Anatomical Ablation of the Atrioventricular Node.

Background: Atrioventricular (AV) conduction ablation has been achieved by targeting the area of penetration of the conduction axis as defined by recording a His bundle potential. Ablation of the His bundle may reduce the possibility of a robust junctional escape rhythm. It was hypothesised that specific AV nodal ablation is feasible and safe. Methods: The anatomical position of the AV node in relation to the site of penetration of the conduction axis was identified as described in dissections and histological sections of human hearts. Radiofrequency (RF) ablation was accomplished based on the anatomical criteria. Results: Specific anatomical ablation of the AV node was attempted in 72 patients. Successful AV nodal ablation was accomplished in 63 patients (87.5%), following 60 minutes (IQR 50-70 minutes) of procedure time, 3.4 minutes (IQR 2.4-5.5 minutes) of fluoroscopy time, and delivery of 4 (IQR 3-6) RF lesions. An escape rhythm was present in 45 patients (71%), and the QRS complex was similar to that before ablation in all 45 patients. Atropine was administered in six patients after the 10-min waiting period and did not result in restoration of conduction. In nine patients, AV conduction could not be interrupted, and AV block was achieved with ablation of the His after delivery of 12 (IQR 8-15) RF lesions. No cases of sudden death were encountered, and all patients had persistent AV block during a median 10.5 months (IQR 5-14 months) of follow-up. Conclusion: Anatomical ablation of the AV node is feasible and safe, and results in an escape rhythm similar to that before ablation.

Catheter ablation vs. antiarrhythmic drug therapy in patients with symptomatic atrioventricular nodal re-entrant tachycardia: a randomized, controlled trial.

AIMS: To conduct a randomized trial in order to guide the optimum therapy of symptomatic atrioventricular nodal re-entrant tachycardia (AVNRT). METHODS AND RESULTS: Patients with at least one symptomatic episode of tachycardia per month and an electrophysiologic diagnosis of AVNRT were randomly assigned to catheter ablation or chronic antiarrhythmic drug (AAD) therapy with bisoprolol (5 mg od) and/or diltiazem (120-300 mg od). All patients were properly educated to treat subsequent tachycardia episodes with autonomic manoeuvres or a 'pill in the pocket' approach. The primary endpoint of the study was hospital admission for persistent tachycardia cardioversion, during a follow-up period of 5 years. Sixty-one patients were included in the study. In the ablation group, 1 patient was lost to follow-up, and 29 were free of arrhythmia or conduction disturbances at a 5-year follow-up. In the AAD group, three patients were lost to follow-up. Of the remainder, 10 patients (35.7%) continued with initial therapy, 11 patients (39.2%) remained on diltiazem alone, and 7 patients (25%) interrupted their therapy within the first 3 months following randomization, and subsequently developed an episode requiring cardioversion. During a follow-up of 5 years, 21 patients in the AAD group required hospital admission for cardioversion. Survival free from the study endpoint was significantly higher in the ablation group compared with the AAD group (log-rank test, P < 0.001). CONCLUSIONS: Catheter ablation is the therapy of choice for symptomatic AVNRT. Antiarrhythmic drug therapy is ineffective and not well tolerated.

Renal denervation for resistant hypertension: acute results and long-term follow-up.

INTRODUCTION: Renal sympathetic hyperactivity is vital for the maintenance and progression of essential hypertension. Catheter-based renal denervation is an evolving concept with favourable results regarding the control of hypertension; however, clinical experience is still limited. METHODS: We enrolled 15 patients with resistant hypertension who underwent percutaneous, catheter-based radiofrequency treatment for renal artery denervation. Patients were followed up for 4 to 13 months. RESULTS: Baseline mean blood pressure was 169/96 mmHg (SD 9/11), and patients were receiving a mean 3.9 ± 0.8 antihypertensive medications. Blood pressure values were reduced to 136/79 mmHg (SD 10/7), and antihypertensive medications to 2.9 ± 0.8 at 6.9 ± 3.4 months after the procedure. All procedures were uneventful and technically easy. The only drawbacks of the procedure are pain that the patient may feel during energy delivery, and the inability to obtain a sustained impedance reduction that allows completion of radiofrequency current delivery at some sites in the renal artery. CONCLUSIONS: Renal denervation facilitates control of resistant hypertension with reduction of medication, and appears to be a safe and technically easy procedure to accomplish.

A tachycardia with varying QRS morphology and RP intervals: differential diagnosis and therapy.

An interesting case of a tachycardia with varying QRS morphology and RP intervals is presented and the electrophysiological differential diagnosis is discussed.

Complications of transseptal catheterization for different cardiac procedures.

BACKGROUND: Cardiac tamponade is the main complication of transseptal catheterization that is necessary for a variety of cardiac interventions and electrophysiology procedures. METHODS: A retrospective assessment of all consecutive procedures that required transseptal puncture by the same experienced operator (with already >100 previous trans-septal procedures) during the period 2000-2012 was performed. We recorded any puncture-related complications of pericardial effusion and cardiac tamponade (acute or delayed). RESULTS: A total of 393 procedures were retrieved: Group 1 [ablation of left-sided accessory pathways (n = 77), atrioventricular nodal reentry tachycardia-left septal access (AVNRT) (n = 12), and Inoue balloon mitral valvuloplasty (n = 27)], and Group 2 [atrial fibrillation (AF) ablation procedures: ostial pulmonary vein isolation (PVI) (including RF (n = 76) and cryo-balloon (n = 30)), circumferential PVI (n = 51), and combined procedures (n = 120)]. In total, 5 cases of tamponade were recorded, four of them were acute and one delayed (occurring 1h after the procedure). All tamponade cases occurred only during or after AF ablation procedures (cryo-balloon ablation = 1, circumferential PVI = 2, and combined procedures = 2). In one case emergency atrial repair following median sternotomy was necessary, and in another a surgical drainage through a limited thoracotomy was performed. The other three cases were treated with pericardiocentesis and drainage for 12h. No patient was on uninterrupted oral anticoagulation during the procedure. CONCLUSIONS: AF ablation is associated with a higher incidence of tamponade compared to other procedures that require transseptal access. Such procedures should only be performed in hospitals with access to emergency surgical support.

Autonomic denervation added to pulmonary vein isolation for paroxysmal atrial fibrillation: a randomized clinical trial.

OBJECTIVES: The aim of this study was to investigate whether the combination of conventional pulmonary vein isolation (PVI) by circumferential antral ablation with ganglionated plexi (GP) modification in a single ablation procedure, yields higher success rates than PVI or GP ablation alone, in patients with paroxysmal atrial fibrillation (PAF). BACKGROUND: Conventional PVI transects the major left atrial GP, and it is possible that autonomic denervation by inadvertent GP ablation plays a central role in the efficacy of PVI. METHODS: A total of 242 patients with symptomatic PAF were recruited and randomized as follows: 1) circumferential PVI (n = 78); 2) anatomic ablation of the main left atrial GP (n = 82); or 3) circumferential PVI followed by anatomic ablation of the main left atrial GP (n = 82). The primary endpoint was freedom from atrial fibrillation (AF) or other sustained atrial tachycardia (AT), verified by monthly visits, ambulatory electrocardiographic monitoring, and implantable loop recorders, during a 2-year follow-up period. RESULTS: Freedom from AF or AT was achieved in 44 (56%), 39 (48%), and 61 (74%) patients in the PVI, GP, and PVI+GP groups, respectively (p = 0.004 by log-rank test). PVI+GP ablation strategy compared with PVI alone yielded a hazard ratio of 0.53 (95% confidence interval: 0.31 to 0.91; p = 0.022) for recurrence of AF or AT. Fluoroscopy duration was 16 ± 3 min, 20 ± 5 min, and 23 ± 5 min for PVI, GP, and PVI+GP groups, respectively (p < 0.001). Post-ablation atrial flutter did not differ between groups: 5.1% in PVI, 4.9% in GP, and 6.1% in PVI+GP. No serious adverse procedure-related events were encountered. CONCLUSIONS: Addition of GP ablation to PVI confers a significantly higher success rate compared with either PVI or GP alone in patients with PAF.

Clinical and angiographic characteristics of patients with coronary artery ectasia.

BACKGROUND: The relationship of the extent of coronary artery ectasia (CAE) with coronary blood flow in the major epicardial arteries has not been adequately assessed. This study aimed at investigating the association of the topographical extent of CAE with coronary flow velocity and clinical characteristics in patients with isolated CAE and in patients with coexisting obstructive coronary artery disease (CAD). METHODS: We reviewed 3764 consecutive coronary angiograms performed at Athens Euroclinic and identified patients with CAE according to standard criteria. The topographical extent of ectasia was considered, and coronary flow velocity was determined using the TIMI frame count (TFC). The severity of CAD was assessed using the modified Gensini index and the number of diseased vessels. Clinical data were correlated with TFC and CAD severity analysis. RESULTS: Ectatic lesions were identified in 119 patients. The mean TFC correlated positively with the topographical extent of CAE (rs=0.733, p<0.001). Stepwise multiple linear regression revealed that the topographical extent of CAE and the maximum diameter of the ectatic segment in the corresponding artery are independent predictors of TFC in LAD and RCA. Using multivariate analysis, a history of myocardial infarction was independently associated with CAE extent, and CAD severity. CONCLUSIONS: The extent of ectasia in the coronary vasculature is correlated with coronary flow velocity and associated with clinical presentation independent of coexisting significant coronary stenoses.

Spot drug-eluting stenting for long coronary stenoses: long-term results of a randomized clinical study.

BACKGROUND: Preliminary results of a randomized trial have suggested that total lesion coverage with drug-eluting stents (DES) is not necessary in the presence of diffuse disease of nonuniform severity. In the present study, we report long-term results of this trial. METHODS: Consecutive, consenting patients with a long (>20 mm) coronary lesion of nonuniform severity and indication for percutaneous coronary intervention were randomized to full stent coverage of the atherosclerotic lesion with multiple, overlapping (full DES group, n = 90) or spot stenting of the hemodynamically significant parts of the lesion only (defined as diameter stenosis > 50%) (spot DES group, n = 89). RESULTS: At a follow-up of 2-7 years, 30 patients with full DES (33.3%) and 12 patients (13.5%) with spot DES had a major adverse cardiac event (MACE) (P = 0.015). Cox proportional hazard model showed that the risk for MACE was almost 65% lower among patients who were subjected to spot DES compared to those who underwent full DES (HR = 0.35, 95% CI = 0.18-0.68, P = 0.002). This association remained significant even after controlling for age, sex, and lesion length, and the type of stent used (HR = 0.41, 95% CI = 0.20-0.81, P = 0.011). CONCLUSIONS: In the presence of diffuse disease of nonuniform severity, selective stenting of only the significantly stenosed parts of the lesion confers better long-term results compared to total lesion coverage with DES.

Autonomic modulation of complex fractionated atrial electrograms in patients with paroxysmal atrial fibrillation.

AIMS: In patients with atrial fibrillation (AF), complex fractionated atrial electrograms (CFAE) have been shown to be located at the anatomic sites of ganglionated plexi (GP). This study aimed at investigating the contribution of parasympathetic activity to formation of CFAE. METHODS: Twelve patients (aged 55 ± 11 years, five females) with paroxysmal AF were studied. Following electroanatomical mapping of the left atrium, GP were identified by high frequency stimulation (HFS), 12-24 V in a conscious state, and assessment of CFAE during AF was performed with the use of dedicated software. Fractionated activity was measured at each GP site by interval confidence levels (ICL) and average complex interval (ACI), and was compared to measurements obtained 1 min after intravenous administration of 1 mg of atropine. RESULTS: In total, 30 out of 48 GP could be identified by HFS. CFAE were detected at all sites where GP were found. ICL was significantly lower after atropine administration only at ARGP (5.4 ± 2.7 vs. 2.8 ± 2.1, p = 0.028), whereas no significant difference was detected pre- or post-atropine at any GP in ACI. Considering all fractionation values from the four GP, a statistically significant reduction of the ICL score was observed (4.6 ± 3.4 vs. 5.8 ± 2.9, p = 0.03) after atropine administration, whereas no significant differences were observed in the ACI score (144.5 ± 24.0 post-atropine vs. 146.7 ± 27.7 pre-atropine, p = 0.620). The average RR interval became significantly shorter post-atropine (575.8 ± 139.1 vs. 637.2 ± 158.7, p = 0.004). CONCLUSION: Our data do not support the hypothesis that parasympathetic activity plays the dominant role in electrogram fractionation.

Rapid pulmonary vein isolation combined with autonomic ganglia modification: a randomized study.

BACKGROUND: Evidence indicates that the combination of left atrial ganglionated plexi (GP) ablation and pulmonary vein (PV) isolation is beneficial for treatment of paroxysmal atrial fibrillation (AF). OBJECTIVE: The purpose of this study was to compare GP and PV ablation with PV isolation alone for treatment of paroxysmal AF. METHODS: Sixty-seven patients with paroxysmal AF were randomized to either PV isolation using a circular catheter suitable for both mapping and ablation (PV group) or anatomic GP modification followed by PV isolation (GP+PV group). Patients were seen at monthly visits, and 48-hour ambulatory ECG recordings were obtained every 3 months for a predefined follow-up period of 12 months. Primary endpoint was freedom from AF or other sustained atrial arrhythmia recurrence 3 to 12 months postablation after one or two procedures, without antiarrhythmic medications. RESULTS: Recurrence of arrhythmia was documented in 18 (54.5%) patients in the PV group 4.7 ± 1.0 months after ablation, and repeat PV isolation was performed in 7 (21.2%) of these patients 5.1 ± 1.1 months after the first procedure. Recurrence of arrhythmia was documented in 9 (26.5%) patients in the GP+PV group 5.0 ± 1.3 months after ablation, and repeat ablation was performed in 6 (17.6%) of these patients 4.3 ± 0.5 months after the first procedure. At the end of follow-up, 20 (60.6%) patients in the PV group and 29 (85.3%) patients in the GP+PV group remained arrhythmia-free (log rank test, P = .019). CONCLUSION: Addition of anatomic GP modification to PV isolation confers significantly better outcomes than PV isolation alone during a follow-up period of 12 months.

An approach to left septal slow pathway ablation.

BACKGROUND: Slow pathway ablation or modification eliminates typical atrioventricular nodal re-entrant tachycardia (AVNRT), but in less than 5% of patients cannot be accomplished from the right side. METHODS: Consecutive, consenting patients (n = 221), aged 37 ± 7 years, 177 women, with slow-fast AVNRT, underwent slow pathway ablation. Mapping was restricted to the inferior part of the triangle of Koch, and end-points of ablation were induction of a junctional rhythm with retrograde atrial conduction and non-inducibility of AVNRT. Unsuccessful cases were ablated via a transeptal approach from the left septum with the aid of a left-sided His recording electrode. RESULTS: Right-sided ablation was successful in 217 of 221 cases. In four patients (1.8%), left-sided ablation was necessary. Procedure, fluoroscopy times, and number of lesions were 105 min (82.4-135) vs. 65 min (60-90) (p = 0.013), 31.9 (23.9-34.3) vs. 9.6 (6.2-14.2) min (p = 0.001), and seven (5.5-7.8) vs. four (4-5; p = 0.004) for left- vs. right-sided procedures, respectively. During a follow-up period of 1-3 years, three patients (1.3%) in the right group had AVNRT recurrence. All had residual dual pathway physiology following ablation, while only 20.3% of patients without AVNRT had residual dual AV nodal conduction (p < 0.001). No conduction disturbances were seen. In the left-sided ablation group, no AVNRT recurrences or AV block were seen. CONCLUSIONS: Ablation with the protocol described offers a high success rate with an extremely low risk of AV block when left-sided ablation is necessary in patients with typical AVNRT who have failed a right-sided approach.

Slow-pathway ablation for atrioventricular nodal re-entrant tachycardia with no risk of atrioventricular block.

BACKGROUND: Slow-pathway ablation or modification eliminates typical atrioventricular nodal re-entrant tachycardia (AVNRT) but with a 1% risk of AV block. We report our experience from a series of consecutive patients with typical AVNRT who were ablated in our unit. METHODS: Consecutive patients (n=227), aged 22 to 56 years, 172 women, with slow-fast AVNRT underwent slow-pathway ablation. Mapping was restricted to the inferior part of the triangle of Koch, at the right or left septum, below the ostium of the coronary sinus, and was aimed at recording multicomponent, low-amplitude potentials. The endpoints of ablation were induction of a retrogradely conducted junctional rhythm, and non-inducibility of AVNRT on isoprenaline. RESULTS: All procedures were successful, with no change in the AH interval. Right-sided ablation was successful in 223 (98.2%) of cases. In four patients (1.8%) left-sided ablation was necessary. Procedure and fluoroscopy times were 70.1 ± 21.4 and 11.2 ± 5.8 min, respectively. In total, 4.5 ± 1.2 radiofrequency lesions per patient were given. During a follow-up period of one to three years, three patients (1.3%) had AVNRT recurrence. All of them had residual dual pathway physiology following ablation, while only 19.6% of patients without AVNRT had residual dual AV nodal conduction (p<0.001). No patient developed AV conduction disturbances. CONCLUSIONS: Ablation at the inferior part of the triangle of Koch with the protocol described offers a high success rate, with no risk of AV block, in patients with typical AVNRT. Residual dual AV nodal conduction carries an increased risk of AVNRT recurrence.

Antiendothelial cell antibodies in patients with coronary artery ectasia.

BACKGROUND: The mechanisms involved in the pathogenesis of coronary artery ectasia (CAE) have not been elucidated. Circulating antiendothelial cell antibodies (AECA) are often detectable in systemic vasculitis and have been implicated in the pathogenesis of endothelial injury. Their prevalence in CAE is not known. METHODS AND RESULTS: Out of 475 consecutive patients subjected to coronary angiography, 27 patients were diagnosed with CAE. Thirty patients matched for age, body mass index, sex, and coronary artery disease prevalence, served as controls. Serum AECA of IgG, IgM, and IgA isotypes were detected using a cell-based enzyme-linked immunosorbent assay (ELISA). Antinuclear antibodies (ANA) and antineutrophil cytoplasmic antibodies (ANCA) were detected using indirect immunofluorescence. IgG and IgM anticardiolipin antibodies (aCL) were detected using commercial ELISA. The prevalence of ANA and ANCA was similar in CAE patients and controls (33.3 vs. 43.3%, and 3.3 vs. 7.4%, respectively). There was no significant difference in IgG or IgM aCL reactivity between patients and controls. Both CAE patients and controls were negative for IgG AECA. The frequency of IgM AECA positivity was similar in CAE patients and controls. The prevalence of AECA of the IgA isotype was significantly higher in CAE patients (37.0 vs. 10%, P<0.05). CONCLUSION: There is increased prevalence of circulating AECA of the IgA isotype in patients with CAE. This provides evidence for a role of autoimmunity in the pathogenesis of certain cases of CAE.

Use of a circular mapping and ablation catheter for ablation of atypical right ventricular outflow tract arrhythmia.

A new technique for ablation of persistent ectopic activity with atypical electrocardiographic characteristics at the vicinity of the right ventricular outflow tract is described. A new circular mapping and ablation catheter initially designed for pulmonary vein ablation was used. Abolition of ectopic activity was achieved with minimal fluoroscopy and ablation times.

Association of neutrophil gelatinase-associated lipocalin with the severity of coronary artery disease.

Serum neutrophil gelatinase-associated lipocalin (NGAL) concentrations were measured in 73 consecutive patients who underwent first-time angiography for suspected coronary artery disease (CAD), and their associations with angiographic indexes of the severity of CAD (i.e., number of diseased vessels and modified Gensini score) were estimated. Median serum NGAL levels in patients with angiographically confirmed CAD were significantly higher than those in patients with normal coronary arteries (29.0 ng/ml [interquartile range 25.2 to 36.8] vs 22.4 ng/ml [interquartile range 17.34 to 32.0], p = 0.004). Statistically significant correlations were observed between serum NGAL level and the number of diseased vessels (r(s) = 0.390, p = 0.01) and modified Gensini score (r(s) = 0.356, p = 0.002). Using multivariate analysis, serum NGAL level was independently associated with the presence and severity of CAD. In conclusion, serum NGAL levels are significantly higher in the presence of CAD and are correlated with the severity of the disease. Further clinical studies are needed to confirm the use of NGAL as a biomarker for the detection and extent of CAD.

Comparison of long versus short ("spot") drug-eluting stenting for long coronary stenoses.

We compared spot drug-eluting stenting (DES) to full stent coverage for treatment of long coronary stenoses. Consecutive, consenting patients with a long (>20 mm) coronary lesion of nonuniform severity and indication for percutaneous coronary intervention were randomized to full stent coverage of the atherosclerotic lesion with multiple, overlapping stenting (full DES group, n = 90) or spot stenting of hemodynamically significant parts of the lesion only (defined as diameter stenosis >50%; spot DES group, n = 89). At 1-year follow-up, 14 patients with full DES (15.6%) and 5 patients (5.6%) with spot DES had a major adverse cardiac event (MACE; p = 0.031). At 3 years, MACEs occurred in 18 patients with full DES (20%) and 7 patients (7.8%) with spot DES (p = 0.019). Cox proportional hazard model showed that the risk for MACEs was almost 60% lower in patients with spot DES compared to those with full DES (hazard ratio 0.41, 95% confidence interval 0.17 to 0.98, p = 0.044). This association remained even after controlling for age, gender, lesion length, and type of stent used (hazard ratio 0.42, 95% confidence interval 0.17 to 1.00, p = 0.05). In conclusion, total lesion coverage with DES is not necessary in the presence of diffuse disease of nonuniform severity. Selective stenting of only the significantly stenosed parts of the lesion is an appropriate therapeutic alternative in this setting, offering a favorable clinical outcome.