Supraventricular Tachycardia (SVT)

The heart has four chambers – the atria above and the ventricles below. Irregular heartbeats typically affect one or the other. Supra ventricular tachycardia or SVT involves the heart beating too quickly or erratically in the upper chambers – the Atria. There is a significant variance in what we consider to be a normal heartbeat. Some people, especially high-performance athletes, have a heartbeat as low as 60 beats per minute. An average person will have between 80 and 100 beats per minute. Anything above 100 beats per minute is known as tachycardia or fast heartbeat. Depending on the specific problem causing the SVT, patients suffering from this condition can have a heartbeat of up to 220 beats per minute. For some, this can cause mild to moderate symptoms, while others may think they’re having a heart attack and end up in the emergency room. SVTS affect us all in different ways.

The Types of Supraventricular Tachycardia

SVT is an umbrella term for all of the conditions causing a fast heartbeat above the ventricles. The most common SVTs include Atrioventricular Nodal Reentrant Tachycardia (AVRNT), Atrioventricular Reciprocating Tachycardia (AVRT), and Atrial Tachycardia (AT). There are several other types of SVT, but these three conditions are by far the most common.

What You Feel With SVTs

SVTs can come with a wide variance in signs and symptoms. Some patients may have very mild symptoms while others experience downright frightening effects. The onset and frequency of SVTs may also vary dramatically between patients. Known as paroxysmal SVT, episodes can come and go over the course of days, weeks, or months without any pattern or perceptible reason. These episodes can occur for a very short period but may last a few days or more. Most commonly, patients with SVT will experience the following

  • A feeling of the heart-pounding
  • A fluttering in the chest
  • Weakness and fatigue
  • Shortness of breath
  • Dizziness
  • Unexplained fainting, known as syncope

The Causes of SVT

In some cases, we can pinpoint the cause of SVT, while in others there may be no obvious reasons for its onset or return. In fact, patients of all ages can experience SVT, though certain patients have a greater risk of developing an SVT including:

  • Those with heart disease
  • Heavy alcohol drinkers
  • Smokers
  • Those using or abusing drugs
  • Those with lung cancer
  • Those taking certain medications

If the cause of the SVT is modifiable, Dr. Moretta will suggest changing a lifestyle habit or medication or treating an underlying condition to improve the arrhythmia. For those who do not have an apparent cause of their SVT, or for whom the risk factors are not modifiable, medical (pharmaceutical drugs), or procedural (ablation) intervention may be called for.

Treatment for SVTs

Treatment for SVT requires a diagnosis from a skilled electrophysiologist like Dr. Moretta. SVT comes in different shapes and sizes and therefore no two treatment plans will be the same. Medical therapy, in the form of antiarrhythmic and anticoagulant medication, is often the easiest and most effective way to treat an SVT. However, some patients – up to 50% – do not achieve acceptable results from their medications or experience unacceptable side effects. For those patients, procedural interventions like cardiac catheter ablation or left atrial appendage closure for patients with stroke risk may be appropriate. These are minimally invasive procedures performed in an EP lab at the hospital. They are not only effective but relatively low risk, especially in the hands of a highly experienced electrophysiologist. Most importantly, early diagnosis is key to unlocking the greatest number of treatment options and preventing a paroxysmal or occasional SVT from becoming persistent.

Prevention of SVT

For some, there is no intervention to prevent the onset of an SVT. However, a good rule of thumb is it your overall health is predictive of your heart health. Doing what you can to reduce the likelihood of heart disease – eating well, exercising, and reducing stress – can all help in the prevention of an SVT or other arrhythmias. An early diagnosis may also uncover underlying concerns such as thyroid issues or medications that can be treated or reevaluated as necessary to improve the arrhythmia.

We look forward to discussing your options further and encourage you to schedule a consultation with our office to learn more about the next steps and treatment options.

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