Disorders of Impulse formation and Conduction

Supraventricular Tachycardia Introduction Tachycardia refers to a heart rate >100 beats per minute (bpm). The tachycardia may be supraventricular or ventricular depending on the origin of the arrhythmia. Supraventricular Tachycardia (SVT): If the tachycardia originates above the bifurcation of the bundle of His, usually in the atria or atrioventricular (AV) junction, the tachycardia is supraventricular. Supraventricular impulses follow the normal AV conduction system, activate the ventricles synchronously and will have narrow QRS complexes measuring <120 milliseconds. The QRS may be wide if there is pre-existent bundle branch block, ventricular aberration, or the impulse is conducted through a bypass tract. Ventricular … Read more

Sinus Arrhythmias means the rhythms or arrhythmias which originate from the sinoatrial node, travel to atrioventricular node and then via bundle of his and purkinjee fibres activates the ventricles to complete the depolarisation and repolarisation cycle. Because it is following the natural path which is fast and specialised to conduct the impulse in a certain way, this kind of rhythm is referred to as sinus rhythm. If the rhythm is somehow not regular and periodic in time but is originating from sinoatrial node, it is known as sinus arrhythmias. What is a Normal Sinus Rhythm? Normal sinus rhythm is reflected … Read more