Focal atrial tachycardias originating from the aorta-mitral continuity: Anatomical and electrophysiological characteristics.

BACKGROUND: The aorta-mitral annulus conjunction (AMC) is an uncommon site of origin of focal atrial tachycardias (ATs). Hence, the electrophysiological and ablation target characteristics are poorly described. OBJECTIVE: The purpose of this study was to describe the characteristics of AMC ATs in detail. METHODS: The study enrolled 650 patients with ATs, 21 (3.2%) of whom had ATs originating from the AMC. A comprehensive evaluation, including electrocardiography, electrophysiology study, computed tomography scan, and intracardiac echocardiography, was performed. RESULTS: The majority (19, 90.5%) of ATs occurred spontaneously. The mean age of this group was 48.9 ± 21.6 years, with 12 being female (57.1%). Seventeen patients had a typical biphasic P wave with a prominent positive component. The earliest activation site in the right atrium was near the His bundle, with average activation -10.3 ± 6.0 ms preceding the P wave. The successful ablation targets were distributed as follows: 1 case at 9 o'clock, 6 cases at 10 o'clock, 7 cases at 11 o'clock, 6 cases at 12 o'clock, and 1 case in the left coronary cusp. The local AMC potential differed from the commonly perceived annular potential and was characterized by a prominent A wave and a smaller V wave (atrial-to-ventricular ratio > 1). The angle of encroachment on the left atrial anterior wall, compressed by the left coronary cusp, was significantly smaller in the AMC ATs group than in the control group consisted of 40 patients who underwent coronary artery CT scans because of the chest pain but without atrial arrhythmias were randomly selected, which may have contributed to the arrhythmia substrate (141.7° ± 11.5° vs 155.2° ± 13.9°; P = .026). CONCLUSION: A new strategy for mapping AMC ATs has been introduced. The ablation target should have an atrial-to-ventricular ratio of >1.

[Improved unilateral puncture PVP based on 3D printing technology for the treatment of osteoporotic vertebral compression fracture].

OBJECTIVE: To investigate the clinical effect of unilateral percutaneous vertebroplasty (PVP) combined with 3D printing technology for the treatment of thoracolumbar osteoporotic compression fracture. METHODS: A total of 77 patients with thoracolumbar osteoporotic compression fractures from October 2020 to April 2022 were included in the study, all of which were vertebral body compression fractures caused by trauma. According to different treatment methods, they were divided into experimental group and control group. Thirty-two patients used 3D printing technology to improve unilateral transpedicle puncture vertebroplasty in the experimental group, there were 5 males and 27 females, aged from 63 to 91 years old with an average of (77.59±8.75) years old. Forty-five patients were treated with traditional bilateral pedicle puncture vertebroplasty, including 7 males and 38 females, aged from 60 to 88 years old with an average of(74.89±7.37) years old. Operation time, intraoperative C-arm X-ray times, anesthetic dosage, bone cement injection amount, bone cement diffusion good and good rate, complications, vertebral height, kyphotic angle (Cobb angle), visual analogue scale(VAS), Oswestry disability index (ODI) and other indicators were recorded before and after surgery, and statistically analyzed. RESULTS: All patients were followed up for 6 to 23 months, with preoperative imaging studies, confirmed for thoracolumbar osteoporosis compression fractures, two groups of patients with postoperative complications, no special two groups of patients' age, gender, body mass index (BMI), time were injured, the injured vertebral distribution had no statistical difference(P>0.05), comparable data. Two groups of patients with bone cement injection, bone cement dispersion rate, preoperative and postoperative vertebral body height, protruding after spine angle(Cobb angle), VAS, ODI had no statistical difference(P>0.05). The operative time, intraoperative fluoroscopy times and anesthetic dosage were statistically different between the two groups(P<0.05). Compared with the traditional bilateral puncture group, the modified unilateral puncture group combined with 3D printing technology had shorter operation time, fewer intraoperative fluoroscopy times and less anesthetic dosage. The height of anterior vertebral edge, kyphosis angle (Cobb angle), VAS score and ODI of the affected vertebrae were statistically different between two groups at each time point after surgery(P<0.05). CONCLUSION: In the treatment of thoracolumbar osteoporotic compression fractures, 3D printing technology is used to improve unilateral puncture PVP, which is convenient and simple, less trauma, short operation time, fewer fluoroscopy times, satisfactory distribution of bone cement, vertebral height recovery and kyphotic Angle correction, and good functional improvement.

PagERF81 regulates lignin biosynthesis and xylem cell differentiation in poplar.

Lignin is a major component of plant cell walls and is essential for plant growth and development. Lignin biosynthesis is controlled by a hierarchical regulatory network involving multiple transcription factors. In this study, we showed that the gene encoding an APETALA 2/ethylene-responsive element binding factor (AP2/ERF) transcription factor, PagERF81, from poplar 84 K (Populus alba × P. glandulosa) is highly expressed in expanding secondary xylem cells. Two independent homozygous Pagerf81 mutant lines created by gene editing, produced significantly more but smaller vessel cells and longer fiber cells with more lignin in cell walls, while PagERF81 overexpression lines had less lignin, compared to non-transgenic controls. Transcriptome and reverse transcription quantitative PCR data revealed that multiple lignin biosynthesis genes including Cinnamoyl CoA reductase 1 (PagCCR1), Cinnamyl alcohol dehydrogenase 6 (PagCAD6), and 4-Coumarate-CoA ligase-like 9 (Pag4CLL9) were up-regulated in Pagerf81 mutants, but down-regulated in PagERF81 overexpression lines. In addition, a transient transactivation assay revealed that PagERF81 repressed the transcription of these three genes. Furthermore, yeast one hybrid and electrophoretic mobility shift assays showed that PagERF81 directly bound to a GCC sequence in the PagCCR1 promoter. No known vessel or fiber cell differentiation related genes were differentially expressed, so the smaller vessel cells and longer fiber cells observed in the Pagerf81 lines might be caused by abnormal lignin deposition in the secondary cell walls. This study provides insight into the regulation of lignin biosynthesis, and a molecular tool to engineer wood with high lignin content, which would contribute to the lignin-related chemical industry and carbon sequestration.

Individualized 3D printed navigation template-assisted atlantoaxial pedicle screws vs. free-hand screws for the treatment of upper cervical fractures.

Objective: This study aims to compare the efficacy and safety of freehand atlantoaxial pedicle screws against custom 3D printed navigation template screws in the treatment of upper cervical fractures. Methods: In our institution from 2010 to 2020, a retrospective cohort analysis of 23 patients with upper cervical fractures was done. These patients were separated into two groups: group A (N = 12), which received customized 3D printed navigation template-assisted screws with virtual reality techniques, and group B (N = 11), which received freehand screws assisted by intraoperative fluoroscopy. Every patient was monitored for more than 1 year. The two groups were contrasted in terms of screw implant accuracy, cervical spine Japanese Orthopaedic Association (JOA) score, American Spinal Injury Association (ASIA) score, visual analogue scale (VAS) score, surgical time, fluoroscopy times, and intraoperative blood loss. Results: A total of 88 atlantoaxial pedicle screws in all, 46 in group A and 42 in group B, were implanted. In group A, the screw insertion accuracy rate was 95.7%, compared to 80.0% in group B (P < 0.05). When compared to group B, group A had shorter surgery times, less blood loss, fewer fluoroscopies, a higher short-term JOA score, and overt pain reduction (P < 0.05). However, there was no discernible difference between the two groups' VAS scores, long-term JOA scores, or ASIA scores (sensory and motor), at the most recent follow-up. Conclusion: Individualized 3D printed guide leads to significant improvement in the screw safety, efficacy, and accuracy, which may be a promising strategy for the treatment of upper cervical fractures.

[Development and clinical application of a new transverse process retractor based on computer-aided design and 3D printing technology].

OBJECTIVE: To manufacture a new type of transverse process retractor by using computer-aided design(CAD) combined with 3D printing technology and investigate its clinical application effect. METHODS: A new type of transverse protrusion retractor was developed by CAD combined with 3D printing technology. From September 2018 to September 2019, the new transverse process retractor was applied in clinic. Sixty patients with lumbar single segment lesions who needed treatment by pedicle screw fixation, bone grafting and interbody fusion were divided into new transverse process retractor group and control group, with 30 cases in each group. There were 14 males and 16 females in new type transverse process retractor group, the age was (68.0±4.3) years old on average; lesion segment of 8 cases were L3,4, 9 cases were L4,5, 13 cases were L5S1;5 cases of lumbar disc herniation, 20 cases of lumbar spinal stenosis, 5 cases of degenerative lumbar spondylolisthesis;new transverse process retractor was used to pedicle screw placement. While there were 15 males and 15 females in control group, with an average age of (69.2±4.5) years old;lesion segment of 8 cases were L3,4, 10 cases were L4,5, 12 cases were L5S1;5 cases of lumbar disc herniation, 21 cases of lumbar spinal stenosis, 4 cases of degenerative lumbar spondylolisthesis;the traditional lamina retractor was used for soft tissue pulling and finished pedicle screw placement by freehand. The length of surgical incision, the time required for inserting a single screw, fluoroscopy times, the times of adjusting the positioning needle or screw in insertion process, and the visual analogue scale (VAS) of surgical incision 72 hours after operation were compared between two groups. RESULTS: Using CAD and 3D printing technology, a new type of transverse protrusion retractor was developed quickly. The length of surgical incision, the time required for inserting a single screw, fluoroscopy time, and the times of adjusting the positioning needle or screw in insertion process in new transverse process retractor group were less than those in control group(P<0.05). There was no significant difference in VAS of lumbar incision pain at 72 hours after operation between two groups(P>0.05). CONCLUSION: Using CAD combined with 3D printing technology to develop a new transverse protrusion retractor has the advantages of convenient design, short development cycle and low cost. It provides a new idea for the research and development of new medical devices. The new transverse process retractor has the advantages of easy operation, reliable fixation, less damage to paravertebral muscle, convenient pedicle screw placement, reducing fluoroscopy time and so on.

Predictors and Long-Term Outcome of Ablation of Discrete Pre-potentials in Patients With Idiopathic Ventricular Arrhythmias Originating From the Aortic Sinuses of Valsalva.

Background: The predictability and long-term outcome of the discrete pre-potential (DPP) of idiopathic ventricular arrhythmias (VAs) arising from the aortic sinuses of Valsalva (ASV) have not been fully identified. Methods: Of 687 consecutive patients undergoing ablation of outflow tract VAs, there were 105 (15.3%) patients with VAs originating from the ASV region who were included. Detailed mapping was performed within the ASV in all patients. Electrocardiographic, electrophysiological parameters, and long-term success rate were compared between patients with and without the DPPs. Results: A DPP was recorded in 67 of 105 (63.8%) patients, including 38 left sinus of Valsalva (LSV)-VAs (38/105, 36.2%) and 29 right sinus of Valsalva (RSV)-VAs (29/105, 27.6%). The patients with DPPs had wider QRS duration (152 ± 17 vs. 145 ± 14 ms, p < 0.001). The average of earliest activation time was significantly earlier in patients with DPPs (-38.6 ± 8.5 vs. -27.7 ± 5.7 ms, p < 0.001). Mean time from the first lesion to elimination of VAs was shorter in patients with DPPs (2.3 ± 2.1 s vs. 4.9 ± 1.0 s, p < 0.001). A stepwise logistic multivariable analysis identified only younger age as a significant predictor of DPP (age ≤ 35.5 years predicted DPP with 92.9% positive predictive value). During a follow-up duration of 42.5 ± 22.3 months, 63 (94.0%) patients with DPPs and 30 (78.9%) patients without DPPs remained free of recurrent VAs (p = 0.027). Conclusion: Discrete pre-potentials were observed in 63.8% of patients with VAs arising from the ASV. Ablation in patients with DPPs was associated with higher long-term success. DPPs were seen more commonly in younger (age ≤ 35.5 years) patients.

[Effectiveness of synchronous unilateral percutaneous kyphoplasty in the treatment of double noncontiguous thoracolumbar osteoporotic vertebral compression fractures].

OBJECTIVE: To investigate the effectiveness of synchronous unilateral percutaneous kyphoplasty (PKP) in the treatment of double noncontiguous thoracolumbar osteoporotic vertebral compression fracture (OVCF). METHODS: Between December 2018 and September 2020, 27 patients with double noncontiguous thoracolumbar OVCF were treated by synchronous unilateral PKP. There were 11 males and 16 females, with an average age of 75.4 years (range, 66-92 years). The fractures were caused by falls in 22 cases and sprains in 5 cases. The time from injury to hospital admission was 0.5-7.0 days, with an average of 2.1 days. The fractured vertebrae located at T 9 in 2 cases, T 10 in 3 cases, T 11 in 10 cases, T 12 in 15 cases, L 1 in 12 cases, L 2 in 6 cases, L 3 in 4 cases, and L 4 in 2 cases. The volume of bone cement injected into each vertebral body, operation time, and intraoperative fluoroscopy times were recorded. Anteroposterior and lateral X-ray films of thoracolumbar spine were taken to observe the anterior height of the injured vertebra, the Cobb angle of kyphosis, and the diffusion and good distribution rate of bone cement in the thoracolumbar spine. Visual analogue scale (VAS) score and Oswestry disability index (ODI) were used to evaluate the pain and functional improvement. RESULTS: All operations completed successfully. The operation time was 34-70 minutes, with an average of 45.4 minutes. The intraoperative fluoroscopy was 21- 60 times, with an average of 38.6 times. The volume of bone cement injected into each vertebral body was 2-9 mL, with an average of 4.3 mL. All patients were followed up 6-21 months, with an average of 11.3 months. X-ray film reexamination showed that the anterior height of the injured vertebra and Cobb angle at each time point after operation were significantly improved than those before operation ( P<0.05), and there was no significant difference between different time points after operation ( P>0.05). The distribution of bone cement was excellent in 40 vertebral bodies, good in 13 vertebral bodies, and poor in 1 vertebral body, and the excellent and good rate was 98.1% (53/54). The pain of all patients significantly relieved or disappeared, and the function improved. The VAS score and ODI at each time point after operation were significantly lower than those before operation ( P<0.05), and there was no significant difference between different time points after operation ( P>0.05). CONCLUSION: For the double noncontiguous thoracolumbar OVCF, the synchronous unilateral PKP has the advantages of simple puncture, less trauma, less intraoperative fluoroscopy, shorter operation time, satisfactory distribution of bone cement, etc. It can restore the height of the vertebral body, correct the kyphotic angle, significantly alleviate the pain, and improve the function.

[Clinical application of three-dimensional printing technique combined with thoracic pedicle screw track detector in thoracic pedicle screw placement].

OBJECTIVE: To investigate the clinical application of three-dimensional (3D) printing technique combined with a new type of thoracic pedicle screw track detector in thoracic pedicle screw placement. METHODS: According to the characteristics of thoracic pedicle and common clinical screw placement methods, a new type of thoracic pedicle screw track detector was independently developed and designed. The clinical data of 30 patients with thoracic vertebrae related diseases who underwent posterior thoracic pedicle screw fixation between March 2017 and January 2020 were retrospectively analysed. Among them, there were 18 males and 12 females with an average age of 56.3 years (range, 32-76 years). There was 1 case of thoracic disc herniation, 4 cases of thoracic canal stenosis, 2 cases of ossification of posterior longitudinal ligament of thoracic vertebra, 16 cases of thoracic trauma, 2 cases of thoracic infection, and 5 cases of thoracic canal occupation. Three-dimensional CT of the thoracic vertebra was routinely performed preoperatively, and the model of the patient's thoracic vertebra was reconstructed and printed out. With the assistance of the model, preoperative simulation was performed with the combination of the new type thoracic pedicle screw track detector, and detected no nails after critical cortical damage. During operation, one side was randomly selected to use traditional hand screws placement (control group), and the other side was selected to use 3D printing technique combined with new type thoracic pedicle screw track detector to assist thoracic pedicle screws placement (observation group). The single screw placement time, adjustment times of single screw, and blood loss during screw placement were compared between the two groups. The accuracy of screw placement in the two groups was evaluated according to postoperative CT imaging data. RESULTS: The single screw placement time, adjustment times of single screw, and blood loss during screw placement in the observation group were significantly less than those in the control group ( P<0.05). Postoperative CT examination showed that the observation group had 87 screws of grade 1, 3 screws of grade 2, and the acceptable screw placement rate was 100% (90/90); the control group had 76 screws of grade 1, 2 screws of grade 2, 11 screws of grade 3, and 1 screw of grade 4, and the acceptable screw placement rate was 86.7% (78/90); showing significant difference in screw placement between the two groups ( χ 2=12.875, P=0.001). All patients were followed up 6-18 months, with an average of 11.3 months. There was no complication of vascular, nerve, spinal cord, or visceral injury, and screws or rods broken, and no patient was revised. CONCLUSION: The 3D printing technique combined with the new type of thoracic pedicle screw track detector assisted thoracic pedicle screw placement is convenient, and significantly improves the accuracy and safety of intraoperative screw placement, and overall success rate of the surgery.

Surgical treatment for upper cervical deformity with atlantoaxial joint dislocation using individualized 3D printing occipitocervical fusion instrument: A case report and literature review.

ABSTRACT: To introduce a novel technique of using individualized 3D printing occipitocervical fusion instrument (3D-OCF) for the treatment of upper cervical deformity with atlantoaxial joint dislocation.The surgery for deformity of the craniocervical junction area is a challenge in the field of spine. If the surgical deviation is too large to injure the spinal cord or vertebral artery, it will cause catastrophic damage to the patient. Therefore, it is controversial whether these patients should undergo surgical treatment. We provide a novel surgical approach for the challenging upper cervical surgery through 3D-OCF and a typical patient.We present a 54-year-old female patient, who suffered from dizziness and numbness in her limbs for 8 months. After the patient was admitted, we performed the three-dimensional CT scan, modeled using Mimics software 17.0, and designed customized occipitocervical fusion instrument. Besides, we repeatedly perform simulated surgery based on 3D-printed models before surgery.The operative time was 142 minutes and the intraoperative blood loss was 700 mL. X-ray showed reduction of atlantoaxial dislocation and accurate position of internal fixation. The patient's symptoms were significantly relieved: the sensation of dizziness and numbness of limbs was obviously relieved, and the sense of banding in chest, abdomen, and ankle was disappeared. At the last follow-up, imaging showed that 3D-OCF had bone-integration and Syringomyelia was disappeared. The patient's cervical JOA (Japanese Orthopaedic Association) score increased from 10 points to 17 points.Individualized 3D-OCF can improve the safety and accuracy of upper cervical surgery, reduce the operative time and the number of fluoroscopy. Our study provides a novel surgical approach for the challenging upper cervical surgery.

Outcomes of Different Ablation Approaches for Para-Hisian Accessory Pathway and Ablation Safety at Each Site.

BACKGROUND: This study describes the electrophysiologic characteristics of the para-hisian accessory pathway (AP), the outcome of different ablation approaches, and ablation safety at different sites. METHOD: A total of 120 patients diagnosed as para-hisian AP were included in this study. The electrophysiologic characteristics and outcomes at different ablation sites were analyzed. RESULTS: In total, 107 APs and 13 APs were diagnosed as right anteroseptal (RAS) and right midseptal (RMS), respectively. The significant ECG difference between RAS and RMS was lead III, which mainly manifested as positive and negative delta waves, respectively. Catheter trauma to AP was recorded in 21 of 120 (17.5%) patients. The recurrence rate of direct ablation at the "bumped" sites was higher than the conventional ablation method (37.5 vs. 14.1 %, p = 0.036). For RAS APs, there was no significant difference in the success rate between the inferior vena cava (IVC) and superior vena cava (SVC) approaches (76.6 vs. 73.3%, p = 0.63). The RAS was separated into three regions: (1) Site 1: superior part above the real "His" recorded site with far-field "His" potential; (2) Site 2 (true para-hisian): the site with near-field "His" potential; and (3) Site 3: inferior part below the biggest real "His" with far-field "His" potential. Mid-septal was defined as an area that is bounded anteriorly by His recording location and posteriorly by the roof of coronary sinus (CS) ostium. The incidence of atrioventricular (AV) conduction injury at different sites was as follows: 3 of 6 (50%) at Site 2, 4 of 13 (30.8%) at RMS, 7 of 34 (20.6%) at Site 3, and 3 of 46 (6.5%) at Site 1. Even if ablation was performed at the atrial side of the para-hisian region, the right bundle branch block (RBBB) was caused in 6 patients (5%). CONCLUSION: Ablation via IVC or SVC was comparative for para-hisian APs, but not for the noncoronary cusp (NCC) approach. The AV conduction injury risk ranks as follows: Site 2 > RMS > Site 3 > Site 1. RBBB could be caused while ablating at the atrial side, which could further demonstrate the His bundle longitudinal dissociation theory.

[3D printing technology assisted the preoperative planning and application value in adult kyphoscoliosis deformity].

OBJECTIVE: To explore the application value of 3D printing technology in preoperative surgery plan and intraoperative auxiliary operation for adult kyphoscoliosis deformity. METHODS: The clinical data of 12 adult patients with kyphoscoliosis deformity treated from September 2017 to January 2019 were retrospectively analyzed. There were 3 males and 9 females, aged from 21 to 63 years old with an average of (47.67±13.32) years old. Among them, 4 cases were congenital kyphoscoliosis, 2 cases were old tuberculosis thoracolumbar kyphosis ; 2 cases were idiopathic kyphoscoliosis, 4 cases were degenerative kyphoscoliosis. The CT scan data of the patient's spine was imported into Mimics17.0 software to establish the three dimensional model of the spine, and the spine model was produced by 3D printer. Using the spine model simulated operation, preoperative surgery program planning and formulated a precise surgery, and further analysed postoperative imaging parameters improvement. All the patients were followed up for more than 1 year. Before and after operation and at the last follow-up, the scoliosis Cobb angle, maximum kyphosis Cobb angle, and coronal plane balance (distance between C 7 plumbline and center sacral vertical line, C7PL-CSVL), sagittal plane balance (sagittal vertical axis, SVA), pelvic parameters and other related imaging parameters were measured to further evaluate its orthopedic effect. RESULTS: Twelve patients with spine deformity were treated with different osteotomy and internal fixation fusion methods under the guidance of a 1∶1 spine model (pedicle screw placement of 4 patients with severe deformity were assisted by pedicle screw guide plates), nail placement and osteotomy have good effects, no major tissue damage such as blood vessels, nerves and spinal cord during and after surgery, no complications such as cerebrospinal fluid leakage and infection. Preoperative Cobb angle of scoliosis was (56.5±22.5) °, Cobb angle of kyphosis was (65.2±19.5) °, C7 PL-CSVL was (45.8±16.9) mm, SVA was (48.7±25.4) mm. Postoperative at 4 weeks, Cobb angle of scoliosis was (20.8±11.5) °, and Cobb angle of kyphosis was (22.0±6.6) °, with correction rates of (65.1±9.7)% and (64.6± 10.6)%, respectively ; C7 PL-CSVL was (22.3±8.9) mm, and SVA was (23.3±13.1) mm, all of which were significantly improved compared with preoperative results. The mean follow-up time was (18.5±7.9) months in 12 patients. At the last follow-up, the Cobb angles of scoliosis and kyphosis were (22.2±10.8) ° and (23.6±7.7) °, respectively, C7 PL-CSVL was (23.5±10.8) mm, and SVA was (24.7±12.5) mm. The results were statistically significant compared preoperative (P<0.05). There was no significant difference at the postoperative at 4 weeks and the last follow-up (P>0.05). CONCLUSION: The 3D print model can visually and clearly show the vertebral morphology and structure of adult kyphoscolisis and its spatial relationship with the adjacent vertebrae, blood vessels, and nerves, which provides a good and intuitive stereoscopic anatomical structure observation for the individualization of the surgical plan. Pre-simulation of operations to determine the internal fixation, fusion segment and osteotomy orthopedic way, may to provide a reference for actual clinical surgery, and can improve the accuracy and safety of surgery.

Ablation of ventricular arrhythmias with predominant monophasic "R" waves in precordial leads from the left sinus of Valsalva: Electrocardiographic and electrophysiologic characteristics.

BACKGROUND: While the left sinus of Valsalva (LSV) is a frequent origin of ventricular arrhythmias (VAs). Uncommonly, VAs with right bundle branch block (RBBB) morphology may be successfully terminated from the LSV. OBJECTIVE: We aimed to investigate the electrocardiographic and electrophysiologic characteristics of VAs with RBBB which were successfully eliminated from the LSV. METHODS: We identified patients with VAs successfully ablated from the LSV from January 2014 to December 2017 and compared electrophysiologic characteristics and ablation sites of those VAs with RBBB versus a control group of patients with left bundle branch block morphology. RESULTS: We identified 18 patients with RBBB and predominant "R" waves in the precordial leads. In 12 (66.7%) patients, a small "s" wave in lead V2 and positive "R" in the remaining pericardial leads could be seen. Overall, a single "V" potential was seen in 72.2% of patients in the study group, while discrete potentials were recorded in 80% of the patients in the control group. The majority (88.9%) of the VAs could only be terminated at the nadir of the LSV in the study group. After mean follow-up of 33 ± 14 months, 93.8% and 92% were free of VAs after initial ablation in study and control group, respectively (P = 0.99). CONCLUSION: Some VAs with predominant monophasic "R" wave in precordial leads could be terminated from LSV, especially a small "s" wave in lead V2 was recorded. The nadir of LSV is highly successful for RBBB VAs and single electrogram was recorded at the target for most of the cases.

Catheter ablation of supraventricular tachycardia in patients with dextrocardia and situs inversus.

BACKGROUND: Dextrocardia with situs inversus is a rare cardiac positional anomaly. Catheter ablation procedures performed in this set of patients have not been sufficiently reported. METHODS: A total of 10 patients with dextrocardia and situs inversus who received catheter ablation for supraventricular tachycardia (SVT) were included from a cohort of over 20 000 cases of catheter ablation for SVT in three centers from 2005 to 2016. All patients underwent electrophysiologic study and catheter ablation of SVT. Ablation targets were selected based on different tachycardia mechanisms with the primary endpoint of noninduction of tachycardia. RESULTS: The average age was 32.4 ± 5.6 years. Congenitally corrected transposition of great arteries (TGA) with situs inversus and D-looping of the ventricles and aorta (congenitally corrected TGA {I,D,D}) was found in four patients, while the other six patients exhibited mirror-image dextrocardia {I,L,L}. The mechanisms of SVT were atrioventricular nodal reentrant tachycardia in four patients, atrioventricular reentrant tachycardia in three, typical atrial flutter in one, intra-atrial reentrant tachycardia in one, and focal atrial tachycardia in one. Immediate procedural success was achieved in 9 out of 10 patients with no procedural complications. During a follow-up period of 6.3 ± 3.5 years on average, all patients remained free from recurrent tachycardia. CONCLUSIONS: For patients with dextrocardia and situs inversus, catheter ablation of SVT is safe and feasible. Differences in catheter maneuver and fluroscopy projection, along with difficulties in distorted anatomy are major obstacles for successful ablation.

Long-term outcome of cryoballoon ablation versus radiofrequency ablation for focal atrial tachycardias originating from the pulmonary veins.

PURPOSE: We aimed to investigate the characteristics of focal atrial tachycardias (ATs) arising from the pulmonary veins (PVs), as well as the safety and long-term efficacy of cryoballoon (CB) versus radiofrequency (RF) ablation in this population. METHODS: Eighty-three patients with ATs arising from PVs from a consecutive series of 487 patients who underwent CB and RF ablation were retrospectively reviewed. Patients who had a prior history of atrial fibrillation (AF) were excluded. The AT origin was confirmed during the conventional electrophysiological study and activation mapping. The ablation approach was at the discretion of the operators. RESULTS: Thirty-five patients were managed with focal ablation, 25 were ablated with unilateral PV isolation (PVI), and the remaining 23 were performed with CB ablation. All procedures were successfully ablated. There was no significant difference in procedure time between CB group and RF focal group (43.7 ± 11.8 min vs. 45.8 ± 11.2 min, P = 0.121), whereas the fluoroscopy time in CB group was longer than in RF PVI group (10.1 ± 2.5 min vs. 8.4 ± 2.8 min, P < 0.001). There was 1 recurrence in CB group, 4 recurrences of AT in RF focal group, and 2 recurrence in RF PVI group (P = 0.643). Repeat ablation was performed in 6 of 7 patients. Seventy-eight patients were available for long-term follow-up. At a mean of 5.4 ± 4.6-year follow-up, 77 of 78 patients were free from AT without antiarrhythmic medication after 1.1 ± 0.3 procedures. No patient had procedural complications and developed AF during the follow-up period. CONCLUSIONS: CB ablation is an effective and safe tool to treat ATs originating from the PVs. The ATs originating from the PVs represent an isolated clinical process and are not likely to be the forerunner of a more diffuse process leading to the development of PV AF.

Procedural findings and clinical outcome of second-generation cryoballoon ablation in patients with variant pulmonary vein anatomy.

INTRODUCTION: The procedural findings and clinical outcome of second-generation cryoballoon (CB2) ablation in patients with variant pulmonary vein (PV) anatomy have not been fully investigated. METHODS: A total of 424 consecutive patients who underwent PV isolation with CB2 were included. Computed tomographic (CT) scan was performed in all patients before the procedure. The study population was divided into common PV, accessory PV, and nonvariant PV groups according to the CT scan. Procedural findings and clinical outcome between the three groups were compared. RESULTS: Variant PV anatomy was observed in 118 of 424 (27.8%) patients. PV isolation was successfully achieved in all patients in three groups with low rates of need for touch-up ablation (P = 0.974). Total procedure time was longer in the accessory PV group compared with nonvariant PV group (53.7 ± 12.9 vs 49.5 ± 8.8 minutes; P < 0.001). More number of applications per patient were required in accessory PV group compared with the nonvariant PV and common PV groups (7.5 ± 2.1 vs 6.5 ± 1.6, P < 0.001; 7.5 ± 2.1 vs 6.8 ± 1.4, P = 0.027, respectively). No significant difference in phrenic nerve (PN) injury was observed between the three groups (P = 0.693). During mean follow-up duration of 16.1 ± 3.3 months, there was no significant difference in rates of atrial fibrillation (AF) recurrences in the three groups (13 of 43 common PV group, 21 of 75 accessory PV group, and 80 of 306 nonvariant PV group, P = 0.178). CONCLUSION: Variant PV patterns are common in patients undergoing ablation for drug-resistant AF. CB2 ablation appears to be a reasonable strategy in the setting of the variant PV anatomy with a small increase in procedure time and the number of cryoapplications.

Predictors of hemoptysis in the setting of pulmonary vein isolation using the second-generation cryoballoon.

INTRODUCTION: To assess the predictors of hemoptysis using second-generation cryoballoon (CB). METHODS: Thirty patients with hemoptysis after second-generation CB ablation and 60 age-, gender-, and body mass index-matched controls were recruited. Anatomic parameters were obtained from preprocedural cardiac computed tomography (CT). Pulmonary vein isolation was performed with 28-mm balloon using single 3-minute freeze technique. RESULTS: Clinical and procedural characteristics were similar between the groups. A shorter distance between left superior PV (LSPV) and left main bronchus (LMB) was associated with hemoptysis (7.8 ± 4.3 mm vs. 12.5 ± 3.5 mm, P < 0.001), whereas no significant difference in the distance between right superior PV (RSPV) and right main bronchus (RMB) was found between groups (11.9 ± 3.5 mm vs. 12.9 ± 4.6 mm, P = 0.089). Additionally, the mean thickness of the connective tissue interposed between RSPV and RMB was significantly thicker than that between LSPV and LMB in both groups (both P < 0.001). A stepwise logistic multivariate analysis identified only the LMB-LSPV distance as an independent predictor of hemoptysis (odd ratio [OR] 2.676; 95% CI 1.121-4.843, P < 0.001). A cutoff value ≤ 9.5 mm predicted hemoptysis after CB ablation with 93.8% sensitivity and 75.0% specificity. CONCLUSION: Hemoptysis is a relatively rare event following second-generation CB ablation. The bronchi location obtained from CT aids in identifying high-risk population for the complication.

Safety and efficacy of catheter ablation of ventricular arrhythmias with para-Hisian origin via a systematic direct approach from the aortic sinus cusp.

BACKGROUND: Catheter ablation of ventricular arrhythmias (VAs) originating from the para-Hisian region could be challenging because of a potential damage to atrioventricular conduction system. OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of catheter ablation of VAs originating from the para-Hisian region via a systematic direct approach from aortic sinus cusps (ASCs). METHODS: Twenty-one consecutive patients with VAs with para-Hisian origin were included. Electrophysiological mapping of the entire right ventricle was initially performed, and then retrograde ASC mapping was performed when the earliest ventricular activation was recorded in the His bundle region. Ablation was preferentially performed within ASCs in all patients. RESULTS: Radiofrequency energy delivery resulted in the elimination of VAs in 17 of 21 patients (81%). In the remaining 4 patients, radiofrequency application was initiated at the target site of the right ventricular septum around the His bundle region and clinical VAs were finally successfully eliminated without junctional rhythm in 2 of 4 patients. During a mean follow-up of 34.8 ± 11.3 months, 1 of the 19 acute successful patients had VA recurrence. No procedure-related complications occurred during ablation or follow-up. CONCLUSION: Catheter ablation of VAs originating from the para-Hisian region via a direct approach from ASCs may be safe and effective in most unselected patients.

Right atrial dual-loop reentrant tachycardia after cardiac surgery: Prevalence, electrophysiological characteristics, and ablation outcomes.

BACKGROUND: Right atrial (RA) dual-loop reentrant tachycardia has been described in patients who have undergone open heart surgery. However, the prevalence, electrophysiological (EP) substrate, and ablation outcomes have been poorly characterized. OBJECTIVE: The purpose of this study was to investigate the prevalence, EP substrate, and ablation outcomes for RA dual-loop reentrant tachycardia after cardiac surgery. METHODS: We identified all patients with atrial tachycardia (AT) after cardiac surgery. We compared EP findings and outcomes of those with RA dual-loop reentrant tachycardia to a control group of patients with RA macroreentrant arrhythmias in the setting of linear RA free-wall (FW) scar. RESULTS: Of the 127 patients with 152 postsurgical ATs, 28 of the ATs (18.4%) had RA dual-loop reentry and 24 of 28 (85.7%) had tricuspid annular reentry combined with FW incisional reentry. An incision length >51.5 mm along the FW predicted the substrate for a second loop. In 22 of 23 patients (95.7%) with initial ablation in the cavotricuspid isthmus, a change in the interval between Halod to CSp could be recorded, and 15 of 23 patients (65.2%) had coronary sinus activation pattern change. Complete success was achieved in 25 of 28 patients (89.3%) in the dual-loop reentry group and in 64 of 69 patients (92.8%) in the control group. After mean follow-up of 33.9 ± 24.2 months, 24 of 28 patients (85.7%) and 60 of 69 patients (86.95%) were free of arrhythmias after the initial procedure in the 2 groups, respectively. CONCLUSION: The prevalence of RA dual-loop reentry is 18.4% of ATs with prior atriotomy scar. A long incision should alert physicians to the possibility of a second loop at the FW. Halo and coronary sinus activation patterns provide important clues to circuit transformation.

"Crosstalk" technique: A comparison between two generations of cryoballoon catheter.

INTRODUCTION: The "Crosstalk" technique: if pulmonary vein isolation (PVI) of the superior one is not achieved due to a gap in the inferior part, it could be done during inferior vein cryoablation. This maneuver minimizes the total energy delivery time and number of lesions. We aimed to correlate the likelihood of crosstalk phenomenon with certain anatomic characteristics. METHODS: A total of 676 patients undergoing a first ablation procedure for paroxysmal or persistent atrial fibrillation (470 first-generation cryoballoon [CB] and 206 second-generation CB) between June 2014 and December 2016 were included. RESULTS: "Crosstalk" phenomenon occurred in 32 patients (18 first-generation CB, 14 second-generation CB). Compared to 54 control patients without crosstalk, the angle between left superior pulmonary vein (LSPV) and left atrial (LA) roof-plane, left pulmonary common ostia were significant parameters associated with crosstalk (odds ratio [OR] = 1.20, ±95% confidence interval [CI]: 1.11-1.31, P < 0.001; OR = 5.67, ±95% CI: 1.08-28.69, P = 0.04). As for angle between LSPV and LA roof-plane, the cut-off value was 28.68° with a sensitivity of 72.22%, a specificity of 81.25%, and an area under the receiver operating characteristic curve of 0.87 to predict the possibility of crosstalk technique application to get isolated in LSPV. Among the crosstalk group, there was no statistical difference between first-generation CB and second-generation CB in pulmonary anatomic characteristics. CONCLUSION: Crosstalk technique can be effective in patients with AF undergoing CB ablation using with both first and second-generation CBs. Anatomic characteristics predictive of crosstalk include a left common ostia and smaller angle between the LSPV and LA roof-plane.

Pulmonary vein isolation with real-time pulmonary vein potential recording using second-generation cryoballoon: Procedural and biophysical predictors of acute pulmonary vein reconnection.

OBJECTIVE: The study sought to evaluate the procedural and biophysical factors related to acute pulmonary vein isolation (PVI) guided by real-time pulmonary vein (PV) potential recordings. METHODS: A total of 180 consecutive patients with drug-resistant atrial fibrillation (AF) undergoing CB2 (second-generation version of cryoballoon) ablation were enrolled. Real-time monitoring of PV potentials was obtained using an inner lumen spiral mapping catheter. RESULTS: Acute isolation was achieved in all PVs without touch-up ablation. Real-time assessment of PV disconnection was possible in 611 of 711 (85.9%) PVs. A total of 617 (86.8%) PVs were isolated during the initial freeze. Longer time cycle integration (TCI) (TTI * freeze cycle, TCI) (254.6 ± 112.8 seconds vs 74.1 ± 59.7 seconds, P < 0.001), time to isolation (TTI) (94.3 ± 34.0 seconds vs 46.3 ± 26.2 seconds, P < 0.001), higher nadir temperature (-45.5 ± 5.3°C vs -50.4 ± 5.5°C, P < 0.001), longer time to -40°C (77.3 ± 22.7 seconds vs 55.7 ± 23.2 seconds, P < 0.001), faster interval rewarming time at 0°C (9.4 ± 4.3 seconds vs 12.4 ± 4.9 seconds, P = 0.008), and total balloon rewarming time (38.1 ± 11.6 seconds vs 47.7 ± 14.0 seconds, P = 0.003) were observed in PVs with acute reconduction. TTI ≤ 65 seconds predicted absence of acute reconnection with 84.2% sensitivity and 75.7% specificity, whereas TCI ≤ 119 seconds presented 94.7% sensitivity and 80.2% specificity. At a mean follow-up of 4.7 ± 1.4 months, 82.2% of patients were free of AF. None of those with PV reconnections suffered from AF recurrences. CONCLUSIONS: The ablation using CB2 is effective in achieving acute PVI. Real-time assessment of PVI could be achieved during CB application in 86% of PVs. The incidence of spontaneous PV reconnection is very low, observed in just 3% of isolated PVs. TTI ≤ 65 seconds and TCI ≤ 119 seconds predicted absence of acute PV reconnection. Although they may identify effective cryoapplications in the acute phase, their performance still needs to be verified in the long term.