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Sinus rhythm with ventricular bigeminy due to digitalis toxicity. Ventricular premature complexes follow each sinus-conducted QRS at a fixed coupling
interval. ST-segment depression and T wave inversion in the sinus-conducted beats is seen in V6; however, since each sinus-conducted beat is a
postextrasystolic one, correct interpretation of ST-T abnormalities is difficult. The sinus rate is not measurable when ventricular bigeminy is present since
consecutive sinus complexes are not present. Although ventricular bigeminy in this patient was associated with a toxic serum level of digoxin, this
arrhythmia is not specific for digitalis intoxication. If a ventricular arrhythmia is due to digitalis toxicity, it is expected to disappear as the serum level of
digitalis is lowered. Note the presence of P waves deforming the ST segments of the premature ventricular depolarizations (arrows); since the intervals
Source: Heart Disease, Current Medical Diagnosis & Treatment 2017
between them and the preceding sinus P waves is not half the measured sinus cycle length, they are probably retrogradely conducted. (Reproduced, with
Citation:
PapadakisN,MA,
McPhee
SJ,
Rabow MW.
Current
Medical Diagnosis &13th
Treatment
2017; 2016
Available
at: http://mhmedical.com/
permission, from
Goldschlager
Goldman
MJ.
Principles
of Clinical
Electrocardiography,
ed. Originally
published
by Appleton
& Lange. Copyright ©
Accessed:
May
13,
2017
1989 by The McGraw-Hill Companies, Inc.)
Copyright © 2017 McGraw-Hill Education. All rights reserved