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Table I-A.3. Electrocardiographic (ECG) Characteristics and Causes of Junctional Rhythms

"

00

Name

ECG Characteristics

Common Causes

PT Considerations

g

Junctional escape

Regular rhythm, rate 20-40;

Usual cause is physio

If occasional and intermittent during

'"

rhythm

inverted P wave before

�

or

logic ro control the

bradycardia or chronic AF, usu

'"

'"

after QRS complex; starts

ventricles in AV

ally insignificant and can treat

:t

with ectopic foci in AV juncblock, sinus brady

(with close watch of possible

>

Z

tion tissue

cardia, AF, sinoatrial

worsening condition via sympc

block, drug intoxicatoms and vital signs); if consistent

g '"

tion

and present secondary to AV

block, acute myocardial infarco

'"

rion, or drug intoxication, can be

�

symptomatic with CHE (See

i!1

Table 1-21.)

�

r

Junctional tachycar

Regular rhythm; rate 100-

Most common with

May produce or exacerbate sympi

dia

180; P wave as above

chronic AFj also with

[Oms of CHF or angina secondary

�

coronary artery disto decreased cardiac output; PT

>

"

ease, rheumatoid

treatment depends on patient tol

;!

heart disease, and

erance-if new, onset should wait

cardiomyopathy

for medical treatment.

AF = atrial fibrillation; AV = atrioventricular; CHF = congestive heart failure.

Sources: Data from 8 Aehlert. ACLS Quick Review Study Guide. St. LoUIS: Mosby, t 994; and EK Chung. Manual of Cardiac Arrhythmias.

Boston: Butterworth-Heinemann, t 986.