SVT is always more symptomatic than sinus tach. Sinus tachycardia has a rate of 100 to 150 beats per minute and SVT has a rate of 151 to 250 beats per minute.

ECG features: P waves are often hidden – being embedded in the QRS complexes; Pseudo R’ wave may be seen in V1 or V2; Pseudo S waves may be seen in leads II, III or aVF; In most cases this results in a ‘typical’ SVT appearance with absent P waves and tachycardia

In sinus tachycardia, there is gradual onset and termination of symptoms like palpitation. SVT typically presents with sudden onset and termination of palpitations, light-headedness, chest pain, abnormal pulsations in the neck and dyspnea lasting between seconds to several hours.

Regular broad complex tachycardias can be ventricular (VT) or supraventricular (SVT with aberrancy) in origin, and differentiation between the two will significantly influence management of your patients. Unfortunately, the electrocardiographic differentiation of VT from SVT with aberrancy is not always possible.

SVT is an abnormal fast heart rhythm starting in the upper chambers (atria) of the heart, leading to a heart rate often between 150 to 250 beats per minute. On an ECG, SVT is identified by a rapid, regular rhythm with typically narrow QRS complexes. Often, P waves are difficult to see.