Search

Background: Catheter ablation is effective in restoring sinus rhythm and left atrial appendage closure (LAAC) is increasingly used for stroke prevention in patients with atrial fibrillation (AF). We aimed to observe the feasibility and safety of performing AF ablation and LAAC in a single (one-stop) procedure., Methods: Consecutive AF patients who underwent the combined procedure of AF ablation and LAAC with WATCHMAN device between March 2017 and September 2018 were prospectively enrolled. Baseline and intra-procedural parameters were evaluated. Three-month and subsequent 1-year follow-up were performed in all and earlier-enrolled subjects, respectively., Results: A total of 178 AF patients (94 males, 68.9 ± 8.1 years) underwent the one-stop procedure with CHA2DS2-VASc score 3.3 ± 1.5 and HAS-BLED score 1.6 ± 1.0, respectively. Pulmonary vein isolation was achieved in all patients while additional linear ablation was applied if the operator deemed necessary, yielding immediate ablation success rate of 98.9% (176/178). In the subsequent LAAC, satisfactory seal (residual leak <5 mm) was achieved in all patients. One stroke and four cardiac perforations occurred peri-operatively. At 3-month follow-up, sinus rhythm and satisfactory seal were maintained in 153/178 (86.0%) and 178/178 (100%) patients, respectively. One stroke and one delayed cardiac tamponade occurred, while no device-related thrombus or device migration was observed. During the 1-year follow-up for the earlier enrolled subjects, 52/72 (72.2%) of the patients maintained sinus rhythm. There was no stroke or systemic embolism observed., Conclusion: Combining catheter ablation and LAAC in a single procedure can be successfully and safely performed in non-valvular AF patients of Chinese population.

Background: The current upper-frequency cutoff of 150 Hz sometimes causes loss of pacemaker spike and misdiagnosis. We hypothesized that low-pass filter (LPF) other than 150 Hz could improve the detection of pacemaker spike. This study aimed to examine the effect of different LPF on pacemaker spike detection in remote and bedside electrocardiogram (ECG)., Methods: Patients with permanent pacemaker implantation were included during routine follow-up. Standard 12-lead ECGs at 6 different upper-frequency cutoff (40, 100, 150, 200, 300, and 400 Hz) were collected. All ECGs were then transmitted to the remote clinic center. Ventricular and atrial pacing were analyzed by 2 independent medical practitioners., Results: A total of 88 patients' ECGs were analyzed (mean age 73.8 ± 10.2 years and 85 with dual-chamber pacemakers). About 75.3% (64/85) of patients were diagnosed as atrial pacing by pacemaker programming. Among 6 different upper-frequency cutoff, the 300 Hz turned out to perform best in detecting atrial-paced spike (area under the curve [AUC] = 0.73, 95% confidence interval [CI]: 0.61-0.84 vs. 0.56, 95% CI: 0.61-0.84 at 150 Hz; P = 0.002) on bedside ECGs. Using programming as the golden standard, the 300 Hz LPF has a sensitivity of 59.4%, specificity of 85.7%, positive predictive value of 92.7% and negative predictive value of 40.9% on bedside ECGs. As for the ventricular pacing, the 300 Hz LPF also had a higher accuracy (AUC = 0.93; 95% CI = 0.84-1.00) than that at 150 Hz (AUC = 0.86; 95% CI: 0.77-0.94; P < 0.001) in detecting ventricular-paced spike on bedside ECGs. The results of remote ECGs were similar with bedside ECGs., Conclusions: A filter of 300 Hz cutoff may be recommended for ECG spike detection. With the recommended parameter, remote ECG can perform as well as bedside ECG.

Background: A high ablation success rate for ventricular arrhythmia (VA) from outflow tract has been achieved, but some of them cannot be eliminated from endocardium. We investigated the association between adenosine sensitivity and ablation success/recurrence rates with a nonirrigated or an irrigated catheter., Methods: According to adenosine test, all patients were divided into a sensitive group (S group) or an insensitive group (I group). The patients of each group were randomized into a nonirrigated catheter (NA) subgroup or an irrigated catheter (IA) subgroup with a 2:1 ratio., Results: In S group of 122 patients (84 in NA subgroup), the ablation success rate was similar between two subgroups (94.7% vs. 90.5%, P > 0.05), but in I group of 94 patients (60 in NA subgroup), it was higher in IA subgroup (94.1%) than that in NA subgroup (73.3%, P < 0.05). The success rate using nonirrigated catheter was significantly higher in S group (90.5%) than that in I group (73.3%, P < 0.01), and the recurrence rate was lower in S group than that in I group (1.3%, vs. 13.6%, P < 0.05). On the contrary, the success rate and the recurrence rate using irrigated catheter were similar between S group and I group (94.7%, 94.1%, P > 0.05, vs. 2.8%, 6.3%, P > 0.05)., Conclusions: Adenosine insensitivity is associated with a lower success rate and a higher recurrence rate for VA patients undergoing nonirrigated catheter ablation. Thus, irrigated catheters should be the first choice for VA ablation in adenosine insensitive patients.

Background: Pulmonary vein antrum isolation (PVAI) of pre-excited atrial fibrillation (AF) is controversial. This study aimed to observe the therapeutic effects of PVAI on pre-excited AF., Methods: Twenty-nine patients with pre-excited AF were prospectively divided into a PVAI group (group I, 19 cases) and a control group (group II, 10 cases). To each case in group I, PVAI was performed, and then electroanatomical mapping of accessory pathways (AP) and ablation were constructed on a three-dimensional (3D) map of the valve annulus. Only AP ablation was performed in each case of group II., Results: Of the 29 cases, three were found to have dual APs, two had intermittent APs, and the remaining 24 had single APs. All APs were successfully ablated after the procedure. There were no significant statistical differences in the AP procedure duration ((77.4 ± 21.3) minutes vs. (85.3 ± 13.1) minutes), the AP ablation time ((204 ± 34) seconds vs. (223 ± 62) seconds) and the AP X-ray exposure time ((18.6 ± 4.4) minutes vs. (19.1 ± 4.5) minutes) respectively between groups I and II. As compared with the control group (5 of 10 cases, 50%), the PVAI group had a significantly lower AF recurrence rate (2 of 19 cases, 11%; P < 0.05) during follow-up of (20.5 ± 10.0) months. All seven patients who recurred were successfully abolished by a second ablation., Conclusions: In patients with pre-excited AF, PVAI is an effective therapeutic approach with a low AF recurrence rate. 3D electroanatomical maps of AP contributed to the high success rate of ablation without significantly prolonging of operational duration and X-ray exposure time.

Background: Substrate modification guided by CARTO system has been introduced to facilitate linear ablation of ventricular tachycardia (VT) after myocardial infarction (MI). However, there is no commonly accepted standard approach available for drawing these ablation lines. Therefore, the aim of the present study was to practically refine this time consuming procedure., Methods: Substrate modification was performed in 23 consecutive patients with frequent VTs after MI using the CARTO system. The initial target site (ITS) for ablation was identified by pace mapping (PM) during sinus rhythm and/or entrainment pacing (EM) during VT. According to the initial target site, two approaches were used. The initial target site in approach one has a similar QRS morphology as VT and an interval from the stimulus to the onset of QRS complex (S-QRS) of = 50 ms during PM in sinus rhythm or a difference of the post pacing interval and VT cycle length = 30 ms during concealed entrainment pacing of VT; The initial target site in approach two has an similar QRS morphology as VT and an S-QRS of < 50 ms during PM in sinus rhythm., Results: Overall, 50 lines were performed with a length of (35 +/- 11) mm. Procedure time averaged (232 +/- 56) minutes, fluoroscopy time (10 +/- 8) minutes. Sixteen patients were initially involved into approach one. After completion of 3 +/- 1 ablation lines, no further VT was inducible in 13 patients. The remaining 3 patients were switched to use the alternative approach. However, in none of them the alternative approaches were successful. Approach two was initially used in 7 patients. After completion of 3 +/- 1 ablation lines, no further VT was inducible in only 2 patients. The remaining 5 patients were switched to approach one, which resulted in noninducibility of VT in 4 of them. The initial successful rate was significantly higher in the group of approach one compared to that in the group of approach two (13/16 patients vs 2/7 patients, P = 0.026)., Conclusions: The approach for substrate modification of VT after MI can be optimized by identifying the appropriate initial target site with specific characteristics within the zone of slow conduction. The refined approach may facilitate linear ablation of VT, and further reduce the procedure and fluoroscopy time.

Background: Atrial tachycardia or flutter is common in patients after orthotopic heart transplantation. Radiofrequency catheter ablation to treat this arrhythmia has not been well defined in this setting. This study was conducted to assess the incidence of various symptomatic atrial arrhythmias and the efficacy and safety of radiofrequency catheter ablation in these patients., Methods: Electrophysiological study and catheter ablation were performed in patients with symptomatic tachyarrhythmia. One Halo catheter with 20 poles was positioned around the tricuspid annulus of the donor right atrium, or positioned around the surgical anastomosis when it is necessary. Three quadripolar electrode catheters were inserted via the right or left femoral vein and positioned in the recipient atrium, the bundle of His position, the coronary sinus. Programmed atrial stimulation and burst pacing were performed to prove electrical conduction between the recipient and the donor atria and to induce atrial arrhythmias., Results: Out of 55 consecutive heart transplantation patients, 6 males [(58 +/- 12) years] developed symptomatic tachycardias at a mean of (5 +/- 4) years after heart transplantation. Electrical propagation through the suture line between the recipient and the donor atrium was demonstrated during atrial flutter or during recipient atrium and donor atrium pacing in 2 patients. By mapping around the suture line, the earliest fragmented electrogram of donor atrium was assessed. This electrical connection was successfully ablated in the anterior lateral atrium in both patients. There was no electrical propagation through the suture line in the other 4 patients. Two had typical atrial flutter in the donor atrium which was successfully ablated by completing a linear ablation between the tricuspid annulus and the inferior vena cava. Two patients had atrial tachycardia which was ablated in the anterior septal and lateral donor atrium. There were no procedure-related complications. Patients were free of recurrent atrial tachyarrhythmias after a follow-up of (8 +/- 7) months., Conclusions: Four electrophysiological mechanisms have been found to contribute to the occurrence of symptomatic supraventricular arrhythmias following heart transplantation. Radiofrequency catheter ablation in patients with atrial flutter/tachycardia is feasible and safe after heart transplantation.

Background: Recently, substrate mapping (SM) has been described to facilitate catheter ablation of stable and unstable ventricular tachycardia (VT) after myocardial infarction. However, SM is time consuming with potential disadvantages of multiple ablation lines such as impairment of ventricular function or proarrhythmia. The aim of the present study was to delineate a stepwise approach to SM to shorten procedure time and limit the possibility of complications., Methods: SM was performed in 14 infarct survivors referred for VT ablation using an electroanatomical mapping system (CARTO) to define infarct regions. A new stepwise approach for SM was designed as follows. The initial ablation site was identified by pace- and entrainment mapping in case of stable VT and by pace mapping only in case of unstable VT. Based on the CARTO voltage mapping, linear ablation was done from this site to the center of the scar and perpendicular to the boundary of the scar or to the mitral annulus. Additional lines were performed only when VT remained inducible. A maximum of 3 ablation lines were created during one procedure., Results: A total of 57 VTs (21 stable, 36 unstable) were induced during the procedures. VT was no longer inducible after the first linear ablation in 2 patients, after the second linear ablation in 6 patients and after the third linear ablation in 3 patients. Either VT or ventricular fibrillation was still inducible at the end of the procedure in 3 patients. Procedure time averaged (291 +/- 85) minutes, fluoroscopy time (10 +/- 7) minutes. VT recurred in 3 patients. Following a second procedure in 2 patients, there were no further VT recurrences. Overall, there was a significant reduction in VT episodes 3 months after [median: 0, interquartile ranges (IQR): 0 - 1] compared with 3 months before ablation (median: 25, IQR: 16 - 105, P < 0.01)., Conclusions: This stepwise approach to SM is effective in facilitating ablation of stable and unstable VT. It reduces procedure and fluoroscopy time, and may help to improve the risk-benefit ratio of VT ablation.