It Reminds Him of When His Heart “Got Very Sick”
ANSWER
Findings on this ECG include sinus rhythm with frequent, consecutive premature ventricular complexes (PVCs) consistent with nonsustained ventricular tachycardia (NSVT). There is also evidence of a probable left atrial enlargement.
The key to interpreting this ECG is to first locate normal-appearing complexes. These are illustrated by the third, fourth, 10th, and 11th complexes on the rhythm strip (lead I) at the bottom of the ECG. Notice that there is a normal-appearing PQRST complex for each of these beats.
The rate of 82 beats/min is calculated from a sum average of all beats on the 12-lead ECG; however, the R-R interval between the third and fourth and the 10th and 11th beats is roughly 60 beats/min, signifying a normal sinus rhythm. All other beats are PVCs arising from the left ventricle (as evidenced by a right bundle branch pattern in lead V1).
Careful inspection will reveal retrograde P waves located in the terminal upstroke of the S wave. NSVT is defined as three or more consecutive PVCs at a rate greater than 100 beats/min with a duration of less than 30 seconds. The pauses seen between a PVC and a normally conducting P wave are caused by retrograde conduction from the ventricle to the atrium, with subsequent block within the atrium.
Finally, left atrial enlargement is evidenced by a biphasic P wave in the normally conducting beat seen in lead V1.
