Supraventricular Arrhythmias
Supraventricular arrhythmias are abnormal heart rhythms that start in the upper chambers of the heart (the atria or the AV node) rather than the ventricles. The most common type is supraventricular tachycardia (SVT), where the heart suddenly accelerates to 150-250 beats per minute, then stops just as abruptly. Most episodes are not life-threatening, but they can be frightening and disruptive.
Key points
- These rhythms start above the ventricles, in the atria or AV node, with SVT racing the heart before stopping abruptly.
- Episodes bring sudden palpitations, chest fluttering or tightness and breathlessness, lasting seconds to hours and sometimes triggered by caffeine or stress.
- Verapamil, a calcium-channel blocker, slows the AV node’s conduction and breaks the abnormal signal loop responsible for most episodes.
What an episode feels like
The hallmark is an abrupt onset of rapid, regular palpitations. Other common sensations include a pounding or fluttering in the chest, lightheadedness, shortness of breath, and mild chest tightness. Episodes can last seconds or hours. Some people feel completely fine between attacks; others notice them triggered by caffeine, alcohol, stress, or lack of sleep.
Seek prompt medical attention if palpitations are accompanied by fainting, severe chest pain, or difficulty breathing.
Slowing and controlling the rhythm
Treatment targets either stopping an acute episode or reducing how often episodes recur. Calcium-channel blockers such as verapamil work by slowing electrical conduction through the AV node, interrupting the re-entry circuit that drives most SVT. Longer-term rhythm management may also involve other agents within the broader heart and blood pressure category, chosen based on the specific arrhythmia type and a person’s overall cardiac health.