rapidly down the Bundle of His, splitting into right and left bundle branches. These branches carry the signal deep into the lower chambers through Purkinje fibers. This rapid distribution ensures both ventricles contract nearly simultaneously and forcefully, maximizing the blood pumped out to the body.
Diagnostic Procedures for Electrical Abnormalities
When the heart’s electrical circuit malfunctions, specialists use detailed procedures to locate the source of the problem. Initial steps often involve external monitoring tools, such as a Holter monitor, which records the heart’s rhythm over 24 to 48 hours to capture intermittent arrhythmias. The most precise method for diagnosing complex rhythm problems is the Electrophysiology (EP) Study.
An EP study is an invasive procedure performed in a specialized lab. Thin, flexible catheters are inserted into a vein, usually in the groin or neck. These catheters are guided using live X-ray imaging to specific locations inside the heart’s chambers. Electrodes at the tips record electrical signals directly from the heart muscle, providing an internal map of impulse travel.
Once the catheters are in place, the electrophysiologist may attempt to reproduce the abnormal rhythm using electrical stimulation or medication. By intentionally starting the arrhythmia under controlled conditions, the specialist identifies the faulty tissue or pathway responsible for the malfunction. This process determines the exact location and mechanism of the electrical disturbance, which is necessary for planning targeted treatment, such as medication, ablation, or device implantation.
Treatment Options Guided by Electrophysiology
Following the diagnostic EP study, common treatments include catheter ablation and the implantation of electronic devices. Catheter ablation is a minimally invasive treatment designed to eliminate the specific tissue causing the arrhythmia. Once the irregular signal is mapped, the doctor delivers energy (heat or extreme cold) through the catheter tip.
This energy creates a small scar that permanently blocks the abnormal electrical signal from traveling through that pathway. For conditions like supraventricular tachycardias, catheter ablation can achieve a success rate exceeding 90 percent. For intermittent atrial fibrillation, the success rate is often between 70 and 75 percent after one procedure.
For patients requiring ongoing electronic support, device implantation is used. A pacemaker is a small device implanted beneath the chest skin to treat bradycardia (a slow heart rate). It monitors the rhythm and sends small, timed electrical pulses to the heart muscle to ensure a steady rate.
An Implantable Cardioverter-Defibrillator (ICD) targets dangerously fast heart rhythms, such as ventricular tachycardia or ventricular fibrillation. The ICD monitors the heart continuously and, if it detects a life-threatening rhythm, delivers a powerful electrical shock to reset the heart. Many modern ICDs also include basic pacemaker functions to regulate slow rhythms.