Initial experience with ablation of the innervation surrounding sinus and atrioventricular nodes to treat paroxysmal bradyarrhythmia / 中华医学杂志(英文版)

BACKGROUND@#The symptomatic bradyarrhythmia is Class I indication for pacing therapy which is not a radical cure. The present study aimed to assess the feasibility and to present the initial results of the restricted ablation of the parasympathetic innervation surrounding sinus and atrioventricular (AV) nodes for treating patients with bradyarrhythmia.@*METHODS@#A total of 13 patients with cardiogenic syncope were included from May 2008 to June 2015. Under the guidance of fluoroscopy and /or three-dimensional geometry by 64-slice spiral computed tomography, atrial activation sequence in sinus rhythm was mapped. Chamber geometry was reconstructed manually or automatically using the Niobe II magnetic navigation system integrated with the CARTO-remote magnetic technology (RMT) system. Cardioneuroablation was targeted at the high-amplitude fractionated electrograms surrounding the regions of His bundle and the site with the earliest activation in sinus rhythm. Areas surrounding the sinus node, AV node, and the phrenic nerve were avoided.@*RESULTS@#Thirteen patients completed the studies. Ablation was successfully performed in 12 patients and failed in one. The high-frequency potential was recorded in atrial electrograms surrounding the sinus or AV nodes in all the patients and disappeared in 15 s after radiofrequency applications. The vagal reaction was observed before the improvement of the sinus and AV node function. No complications occurred during the procedures. Patients were followed up for a mean of 13.0 ± 5.9 months. During the follow up ten patients remained free of symptoms, and two patients had a permanent cardiac pacemaker implanted due to spontaneous recurrence of syncope. The heart rate of post-ablation was higher than pre-ablation (69.0 ± 11.0 vs. 49.0 ± 10.0 beats/min, t = 4.56, P = 0.008). The sinus node recovery time, Wenckebach block point, and atrium-His bundle interval were significantly shorter after ablation (1386.0 ± 165.0 vs. 921.0 ± 64.0 ms, t = 7.45, P = 0.002; 590.0 ± 96.0 vs. 464.0 ± 39.0 ms, t = 2.38, P = 0.023; 106.0 ± 5.0 vs. 90.0 ± 12.0 ms, t = 9.80, P = 0.013 before and after ablation procedure, respectively).@*CONCLUSIONS@#Ablation of sinoatrial and AV nodal peripheral fibrillar myocardium electrical activity might provide a new treatment to ameliorate paroxysmal sinus node dysfunction, high degree AV block, and vagal-mediated syncope.

Transient ST-segment elevation after transseptal puncture for atrial fibrillation ablation in two cases / 中华医学杂志(英文版)

The present report demonstrates two cases of transient inferior ST-segment elevation accompanied by profound hypotension and bradycardia immediately after transseptal puncture for catheter ablation of atrial fibrillation. This rare complication of transseptal puncture was resolved quickly within several minutes. The most likely mechanism of this phenomenon is coronary vasospasm, although coronary embolism can not be ruled out completely. This complication is characterized as follows: (1) The right coronary artery might be the most likely involved vessel and therefore myocardial ischemia usually occurs in the inferior wall of left ventricular; (2) Reflex hypotension and bradycardia by the Bezold-Jarisch reflex secondary to inferior ischemia often occur at the same time. Though it appears to be a transient and completely reversible phenomenon, there are still potential life-threatening risks because of myocardial ischemia and profound haemodynamic instability. Clinical cardiologists should be aware of this rare complication and properly deal with it.

Ultrasonic destruction of albumin microbubbles enhances gene transfection and expression in cardiac myocytes / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>It has been proven that ultrasonic destruction of microbubbles can enhance gene transfection efficiency into the noncardiac cells, but there are few reports about cardiac myocytes. Moreover, the exact mechanisms are not yet clear; whether the characteristic of microbubbles can affect the gene transfection efficiency or not is still controversial. This study was designed to investigate whether the ultrasound destruction of gene-loaded microbubbles could enhance the plasmids carried reporter gene transfection in primary cultured myocardial cell, and evaluate the effects of microbubbles characteristics on the transgene expression in cardiac myocytes.</p><p><b>METHODS</b>The β-galactosidase plasmids attached to the two types of microbubbles, air-contained sonicated dextrose albumin (ASDA) and perfluoropropane-exposed sonicated dextrose albumin (PESDA) were prepared. The gene transfection into cardiac myocytes was performed in vitro by naked plasmids, ultrasound exposure, ultrasonic destruction of gene-loaded microbubbles and calcium phosphate precipitation, and then the gene expression and cell viability were analyzed.</p><p><b>RESULTS</b>The ultrasonic destruction of gene-loaded microbubbles enhanced gene expression in cardiac myocytes compared with naked plasmid transfection ((51.95 ± 2.41) U/g or (29.28 ± 3.65) U/g vs. (0.84 ± 0.21) U/g, P < 0.01), and ultrasonic destruction PESDA resulted in more significant gene expression than ASDA ((51.95 ± 2.41) U/g vs. (29.28 ± 3.65) U/g, P < 0.05). Ultrasonic destruction of microbubbles during calcium phosphate precipitation gene transfection enhanced β-galactosidase activity nearly 8-fold compared with calcium phosphate precipitation gene transfection alone ((111.35 ± 11.21) U/g protein vs. (14.13 ± 2.58) U/g protein, P < 0.01). Even 6 hours after calcium phosphate precipitation gene transfection, ultrasound-mediated microbubbles destruction resulted in more intense gene expression ((35.63 ± 7.65) U/g vs. (14.13 ± 2.58) U/g, P < 0.05).</p><p><b>CONCLUSIONS</b>Ultrasonic destruction of microbubbles might be a promising method for the delivery of non-viral DNA into cardiac myocytes, and the gene tranfection is related to the characteristics of microbubbles.</p>

Pulmonary vein tachycardia after pulmonary vein isolation in patients with atrial fibrillation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Pulmonary vein (PV) isolation has been developed to treat patients with atrial fibrillation (AF), and the electrophysiological endpoint of PV isolation is the disappearance or dissociation of pulmonary vein potentials (PVPs). Pulmonary vein tachycardia (PVT) is the dissociated PV rhythm with a rapid rate. However, the characteristics and significance of PVT after pulmonary vein isolation in patients with AF remains unclear.</p><p><b>METHODS</b>From June 2003 to June 2005, a total of 285 consecutive patients with drug refractory AF were included in this study, and they underwent segmental pulmonary vein ablation (SPVA) or circumferential pulmonary vein ablation (CPVA). PV isolation was the initial endpoint for both approaches with documenting disappearance or dissociation of PVPs. PVT was characterized as dissociated activities within PVs with a circle length (CL) of < 300 ms, and was classified into organized PVT or disorganized PVT according to the variance of CL. Systematic follow-up was conducted after initial procedures. Continuous variables were analyzed by Student's t test and categorical variables were analyzed by chi-square test.</p><p><b>RESULTS</b>Three hundred and fifteen PVs were ablated in 85 patients underwent SPVA approach, 400 circular lesions surrounding ipsilateral PVs (including 790 PVs) were produced in the rest of 200 patients received CPVA approach. Electrical isolation was achieved in all of these PVs. Of these, PVPs were abolished in 89.8% (992/1105) of the ablated PVs, dissociated PV rhythms were documented in the rest 10.2 % (113/1105) of the treated PVs. Among the 113 dissociated PV rhythms, 28 met the criteria of PVT with mean CL of (155 +/- 43) ms (2 PVTs in 2 patients received SPVA, 26 PVTs in 18 patients underwent CPVA). PVT was more frequently documented in patients underwent CPVA approach [9.0% (18/200) vs 2.3% (2/85), P = 0.04]. During the 6-month follow-up, it was indicated that no significant difference existed in AF free rate between patients with PVT and those without PVT (P = 0.75).</p><p><b>CONCLUSIONS</b>PVT dissociated from LA activations can be documented after PV isolation, especially in patients underwent CPVA approach. However, PVT does not affect the follow-up results.</p>

Comparison of different pulmonary vein isolation strategies for patients with paroxysmal atrial fibrillation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To compare two catheter ablation strategies for pulmonary vein (PV) isolation in patients with paroxysmal atrial fibrillation (PAF).</p><p><b>METHODS</b>Fifty consecutive patients who underwent PV isolation by circumferential PV ablation (CPVA group) were compared with 50 consecutive patients who underwent PV isolation by segmental PV ablation (SPVA group). The enrolled subjects in this retrospective study were patients with frequent attacks (more than 3 times per month) and symptomatic PAF. Procedure-related parameters, safety and clinical outcome within 6 months after procedures for the 2 strategies were analyzed.</p><p><b>RESULTS</b>The characteristics and mean procedure time were comparable between the 2 groups. The mean fluoroscopy time and mean ablation time were 57 min +/- 11 min and 42 min +/- 9 min in the SPVA group and 31 min +/- 8 min and 61 min +/- 13 min in the CPVA group (both P < 0.01), respectively. After the first procedure, symptomatic atrial tachyarrhythmias (ATa) recurred in 24 (48%) of 50 patients who underwent SPVA and 15 (30%) of 50 patients who underwent CPVA within 3 months (P = 0.10). During 6 months of follow-up, 82% of patients with CPVA and 60% of patients with SPVA were free of symptomatic ATa without any antiarrhythmic drugs for at least 3 months (P < 0.05). One patient per each group developed asymptomatic right superior PV stenosis.</p><p><b>CONCLUSION</b>In patients with PAF, CPVA compares favorably with SPVA, but either of them yields a similar clinical safety.</p>

Impact of different ablation strategies on the delayed cure after trans-catheter ablation for treating patients with atrial fibrillation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Delayed cure had been observed in recurrent cases after index ablation of atrial fibrillation (AF), however, its mechanism and incidence have not been elucidated in detail. This study aims to investigate the impact of different ablation strategies on the incidence of delayed cure and its possible mechanisms after trans-catheter ablation of AF.</p><p><b>METHODS</b>One hundred and fifty-one consecutive cases with highly symptomatic, drug refractory AF were included in this study [M/F = 109/42, mean age (56.0 +/- 11.2) (18 - 79) years]. Segmental pulmonary vein ablation (SPVA) was performed in 83 patients with the guidance of circular mapping catheter (SPVA Group), circumferential PV linear ablation (CPVA) was carried out in the rest 68 cases under the guidance of 3 dimensional mapping system in conjunction with circular mapping catheter (CPVA Group). Delayed cure was defined as that early recurrence of atrial tachyarrhythmias (AF, atrial tachycardia, or atrial flutter) after ablation procedure was no longer observed during subsequent follow-up, and stable sinus rhythm was maintained > or = 2 months.</p><p><b>RESULTS</b>Early recurrence of atrial tachyarrhythmias was detected in 41 cases from SPVA group and 23 cases from CPVA group, and delayed cure occurred in 21.9% (9/41) of the cases from SPVA group and 47.8% (11/23) of the cases from CPVA group, more delayed cure in later group was observed (P < 0.05). Meanwhile, patients in SPVA group took a longer time to achieve a delayed cure [(27.0 +/- 18.0) days vs (14.0 +/- 8.1) days, P < 0.05], and presented more recurrent episodes [(3.50 +/- 1.08) times a week vs (2.42 +/- 1.11) times a week, P < 0.05]. However, recurrent episodes after index ablation were markedly decreased in cases with delayed cure from both groups (P < 0.05).</p><p><b>CONCLUSIONS</b>Despite of an early recurrence of atrial tachyarrhythmias after index ablation of AF, delayed cure occurs in a significant number of patients undergoing either SPVA or CPVA. However, different ablation strategies place different impact on the delayed cure, more delayed cure is obtained with CPVA approach, and the delayed cure occurs earlier with this approach; the average recurrent episodes before delayed cure are also less frequently detected in CPVA group compared with those in SPVA group.</p>

Recurrent atrial tachycardia and atrial fibrillation after circumferential pulmonary vein ablation: what's the difference? / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Recurrent atrial tachyarrhythmia (ATa) after circumferential pulmonary vein ablation (CPVA) includes atrial tachycardia (AT) and atrial fibrillation (AF). However, whether there are some differences in clinical course and mechanisms between the recurrent AT and the recurrent AF remained unclear. This study was conducted to investigate the incidence, mechanism, clinical course of the recurrent AT and AF in patients under CPVA.</p><p><b>METHODS</b>One hundred and thirty consecutive patients (M/F = 95/35) with highly symptomatic and multiple antiarrhythmic drugs (AADs) refractory paroxysmal (n = 91) or persistent (n = 39) AF were included. The ablation protocol consisted solely of two continuous circular lesions around the ipsilateral pulmonary veins (PV) guided by CARTO system. The endpoint of CPVA is PV isolation. For patients with recurrent ATa within 2 months after the initial procedure, cardioversion with direct current was attempted if the ATa lasted for more than 24 hours. A repeat ablation procedure was performed only for patients with AADs refractory recurrent ATa and at least followed up for 2 months after the initial procedure.</p><p><b>RESULTS</b>Within 2 months after the initial procedure, 52 patients (40.0%) had experienced episodes of symptomatic recurrent ATa. Among them, 23 patients (44.2%) with recurred AT alone (AT group), 14 patients (26.9%) with recurred AF alone (AF group), and 15 patients (28.8%) with recurred AT and AF (AT plus AF group). The delayed cure rate (65.2%) in AT group was significant higher than that in AF group (21.4%, P < 0.05) and AF plus AT group (26.7%, P < 0.05). A repeat ablation was performed in 21 patients, including 6 patients with recurrent AT alone, 8 patients with recurrent AF alone, and 7 patients with recurrent AF plus AT. The mean number of PV gaps was 1.2 +/- 0.4 in AT group, which was significantly lower than that in AF group (2.6 +/- 0.7, P < 0.05) and AF plus AT group (2.0 +/- 0.6, P < 0.05). Delayed cure rate and number of PV gaps between AF group and AF plus AT group were comparable (P > 0.05).</p><p><b>CONCLUSIONS</b>Present study indicates that recurrent AT and AF after CPVA have the different clinical course and different electrophysiological findings during repeat procedure as follows: (1) After CPVA, spontaneous resolution of recurrent ATa was mainly found in patients with recurrent AT alone (about two thirds patients). (2) The type of recurrent ATa after CPVA is associated with the number of PV gaps.</p>