P-wave morphology in focal atrial tachycardia: development of an algorithm to predict the anatomic site of origin.
OBJECTIVE
The purpose of this study was to perform a detailed analysis of the P-wave morphology (PWM) in focal atrial tachycardia (AT) and construct and prospectively evaluate an algorithm for identification of the anatomic site of origin.


BACKGROUND
Although smaller studies have described the PWM from particular anatomic locations, a detailed algorithm characterizing the likely location of a tachycardia associated with a P-wave of unknown origin has been lacking.


METHODS
The PWMs for 126 consecutive patients undergoing successful radiofrequency ablation of 130 ATs are reported. P waves were included only when the onset was preceded by a discernible isoelectric segment. P waves were classified as positive (+), negative (-), isoelectric, or biphasic. Sensitivity, specificity, and predictive values were calculated. On the basis of these results, an algorithm was constructed and prospectively evaluated in 30 new consecutive ATs.


RESULTS
The distribution of ATs was right atrial (RA) in 82 of 130 (63%) and left atrial (LA) in 48 of 130 (37%). Right atrial sites included crista (n = 28), tricuspid annulus (n = 29), coronary sinus (CS) ostium (n = 14), perinodal (n = 7), right septum (n = 1), and RA appendage (n= 3). Left atrial sites included pulmonary veins (n = 32), mitral annulus (n = 8), CS body (n= 3), left septum (n = 3), and LA appendage (n = 2). In electrocardiographic lead V1, a negative or +/- P-wave demonstrated a specificity of 100% for a RA focus, and a + or -/+ P-wave demonstrated a sensitivity of 100% for a LA focus. A characteristic PWM was associated with high sensitivity and specificity at common atrial sites for tachycardia foci. A P-wave algorithm correctly identified the focus in 93%.


CONCLUSIONS
Characteristic PWMs corresponding to known anatomic sites for focal AT are associated with high specificity and sensitivity. A P-wave algorithm correctly identified the site of tachycardia origin in 93%.
Kistler
Peter M
PM
Department of Cardiology, Royal Melbourne Hospital, Melbourne, Australia.
Roberts-Thomson
Kurt C
KC
Haqqani
Haris M
HM
Fynn
Simon P
SP
Singarayar
Suresh
S
Vohra
Jitendra K
JK
Morton
Joseph B
JB
Sparks
Paul B
PB
Kalman
Jonathan M
JM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D017115:Catheter Ablation; D002648:Child; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013612:Tachycardia, Ectopic Atrial / Q000503:physiopathology*