The heart’s ability to pump blood depends on more than muscle strength or healthy arteries. Every beat is coordinated by a signaling system that tells the heart when to contract, how quickly to beat, and how to synchronize the movement of its chambers. When that system functions properly, the heart maintains a steady rhythm that supports circulation throughout the body.
When those signals become disorganized or interrupted, the result is a heart rhythm disorder, or arrhythmia. These conditions can cause symptoms ranging from palpitations and fatigue to stroke risk or life-threatening rhythm disturbances. Diagnosing and correcting them requires a highly specialized field of cardiology known as cardiac electrophysiology.
At CardioVascular Health Clinic, Dr. Monica Lo specializes in diagnosing and treating disorders of the heart’s electrical system. Her work focuses on identifying the source of abnormal rhythms and restoring the signals that allow the heart to beat normally again.
Cardiology often focuses on the heart’s blood vessels and circulation, but electrophysiology examines something different: the signals that control every heartbeat.
“Many cardiologists treat the ‘plumbing’ of the heart—the arteries and blood flow,” Dr. Lo says. “Electrophysiologists focus on the electrical system. In that sense, cardiologists are the plumbers, and I’m the electrician.”
Electrophysiology is one of the most specialized areas of cardiology because it involves studying signals that occur in milliseconds and mapping how they travel through the heart. Using specialized catheters, imaging systems, and diagnostic tools, electrophysiologists can identify subtle disruptions in those signals and correct them with targeted treatments.
Each heartbeat begins with a signal generated inside the heart. At the top of the right upper chamber is a cluster of specialized cells called the sinoatrial (SA) node, which acts as the heart’s natural pacemaker. These cells automatically produce electrical impulses that trigger the heart muscle to contract.
The signal spreads across the upper chambers, causing them to contract and pushing the blood into the lower chambers before reaching the atrioventricular (AV) node, where it briefly pauses. From there it travels through specialized fibers that rapidly distribute the signal across the ventricles so the heart chambers contract in the correct sequence.
Although physicians describe this process as electrical activity, it is not electricity in the traditional sense of “plugging something in.” Instead, it is driven by tiny movements of charged particles—primarily sodium, potassium, and calcium—moving in and out of heart cells. These movements generate impulses that neighboring cells detect and pass along, allowing the signal to move across the heart in a coordinated chain reaction.
“It's like the heart has its own internal battery,” Dr. Lo says. “That battery generates signals that tell the heart muscle when to contract and when to relax. As long as those signals travel through the heart the way they’re supposed to, the rhythm of your heartbeat stays steady.”
Electrophysiologists study those signals using tools such as electrocardiograms, wearable monitors, implantable loop recorders, and electrophysiology studies, where catheters with tiny electrodes measure electrical activity directly inside the heart.
Arrhythmias–or irregular heartbeats–occur when the signals controlling the heartbeat do not travel through the heart as they should. The signal may begin in the wrong place, move too quickly or too slowly, or circulate repeatedly through an abnormal electrical pathway. When that happens, the heart may beat too fast, too slow, or irregularly, sometimes interfering with how effectively the heart pumps blood.
One example is supraventricular tachycardia (SVT), in which an abnormal electrical circuit causes the heart rate to suddenly accelerate.
“A patient might feel completely normal, and then suddenly their heart rate jumps to 200 beats per minute or more,” Dr. Lo says. “It can be frightening, especially because it can happen unexpectedly.”
Symptoms of arrhythmias can vary widely. Some people feel their heart racing, pounding, or fluttering, while others experience fatigue, dizziness, or a reduced ability to exercise. In some cases, symptoms are subtle and easy to overlook, which can make diagnosis difficult.
This is often true of another common arrhythmia called atrial fibrillation (AFib), a condition in which electrical signals in the upper chambers of the heart become disorganized. AFib can reduce the heart’s efficiency and increase the risk of blood clots forming in the heart that may travel to the brain and cause a stroke.
“Sometimes patients with AFib don’t feel palpitations at all,” Dr. Lo says. “They may just feel unusually tired or notice they can’t do the things they used to do. Early diagnosis matters because atrial fibrillation can increase stroke risk and affect overall heart function.”
Another challenge to accurate diagnosis is how, when, and why the arrhythmia develops. Certain rhythm disorders are caused by extra electrical pathways that people are born with. Others develop later in life due to heart disease, high blood pressure, sleep apnea, or structural changes in the heart.
“Unlike coronary artery disease, which tends to develop later in life, electrical rhythm disorders can occur across a wide range of ages,” Dr. Lo says, “so my patients range from teenagers to people in their eighties and nineties.”
Electrophysiology testing allows physicians to analyze how signals travel through the heart and identify the pathways responsible for these abnormal rhythms so they can develop the most effective treatment possible.
Treatments for arrhythmias focus on restoring the normal flow of electrical signals through the heart. For example, if the heart’s natural signals become too slow or irregular, physicians may implant a pacemaker, a small device that monitors the heart’s rhythm and provides signals when needed.
However, while some surgeons can implant a pacemaker, says Dr. Lo, they may not be able to manage the long-term settings. Electrophysiologists receive specialized training in managing these devices and adjusting them to match each patient’s needs, fine-tuning them so patients can live their lives normally
“Technology is there to support what the body needs, not replace it,” Dr. Lo explains. “The goal is to help the heart do what it’s supposed to do naturally.”
Other rhythm disorders occur because a signal becomes trapped in an abnormal electrical pathway. Using mapping technology, electrophysiologists can create a three-dimensional model of the heart’s electrical activity to pinpoint the abnormal circuit. Once identified, the physician can perform catheter ablation, a minimally invasive procedure that delivers targeted energy through a catheter and eliminates the tiny area of tissue responsible for the faulty signal.
“In medicine, there are very few specialties where we can say we cured something,” Dr. Lo says, “but electrophysiology is one of them. If we can eliminate the abnormal pathway, the arrhythmia can be permanently resolved.”
For some patients—particularly younger individuals with intermittent episodes of rapid heart rhythm—this approach can eliminate the need for lifelong medication.
“If the episodes are unpredictable, patients may not want to take medication for something that only happens occasionally,” she explains. “By treating the abnormal circuit, we can remove the source of the problem so they don’t have to worry about it happening again.”
Electrophysiology remains one of the most specialized areas of cardiovascular medicine. Physicians who pursue the field complete additional years of training focused entirely on heart rhythm disorders, catheter procedures, and cardiac device therapy. At the same time, the field itself has evolved dramatically in recent decades as new technologies have transformed how physicians diagnose and treat arrhythmias.
“Years ago, treating certain arrhythmias required open-heart surgery,” Dr. Lo says. “Now we can treat many of them with minimally invasive catheter procedures.”
Modern electrophysiology relies on advanced technologies that allow physicians to study how electrical signals move through the heart in real time. Three-dimensional mapping systems can recreate the heart’s electrical activity with remarkable precision, helping physicians pinpoint abnormal pathways while reducing reliance on traditional X-ray imaging.
“Mapping allows us to see exactly how electricity travels through the heart,” Dr. Lo says. “That makes it easier to distinguish normal signals from abnormal ones and treat the problem without affecting healthy heart tissue.”
These advances have made arrhythmia treatment significantly more precise and effective, allowing physicians to correct electrical problems in ways that were not possible just a generation ago. But using these technologies effectively requires significant expertise in both diagnosing complex rhythm disorders and selecting the right treatment approach for each patient.
Dr. Lo has spent much of her career working at the forefront of these developments. With more than a decade of experience treating complex arrhythmias, she brings extensive electrophysiology expertise to CardioVascular Health Clinic.
Prior to joining the clinic, she helped establish a complex arrhythmia ablation program in Little Rock, Arkansas, that grew into one of the country’s leading centers for advanced rhythm procedures. Programs like this often treat large numbers of complex cases, allowing physicians like Dr. Lo to develop deeper experience with difficult arrhythmias and advanced catheter techniques.
That experience matters for patients because it translates into more accurate diagnoses, greater procedural precision, and access to advanced treatments that may not be widely available elsewhere in the region.
In addition to her clinical work, Dr. Lo has played a significant role in advancing the broader field of electrophysiology through research and clinical trials. She has participated in numerous studies evaluating next-generation catheter technologies designed to improve the safety, durability, and effectiveness of arrhythmia treatments, including the VOLT-AF IDE clinical trial, which examined a new pulsed field ablation catheter for treating atrial fibrillation.
Pulsed field ablation represents one of the most promising recent developments in electrophysiology. Traditional ablation techniques rely on radiofrequency to destroy abnormal tissue, but pulsed field ablation uses precisely controlled electrical fields that selectively affect heart cells while minimizing injury to nearby structures.
For the VOLT-AF IDE study, Dr. Lo served as both an investigator and author and was one of the top enrolling physicians in the trial. In that role, she treated a high number of patients using the technology as it was being evaluated, gaining extensive hands-on experience with how it performs across a range of clinical scenarios.
That level of involvement matters because physicians who lead clinical trials are often among the first to assess how new treatments translate from research into real-world patient care. Their experience helps guide how these technologies are refined, applied safely, and matched to the patients who will benefit most. For patients, it means access to a physician who is not only using advanced therapies, but actively contributing to how those treatments are developed and delivered.
Heart rhythm disorders can affect everything from daily energy levels to long-term cardiovascular health and when specialized care is needed, where and how that care is delivered can make a meaningful difference. With Dr. Lo joining CardioVascular Health Clinic, arrhythmia patients across Oklahoma now have access to advanced electrophysiology expertise and leading-edge arrhythmia treatments in a setting that is more accessible and easier to navigate.
Historically, patients with complex arrhythmias often needed to travel to larger metropolitan areas or major academic medical centers for specialized care. While those centers provide important resources, they can also feel overwhelming to navigate, especially for patients already dealing with new or uncertain symptoms.
“Patients shouldn’t have to leave their community to receive the most advanced treatment options available,” Dr. Lo says. “Now we are able to provide world-class electrophysiology care right here in Oklahoma.”
At CardioVascular Health Clinic, care is delivered in a more focused, outpatient setting that is designed to be easier—and less intimidating—for patients. Advanced electrophysiology capabilities, including complex ablation procedures and specialized diagnostics, are available without the scale and complexity of a large hospital system. And, because electrophysiology is integrated with other cardiovascular specialties, evaluation and treatment can also happen more quickly and collaboratively.
“If a vascular physician notices an irregular pulse, we can quickly evaluate it,” Dr. Lo says. “That’s important because if someone has atrial fibrillation and isn’t on blood thinners, their risk of stroke increases.”
For patients, this means fewer barriers to care, clearer answers, and access to advanced arrhythmia treatment in a setting that is more approachable and easier to navigate.
Through advanced electrophysiology care, Dr. Monica Lo and the team at CardioVascular Health Clinic are helping patients across Oklahoma better understand their heart rhythm and access leading-edge treatments designed to restore a healthy, steady heartbeat. If you have been experiencing symptoms such as dizziness, fatigue, or irregular heart rhythms, an evaluation from an electrophysiology specialist can provide answers and a path forward. Contact CardioVascular Health Clinic to schedule an appointment and learn more about advanced arrhythmia care.
