Expert consensus on acute management of ventricular arrhythmias - VT network Austria.

The Arrhythmia Working Group of the Austrian Society of Cardiology (ÖKG) has set the goal of systematically structuring and organizing the acute care of patients with ventricular arrhythmias (VA), i.e. ventricular tachycardia (VT) or ventricular fibrillation (VF) in Austria. Within a consensus paper, national recommendations on the basic diagnostic work-up of VA (12-lead ECG, medical history, family history, laboratory analyses, echocardiography, search for reversible causes, ICD interrogation), as well as further medical treatment and therapeutic measures (indication of coronary angiography, ablation therapy) are established. Since acute ablation of VT is indicated in the current ESC guidelines as a class IB indication for scar-associated incessant VT or electrical storm (ES; ≥ 3 ICD therapies in 24 h) as well as for ischemic cardiomyopathy (iCMP) with recurrent ICD shocks, organizational measures must be taken to ensure that these guidelines can be implemented. Therefore, a VT network will be established covering all areas in Austria, consisting of primary and secondary VT centers. Organizational aspects of an acute VT network are defined and should subsequently be implemented by the participating hospitals. All electrophysiologic centers in Austria that deal with VT ablation are to be integrated into the network in the medium-term. Centers that co-operate in the network are divided into primary and secondary VT centers according to predefined criteria.

Renal denervation for mild-moderate treatment-resistant hypertension : A timely intervention?

BACKGROUND: Renal denervation (RDN) has been proposed as a novel antihypertensive intervention for treating resistant hypertension. It remains to be investigated which patient groups can potentially benefit from RDN. The present study aimed to evaluate the efficacy and safety of RDN in patients with mild-moderate resistant hypertension, i. e., systolic office blood pressure (BP) of 140-160 mm Hg despite treatment with three antihypertensive drugs including one diuretic, or mean systolic BP by ambulatory BP monitoring (ABPM) of 135-150 mm Hg. METHODS: We evaluated data from four relevant clinical studies, all conducted in Europe, comprising 185 eligible patients. The patients' age was 62.1 ± 10.3 years and 73% were male (RDN group n = 149, control group n = 36). RESULTS: A self-control comparison showed that RDN led to significantly reduced ABPM at the 6­month follow-up (systolic ABPM: 147.3 ± 13.4 mm Hg vs. 136.9 ± 15.5 mm Hg; diastolic ABPM: 81.1 ± 9.6 mm Hg vs. 76.2 ± 9.7 mm Hg; p < 0.001). RDN was associated with a greater improvement in ABPM as compared with that in the control group (∆systolic-ABPM: -10.4 ± 9.4 vs. -3.5 ± 9.6 mm Hg, p < 0.001; ∆diastolic-ABPM: -5 ± 5.8 vs. -2.1 ± 5.5 mm Hg; p = 0.005, respectively). The decrease of office BP in the RDN group was also statistically significant. RDN led to a reduced number of antihypertensive medications. No severe adverse events were found during follow-up. Regression analysis showed that the available baseline characteristics did not correlate with the ABPM improvement after RDN. CONCLUSION: RDN appears to be a safe and effective intervention for patients with mild-moderate resistant hypertension; however, randomized studies are warranted.

Number of ablated spots in the course of renal sympathetic denervation in CKD patients with uncontrolled hypertension: EnligHTN vs. Standard irrigated cardiac ablation catheter / Número de puntos de ablación en el curso de la denervación simpática renal en los pacientes de ERC con hipertensión incontrolable: EnligHTN vs. catéter de ablación cardiaca irrigada

Background: Hypertension was both a mutual cause and the main concern of chronic kidney disease (CKD). Blood pressure control is more problematic in the company of CKD. This study compares the effects of renal sympathetic denervation (RSD) on 24-h ambulatory blood pressure measurements (ABPM) and renal function in individuals with CKD and uncontrolled hypertension by unlike a number of ablated spots using the EnligHTN catheter and the standard irrigated cardiac ablation catheter (SICAC), Flexability. Methods: The 112 subjects were randomly divided into two groups according to the catheter that would be used in the procedure EnligHTN (n=56) or Flexability (n=56). Into each group, we created 5 subgroups according to the number of ablated spots: 4, 8, 12, 16 and 20. All of them were followed for exactly 6 months to assess all the parameters measured in this investigation. Results: Comparing the Δ 24-h systolic ABPM according to the number of ablated spots 4 and 20 for EnligHTN vs. Flexability, respectively, the differences were: −3.6±0.9 vs. −6.3±1.4mmHg (P<0.0001), and −13.9±4.8 vs. −36.3±4.3mmHg (P<0.0001). The comparisons between Δ estimated glomerular filtration rate (eGFR) according to the number of ablated spots 4 and 20 for EnligHTN vs. Flexability, respectively, were: +2.7±4.0 vs. +6.0±8.4mL/min/1.73m2 (P=0.2287), and +11.9±6.0 vs. +21.4±8.7mL/min/1.73m2 (P=0.0222). Conclusion: The RSD reduced the mean 24-h ABPM in subjects with CKD and uncontrolled hypertension and improved the renal function in both groups. These effects were more marked and important in subgroups underwent a great number of ablated spots using the SICAC (AU)

Antecedentes: La hipertensión constituye una causa común y un gran problema en la enfermedad renal crónica (ERC). El control de la presión arterial es más problemático en los casos de ERC. Este estudio compara los efectos de la denervación simpática renal sobre el monitoreo ambulatorio de la presión arterial (MAPA) de 24 h, así como la función renal en individuos con ERC e hipertensión incontrolable, utilizando indistintamente un número de puntos de ablación con el catéter EnligHTN y el catéter estándar de ablación cardiaca irrigada (SICAC) Flexability. Métodos: Se dividió aleatorizadamente a los 112 sujetos en 2 grupos, en función del catéter utilizado en el procedimiento, EnligHTN (n=56) o Flexability (n=56). Dentro de cada grupo creamos 5 subgrupos con arreglo al número de puntos de ablación: 4, 8, 12, 16, 20. Se realizó a todos ellos un seguimiento durante 6 meses exactos, para valorar los parámetros medidos en este estudio. Resultados: Comparando la Δ de la MAPA sistólica 24 h con arreglo al número de los puntos de ablación 4 y 20 para EnligHTN vs. Flexability, respectivamente, las diferencias fueron: −3,6±0,9 vs.−6,3±1,4mmHg (p<0,0001) y −13,9±4,8 vs. −36,3±4,3mmHg (p<0,0001). Las comparaciones entre la Δ de la tasa de filtración glomerular estimada con arreglo a los puntos de ablación 4 y 20 para EnligHTN vs. Flexability, respectivamente, fueron: +2,7±4 vs. +6±8,4mL/min/1,73 m2 (p=0,2287) y +11,9±6 vs. +21,4±8,7mL/min/1,73 m2 (p=0,0222). Conclusión: La denervación simpática renal redujo la MAPA media de 24 h en los sujetos con ERC e hipertensión incontrolable y mejoró la función renal en ambos grupos. Estos efectos fueron más marcados e importantes en los subgrupos sometidos a un gran número de puntos de ablación utilizando el catéter SICAC (AU)

Number of ablated spots in the course of renal sympathetic denervation in CKD patients with uncontrolled hypertension: EnligHTN vs. Standard irrigated cardiac ablation catheter.

BACKGROUND: Hypertension was both a mutual cause and the main concern of chronic kidney disease (CKD). Blood pressure control is more problematic in the company of CKD. This study compares the effects of renal sympathetic denervation (RSD) on 24-h ambulatory blood pressure measurements (ABPM) and renal function in individuals with CKD and uncontrolled hypertension by unlike a number of ablated spots using the EnligHTN catheter and the standard irrigated cardiac ablation catheter (SICAC), Flexability. METHODS: The 112 subjects were randomly divided into two groups according to the catheter that would be used in the procedure EnligHTN (n=56) or Flexability (n=56). Into each group, we created 5 subgroups according to the number of ablated spots: 4, 8, 12, 16 and 20. All of them were followed for exactly 6 months to assess all the parameters measured in this investigation. RESULTS: Comparing the Δ 24-h systolic ABPM according to the number of ablated spots 4 and 20 for EnligHTN vs. Flexability, respectively, the differences were: -3.6±0.9 vs. -6.3±1.4mmHg (P<0.0001), and -13.9±4.8 vs. -36.3±4.3mmHg (P<0.0001). The comparisons between Δ estimated glomerular filtration rate (eGFR) according to the number of ablated spots 4 and 20 for EnligHTN vs. Flexability, respectively, were: +2.7±4.0 vs. +6.0±8.4mL/min/1.73m2 (P=0.2287), and +11.9±6.0 vs. +21.4±8.7mL/min/1.73m2 (P=0.0222). CONCLUSION: The RSD reduced the mean 24-h ABPM in subjects with CKD and uncontrolled hypertension and improved the renal function in both groups. These effects were more marked and important in subgroups underwent a great number of ablated spots using the SICAC.

[Catheter ablation of premature ventricular complexes in a patient with progressive heart failure]. / Katheterablation einer linksventrikulären Extrasystolie bei progredienter Herzinsuffizienz.

Ischemic heart disease is characterized by hemodynamic adaptations and an increased risk of ventricular arrhythmias. Frequent premature ventricular complexes (PVCs) have been associated with ventricular reentry arrhythmias and can promote the worsening of left ventricular function. This case report discusses the beneficial effects of catheter ablation of frequent premature ventricular complexes originating remote from the healed myocardial infarction scar in the treatment of progressive heart failure.

[Treatment of atrial fibrillation: behavioral, pharmacologic and catheter-based perspectives]. / Therapie des Vorhofflimmerns: Verhaltensorientierte, pharmakologische und katheter-interventionelle Perspektiven.

Atrial fibrillation (AF) is the most common heart rhythm disorder, with increasing prevalence in the aging population. The clinical presentation and evolution of AF can be highly variable. Therefore, treatment of AF can be challenging in some patients. This review summarizes recent developments in both prevention of thromboembolic events and rate/rhythm control highlighting the possibilities of behavioral, pharmacological, and catheter-based perspectives.

[Arrhythmias in patients with surgically corrected tetralogy of Fallot]. / Arrhythmien bei Patienten mit operativ korrigierter Fallot-Tetralogie.

The population of adults with surgically corrected tetralogy of Fallot (TOF) is increasing. Atrial and ventricular arrhythmias are prevalent, and therapeutical approaches including implantable cardioverter-defibrillators and radiofrequency catheter ablation need to be considered carefully for the prevention of hemodynamic deterioration and sudden cardiac death. Complex anatomy, myocardial hypertrophy, and broad channels of slow conduction may in part explain some challenges regarding risk stratification, and identification/modification of the arrhythmogenic substrate in these patients. The aim of this brief review is 2-fold: (1.) To present insights into characteristics of typical TOF related arrhythmias and (2.) to reflect therapeutical concepts targeting tachyarrhythmias in these patients by focusing on catheter ablation.

Esophageal damage during radiofrequency ablation of atrial fibrillation: impact of energy settings, lesion sets, and esophageal visualization.

INTRODUCTION: Atrioesophageal fistula is an uncommon but often lethal complication of atrial fibrillation (AF) ablation. The purpose of our study was to prospectively investigate the incidence of esophageal ulcerations (ESUL) as well as the impact of energy settings, radiofrequency lesion sets, and direct visualization of the esophagus on esophageal wall injury. METHODS AND RESULTS: One hundred seventy-five patients, 57.1% paroxysmal AF, 78.5% male, underwent AF ablation and esophagoscopy 24 hours thereafter. We performed a 2:1:1-randomization as follows: CONTROL GROUP: Ablation without visualization of the esophagus using 25 Watt (W) power limit on the posterior wall, n = 70. Visualization and 15 W maximum: Ablation guided by barium visualization of the esophageal course using a limit of 15 W, n = 35. Visualization and 25 W "short burns": Ablation guided by barium visualization using 25 W and "short burns" (max. 5 sec), n = 35. Patients performed under general anesthesia (n = 35) were separated as a nasogastric tube for visualization of the esophagus was used. In total, we found 2.9% of patients (5/175) presenting ESUL. Parameters discriminating the development of ESUL in a specific patient were type of AF, maximum energy delivered, usage of a nasogastric tube, and additional left atrial lines. Visualization of the esophageal course by barium contrast was not able to prevent ESUL. CONCLUSION: ESUL is a rare finding when using a reasonable energy maximum of 25 W with open-irrigated tip catheters at the posterior wall. Lower energy settings may increase safety without losing efficacy. Additional linear radiofrequency lesions increase the risk of ESUL development.

[Nightmares in atrial fibrillation ablation--identification, management, and prevention of complications in radiofrequency ablation of atrial fibrillation]. / Albträume der Vorhofflimmerablation. Identifizierung, Management und Prävention von Komplikationen im Rahmen der Radiofrequenzablation von Vorhofflimmern.

Radiofrequency ablation is increasingly being established as a curative treatment option for atrial fibrillation refractory to antiarrhythmic drug therapy. Especially catheter ablation of atrial fibrillation is associated with significant procedure-related risks, as this is one of the most complex interventional electrophysiologic procedures. Knowledge about common and infrequent complications, incidence, etiology, and techniques for prevention should minimize risk and help to further increase procedural success. This paper intends to provide a practice-oriented summary of international surveys and consensus documents in comparison with data from our own electrophysiologic laboratory. Great attention will be laid upon early recognition and technical as well as procedure-related possibilities to prevent any complication.

[Phrenic nerve stimulation in biventricular cardiac pacemakers]. / N.-phrenicus-Stimulation bei biventrikulären Schrittmachern. Stufenschema zum intraoperativen Vorgehen.

BACKGROUND: Phrenic nerve stimulation (PNS) complicates the positioning of the left ventricle lead. We present a step-by-step approach to correct PNS during implantation, as established in our daily routine. METHODS: The incidence of PNS, its successful correction, and long-term results (median 27 months) were analyzed retrospectively in 266 lead positions. RESULTS: Phrenic nerve stimulation occurred in 13.9% of the lead positions. Multivariate analysis (P<0.02) showed that PNS only depended on the place of stimulation (coronary sinus side branch). Lead type, CRT indication, and patient's sex had no significant correlation. Following the step-by-step approach presented here, PNS was corrected satisfactorily in all cases. CONCLUSIONS: Approach in case of PNS: 1. push or pull the lead within the same vein, 2. change to a different vein, 3. maintain position in case of a safe distance between the phrenic nerve and the pacing threshold, 4. change the lead type to achieve stable anchorage at adequate positions, 5. use a device featuring electronic repositioning.

Short- and long-term experience in pulmonary vein segmental ostial ablation for paroxysmal atrial fibrillation.

INTRODUCTION: Segmental ostial pulmonary vein isolation (PVI) is considered a potentially curative therapeutic approach in the treatment of paroxysmal atrial fibrillation (PAF). There is only limited data available on the long-term effect of this procedure. METHODS: Patients (Pts) underwent a regular clinical follow up visit at 3, 6 and 24 months after PVI. Clinical success was classified as complete (i.e. no arrhythmia recurrences, no antiarrhythmic drug), partial (i.e. no/only few recurrences, on drug) or as a failure (no benefit). The clinical responder rate (CRR) was determined by combining complete and partial success. RESULTS: 117 patients (96 male, 21 female), aged 51+/-11 years (range 25 to 73) underwent a total of 166 procedures (1.4/patient) in 2-4 pulmonary veins (PV). 115 patients (98%) had AF, 2 patients presented with regular PV atrial tachycardia. ,109/115 patients. exhibited PAF as the primary arrhythmia (versus persistent AF). A total of 113 patients with PVI in the years 2001 to 2003 were evaluated for their CRR after 6 (3) months. A single intervention was carried out in 63 patients (55.8%), two interventions were performed in 45 patients (39.8%) and three interventions in 5 patients (4.4%). The clinical response demonstrated a complete success of 52% (59 patients), a partial success of 26% (29 patients) and a failure rate of 22% (25 patients), leading to a CRR of 78% (88 patients). Ostial PVI in all 4 PVs exhibited a tendency towards higher curative success rates (54% versus 44% in patients with 3 PVs ablated for the 6 month follow up). Long-term clinical outcome was evaluated in 39 patients with an ablation attempt at 3 PVs only (excluding the right inferior PV in our early experience) and a mean clinical follow up of 21+/-6 months. At this point in time the success rate was 41% (complete, 16 patients) and 21% (partial, 8 patients), respectively, adding up to a CRR of 62% (24 patients). In total, 20 patients (17.1%) had either a single or 2 (3 patients, 2.6%) complications independent of the number of procedures performed with PV stenosis as the leading cause (7.7%). CONCLUSION: The CRR of patients with medical refractory PAF in our patient cohort is 78% at the 6 month follow up. PV stenosis is the main cause for procedure-related complications. Ablation of all 4 PV exhibits a tendency towards higher complete success rates despite equal CRR. Calculation of the clinical response after a mid- to long-term follow of 21+/-6 months in those patients with an ostial PVI in only 3 pulmonary veins (sparing the right inferior PV) shows a further reduction to 62%, exclusively caused by a drop in patients with a former partial success. To evaluate the long-term clinical benefit of segmental ostial PVI in comparison with other ablation techniques, more extended follow up periods are mandatory, including a larger study cohort and a detailed description of procedural parameters.

Recent developments in cardiovascular drug therapy: treatment of atrial arrhythmias with new class III drugs and beyond.

Despite recent advances in non-pharmacologic approaches antiarrhythmic drugs still play a dominant role in the treatment of cardiac arrhythmias. Large randomized controlled clinical trials have pointed out the importance of a proper benefit to risk evaluation in various patient subsets. This led to a continuous decline in the use of sodium channel blockers due to their possible proarrhythmic effects particularly in patients with reduced left ventricular function and ischemic heart disease. On the contrary, beta-blockers and more complex class III compounds such as sotalol and amiodarone have been prescribed increasingly. However, side effects commonly observed boosted the development of agents with simpler ion channel-blockade and less adverse reactions. In this review newer so-called "pure" class III agents will be discussed. Their common mechanism of action is an antifibrillatory effect both on the atrial and ventricular level. Clinically, they are used in the chemical cardioversion and the prevention of atrial fibrillation or atrial flutter as well as for the maintenance of sinus rhythm after its successful restoration. This report contains a detailed analysis of the pharmacokinetics, results of clinical studies and implications regarding the use in daily practice for three distinct compounds: ibutilide, dofetilide and azimilide. As efficacy is still limited their current and future role in hybrid therapies combining drug therapy with alternative treatment modalities (catheter ablation, pacemakers and implantable cardioverter defibrillators) is discussed. In addition, an outlook for a future drug design implementing changes in electrically remodeled atrial tissue will be given.

Transvenous left ventricular lead implantation with the EASYTRAK lead system: the European experience.

Several independent studies suggest that resynchronization therapy--achieved by left- or biventricular pacing--improves hemodynamics in heart failure patients with interventricular conduction disturbances. Delivery of this new therapy in an effective and minimally invasive manner presents technical challenges, as transvenous access to the left ventricle is required. Since 1999, a novel over-the-wire approach combining standard pacing lead and angioplasty technology has been evaluated in several European countries. This new left ventricular lead, the EASYTRAK system (Guidant, St. Paul, MN), has been clinically evaluated in 2 phases. The first phase was a clinical investigation to obtain the CE-mark (i.e. European Commission approval). The second phase, which started immediately after the CE-mark was obtained, consisted of a postmarket surveillance called the European registry. This article reports on the results of the pre-CE-mark clinical investigation and the preliminary results of the European registry (first 150 patients). During the pre-CE-mark clinical investigation of the EASYTRAK system, lead performance was assessed in 36 successfully implanted patients. The patients had indications for VVI-pacing, symptoms of heart failure and significant left ventricular dysfunction. The left ventricular lead was implanted in conjunction with a conventional right ventricular lead and a new heart failure device (CONTAK TR, Guidant, Brussels, Belgium). Lead measurements (threshold, sensing, and impedance) were performed at implant and subsequent follow-ups. The stimulation thresholds at 0.5 msec impulse width were acceptable, although (as expected) slightly higher than with standard right ventricular pacing leads: 1.39 +/- 1.15 V at implant, 1.72 +/- 1.26 V at predischarge, 1.54 +/- 0.88 V at 2 weeks, 1.38 +/- 0.80 V at 6 weeks, and 1.24 +/- 0.73 V at 12 weeks. R-wave and impedance measurements were stable over time. A revision of the EASYTRAK lead was required in 3 patients. No perforations were observed. During the second phase of the European registry, 150 implants were attempted in 63 centers from November 1999 to January 2000. The EASYTRAK was implanted with a pulse generator offering, in addition to resynchronization therapy, either tachycardia monitoring (CONTAK TR) or implantable cardioverter defibrillator therapy (CONTAK CD), depending on the patient indication. Over half of the centers involved had not previously implanted the EASYTRAK system. Total implant success rate was 83% (135/150), skin-to-skin duration of the implant was 169 +/- 81 minutes (range, 53-480 minutes), with a clear learning curve. Once the coronary sinus was found, the implant success rate was 92%. One lead dislodgment and 2 cases of phrenic nerve stimulation were reported. We conclude that the new EASYTRAK lead design for transvenous left ventricular lead implantation seems to be a suitable and safe tool for delivering resynchronization therapy to heart failure patients.

[Pacemaker in therapy of heart failure--biventricular stimulation]. / Schrittmacher zur Therapie der Herzinsuffizienz--biventrikuläre Stimulation.

The management of congestive heart failure remains a therapeutic challenge despite recent advances in drug therapy, including ACE inhibitors, beta blockade and spironolacton treatment. Patients affected with the disease still have a restricted quality of life and a poor prognosis in the long run. Epidemiologically, the incidence and prevalence are increasing due to improved survival from both coronary artery disease and arterial hypertension. A subgroup of patients presents with marked prolongation of the QRS-complex in the surface ECG, mostly with a left bundle branch block pattern. This acts as a marker for interventricular conduction abnormality and specifically indicates a reduced left ventricular systolic function. Biventricular pacing tries to resynchronize the abnormal activation pattern by actively influencing diastolic filling and systolic function. The mechanisms involved are supposed to be restoration of left ventricular septal mechanical synchrony, reduction in presystolic mitral regurgitation and optimization of diastolic function with the maximization of diastolic filling time. In this article the current role and future directions of biventricular pacing are discussed.

Absence of significant changes in heart rate variability after slow pathway ablation of AV nodal reentrant tachycardia by using serial Holter recordings.

BACKGROUND: Persistent inappropriate sinus tachycardia may evolve as a complication after radiofrequency (RF) fast pathway ablation of atrioventricular nodal reentrant tachycardia (AVNRT). Parasympathetic denervation may serve as one of the possible mechanisms. We performed a study to show the prevalence of this phenomenon in RF ablation of the slow pathway. METHODS AND RESULTS: Thirty-three patients (25 women, 8 men) aged 53 +/- 16 years were investigated. A median of 3 pulses was used to selectively modify or ablate the slow pathway and render AVNRT noninducible. Heart rate (HR) and different indexes in the time and frequency domain of heart rate variability were evaluated in serial 24-hour Holter recordings. Data were obtained 1 day, 1 month, and 3 months after the procedure and compared with preablation values. Despite a trend of increasing HR and decreasing heart rate variability within the first month after RF ablation, no significant changes were detected. CONCLUSIONS: RF ablation of the slow pathway in AVNRT does not change parameters of HR and heart rate variability significantly by means of serial 24-hour Holter recordings.

[Subpectoral venous approach in implantable cardioverter defibrillator systems (ICD)]. / Subpektoraler Venenzugang bei implantierbarem Cardioverter-Defibrillator-System (ICD).

Lead complications may have fatal consequences for ICD patients. Lead fractures have been reported to occur a long time after subclavian puncture during ICD-implantation. Damage can also be caused by the patient manipulating subcutaneous lead segments. In this report we describe a simple implantation technique which avoids the risks related to subcutaneous lead position and transmuscular subclavian vein puncture. In 16 patients, after preparation of the site of the device, we chose the subpectoral venous approach for the implantation of the leads from the ICD. Available approaches are the pectoral vein, the subpectoral section of the cephalic vein or a puncture of the subclavian vein which is fully visible from that size. Once the pectoral muscle has been sutured, the entire system is protected behind it. Apart from an early postoperative lead dislocation, no complications were observed in association with the operating technique within a mean follow-up period of 10.7 +/- 6.7 (SD) months. The advantages of this technique are as follows: There is no transmuscular subclavian puncture or exposure of the deltoideopectoral groove. The entire ICD system is situated under the pectoralis major muscle. Subcutaneous lead positions with the potential complications mentioned above can thus be avoided. The fact that a more complex technique and therefore a slightly lengthier operating time is required and that this technique is not particularly suitable for local anaesthesia may be regarded as disadvantages. Due to the small number of cases and the short follow-up period, a final conclusion on the application of this technique is not possible to date.

[High frequency catheter ablation in AV-nodal reentry tachycardia: clinical significance of slow pathway potentials and junctional tachycardia]. / Hochfrequenz-Katheterablation bei AV-nodaler Reentry-Tachykardie: Klinische Bedeutung von Slow-Pathway-Potentialen und junktionaler Tachykardie.

During slow pathway-ablation of AV nodal reentrant tachycardia (AVNRT) with a mean cycle length of 355 +/- 70 ms the clinical significance of slow pathway electrograms (SP-EGM) and junctional tachycardias (JT) was evaluated in 39 patients (9 male, 30 female; mean age 57 +/- 15 years). After two patients were excluded from further investigation because of inadvertent procedural complete heart block, typical SP-EGM were recorded in 30/37 patients (81%) before successful RF administration in the posteroseptal portion of the right atrium. Signals were recorded 61 +/- 22 and 34 +/- 24 ms after atrial activation in the His bundle and proximal coronary sinus catheter, respectively. Additionally, timing was noted 15 +/- 10 ms before the His spike; the duration of SP-EGM was 27 +/- 7 ms, and the A/V relation of the SP-EGM was calculated as 0.59 +/- 0.51 in the ablation bipole. JT was observed in 24/37 patients (78%), with a mean cycle length of 511 +/- 92 ms. The first tachycardia beat appeared initially 4.1 +/- 3.8 s after delivery of the successful RF administration and lasted 18 +/- 8 s. In 14/37 patients (38%) either SP-EGM or JT was missing; in one patient neither of these two was recorded despite successful ablative therapy. The success rate, defined by noninducibility of AVNRT, was 95% (35/37). In 11% (4/37) AVNRT recurred during a mean follow-up of 5 +/- 4 months. In summary, SP-EGM and JT were recorded reproducibly and proved to be a useful tool as electrographic mapping approach of slow pathway ablation in AVNRT.

Successful radiofrequency ablation of adenosine-sensitive right ventricular outflow tract tachycardia.

We report on a patient without evidence of structural heart disease who presented with adenosine-sensitive sustained ventricular tachycardia with left bundle branch block and right axis QRS morphology. Endocardial catheter mapping revealed the origin of ventricular tachycardia to be located in the right ventricular outflow tract, where the earliest endocardial activation during ventricular tachycardia was registered 30-40 ms prior to onset of QRS complex in the surface ECG. Pace-mapping provided no additional information; we found a good match between 12 lead surface ECGs registered during spontaneous episodes of ventricular tachycardia and those recorded during pacing in a relatively large area in the right ventricular outflow tract. The 10th application of radiofrequency current abolished ventricular tachycardia temporarily, but it recurred within 30 min. After the 28th radiofrequency current delivery ventricular tachycardia was permanently abolished.