The Care You Need When Your Heart Rhythm Feels Off 

Cardiac arrhythmias occur when the heart’s electrical system causes the heartbeat to run too fast, too slow or out of pattern. Some rhythm changes feel obvious. Others cause no symptoms at all but still need medical attention, especially when episodes repeat or you have certain risk factors. At Keck Medicine of USC, our electrophysiology team evaluates the full range of rhythm disorders. We offer options from monitoring and medication to catheter ablation and device therapy.  

What Are Cardiac Arrhythmias? 

Your heart has its own electrical “pacemaker” system. When those signals fire too quickly, too slowly or in the wrong sequence, your heartbeat can change. Some arrhythmias never lead to serious problems. Others become serious based on the arrhythmia type and your overall heart health.  

Symptoms of Cardiac Arrhythmias 

You may notice symptoms during exercise, while resting or when you try to sleep. You may also feel nothing at all, even if episodes continue. Heart arrhythmia symptoms can include:  

• A feeling that your heart feels palpitating, fluttering, pounding or racing 
• An unusually low pulse 
• Chest pains 
• Dizziness or fainting spells 
• Fatigue or listlessness 
• Shortness of breath 

Call 911 right away for chest pain, severe shortness of breath, fainting or stroke symptoms (face droop, weakness on one side, trouble speaking).  

Common Types of Cardiac Arrhythmias 

Arrhythmias can start in the heart’s upper chambers or lower chambers. Determining the type of arrhythmia you have helps your team decide which tests to apply. Then, we choose treatments that fit your symptoms and your goals. 

• Supraventricular tachycardia (SVT) often causes a sudden, fast heartbeat and typically starts in the upper chambers of the heart. In many cases, SVT is not dangerous, but episodes can feel intense or disruptive.  
• Ventricular tachycardia (VT) starts in the lower chambers of the heart. VT can become dangerous, especially in people with heart disease or a prior heart attack. If you have symptoms that feel urgent, call 911.  
• Other common arrhythmias can cause an irregular rhythm rather than a fast rhythm, and some cause a slow rhythm. Your care team may also diagnose atrial fibrillation (AFib), atrial flutter, premature beats (extra beats) or bradycardia (a heartbeat that runs too slow). The right treatments depend on the rhythm type, how often it happens and your overall heart health. 

How We Diagnose Cardiac Arrhythmias 

A clear diagnosis helps your care team match your symptoms to the rhythm pattern causing them. We start by talking about what you feel when it happens and what may trigger episodes. Many people begin with an electrocardiogram (EKG/ECG) with their primary care clinician, then see a specialist with us for additional testing when symptoms continue or the rhythm needs a closer look. Your evaluation may include: 

• An electrocardiogram (EKG/ECG) to record your heart rhythm 
• An echocardiogram to assess heart structure and valve health 
• Additional testing based on your symptoms and risk factors 

Ambulatory Monitoring of Cardiac Arrhythmias 

Ambulatory monitoring of cardiac arrhythmias lets your team record your heart rhythm while you go about your daily life. This helps us capture changes that come and go. Depending on your symptoms and how often your episodes occur, your team may recommend: 

• A Holter monitor that records your heart rhythm continuously, often for 24 to 48 hours or longer 
• An event recorder that you wear or carry that records when symptoms occur or when the device detects a change 
• An implantable loop recorder placed under the skin that can record for up to three years 
• Patch monitoring with a small wearable patch that records continuously for several days 

Treatments We Offer for Cardiac Arrhythmias 

Your treatment plan depends on the type of arrhythmia, your symptoms and your overall heart health. Some arrhythmias are not dangerous and may not need treatment. When treatment makes sense, your care team may recommend one option or a combination of the following: 

• Medication, which can help control heart rate, reduce episodes or treat related conditions that affect rhythm. 
• Cardioversion, which uses a quick, controlled electrical shock to restore a normal rhythm for some arrhythmias, while you receive IV medication so you stay comfortable. 
• Catheter ablation and electrophysiology studies, which can help your team locate where the rhythm problem starts and treat it. When appropriate, specialists use advanced tools, such as intracardiac ultrasound and 3D mapping, to pinpoint the “short circuit,” then apply energy to stop it. 
• Device therapy, which may include implantable devices, such as pacemakers or defibrillators, based on the rhythm problem and your risk profile. 
• Long-term follow-up care, which may include monitoring and check-ins so your team can adjust treatment as your needs change.