[Radiofrequency catheter ablation in patients with Mahaim-type slow-conduction accessory right atrioventricular pathway].
In some cases undergoing radiofrequency catheter ablation (RFCA) of accessory pathway (AP), a Mahaim-like right-sided atrioventricular AP (M-AP) showing slow and decremental conduction is observed. Among 200 consecutive patients referred to our Institution up to September 1993 for arrhythmias related to an AP and undergoing RFCA, 8 patients (6 males, 2 females; mean age 24 +/- 8 years, range 8-35) showed a M-AP. Seven out of 8 patients have been complaining episodes of palpitation for 13 +/- 7 years (range 1-20), while 1 subject was an asymptomatic young athlete. In 2/8 patients an Ebstein disease (Eb) was present and they had previously undergone right-sided Kent bundle (Kb) ablation elsewhere. During sinus rhythm, QRS was normal in 1 patient, while it showed ventricular preexcitation due to right-sided Kb in 3 patients and right bundle branch block in another 4 patients. A left bundle branch block morphology (LBBBM) reentrant tachycardia (RT) was observed in 7 patients (in 1, only after RFCA of a right-sided Kb); 3 showed also orthodromic RT. In the asymptomatic young athlete, a preexcitation atrial fibrillation with very rapid ventricular response was inducible. All patients underwent diagnostic electrophysiologic (EP) study and RFCA in the same session. In 2/8 patients M-AP was manifest only after right-sided Kb RFCA. In all patients, associated EP abnormalities were noted: in 5/8 patients a dual A-V node pathway was present and in 5/8 patients 6 right-sided Kbs were associated. Patients have been divided in 3 groups, according to the mechanism involving the M-AP in the RT. In the 2 Group I patients showing also Eb, antidromic LBBBM RT and orthodromic RT involving the M-AP anterogradely and retrogradely, respectively, were observed; both arrhythmias were abolished by ablating the M-AP. The 3 Group II patients showed only antidromic LBBBM RT, involving a fast A-V node pathway retrogradely; also in these patients, the M-AP was the target of RFCA. This was performed only in 1 patient, in whom A-V node RT was also observed and ablated after RFCA of M-AP; as to the other 2 patients, in 1 the ablation of M-AP was not considered mandatory, since it was responsible for inducible not sustained LBBBM RT observed only after RFCA of a Kb in the same EP session, while in the other it was not possible because of a prolonged traumatic conduction block through the M-AP.(ABSTRACT TRUNCATED AT 400 WORDS)
Divisione di Cardiologia, IRCCS Policlinico S Matteo, Università degli Studi, Pavia.
R
R
De Ponti
C
C
Storti
A
A
Stanke
A A
AA
Ferrari
M
M
Longobardi
J A
JA
Salerno-Uriarte
D000293:Adolescent; D000328:Adult; D001145:Arrhythmias, Cardiac / Q000503:physiopathology / Q000601:surgery*; D002037:Bundle-Branch Block / Q000503:physiopathology / Q000601:surgery; D017115:Catheter Ablation; D002648:Child; D004437:Ebstein Anomaly / Q000150:complications / Q000503:physiopathology; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D011227:Pre-Excitation, Mahaim-Type / Q000503:physiopathology / Q000601:surgery*; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000503:physiopathology / Q000601:surgery
Ablazione transcatetere mediante radiofrequenza in pazienti con via anomala atrioventricolare destra a conduzione lenta tipo Mahaim.