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Normal Sinus Rhythm with an Aberrantly Conducted Premature Atrial Complex and an Apparent Brief Sinus Pause

Image 1 of 3 in Series "An Apparent Sinus Pause Resulting from Normal Physiology"

Description

The rhythm is normal sinus rhythm at a rate of approximately 76/min. The third QRS complex is an aberrantly conducted premature atrial complex (PAC) and a brief sinus pause of 1.4 seconds appears to follow the eighth QRS complex.

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This image is part of the series "An Apparent Sinus Pause Resulting from Normal Physiology"

Other images in this series

Normal Sinus Rhythm with an Aberrantly Conducted Premature Atrial Complex

by: Joe B. Calkins, Jr., M.D.

Rhythm strips recorded from leads V1, II and V5 are shown. The first premature atrial complex (PAC) is shown as a negative deflection at the end of the second T wave (arrow). It occurs while the His Purkinje system is in its relatively refractory period, which results in an aberrant conduction.

Normal Sinus Rhythm with a Non Conducted Premature Atrial Complex

by: Joe B. Calkins, Jr., M.D.

Rhythm strips recorded from leads V1 (top), II (middle) and V5 (bottom) are shown. Close inspection of the T wave following the eighth QRS complex reveals superimposition of an upright deflection which represents a second PAC (arrow). It follows the preceding P wave at such a short interval that the AV node is in its absolute refractory period and the PAC is not conducted to the ventricles. The combination of the non-conducted PAC and the resulting noncompensatory pause cause a delay which appears to be a brief sinus pause, but is actually the result of normal physiology.