Ultrasound guidance for femoral venous access in patients undergoing pulmonary vein isolation: A quasi-randomized study.

INTRODUCTION: Routine ultrasound (US) guidance for femoral venous access to decrease vascular complications of atrial fibrillation (AF) ablation procedures has been advocated. However, the benefit has not been unequivocally demonstrated by randomized-trial data. METHODS: Consecutive patients undergoing pulmonary vein isolation (PVI) on uninterrupted anticoagulant treatment were included. A quasi-random allocation to either US-guided or conventional puncture group was based on which of the two procedure rooms the patient was scheduled in, with only one of the rooms equipped with a US machine including a vascular transducer. The same four novice operators in rotation, with no relevant previous experience in US-guided vascular access performed venous punctures in both rooms. Major and minor vascular complications and the rate of prolonged hospitalization were compared. Major vascular complication was defined as groin hematoma, arteriovenous fistula, or pseudoaneurysm. Hematoma was considered as a major vascular complication if it met type 2 or higher Bleeding Academic Research Consortium criteria (requiring nonsurgical, medical intervention by a health care professional; leading to hospitalization or increased level of care, or prompting evacuation). RESULTS: Of the 457 patients 199 were allocated to the US-guided puncture group, while the conventional, palpation-based approach was performed in 258 cases. Compared with the conventional technique, US guidance reduced the rate of any vascular complication (11.63% vs. 2.01%, p < .0001), including both major (4.26% vs. 1.01%, p = .038) and minor (7.36% vs. 1.01%, p = .001) vascular complications. In addition, the rate of prolonged hospitalization was lower in the US-guided puncture group (5.04% vs. 1.01%, p = .032). CONCLUSION: The use of US for femoral vein puncture in patients undergoing PVI decreased the rate of both major and minor vascular complications. This quasi-randomized comparison strongly supports adapting routine use of US for AF ablation procedures.

A head-to-head comparison of laser vs. powered mechanical sheaths as first choice and second line extraction tools.

AIMS: During transvenous lead extraction (TLE) longer dwelling time often requires the use of powered sheaths. This study aimed to compare outcomes with the laser and powered mechanical tools. METHODS AND RESULTS: Single-centre data from consecutive patients undergoing TLE between 2012 and 2021 were retrospectively analysed. Efficacy and safety of the primary extraction tool were compared. Procedures requiring crossover between powered sheaths were also analysed. Moreover, we examined the efficacy of each level of the stepwise approach. Out of 166 patients, 142 (age 65.4 ± 13.7 years) underwent TLE requiring advanced techniques with 245 leads (dwelling time 9.4 ± 6.3 years). Laser sheaths were used in 64.9%, powered mechanical sheaths in 35.1% of the procedures as primary extraction tools. Procedural success rate was 85.5% with laser and 82.5% with mechanical sheaths (P = 0.552). Minor and major complications were observed in similar rate. Procedural mortality occurred only in the laser group in the case of three patients. Crossover was needed in 19.5% after laser and in 12.8% after mechanical extractions (P = 0.187). Among crossover procedures, only clinical success favoured the secondary mechanical arm (87.1 vs. 54.5%, aOR: 0.09, 95% CI: 0.01-0.79, P = 0.030). After step-by-step efficacy analysis, procedural success was 64.9% with the first-line extraction tool, 75.1% after crossover, 84.5% with bailout femoral snare, and 91.8% by non-emergency surgery. CONCLUSION: The efficacy and safety of laser and mechanical sheaths were similar, however in the subgroup of crossover procedures mechanical tools had better performance regarding clinical success. Device diversity seems to help improving outcomes, especially in the most complicated cases.

Is prophylactic ablation of the cavotricuspid and peri-incisional isthmus justified in patients with postoperative atrial flutter after right atriotomy?

BACKGROUND: The two most common postoperative atrial flutter (AFL) circuits after right atriotomy are the cavotricuspid isthmus (CTI) dependent and the lateral, peri-incisional. We investigated whether radiofrequency ablation (RFA) of both circuits results in more favorable long-term outcomes. METHODS: Single-center retrospective cohort study of consecutive patients who underwent RFA of AFL after open-heart surgery. The effect of surgery type and RFA strategy on AFL recurrence was evaluated. RESULTS: One hundred and forty-two patients (mean age 64.5 ± 12.7 years, 65.% male) were enrolled. Patients with right atrial (RA) flutter (n = 124) were divided into two groups based on the index RFA procedure: only one RA circuit was ablated (Group 1, n = 84, 67.7%) or both the CTI and the peri-incisional circuit ablated (Group 2, n = 40, 32.3%). The previous open-heart surgery was categorized based on the extension of the RA incision: limited (Type A) or extended (Type B) atriotomy. After a mean follow-up of 36 ± 28 months, flutter recurrence was not different among patients with limited RA atriotomy (25% vs. 22% in Groups 1A and 2A, respectively, p = 1.0). However, after type B surgery, ablation of both AFL circuits was associated with a reduced recurrence rate (63% vs. 26% in Groups 1B and 2B, respectively, p = .002). CONCLUSIONS: In patients with postoperative RA flutter after extended right atriotomy, ablation of both the CTI and the peri-incisional isthmus significantly reduces the AFL recurrence rate. Prophylactic ablation of both isthmi, even if not proven to support reentry, is reasonable in this population.

Is adenosine useful for the identification of atrial fibrillation triggers?

INTRODUCTION: Both isoproterenol (Iso) and adenosine (Ado) are used to induce atrial fibrillation (AF) in the electrophysiology lab. However, the utility of Ado has not been systematically established. OBJECTIVE: The purpose of this study was to compare Ado to Iso for the induction of paroxysmal AF. METHODS: Forty patients (16 women; mean age, 60 ± 12 years) with paroxysmal AF, presenting for ablation were prospectively included of whom 36 (90%) received Ado (18-36 mg) and/or Iso (3-20 µg/min incremental dose) in a randomized order (26 [72%] received both drugs). RESULTS: AF was induced with Iso in 15 of 32 (47%) and with Ado in 12 of 30 (40%) patients (P = 0.9). Iso-triggered AF started from the left pulmonary veins (PVs) in 11 of 15 (73%), from the right PVs in 3 of 15 (20%), and from the coronary sinus (CS) in 1 of 15 (7%) cases. Ado-induced AF episodes originated from the left PVs in 6 of 12 (50%), from the right atrium (RA) in 4 of 12 (33%), and from the CS in 2 of 12 (17%) cases. Altogether, Iso-induced AF was more likely initiated from the PVs (93%) compared with Ado (50%) ( P = 0.02). Ado-induced non-PV triggers were not predictive of arrhythmia recurrence after PV isolation. CONCLUSION: Ado much more frequently induces non-PV triggers, especially from the RA. The clinical significance of these foci, however, is questionable.

Primary cardiac angiosarcoma: A case report.

Cardiac angiosarcomas are the most common primary malignant cardiac tumors in adults. The diagnosis is often delayed due to nonspecific clinical symptoms at presentation. The cornerstones of diagnosis are echocardiography and the histological evaluation of the cardiac biopsy. The knowledge on the treatment is limited; the outcomes of chemotherapy, radiotherapy, complete surgical removal, and heart transplantation are controversial. We report a 38-year-old woman with a primary heart tumor which infiltrated the right atrial wall and the pericardium and caused pericardial effusion. Angiosarcoma was verified histologically. The surgical excision could not be radical, and the patient died 3 months from diagnosis.

The role of immunotherapy in early-stage and metastatic NSCLC.

In the past decade we have seen new advances and thus remarkable progress in the therapeutic options for non-small cell lung cancer (NSCLC). Among cytostatic therapies with new approaches in molecularly targeted therapies, we see new developments in a wide range of applications for immunotherapies. In this review we discuss the new potential modalities for the use of immune checkpoint inhibitors (ICIs) in the frontlines, including in early-stage (perioperative) and metastatic settings. The perioperative use of ICIs in both neoadjuvant and adjuvant settings may show benefits for patients. In early-stage NSCLC (from stage IIB and above) a multimodality approach is recommended as the gold standard for the treatment. After surgical resection platinum-based adjuvant chemotherapy has been the standard of care for many years. Based on the benefit of disease-free survival, the approval of adjuvant atezolizumab and adjuvant pembrolizumab was a significant breakthrough. In the metastatic setting, the use of immune checkpoint inhibitors with chemotherapy, regardless of PD-L1 expression or ICI alone (PD-L1 expression equal to or greater than 50%) also improves overall survival and progression-free survival.

Perceived university support and environment as a factor of entrepreneurial intention: Evidence from Western Transdanubia Region.

The exploration of entrepreneurship has become a priority for scientific research in recent years. Understanding this phenomenon is particularly important for the transformation of entrepreneurship into action, which is a key factor in early-stage entrepreneurial activity. This gains particular relevance in the university environment, where, in addition to the conventional teaching and research functions, the entrepreneurial university operation based on open innovation, as well as the enhancement of entrepreneurial attitudes of researchers and students, are receiving increased attention. This study is based on a survey conducted among students attending a Hungarian university of applied science in Western Transdanubia Region who have demonstrated their existing entrepreneurial commitment by joining a national startup training and incubation programme. The main research question of the study is to what extent student entrepreneurship intention is influenced by the environment of the entrepreneurial university ecosystem and the support services available at the university. A further question is whether these factors are able to mitigate the negative effects of internal cognitive and external barriers by enhancing entrepreneurial attitudes and perceived behavioural control. The relatively large number of students involved in the programme allows the data to be analysed using SEM modelling. The results indicate a strong covariance between the perceived university support and environment among students. Another observation is the distinct effect of these institutional factors on perceived behavioural control of students.

Immune-related adverse events of anti-PD-1 immune checkpoint inhibitors: a single center experience.

Objectives: Immune checkpoint inhibitors (ICIs) stimulate antitumor immune responses and, in parallel, they might trigger autoimmune and other immunopathological mechanisms eventually leading to immune-related adverse events (irAE). In our study, we assessed patients with malignancies who underwent anti-PD-1 treatment at the University of Debrecen, Clinical Center. Patients and methods: Between June 2017 and May 2021, 207 patients started ICI treatment at our university. A total of 157 patients received nivolumab and 50 were treated with pembrolizumab. We looked for factors associated with the development of irAEs. In addition to correlation studies, we performed binary logistic regression analysis to determine, which factors were associated with irAEs. We also performed Forward Likelihood Ratio (LR) analysis to determine independent prognostic factors. Results: At the time of data analysis, the mean duration of treatment was 2.03 ± 0.69 years. ROC analysis determined that 9 or more treatment cycles were associated with a significantly higher risk of irAEs. A total of 125 patients received ≥9 treatment cycles. Three times more patients were treated with nivolumab than pembrolizumab. Of the 207 patients, 66 (32%) developed irAEs. Among the 66 patients who developed irAEs, 36 patients (55%) developed one, 23 (35%) developed two, while 7 (10%) developed three irAEs in the same patient. The most common irAEs were thyroid (33 cases), dermatological (25 cases), pneumonia (14 cases) and gastrointestinal complications (13 cases). Patients who developed irAEs received significantly more treatment cycles (21.8 ± 18.7 versus 15.8 ± 17.4; p=0.002) and were younger at the start of treatment (60.7 ± 10.8 versus 63.4 ± 10.1 years; p=0.042) compared to patients without irAEs. Pembrolizumab-treated patients developed more but less severe irAEs compared to those receiving nivolumab. Conclusion: ICI treatment is very effective, however, irAEs may develop. These irAEs might be related to the number of treatment cycles and the type of treated malignancy.

Reimplantation and long-term mortality after transvenous lead extraction in a high-risk, single-center cohort.

PURPOSE: The use of cardiac implantable electronic devices (CIEDs) has increased significantly over the last decades. With the development of transvenous lead extraction (TLE), procedural success rates also improved; however, data regarding long-term outcomes are still limited. The aim of our study was to analyze the outcomes after TLE, including reimplantation data, all-cause and cause-specific mortality. METHODS: Data from consecutive patients undergoing TLE in our institution between 2012 and 2020 were retrospectively analyzed. Periprocedural, 30-day, long-term, and cause-specific mortalities were calculated. We examined the original and the revised CIED indications and survival rate of patients with or without reimplantation. RESULTS: A total of 150 patients (age 66 ± 14 years) with 308 leads (dwelling time 7.8 ± 6.3 years) underwent TLE due to pocket infection (n = 105, 70%), endocarditis (n = 35, 23%), or non-infectious indications (n = 10, 7%). All-cause mortality data were available for all patients, detailed reimplantation data in 98 cases. Procedural death rate was 2% (n = 3), 30-day mortality rate 2.6% (n = 4). During the 3.5 ± 2.4 years of follow-up, 44 patients died. Arrhythmia, as the direct cause of death, was absent. Cardiovascular cause was responsible for mortality in 25%. There was no significant survival difference between groups with or without reimplantation (p = 0.136). CONCLUSIONS: Despite the high number of pocket and systemic infection and long dwelling times in our cohort, the short- and long-term mortality after TLE proved to be favorable. Moreover, survival without a new device was not worse compared to patients who underwent a reimplantation procedure. Our study underlines the importance of individual reassessment of the original CIED indication, to avoid unnecessary reimplantation.

Randomized trial of intracardiac echocardiography during cavotricuspid isthmus ablation.

UNLABELLED: Randomized Trial of ICE During CTI Ablation. INTRODUCTION: Despite a high success rate, radio-frequency ablation (RFA) of the cavotricuspid isthmus (CTI) can be unusually challenging in some cases. We postulated that visualization of the CTI with intracardiac echocardiography (ICE) could maximize the success rate, decrease the procedure and ablation time, and minimize the radiation exposure. METHODS AND RESULTS: In our prospective, randomized study, we included 102 patients scheduled for CTI ablation. We randomized patients in 2 groups: guided only by fluoroscopy (n = 52) or ICE-guided (n =50) group. Procedure time, fluoroscopy time, and the time spent for RFA were significantly shorter, radiation exposure (dose-area product-DAP) and the sum of delivered radio frequency energy were significantly lower in the ICE-group (68.06 ± 15.09 minutes vs 105.94 ± 36.51 minutes, P < 0.001, 5.54 ± 3.77 minutes vs 18.63 ± 10.60 minutes, P <0.001, 482.80 ± 534.12 seconds vs 779.76 ± 620.82 seconds, P = 0.001 and 397.62 ± 380.81 cGycm(2) vs 1,312.92 ± 1,129.28 cGycm(2) , P < 0.001, 10,866.84 ± 6,930.84 Ws vs 16,393.56 ± 13,995.78 Ws, P = 0.048, respectively). Seven patients (13%) from the fluoroscopy-only group crossed over to ICE-guidance because of prolonged unsuccessful RFA and were all treated successfully. Four vascular complications and 2 recurrences were equally distributed between the 2 groups. CONCLUSIONS: ICE-guided ablation of the CTI significantly shortens the procedure and fluoroscopy time, markedly decreases radiation exposure, and time spent for ablation in comparison with fluoroscopy-only procedures. At the same time, visualization with ICE allowed successful ablation in challenging cases. (J Cardiovasc Electrophysiol, Vol. 23, pp. 996-1000, September 2012).

Randomized trial of intracardiac echocardiography-guided slow pathway ablation.

PURPOSE: Radiofrequency (RF) catheter ablation of the slow pathway (SP) in atrioventricular nodal reentry tachycardia (AVNRT) is highly effective; however, it may require prolonged fluoroscopy and RF time. We postulated that visualization of the SP region with intracardiac echocardiography (ICE) could decrease ablation time, minimize radiation exposure, and facilitate SP ablation compared to the standard, fluoroscopy-guided approach. METHODS: In our study, we randomized 91 patients undergoing electrophysiologic study and SP ablation for AVNRT into 2 groups: fluoroscopy-only (n = 48) or ICE-guided (n = 43) group. Crossover to ICE-guidance was allowed after 8 unsuccessful RF applications. RESULTS: Mapping plus ablation time (mean ± standard deviation: 18.8 ± 16.1 min vs 11.6 ± 15.0 min, p = 0.031), fluoroscopy time (median [interquartile range]: 4.9 [2.93-8.13] min vs. 1.8 [1.2-2.8] min, p < 0.001), and total ablation time (144 [104-196] s vs. 81 [60-159] s, p = 0.001) were significantly shorter in the ICE group. ICE-guidance was associated with reduced radiation exposure (13.2 [8.2-13.4] mGy vs. 3.7 [1.5-5.8] mGy, p < 0.001). The sum of delivered RF energy (3866 [2786-5656] Ws vs. 2283 [1694-4284] Ws, p = 0.002) and number of RF applications (8 [4.25-12.75] vs. 4 [2-7], p = 0.001) were also lower with ICE-guidance. Twelve (25%) patients crossed over to the ICE-guided group. All were treated successfully thereafter with similar number, time, and cumulative energy of RF applications compared to the ICE group. No recurrence occurred during the follow-up. CONCLUSIONS: ICE-guidance during SP ablation significantly reduces mapping and ablation time, radiation exposure, and RF delivery in comparison to fluoroscopy-only procedures. Moreover, early switching to ICE-guided ablation seems to be an optimal choice in challenging cases.

Electrogram analysis at the His bundle region and the proximal coronary sinus as a tool to predict left atrial origin of focal atrial tachycardias.

AIMS: Early activation at the His bundle (HB) region or proximal coronary sinus (CS) during focal atrial tachycardias (FATs) often necessitates biatrial mapping. Analysis of CS electrograms (EGMs) consisting of a near-field (N) component from CS musculature and a far-field (F) component from left atrial (LA) myocardium can uncover LA activation preceding right atrial (RA) activation. A similar pattern might be observed at the HB. METHODS AND RESULTS: Eight patients underwent RA and LA pacing testing the hypothesis that N and F components originating from the RA and LA septum are present in the HB atrial EGM (Pacing group). In this group N preceded F (N-F sequence) in all, while F preceded N (F-N sequence) in seven of eight patients during RA and LA pacing, respectively. Twenty-seven patients with FAT demonstrating earliest activation at the HB or proximal CS during limited RA mapping were also studied (FAT group). Two observers analysed the EGMs at the earliest site during FAT. They found an N-F sequence in 17 (94%) and 16 (89%) of 18 RA FAT and an F-N sequence in seven (78%) and eight (89%) of nine LA FAT, respectively. The F-N sequence predicted the need for LA access with a sensitivity of 78 and 89% and a specificity of 94 and 89%. CONCLUSION: Near-field and F components from RA and LA activation can be identified in the HB atrial EGM. Earliest atrial EGM analysis at the HB or CS can predict the need for LA access during FAT ablation.

Effect of the replacement of tripodal 4N donors by two 2N chelators on the redox and cytotoxic activity of maltolato and deferipronato containing Co(III) complexes.

Fourteen novel CoIII ternary complexes with the general formula [Co(4N)(2O)]X2 or [Co(2N)2(2O)]X2 where 4N = tris(2-aminoethyl)amine (tren) or tris(2-pyridylmethyl)amine (tpa); 2N = 1,10-phenantroline (phen), 2,2'-bipyridine (bipy), 1,2-diaminoethane (en) or 2-(aminomethyl)pyridine (ampy) and 2O = 1,2-dimethyl-3-hydroxy-4(1H)-pyridinone (dhpH), 3-hydroxy-2-methyl-4-pyrone (maltH) or 2-ethyl-3-hydroxy-4H-pyran-4-one (etmaltH) were synthesized, characterized and their redox features explored. Molecular structure of some selected [Co(2N)2(2O)](ClO4)2 (2N = phen, bipy, en; 2O = dhp, malt) or [Co(4N)(2O)](ClO4)2 (4N = tpa; 2O = etmalt) type complexes were assessed by X-ray diffraction and showed the expected octahedral geometry. Replacement of the 4N donor ligands by two 2N donor ligands resulted in the decrease of the cathodic peak potential of the complexes indicating easier reduction and allowing therefore the tailoring of the redox properties of the complexes. Screening of selected compounds against a human derived cancer cell line, HeLa, showed that, unlike the [Co(4N)(2O)]X2 derivatives, the complexes containing 2N = bipy or phen ligands have better anticancer activity than cisplatin or carboplatin.

Management of cardiac implantable electronic device infection using a complete interdisciplinary approach.

Technological advances and increasing operator experience have improved the success rate of transvenous lead extraction (TLE). However, in some cases-especially with longer lead dwelling time-TLE can be highly complicated. In this case report, the authors present an unusual case of implantable cardioverter defibrillator (ICD) pocket infection diagnosed by 18F­fluorodeoxyglucose positron emission tomography/computed tomography (18F­FDG-PET/CT). Complete lead extraction required a combined transvenous and surgical approach. Contralateral reimplantation failed due to occlusion of the right brachiocephalic vein. Therefore, a subcutaneous ICD was implanted. This case highlights the importance of an interdisciplinary approach to the treatment of cardiac implantable electronic device infection.

Automated procedure assessing the accuracy of HRCT-PET registration applied in functional virtual bronchoscopy.

BACKGROUND: Bronchoscopy serves as direct visualisation of the airway. Virtual bronchoscopy provides similar visual information using a non-invasive imaging procedure(s). Early and accurate image-guided diagnosis requires the possible highest performance, which might be approximated by combining anatomical and functional imaging. This communication describes an advanced functional virtual bronchoscopic (fVB) method based on the registration of PET images to high-resolution diagnostic CT images instead of low-dose CT images of lower resolution obtained from PET/CT scans. PET/CT and diagnostic CT data were collected from 22 oncological patients to develop a computer-aided high-precision fVB. Registration of segmented images was performed using elastix. RESULTS: For virtual bronchoscopy, we used an in-house developed segmentation method. The quality of low- and high-dose CT image registrations was characterised by expert's scoring the spatial distance of manually paired corresponding points and by eight voxel intensity-based (dis)similarity parameters. The distribution of (dis)similarity parameter correlating best with anatomic scoring was bootstrapped, and 95% confidence intervals were calculated separately for acceptable and insufficient registrations. We showed that mutual information (MI) of the eight investigated (dis)similarity parameters displayed the closest correlation with the anatomy-based distance metrics used to characterise the quality of image registrations. The 95% confidence intervals of the bootstrapped MI distribution were [0.15, 0.22] and [0.28, 0.37] for insufficient and acceptable registrations, respectively. In case of any new patient, a calculated MI value of registered low- and high-dose CT image pair within the [0.28, 0.37] or the [0.15, 0.22] interval would suggest acceptance or rejection, respectively, serving as an aid for the radiologist. CONCLUSION: A computer-aided solution was proposed in order to reduce reliance on radiologist's contribution for the approval of acceptable image registrations.

Converging methods in the assessment of sympathetic baroreflex sensitivity.

AIMS: Abnormalities of the sympathetic baroreflex regulation are documented in various diseases. The recording of sympathetic nerve activity allows for the calculation of baroreflex gain but this is not available in practice. A non-invasive method based on blood pressure during the late phases of Valsalva manoeuvre (VM) was proposed. Sympathetic gain could be calculated from the pressure fluctuations following ventricular extrasystole or non-sustained ventricular tachycardia (NSVT). METHODS AND RESULTS: We assessed both indices in 25 subjects with no significant cardiovascular disease. VM was performed at 40 mmHg for 12 s. Paced NSVT consisted of five to six cycles. The sympathetic gains were determined based on the recovery of mean arterial pressure (MAP, mmHg/s). The maximum slope of five consecutive MAP elevations occurring within a 15-cycle period after NSVT was calculated. This MAP turbulence slope (MAP(TS)) was expressed in mmHg/cycle. Five patients were excluded because of unacceptable VM. VM-derived sympathetic gain (SBRS(vals)) and the NSVT-derived gain (SBRS(NSVT)) correlated closely (R = 0.86, P < 0.001). Their mean difference was 3.2 +/- 4.8 mmHg. Both SBRS(vals) and SBRS(NSVT) correlated closely with MAP(TS) (R = 0.77, P < 0.001 and R = 0.86, P < 0.001, respectively). CONCLUSION: The sympathetically mediated arterial pressure recovery is an analogous process following both VM and NSVT. SBRS(NSVT) or MAP(TS) may be useful in the assessment of patients with implanted antiarrhythmic devices.

Characterization of a rare bla VIM-4 metallo-ß-lactamase-producing Serratia marcescens clinical isolate in Hungary.

A carbapenem-resistant S. marcescens isolate was recovered from a patient with an inflammed pacemaker inplantation pocket from a Cardiac Surgery ward in a Hungarian University Hospital. Phenotypic tests and polymerase chain reaction (PCR) confirmed a very rare gene responsible for production of a carbapenemase ( bla VIM-4 ), which was further characterized by Sanger-sequencing. The characterization of this S. marcescens strain emphasizes the ongoing emergence of novel or rare carbapenemases. Strains expressing a weak carbapenemase like this strain might go unrecognized by routine diagnostics due to low minimum inhibitory concentrations (MICs) for the bacterial strains producing such enzymes.

Ablation of posteroseptal and left posterior accessory pathways guided by left atrium-coronary sinus musculature activation sequence.

INTRODUCTION: While some posteroseptal and left posterior accessory pathways (APs) can be ablated on the tricuspid annulus or within the coronary venous system, others require a left-sided approach. "Fragmented" or double potentials are frequently recorded in the coronary sinus (CS), with a smaller, blunt component from left atrial (LA) myocardium, and a larger, sharp signal from the CS musculature. METHODS AND RESULTS: Forty patients with posteroseptal or left posterior AP were included. The LA-CS activation sequence was determined at the earliest site during retrograde AP conduction. Eleven APs (27.5%) were ablated on the tricuspid annulus (right endocardial), 9 (22.5%) inside the coronary venous system (epicardial), and 20 (50%) on the mitral annulus (left endocardial). A "fragmented" or double "atrial" potential was recorded in all patients inside the CS at the earliest site during retrograde AP conduction. Sharp potential from the CS preceded the LA blunt component (sharp/blunt sequence) in all patients with an epicardial AP, and in 10 of 11 (91%) patients with a right endocardial AP. Therefore, 18 of 19 (95%) APs ablated by a right-sided approach produced this pattern. The reverse sequence (blunt/sharp) was recorded in 19 of 20 (95%) patients with a left endocardial AP. CONCLUSION: During retrograde AP conduction, the sequence of LA-CS musculature activation-as deduced from analysis of electrograms recorded at the earliest site inside the CS-can differentiate posteroseptal and left posterior APs that require left heart catheterization from those that can be eliminated by a totally venous approach.

Coexistent right- and left-sided slow pathways participating in distinct AV nodal reentrant tachycardias.

We report a patient with two distinct atrioventricular (AV) nodal slow pathways, participating in two different AV nodal reentrant tachycardias--one eliminated from the right, the other only after ablation on the left side of the posterior septum. The case provides support for the concept of the posterior AV nodal extensions--a biatrial structure in most hearts--representing the anatomic basis of slow pathway conduction.