Typical<unk>  is recognized on an electrocardiogram by presence of characteristic<unk>  waves" at a regular rate of 200 to 300 beats per minute.<unk>  waves may not be evident on an ECG in atypical forms of<unk> . Individual<unk>  waves may be symmetrical, resembling p-waves, or maybe asymmetrical with a "sawtooth" shape, rising gradually and falling abruptly or vice versa. If<unk>  is suspected clinically but is not clearly evident on ECG, acquiring a Lewis lead ECG may be helpful in revealing<unk>  waves. Classification There are two types of<unk> , the common type I and rarer type II. Most individuals with<unk>  will manifest only one of these. Rarely someone may manifest both types; however, they can manifest only one type at a time. Type I AV nodal block.<unk>  with a two to one block. Note the P waves hiding in the T waves in leads V1 and V2 Type I<unk> , also known as common<unk>  or typical<unk> , has an<unk>  rate of 240 to 340 beats/minute. However, this rate may be slowed by antiarrhythmic agents. The reentrant loop circles the right atrium, passing through the cavo-tricuspid isthmus – a body of fibrous tissue in the lower atrium between the inferior vena cava, and the tricuspid valve. Type I<unk>  is further divided into two subtypes, known as counterclockwise<unk>  and clockwise<unk>  depending on the direction of current passing through the loop. * Counterclockwise<unk>  (known as cephalad-directed<unk>  is more commonly seen. The<unk>  waves in this rhythm are inverted in ECG leads II, III, and aVF. * The re-entry loop cycles in the opposite direction in clockwise<unk> , thus the<unk>  waves are upright in II, III, and aVF. Type II Type II (atypical)<unk>  follows a significantly different re-entry pathway to type I<unk> , and is typically faster, usually 340–350 beats/minute. Atypical<unk>  rarely occurs in people who have not undergone previous heart surgery or previous catheter ablation procedures. Left<unk>  is considered atypical and is common<unk> ter incomplete left<unk>  ablation procedures. Atypical<unk>  originating from the right atrium and heart's septum have also been described.
Atrial flutter
Ventricular flutter
Sinus arrhythmia
Supraventricular tachycardia
Atrial fibrillation
Ventricular fibrillation
Left bundle branch block
Junctional tachycardia