The AHA Guidelines and Scientific Statements Handbook

The AHA Guidelines and Scientifi c Statements Handbook

but long-lasting episodes of AVNRT when vagal
maneuvers alone are ineffective for the termination of
tachycardia episodes. Candidates should have normal
left ventricular function, no bradycardia and no preex-
citation. Oral single-dose of diltiazem (120 mg) plus
propranolol (80 mg) was more effective in terminating
PSVT than both placebo and fl ecainide [13].
Radiofrequency (RF) catheter ablation is successful
in 96% [14–16]. Ablation of the slow pathway, which
is the preferable approach, has markedly reduced the
risk of AV-block to less than 1%. In one long-term
follow-up (10 years) study after RF ablation no
AVNRT recurrences were observed, but 24% suffered
from new arrhythmias or late AV block [17].
Slow pathway cryoablation has been associated
with higher recurrence rates than radiofrequency
ablation (7–20% vs. 5.6%) in some studies [18,19].
AV-block is not guaranteed by negative cryomap-
ping, stressing the need for careful surveillance [18].
Newer concepts relative to pathogenesis of AVNRT
relate to involvement of the right and left inferior
nodal extensions. These concepts explain the need
for ablation of AVNRT (in rare patients) from the
coronary sinus or mitral annulus [20].

Focal and nonparoxysmal junctional tachycardia
Focal junctional tachycardia
Other terms for this tachycardia are automatic or
junctional ectopic tachycardia. The arrhythmia

origin is the AV node or His bundle. The abnormally

rapid discharges from the junctional region results

in varied ECG manifestations because it does not

require participation of either the atrium or the ven-

tricle for its propagation. The heart rate ranges

between 110 and 250 bpm, with narrow or typical

bundle branch block conduction pattern. Atrioven-

tricular dissociation is often present. The arrhyth-

mia is rare and seen in young adults. It is usually

exercise or stress-related, and may occur in patients

with structurally normal hearts or in patients with

congenital abnormalities. It may, if untreated,

produce congestive heart failure, especially if it is

incessant.

Drug therapy is only variably successful [21].

Catheter ablation is associated with risk of AV-block

[22,23] (Table 16.4).

Nonparoxysmal junction tachycardia

This is a benign arrhythmia characterized by narrow

complex tachycardia with rates of 70–120 bpm. The

arrhythmia may be a marker for serious underlying

conditions (digitalis toxicity, postcardiac surgery,

hypokalemia or myocardial ischemia) and may be

observed in conjunction with chronic obstructive

lung disease with hypoxia, and infl ammatory myo-

carditis. It shows a typical “warm-up” and “cool-

down” pattern and cannot be terminated by pacing

maneuvers. Unlike the more rapid form of focal

Table 16.4 Recommendations for the treatment of focal and nonparoxysmal junctional tachycardia syndromes

Tachycardia Recommendation Classifi cation Level of evidence

Focal junctional tachycardia Beta-blocker IIa C
Flecainide IIa C
Propafenone IIa C
Sotalol IIa C
Amiodarone* IIa C
Catheter ablation IIa C

Nonparoxysmal junctional tachycardia Reverse digitalis toxicity I C
Correct hypokalemia I C
Treat myocardial ischemia I C
Beta-blockers, calcium channel blockers IIa C

The order in which treatment recommendations appear in this table within each class of recommendation does not necessarily refl ect a preferred sequence of
administration.

• Data available for pediatric patients only.