Utility of tachycardia cycle length variability in discriminating atrial tachycardia from ventricular tachycardia.
BACKGROUND
Inappropriate implantable cardioverter-defibrillator (ICD) therapy of atrial tachycardia (AT) with 1:1 atrioventricular (AV) conduction is common because it is difficult to discriminate from ventricular tachycardia (VT) with 1:1 retrograde conduction. Tachycardia cycle length (CL) variability and the relationship between atrial and ventricular CLs may be useful in discriminating AT from VT with 1:1 retrograde conduction.


OBJECTIVE
The purpose of this study was to evaluate the usefulness of the relationship between the atrial and ventricular CLs in differentiating AT with 1:1 conduction from VT with 1:1 retrograde conduction.


METHODS
We studied 71 patients who had a tachycardia with a 1:1 AV relationship and significant CL variability. Thirty-nine patients had AT (21 inducible and 18 simulated), and 32 patients had VT (11 inducible and 21 simulated). The relationship between atrial and ventricular CLs was examined.


RESULTS
A change in atrial CL predicted the change in subsequent ventricular CL in 37 (95%) of 39 patients with AT and in none of the patients with VT. A change in preceding ventricular CL predicted the change in atrial CL in 31 (97%) of 32 patients with VT and in only one (3%) of 39 patients with AT. The sensitivity, specificity, and positive and negative predictive values of a change in atrial CL predicting the change in ventricular CL for AT with significant CL variability were 95%, 100%, 100%, and 94%, respectively. The corresponding values for the change in preceding ventricular CL predicting the change in atrial CL for AT with significant CL variability were 97%.


CONCLUSIONS
The relationship between atrial and ventricular CL is useful in differentiating AT from VT with retrograde conduction. A change in atrial CL that predicts the change in subsequent ventricular CL rules in AT and excludes VT.
Jongnarangsin
Krit
K
Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, USA. kritj@med.umich.edu
Pumprueg
Satchana
S
Prasertwitayakij
Narawudt
N
Crawford
Thomas C
TC
Mukerji
Siddharth
S
McLemore-McGregor
Rita
R
Chen-Scarabelli
Carol
C
Ebinger
Matthew
M
Good
Eric
E
Chugh
Aman
A
Bogun
Frank
F
Pelosi
Frank
F
Oral
Hakan
H
Morady
Fred
F
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D017147:Defibrillators, Implantable; D003937:Diagnosis, Differential; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013617:Tachycardia, Supraventricular / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy