Tachycardia, a resting heart rate above 100 beats per minute, can often be slowed or stopped depending on its type and cause. Some episodes respond to simple breathing techniques you can do at home, while others require medication, a medical procedure, or emergency care. The right fix depends entirely on what’s driving your fast heart rate.
Know Which Type You’re Dealing With
Not all fast heart rates need the same fix, and some don’t need fixing at all. Sinus tachycardia is the most common type. It happens when your heart speeds up in response to something predictable: stress, anxiety, exercise, fever, or dehydration. This is your heart doing its job. It resolves when the trigger goes away.
Supraventricular tachycardia (SVT) starts in the upper chambers of the heart and causes sudden episodes where your heart races, often at 150 beats per minute or higher, for no obvious reason. These episodes can last seconds or hours. Ventricular tachycardia starts in the lower chambers and is more dangerous because it can prevent the heart from pumping blood effectively. Ventricular fibrillation, the most severe form, causes blood pressure to drop dramatically and can be fatal within minutes if the rhythm isn’t reset.
If your fast heart rate comes with fainting, severe chest pain, difficulty breathing, confusion, or a sudden drop in blood pressure, that’s an emergency. Brief episodes of SVT that resolve on their own are common and not immediately dangerous, but recurring episodes should be evaluated with an ECG so you and your doctor know exactly what’s happening.
Vagal Maneuvers: Stopping an Episode in the Moment
During an SVT episode, you can sometimes reset your heart rhythm using vagal maneuvers. These techniques stimulate the vagus nerve, which slows electrical signals through the heart. They work in about 20 to 40% of cases, and a modified version can push that success rate above 40%.
The simplest approach is the Valsalva maneuver. Lie on your back, take a deep breath, then bear down hard as if you’re trying to push air out against a closed throat. Hold this for 10 to 15 seconds. A practical variation: try blowing into a 10 mL syringe hard enough to move the plunger, and sustain it for the same duration.
The modified Valsalva maneuver roughly doubles the success rate of the standard version. Start sitting upright, then blow against a closed throat or syringe. Immediately lie flat while someone raises your legs to a 45- to 90-degree angle (or pull your knees to your chest). Keep blowing for 10 to 15 seconds, then hold the leg position for 45 seconds to one minute. The combination of straining and the sudden leg elevation creates a stronger vagal response.
Other quick techniques include splashing ice-cold water on your face, holding your breath briefly, or coughing forcefully. These are less studied but work through the same nerve pathway. If one attempt doesn’t work, you can try again after about a minute.
Fix the Underlying Triggers
Many cases of tachycardia are the heart reacting to something fixable in the body. Addressing the root cause is often all it takes.
Dehydration. When you lose fluid, your blood volume drops, and your heart compensates by beating faster. Losing as little as 3% of your body weight in fluid (about 4.5 pounds for a 150-pound person) can noticeably increase heart rate, especially when you stand up. Moderate dehydration at 5% body mass loss produces even larger heart rate swings. Steady water intake throughout the day, particularly during heat or exercise, prevents this entirely.
Electrolyte imbalances. Magnesium and potassium work together to keep heart cells electrically stable. When magnesium drops too low, it disrupts how potassium moves in and out of heart muscle cells, destabilizing the resting electrical charge and triggering arrhythmias including SVT. Chronic use of certain medications like acid-reducing drugs can quietly deplete magnesium over time. If you have recurring episodes, your doctor can check your levels with a simple blood test. Dietary sources of magnesium (nuts, leafy greens, seeds) and potassium (bananas, potatoes, beans) help maintain balance.
Stimulants. Caffeine, nicotine, and alcohol are all known to trigger extra heartbeats and episodes of tachycardia. Reducing or eliminating these can meaningfully reduce how often episodes occur. There’s no universal “safe” threshold; some people are far more sensitive than others. If you notice a pattern between your intake and your symptoms, cutting back is a straightforward first step.
Stress and anxiety. Chronic stress keeps your sympathetic nervous system activated, which directly raises your resting heart rate. Regular physical activity, adequate sleep, and stress-reduction practices like slow breathing or meditation can lower your baseline heart rate over weeks.
Medications for Ongoing Rate Control
When lifestyle changes and vagal maneuvers aren’t enough, medications can keep the heart rate in a normal range or prevent episodes from starting. The two most common classes used for tachycardia are beta-blockers and calcium channel blockers.
Beta-blockers reduce the effect of adrenaline on the heart, slowing the heart rate and lowering blood pressure. They’re typically a first-line option for people with frequent SVT or sinus tachycardia that doesn’t respond to other measures.
Calcium channel blockers work by preventing calcium from entering heart and artery cells. Since calcium makes these cells contract more forcefully, blocking it relaxes blood vessels and slows the heart rate. These are particularly useful when beta-blockers aren’t tolerated or when the tachycardia involves the upper chambers of the heart.
Both types of medication are taken daily for prevention rather than used to stop an acute episode. Finding the right medication and dose often requires some adjustment, and side effects like fatigue, dizziness, or low blood pressure are common early on. For acute episodes in a medical setting, a fast-acting drug that briefly blocks electrical conduction in the heart can reset the rhythm almost instantly.
Catheter Ablation for a Long-Term Fix
If your tachycardia keeps returning despite medication, catheter ablation offers a more permanent solution. During the procedure, a thin tube is threaded through a blood vessel (usually in the groin) to the heart. The tip delivers either heat or cold to destroy the small area of tissue responsible for the abnormal electrical signals.
The success rates are strong. After a single procedure, about 73% of patients remain free of their tachycardia over a three-year follow-up period. With a second procedure if needed, that number rises to around 85%. Success is highest in the first year (about 82%) and gradually decreases slightly over time, which is why some patients need a repeat ablation.
Recovery is relatively quick. You’ll typically be monitored in the hospital for at least 24 hours after the procedure. Most people return to normal activities within a few days, though strenuous exercise is usually restricted for one to two weeks. The procedure carries small risks of bleeding, infection, or damage to blood vessels, but serious complications are uncommon.
Ablation is most commonly recommended for SVT, particularly when episodes are frequent, disruptive to daily life, or don’t respond well to medication. For many people, it eliminates the need for daily heart rate medication entirely.
What to Do During a Severe Episode
Most SVT episodes feel alarming but resolve within minutes and aren’t dangerous. The key distinction is between a fast heart rate that’s uncomfortable and one that’s compromising blood flow. If a racing heart is accompanied by fainting, severe lightheadedness, chest pain, sudden confusion, or signs of shock (cold, clammy skin, very low blood pressure), that episode needs emergency treatment.
In the emergency setting, the treatment approach depends on stability. For someone who is stable, doctors typically start with vagal maneuvers and, if those fail, move to medications. For someone who is unstable, synchronized cardioversion (a controlled electrical shock timed to the heart’s rhythm) is used to reset the heart immediately. Sedation is given beforehand.
If you have a known SVT diagnosis and your episodes are brief, self-limiting, and respond to vagal maneuvers, you may not need emergency care each time. But any episode with new or worsening symptoms, or one that lasts longer than usual and doesn’t respond to your usual techniques, warrants urgent evaluation.