The heart’s electrical system orchestrates its rhythmic beating, but disruptions can lead to irregular heartbeats, known as arrhythmias. Supraventricular tachycardia (SVT) and atrial fibrillation (AFib) are two common types originating from the upper chambers of the heart. Individuals can experience both SVT and AFib, either at different times or concurrently.
Understanding Supraventricular Tachycardia and Atrial Fibrillation
Supraventricular tachycardia (SVT) refers to a rapid heart rate that begins in the upper chambers of the heart. This condition typically results in a regular, fast heartbeat, often ranging from 150 to 220 beats per minute. Episodes of SVT can start and stop abruptly, and while they may feel alarming, they are generally not life-threatening.
Atrial fibrillation (AFib), on the other hand, involves chaotic and irregular electrical signals in the heart’s upper chambers. This causes them to quiver rather than contract effectively, leading to an irregular and often rapid heart rate in the lower chambers. AFib carries a more serious risk of complications, particularly stroke, because blood can pool in the quivering atria and form clots.
A key distinction between SVT and AFib lies in their rhythm: SVT typically presents as a rapid, regular rhythm, whereas AFib is characterized by an irregular and chaotic rhythm. Although AFib is technically a form of SVT, it is often treated as a distinct condition due to its unique characteristics and associated risks.
Factors Contributing to Co-Existence
Several factors can increase susceptibility to both SVT and AFib, often due to shared vulnerabilities in the heart’s electrical system. Age increases the risk for both conditions. Pre-existing heart conditions, such as structural heart disease, heart failure, or coronary artery disease, also contribute to both arrhythmias.
Other medical conditions and lifestyle factors also contribute. High blood pressure, obesity, and sleep apnea are common in individuals with either SVT or AFib and can contribute to both. Excessive alcohol consumption and certain thyroid conditions can also irritate the heart’s electrical system, increasing susceptibility to irregular rhythms.
Physiological mechanisms also link the two conditions. Abnormal electrical pathways or irritable tissue in the upper chambers of the heart can lead to both arrhythmias. An episode of SVT can even trigger the onset of AFib, indicating a complex interplay between their electrical circuits. Increased atrial size or stretch during SVT may also contribute to AFib development.
Identifying and Diagnosing Both Conditions
Identifying and distinguishing between SVT and AFib involves evaluating symptoms and utilizing diagnostic tools. Common symptoms like palpitations, shortness of breath, dizziness, and fatigue can overlap. However, the regularity of heartbeats during an episode provides an initial clue: SVT is typically regular, while AFib is irregularly irregular.
Electrocardiograms (ECGs) are key diagnostic tools, capturing the heart’s electrical activity. For sporadic arrhythmias, a Holter monitor, a portable ECG device worn for 24 to 48 hours, records continuous heart activity during daily routines. An event monitor may be used for longer periods, activated by the patient when symptoms occur.
For a more detailed assessment, an electrophysiology (EP) study can be performed. This invasive procedure guides thin wires into the heart to map its electrical pathways and pinpoint the origin of irregular beats. This evaluation helps medical professionals diagnose and distinguish between SVT and AFib, especially when both are suspected.
Navigating Treatment for Both Conditions
Managing both SVT and AFib requires an individualized treatment approach, considering episode frequency, severity, and overall patient health. Medications are often the first line of treatment, with beta-blockers and calcium channel blockers commonly used to control heart rate. Antiarrhythmic drugs may also be prescribed to restore and maintain a normal heart rhythm. Since AFib carries a stroke risk, anticoagulants (blood thinners) are frequently prescribed to prevent blood clot formation, regardless of co-existing SVT.
For individuals not adequately managed by medication, procedural interventions may be considered. Cardioversion involves delivering a controlled electrical shock to the chest to reset the heart’s rhythm. Catheter ablation is another option, where small areas of heart tissue responsible for irregular electrical signals are precisely targeted and destroyed.
Sometimes, a single ablation procedure can address pathways involved in both SVT and AFib, or separate ablations may be necessary. Lifestyle modifications also play a significant role in managing both conditions, including addressing shared risk factors like high blood pressure, maintaining a healthy weight, managing sleep apnea, and moderating alcohol and caffeine intake. Collaborative care with a cardiologist or electrophysiologist is important to determine the most effective treatment strategy.