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Abstract: Aims: This study investigates the influence of cardiac resynchronisation therapy (CRT) on sleep disordered breathing (SDB) in patients with severe heart failure (HF). Methods and results: Seventy-seven patients with HF (19 females; 62.6±10 years) eligible for CRT were screened for presence, type, and severity of SDB before and after CRT initiation (5.3±3 months) using cardiorespiratory polygraphy. NYHA class, frequency of nycturia, cardiopulmonary exercise, 6-minute walking test results, and echocardiography parameters were obtained at baseline and follow-up. Central sleep apnoea (CSA) was documented in 36 (47%), obstructive sleep apnoea (OSA) in 26 (34%), and no SDB in 15 (19%) patients. CRT improved clinical and haemodynamic parameters. SDB parameters improved in CSA patients only (apnoea hypopnoea index: 31.2±15.5 to 17.3±13.7/h, p <0.001; SaO2min: 81.8±6.6 to 84.8±3.3%, p =0.02, desaturation: 6.5±2.3 to 5.5±0.8%, p =0.004). Daytime capillary pCO2 was significantly lower in CSA patients compared to those without SDB with a trend towards increase with CRT (35.5±4.2 to 37.9±5.7 mm Hg, ns). After classifying short term clinical and haemodynamic CRT effects, improved SDB parameters in CSA occurred in responders only. Conclusions: In patients with severe HF eligible for CRT, CSA is common and can be influenced by CRT, this improvement depends on good clinical and haemodynamic response to CRT. [Copyright &y& Elsevier]

Substrate Description and Ablation of VT. Introduction: The aim of this study was to describe the arrhythmogenic substrate in postinfarction patients with ventricular tachycardia (VT) guiding the placement of individual strategic linear lesions transecting all potential isthmuses using target area maps with limited mapping points to allow short procedure times. Methods and Results: In 28 patients with pleomorphic, unstable, and/or incessant VT, electroanatomic voltage mapping was performed in conjunction with limited sinus rhythm mapping, pace mapping, and activation mapping. Radiofrequency (RF) energy was applied directly within the low-voltage areas of the chronically infarcted areas or in the border zone. Ablation lines typically were perpendicular to the course of the presumed central common pathways. The maps consisted of 63 ± 30 mapping points. An average lesion line length of 46 ± 21 mm was placed with 17 ± 7 RF pulses. Twenty-two (79%) of the 28 patients were rendered completely noninducible at the end of the procedure. Procedure time measured 134 ± 41 minutes . No major complications were observed. Six (27%) of 22 patients who were rendered completely noninducible experienced VT recurrence during follow-up versus 4 (67%) of 6 patients who were still inducible after ablation (P = 0.06) . Conclusion: Individually tailored substrate description guiding the placement of linear lesion lines transecting potential isthmuses rendered 80% of the patients completely noninducible. The construction of regional target area maps allowed short procedure times, with a resulting low incidence of complications in these critically ill patients. (J Cardiovasc Electrophysiol, Vol. 14, pp. 675-681, July 2003). [ABSTRACT FROM AUTHOR]

Dual-chamber ICDs are increasingly used to avoid inappropriate shocks due to supraventricular tachycardias. Additionally, many ICD patients will probably benefit from dual chamber pacing. The purpose of this pilot study was to evaluate the intraoperative performance and short-term follow-up of an innovative single pass right ventricular defibrillation lead capable of bipolar sensing and pacing in the right atrium and ventricle. Implantation of this single pass right ventricular defibrillation lead was successful in all 13 patients (age 63 ± 8 years; LVEF 0.44 ± 0.16; New York Heart Association [NYHA] 2.4 ± 0.4, previous open heart surgery in all patients). The operation time was 79 ± 29 minutes, the fluoroscopy time 4.7 ± 3.1 minutes. No perioperative complications occurred. The intraoperative atrial sensing was 1.7 ± 0.5 mV, the atrial pacing threshold product was 0.20 ± 0.14 V/ms (range 0.03-0.50 V/ms). The defibrillation threshold was 8.8 ± 2.7 J. At prehospital discharge and at 1-month and 3-month follow-up, atrial sensing was 1.9 ± 0.9, 2.1 ± 0.5, and 2.7 ± 0.6 mV, respectively, (P = NS, P < 0.05, P < 0.05 to implant, respectively), the mean atrial threshold product 0.79, 1.65, and 1.29 V/ms, respectively. In two patients, an intermittent exit block occurred in different body postures. All spontaneous and induced ventricular arrhythmias were detected and terminated appropriately. Thus, in a highly selected patient group, atrial and ventricular sensing and pacing with a single lead is possible under consideration of an atrial pacing dysfunction in 17% of patients. [ABSTRACT FROM AUTHOR]

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. Yet tools and techniques used for confirmation of PVI vary greatly, and it is unclear whether the use of any particular combination of tools and techniques provides greater sensitivity for identifying gaps periprocedurally. It has been suggested that the use of a high-density mapping catheter, which enables simultaneous recording of adjacent bipolar EGMs in two directions, may provide improved sensitivity for gap identification. Anonymized, acute procedural data was prospectively collected in AF ablation cases utilizing various workflows for confirmation of PVI. Post-hoc analysis was performed to evaluate the incidence of gaps detected by different diagnostic catheter technologies, including a high-density mapping catheter and circular mapping catheters (CMCs), and common techniques such as pacing the ablation lines. A total of 139 cases were included across three subgroup analyses: 99 cases were included in an indirect comparison of three mapping catheter technologies, revealing gaps in 36.7%, 38.9%, and 81.8% of cases utilizing a 10-pole CMC, 20-pole CMC, and a high-density mapping catheter, respectively; a direct comparison of diagnostic catheter technologies in 18 cryoballoon ablation cases revealed residual gaps in 22.2% of patients identified by high-density mapping which were missed previously with the use of a 3.3F CMC; in 22 cases utilizing a technique of pacing the ablation lines, high-density mapping identified residual gaps in 68.2% of patients. This proof of concept analysis demonstrated that the use of a high-density catheter which records orthogonal bipoles simultaneously, appears to improve acute detection of gaps in PVI lines relative to other commonly utilized techniques and technologies. The long-term impact of ablating these concealed gaps remains unclear. Further study, including direct comparison of diagnostic catheter technologies in a randomized setting with long-term followup, is warranted. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to analyze trigger activity in the long-term follow-up after left atrial (LA) linear ablation. Background: Interventional strategies for curative treatment of atrial fibrillation (AF) are targeted at the triggers and/or the maintaining substrate. After substrate modification using nonisolating linear lesions, the activity of triggers is unknown. Methods: With the LA linear lesion concept, 129 patients were treated using intraoperative ablation with minimal invasive surgical techniques. Contiguous radiofrequency energy-induced lesion lines involving the mitral annulus and the orifices of the pulmonary veins without isolation were placed under direct vision. Results: After a mean follow-up of 3.6 ± 0.4 years, atrial ectopy, atrial runs, and reoccurrence of AF episodes were analyzed by digital 7-day electrocardiograms in 30 patients. Atrial ectopy was present in all patients. Atrial runs were present in 25 of 30 patients (83%), with a median number of 9 runs per patient/week (range 1 to 321) and a median duration of 1.2 s/run (range 0.7 to 25), without a significant difference in atrial ectopy and atrial runs between patients with former paroxysmal (n = 17) or persistent AF (n = 13). Overall, 87% of all patients were completely free from AF without antiarrhythmic drugs. Conclusions: A detailed rhythm analysis late after specific LA linear lesion ablation shows that trigger activity remains relatively frequent but short and does not induce AF episodes in most patients. The long-term success rate of this concept is high in patients with paroxysmal or persistent AF. [Copyright &y& Elsevier]

Studies analyzing the diagnostic value of 12-lead electrocardiographic criteria differentiating slow–fast atrioventricular nodal reentrant tachycardia (AVNRT) from atrioventricular reentrant tachycardia (AVRT) due to concealed accessory pathway have shown inconsistent results. In 97 patients (50 with AVNRT, 47 with AVRT) 12-lead electrocardiograms (ECGs) were recorded during sinus rhythm and tachycardia (QRS &#60;120 ms). The ECGs were blinded for diagnosis and patient and analyzed independently by 2 electrophysiologists. The studied criteria differentiating AVNRT from AVRT included pseudo-r′/S, the presence of a retrograde P wave, RP interval, ST-segment depression ≥2 mm with the number and location of the affected leads, QRS amplitude, and cycle length alternans. [Copyright &y& Elsevier]

Objectives: The aim of this study was to analyze different anatomic mapping approaches for successful ablation of outflow tract tachycardia with R/S transition in lead V3. Background: Idiopathic ventricular tachycardia can originate from different areas in the outflow tract, including the right and left ventricular endocardium, the epicardium, the pulmonary artery, and the aortic sinus of Valsalva. Although electrocardiographic criteria may be helpful in predicting the area of origin, sometimes the focus is complex to determine, especially when QRS transition in precordial leads is in V3. Methods: We analyzed surface electrocardiograms of 33 successfully ablated patients with outflow tract tachycardia: 20 from the right ventricular outflow tract (RVOT) and 13 from different sites. The R/S transition was determined, and the different anatomic approaches needed for successful catheter ablation were studied. Results: Overall, R/S transition in lead V3 was present in 19 (58%) of all patients. In these patients, mapping was started and successfully completed in the RVOT in 11 of 19 (58%) patients. The remaining eight patients with R/S transition in lead V3 needed five additional anatomic accesses for successful ablation: from the left ventricular outflow tract (n = 3), aortic sinus of Valsalva (n = 2), coronary sinus (n = 1), the epicardium via pericardial puncture (n = 1), and the trunk of the pulmonary artery (n = 1), respectively. Conclusions: A R/S transition in lead V3 is common. In patients with outflow tract tachycardia with R/S transition in lead V3, a stepwise endocardial and epicardial mapping through up to six anatomic approaches can lead to successful radiofrequency catheter ablation. [Copyright &y& Elsevier]

Increased expression of connexin43 gap junctions in smooth muscle cells (SMC) is implicated in the response to primary arterial injury and in the early stages of human coronary atherosclerosis, but the relevance of these findings to restenosis is unknown. Here we investigated the expression of connexin43 gap junctions in restenotic aortas of cholesterol-fed double injured rabbits. Immunofluorescence confocal microscopy was used to evaluate temporal and spatial expression patterns and to characterize the major expressing cell type. Parallel studies were conducted by electron microscopy, in situ hybridization and Northern blot analysis. Connexin43 gap junctions- and connexin43 mRNA-expressing cells were abundant in the media of non-injured control aorta. Following primary injury and 6 weeks cholesterol diet, connexin43 gap junctions were found distributed throughout the primary intimal layer; although medial expression was reduced, the overall mRNA expression level remained similar to that of non-injured controls. After secondary injury, no major change in distribution pattern of connexin43 gap junctions occurred up to day 10, when marked neointimal labeling was observed. This overall pattern persisted, though with some diminution, at later stages. On the mRNA level total connexin43 mRNA expression declined to about 40% of control values within 4 days after secondary injury (P&#60;0.05), but subsequently increased fourfold, attaining levels double that of non-injured controls in the 10-day group (P&#60;0.005 versus control and 4 days). At later stages mRNA expression levels returned to values similar to those of non-injured controls. At all stages, connexin43 gap junctions were localized to the SMC, not to macrophages. We conclude that the enhanced gap junction formation may contribute to the coordination of the response of SMC after secondary injury, particularly in the early phase of restenosis. [Copyright &y& Elsevier]