Cardiac Electrophysiology

Cardiac Electrophysiology: Diagnosing and Treating Heart Rhythm Disorders 

Carondelet Health Network and Carondelet Medical Group are home to one of the very few cardiac electrophysiologists in Southern Arizona, which means you have access to advanced and up-to-date procedures in cardiac electrophysiology, all close to home.  

Cardiac electrophysiology is a specialized field of cardiology that focuses on the electrical activities of the heart. Its primary purpose is to diagnose and treat heart rhythm disorders. Maintaining a regular heart rhythm is crucial for the heart to pump blood effectively throughout the body.  

When these electrical signals become erratic, it can lead to various symptoms, ranging from mild palpitations to life-threatening conditions.

Diagnosing Heart Rhythm Disorders 

The first step for a diagnosis is an office evaluation to understand the patient's symptoms and medical history, potentially minimizing the need for extensive and costly testing.  

Heart rhythm disorders can manifest in various ways. Some are accompanied by noticeable symptoms, while others may be asymptomatic. The severity of these disorders also varies significantly; some pose no immediate threat and others can be life-threatening, necessitating prompt intervention. A diagnosis may require a procedure, medications or implantable devices like pacemakers and defibrillators. 

The initial diagnostic phase often involves assessing the overall health of the heart. Several non-invasive tests are commonly employed: 

• Echocardiogram – an ultrasound imaging technique to evaluate the muscle strength and valve function of the heart. 
• Stress Test - to assess the heart's response to physical exertion and evaluate for underlying coronary risk. 

Various forms of EKG (electrocardiogram) monitoring are utilized. For patients experiencing symptoms, an EKG monitor can record the heart rhythm. However, some individuals experience symptoms infrequently, making short-term monitoring inadequate. In such cases, long-term monitoring becomes necessary through various devices: 

• External Monitors - typically worn for 24 hours to 30 days to capture intermittent rhythm disturbances. 
• Implantable Loop Recorder (ILR) - for patients with very infrequent symptoms, an ILR may be implanted just under the skin on the chest. This small monitor can record the heart’s electrical activity for an extended period, potentially two to three years if necessary. ILRs are particularly useful for diagnosing the cause of symptoms like fainting, rapid heartbeat, lightheadedness or dizziness when these events are not frequent enough to be captured by external monitors.

In situations where a more definitive diagnosis is needed, especially when a dangerous rhythm disorder is suspected, an electrophysiology study (EP study) may be performed. 

Electrophysiology Study (EP Study) 

An EP study is a low-risk outpatient procedure where typically three catheters (insulated wires) are inserted into a femoral vein in the right groin. These catheters are then carefully advanced into the different chambers of the heart and positioned at strategic locations. 

Once the catheters are in place, they serve a dual purpose:

• Recording Electrical Signals: The catheters detect and transmit electrical signals originating from the heart into a computer mapping system for detailed analysis. 
• Stimulating the Heart: The catheters can also be used to electrically stimulate the heart to elicit the abnormal heart rhythm that is suspected. By carefully observing how the heart responds to this stimulation, electrophysiologists can pinpoint the origin and characteristics of the rhythm disorder. 

A significant advantage of an EP study is the potential for immediate treatment. Once the abnormal rhythm is consistently brought on and its source is identified, it can often be eliminated during the same procedure through a technique called ablation. 

Treating Heart Rhythm Disorders 

The treatment of heart rhythm disorders is multifaceted and tailored to the specific type and severity of the arrhythmia. Atrial fibrillation is a common form of arrhythmia treated at Carondelet Health. Treatment options range from simple reassurance to medications, curative procedures, and implantable devices.

Catheter Ablation 

Carondelet Health Network offers treatments for abnormal heart rhythms such as ablation. This procedure involves applying energy to the specific area of the heart muscle that is generating the irregular electrical signals, effectively extinguishing this abnormal activity. Various energy sources can be used for ablation: 

• Radiofrequency Energy: This is the most common method due to its flexibility and speed of application. It works by heating up the targeted tissue to destroy it and prevent it from conducting abnormal electrical impulses. 
• Freezing Energy (Cryoablation): This technique utilizes freezing temperatures to ablate the problematic heart tissue and can be delivered through a freezing catheter or a balloon. Balloon cryoablation is often used to ablate the circumference of the pulmonary veins where they connect to the back of the heart, a common source of abnormal rhythms, particularly atrial fibrillation (AF). 
• Other Investigational Modalities: Additional energy sources for ablation include laser, high-frequency ultrasound, and microwave energy. More than one modality employed during a procedure if necessary. 

The choice of ablation technique depends on several factors, including the location and complexity of the rhythm disorder. Some arrhythmias originate from a single site, while others are caused by multiple active sites, making them more challenging to eradicate. Atrial fibrillation (AF) is a common rhythm disorder arising from multiple sites generating abnormal electricity in the upper chambers of the heart 

Implantable Devices 

For certain heart rhythm disorders, implantable devices play a crucial role in either regulating the heart rhythm or preventing life-threatening events: 

• Pacemaker Implantation: A pacemaker is a small, battery-operated device that can regulate the speed or rhythm of a beating heart. It is primarily used to treat bradycardia, a condition characterized by an unusually slow heart rate. The pacemaker is typically implanted under the skin, usually below the left collarbone, and connected to the heart via wires threaded through a large vein. It works on demand, delivering electrical pulses only when the heart beats too slowly or misses a beat, ensuring a regular heartbeat. Pacemakers can be programmed to respond to the body’s needs, increasing the heart rate during physical activity, for example. 
• Implantable Cardioverter Defibrillator (ICD) Implantation: An ICD is another implantable electronic device that continuously monitors the heart rhythm. If it detects a very fast, abnormal heart rhythm, it delivers electrical energy to the heart muscle to restore a normal rhythm. Similar to pacemakers, ICDs are usually surgically implanted under the skin below the left collarbone, with a wire connecting it to the heart. ICDs are often recommended for individuals who have experienced a serious episode of an abnormally fast heart rhythm or are at high risk of developing them.
• Cardiac Resynchronization Therapy (CRT): This therapy is specifically designed for patients with weak heart muscles who often experience disorganized muscle function, where the left and right ventricles do not beat in coordination. This lack of synchrony further weakens the heart's pumping ability, leading to symptoms like shortness of breath and fatigue. CRT involves implanting a pacemaker with wires that are threaded to both ventricles to help them beat in a more organized and efficient way. CRT is frequently performed in conjunction with defibrillator implantation. 

What does a cardiac electrophysiologist do? 

Cardiac electrophysiologists are cardiologists who have undergone additional training to diagnose and treat the heart's electrical system. These physicians clarify, diagnose and treat the complex electrical activities of the heart, ultimately working to maintain a healthy heart rhythm. 

Conclusion: Maintaining the Heart's Crucial Rhythm 

Through a comprehensive approach that includes careful patient evaluation, advanced diagnostic tools like EKG monitoring, ILRs, and EP studies, and sophisticated treatment options such as catheter ablation and implantable devices, cardiac electrophysiologists play a critical role in addressing a wide spectrum of heart rhythm disorders.