An SVT ECG refers to the electrocardiogram (ECG) findings associated with Supraventricular Tachycardia (SVT). SVT is a heart rhythm problem characterized by a rapid heart rate originating above the ventricles. The ECG helps to diagnose SVT by showing specific characteristics.
Key ECG Characteristics of SVT
The hallmark of SVT on an ECG includes:
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Rapid Heart Rate: Typically, the heart rate is greater than 100 beats per minute (bpm), and can often be much higher.
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Narrow QRS Complex: The QRS complex is usually narrow, measuring less than 120 milliseconds. This indicates that the rapid rhythm originates above the ventricles, either in the atria or the atrioventricular (AV) node, as noted in the reference: "Supraventricular tachycardia (SVT) is a dysrhythmia originating at or above the atrioventricular (AV) node and is defined by a narrow complex (QRS < 120 milliseconds) at a rate 100 beats per minute (bpm)."
Examples of SVT ECG Findings:
To illustrate, consider the following examples:
- Example 1: An ECG showing a heart rate of 180 bpm with a QRS duration of 80 milliseconds. This is highly suggestive of SVT.
- Example 2: An ECG with a consistent, rapid rhythm where the QRS complexes are all of normal width, but the P waves (atrial activity) are difficult to distinguish due to the fast rate.
Additional Points
- While a narrow QRS complex is typical, certain types of SVT might present with a wide QRS complex if there is aberrant conduction.
- P waves may be absent or difficult to identify, or they may appear different from normal sinus rhythm.
- The regularity of the rhythm can also be a diagnostic feature; SVT is generally a regular rhythm.
