Impact of ablation index settings on pulmonary vein reconnection.

PURPOSE: Ablation index (AI) is a radiofrequency lesion quality marker. The AI value that allows effective and safe pulmonary vein isolation (PVI) is still debated. We evaluated the incidence of acute and late PV reconnection (PVR) with different AI settings and its predictors. METHODS: The Ablation Index Registry is a multicenter study that included patients with paroxysmal/persistent atrial fibrillation (AF) who underwent first-time ablation. Each operator performed the ablation using his preferred ablation catheter (ThermoCool® SmartTouch or Surround Flow) and AI setting (380 posterior-500 anterior and 330 posterior-450 anterior). We divided the study population into two groups according to the AI setting used: group 1 (330-450) and group 2 (380-500). Incidence of acute PVR was validated within 30 min after PVI, whereas the incidence of late PVR was evaluated at repeat procedure. RESULTS: Overall, 490 patients were divided into groups 1 (258) and 2 (232). There was no significant difference in the procedural time, fluoroscopy time, and rate of the first-pass PVI between the two study groups. Acute PVR was observed in 5.6% PVs. The rate of acute PVR was slightly higher in group 2 (64/943, 6.8%, PVs) than in group 1 (48/1045, 4.6% PVs, p = 0.04). Thirty patients (6%) underwent a repeat procedure and late PVR was observed in 57/116 (49%) PVs (number of reconnected PV per patient of 1.9 ± 1.6). A similar rate of late PVR was found in the two study groups. No predictors of acute and late PVR were found. CONCLUSION: Ablation with a lower range of AI is highly effective and is not associated with a higher rate of acute and late PVR. No predictors of PV reconnection were found.

[The predictive value of junctional beats during the radiofrequency transcatheter ablation of the slow pathway of the nodal reentry circuit]. / Valore predittivo dei battiti giunzionali durante l'ablazione transcatetere mediante radiofrequenza della via lenta del circuito di rientro nodale.

BACKGROUND: Junctional beats (JB) are often recorded during slow pathway (SP) radiofrequency (RF) ablation in patients with atrioventricular nodal reentrant tachycardia (AVNRT). Neither the correlation between JBs and SP potentials nor the role of mechanically-evoked JBs has been clarified yet. METHODS: Two hundred-eleven consecutive patients, with common AVNRT, underwent RF transcatheter ablation guided by Jackman SP potential searching. If we were unable to record an SP potential or if 4 RF pulses delivered on ideal ablation sites were ineffective, the ablation was carried out on anatomical landmarks. Light pressure was applied with the ablation catheter to each ablation site before RF delivery in order to evaluate the inducibility of JBs. RESULTS: Transcatheter ablation was performed successfully in 209/211 (99%) patients. In 17 (8.1%) patients, no SP potential was recorded. JBs were observed more often delivering RF in the mid-septal region, whereas SP potentials were more often recorded at the base of the Koch triangle. The success rate (successful pulses/overall pulses) was higher in the mid-septal (58.6% in M1, 77.8% in M2) than in the postero-septal region (4% in PSC, 16.8% in P1). JBs showed a higher specificity (73.2 vs 5.3%), positive (55.5 vs 24.6%) and negative predictive value (97.3 vs 63.8%) than SP potential in identifying the successful ablation site. Mechanical JBs were evoked in 23 patients on 29 ablation sites, and 18/29 (62.1%) of them were successful ablation sites. CONCLUSIONS: The recording of JBs during or before RF ablation is a useful parameter to guide SP ablation in patients with AVNRT. Although the underlying mechanism has not been clarified yet, their preferential occurrence in the mid-septal region suggests that they might be due to thermal stimulation of compact atrioventricular node.

Feasibility and safety of two French electrode catheters in the performance of electrophysiological studies.

UNLABELLED: The aim of this study was to analyze prospectively the feasibility and safety of using 2 Fr versus 6 Fr standard electrode catheters for diagnostic electrophysiological study. METHODS: Two hundred and five consecutive patients were randomized to receive the 6 Fr approach (3 quadripolar, 6 Fr, electrode catheters inserted through the left or right femoral vein and placed in the high right atrium, right ventricular apex, and His bundle area) or the 2 Fr approach (3 quadripolar, 2 Fr, electrode catheters inserted through a single, 7 Fr, triple lumen, guiding catheter and positioned at the same sites as the 6 Fr approach). RESULTS: Introduction time was shorter in the 2 Fr group (133.3 +/- 65 s, range 87-669 s) than in the 6 Fr group (242.8 +/- 91.8 s, range 168-1024 s, P < 0.001). The overall fluoroscopy time was longer in the 2 Fr group (141.2 +/- 40.1 s, range 78-312 s) than in the 6 Fr group (126.4 +/- 39.7 s, range 58-341 s, P = 0.009). However in the last 100 patients there was no more difference between the two groups (137.6 +/- 28.2 s vs 128.4 +/- 23.2 s, P = 0.07). There was no significant difference between 2 Fr and 6 Fr groups in the mean atrial (5.9 +/- 2.2 mV, range 2.2-11.3 mV, vs 6.1 +/- 2.3 mV, range 2.4-12.4 mV, P = 0.57) and ventricular (5.6 +/- 2.1 mV, range 1.9-9.7 mV, vs 5.7 +/- 2.2 mV, range 2.3-10.5 mV, P = 0.66) activation potential amplitudes recorded during sinus rhythm, or in the rate of stable His bundle potential recording (P = 0.3), and catheter dislodgment (P = 0.54). The overall number of complications was significantly higher in the 6 Fr group than in the 2 Fr group (29 vs 5, P = 0.001), as well as the number of entry site related complications (3 vs 12, P = 0.02) and catheter manipulation related complications (2 vs 17, P < 0.001). CONCLUSIONS: The results of this study show that the use of 2 Fr electrode catheters reduces the rates of entry site and catheter manipulation related complications during EPS. Despite their small size, these catheters allow quick and precise positioning of the electrode.

[Computerized follow-up cards for ambulatory patients with implanted pacemaker or defibrillator]. / La carta sanitaria informatizzata nella gestione ambulatoriale del paziente con pacemaker o defibrillatore impiantabile.

The follow up of pacemaker and defibrillator dependent patients has a significant role for both the evaluation of pacing effectiveness and check of hemodynamic advantages about patient's quality of life. The bulky paper archives are often inaccurate, hampering the consultation. At present the paper card is the only document which can be utilized to record some data concerning the implant and patient clinical story. Therefore, there is the necessity for a card that can include all patient's data, and the implant and programming pacemaker/defibrillator data during follow up. This new pacemaker card has portable file or data-base including shared data with safety mechanism, which can be utilized in several controls by different users (physicians, hospital ward, primary care units, insurance companies). The pacemaker card includes a chip that permits to store a considerable amount of data; it can be update in every further medical control, in observance of laws. The card Chip Operating System (C.O.S.) consists of a microchip with a memory completely managed by the operating system inside the chip itself. The card can be read by means of a GCR-200 modem linked with a PC IBM-compatible computer and the data can be updated during the follow up. The pacemaker-defibrillator card will appear immediately on screen, and it can be printed, updated and/or modified by a Microsoft Windows operating programme. With this pacemaker card we are able to ensure serviceable medical work, particularly in terms of cost/benefit ratio giving to patient more and more reasoning and safe service.

[Atrioventricular conduction before and after the radiofrequency catheter ablation of a nodal reentry tachycardia circuit]. / Conduzione atrioventricolare prima e dopo ablazione transcatetere mediante radiofrequenza di circuito di tachicardia reciprocante nodale.

Aim of our study was to retrospectively evaluate atrioventricular conduction 24 hours after selective radiofrequency catheter ablation of the fast pathway or after selective ablation of the slow pathway of the atrioventricular nodal reentrant tachycardia circuit. Electrophysiologic modifications were retrospectively analyzed in 47/48 patients successfully submitted to fast pathway ablation and in 90/93 patients successfully submitted to slow pathway ablation. The atrioventricular conduction intervals (P-Q and A-H), both anterograde and retrograde Wenckebach point, the effective refractory period of atrioventricular node and the atrioventricular node function curve were evaluated before and after selective radiofrequency catheter ablation of slow and fast pathway. We identified the fast pathway ablation potential as: A:V ratio > or = 2:1, His electrogram < or = 150 microV. The slow pathway potential was identified as the widest, sharpest and latest atrial electrogram recorded during sinus rhythm in the posteroseptal region of the atrioventricular junction or as the widest, sharpest and earliest observed during retrograde conduction. We observed a significant increase in the P-Q and A-H intervals in patients submitted to fast pathway ablation, while no significant modification of these parameters was appreciated in patients submitted to slow pathway ablation. No significant modification of anterograde Wenckebach point (NS) was observed in patients submitted to successfully ablation of fast pathway while a statistically significant increase in anterograde Wenckebach point (p = 0.03) was observed in patients submitted to slow pathway ablation. After selective fast pathway ablation, retrograde conduction was absent in 82.9% of patients submitted to ablation; in the remaining 17.1% a significant increase of retrograde Wenckebach point was observed.(ABSTRACT TRUNCATED AT 250 WORDS)