SVT vs. Sinus Tachycardia on ECG: Key Differences Explained

Sinus tachycardia and supraventricular tachycardia (SVT) can both cause a heart rate of over 100 beats per minute (bpm). However, there are some key differences between the two arrhythmias that can help to distinguish them on an electrocardiogram (ECG).

P waves

The first key difference between sinus tachycardia and SVT is the appearance of the P waves. In sinus tachycardia, the P waves are usually present and upright, as they are when the heart is beating in a normal sinus rhythm. However, in SVT, the P waves may be absent, hidden within the QRS complexes, or inverted.

PR interval

The PR interval is the time between the beginning of the P wave and the beginning of the QRS complex. In sinus tachycardia, the PR interval is usually normal, at around 0.12 to 0.20 seconds. However, in SVT, the PR interval may be shortened, prolonged, or variable.

QRS complex

The QRS complex is the time from the beginning of the QRS complex to the end of the QRS complex. In sinus tachycardia, the QRS complex is usually normal, at around 0.08 to 0.12 seconds. However, in SVT, the QRS complex may be widened, narrowed, or have an unusual shape.

Heart rate

The heart rate in sinus tachycardia is usually between 100 and 160 bpm. In SVT, the heart rate is usually between 150 and 250 bpm.

Symptoms

Sinus tachycardia is usually asymptomatic, as it is often caused by factors such as exercise, fever, or anxiety. However, SVT can cause symptoms such as palpitations, chest pain, shortness of breath, lightheadedness, or fainting.

Treatment

Sinus tachycardia usually does not require treatment, as it will usually resolve on its own. However, SVT may require treatment with medications, surgery, or ablation procedures.

If you are experiencing symptoms of sinus tachycardia or SVT, it is important to see a doctor so that the arrhythmia can be diagnosed and treated appropriately.