[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.

[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.

[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.

Established and evolving indications for cardiac resynchronisation.

Randomised trials involving large number of patients have demonstrated the benefits of cardiac resynchronisation therapy (CRT) in patients with heart failure who have failed optimal medical treatment. Echocardiography plays an important role in defining dyssynchrony which is key to optimal patient selection. The electrocardiographic criteria for patient selection is supplemented by the finding of dyssynchrony on Doppler myocardial imaging, and echocardiography with Doppler myocardial imaging may eventually replace the electrocardiographic criteria for selection of patients who derive benefit from CRT.

The evaluation of run-off prior to infra-inguinal bypass reconstruction - a modified scoring system based on flow measurement.

OBJECTIVES: To compare angiographic scoring and flow measurements in the assessment of run-off prior infra-inguinal bypass. PATIENTS AND METHODS: In a series of 108 consecutive infra-inguinal bypasses, run-off was scored on the basis of pre- and post-operative angiograms and related to intra- and post-operative flow rates as determined by Doppler ultrasonography. RESULTS: There was a highly significant correlation between the angiographic score and flow (p = 0.0000), as well as between angiographic score (p = 0.0000), flow (p = 0.0000) and the level of distal anastomosis. Flow determined per crural vessel (quotient of flow to angiographic score) proved to be independent of the level of distal bypass anastomosis (p = 0.20). CONCLUSION: In this study, angiographic scoring and Doppler flow measurements were equally valid means for the assessment of run-off. Our system allows an objective assessment of run-off independently of the distal bypass anastomosis level and provides a functional estimation of run-off.

Assessment of ventricular filling volumes with an automated color Doppler method: validation in a pulsatile flow model.

OBJECTIVE: Determination of ventricular filling volumes with the use of Doppler echocardiographic measurements critically depends on the presence of a circular-shaped flow area and a flat velocity profile across it because evaluation of flow volume is usually based on echocardiographic measurements of its diameter and pulsed Doppler recordings within the center of this area. The approach may be limited at the mitral and tricuspid ring levels as a result of their noncircular shape and because nonflat velocity profiles are present. The purpose of this study was to examine in a pulsatile flow model simulating ventricular inflow conditions the accuracy of an automated method based on the analysis of color Doppler flow velocities for evaluation of flow volumes. MATERIALS AND METHODS: A recently-developed automated Doppler method that takes into account the velocity distribution across a region of interest was examined in a pulsatile flow model by using flows with waveforms characteristic for ventricular inflow through tubes with elliptically-shaped cross-sectional areas. Color Doppler imaging was performed against flow direction along the major and minor axes of the tubes with major diameters ranging between 3 and 5 cm and major-to-minor diameter ratios of 1.5 and 2.0. RESULTS: A close correlation was found between flow volumes measured by the Doppler technique for registrations along the minor or major axis of the ellipses and actual values (r = 0.99, standard error of the estimate = 0.44 to 1.98 mL), with a systematic underestimation or overestimation, respectively, depending on the diameter ratio. Averaging of the data derived from 2 orthogonal measurements by using the geometric mean value yielded an excellent agreement between Doppler data and actual flow volumes. CONCLUSION: This automated color Doppler method enables reliable determination of flow volumes in a pulsatile flow model simulating ventricular inflow conditions with the use of 2 orthogonal imaging views. The data indicate that the method may improve the noninvasive evaluation of ventricular filling volumes.

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.

Three-dimensional transesophageal echocardiography (TEE) and other future directions.

As faster imaging systems enter the market, three-dimensional echocardiography is gearing up to become a useful tool in assisting the clinician to image the heart in many innovative projections. What started out as a novel idea of displaying a three-dimensional anatomic picture of the heart now provides a multitude of views of the heart and its structures. Information gained from anatomic and dynamic data has helped clinicians and surgeons in making clinical decisions. In the future, this imaging modality may become a routine imaging modality for assessing cardiac pathology and may serve to increase understanding of the dynamics of the heart.

Usefulness of motion patterns indentified by tissue Doppler echocardiography for diagnosing various cardiac masses, particularly valvular vegetations.

This study sought to test whether anomalous cardiac and aortic structures can be differentiated from native tissue and artifacts by physical properties of tissue motion using transesophageal tissue Doppler echocardiography (TDE). TDE was employed in 85 consecutive patients after anomalous structures had been detected by conventional transesophageal echocardiography (TEE). The control group consisted of 40 randomized patients. Certainty of diagnosis was divided into 4 categories, and TDE signals were related to particular anomalous structures by a blinded second observer. A mechanical model of a beating ventricle was constructed and suspended in a water bath. Synthetic material was utilized to simulate anomalous intracavitary structures with varying shape, consistency, and attachment. Incoherent motion was present in endocarditic vegetations, freely oscillating thrombi, fourth-degree aortic plaques, Chiari network, valvular prolapse, tumors, and in normal valve leaflets and papillary muscles. Within 15 seconds vegetations could be detected in 17 patients (68%) using TDE versus 5 patients (20%) using only conventional imaging. Coherent motion with a phase difference occurred due to damped oscillation. This phenomenon occurred in 5 patients with thrombi of the left atrial appendage (100%), in 3 ventricular clots (75%), and in 2 hypernephroma in the right atrium (100%). Rapid identification of clots could be achieved in 15 patients (71%) versus 12 patients (57%). Concordant motion was shown in third-degree aortic plaques, postrheumatic valvular lesions, and aortic intramural hematomas, but diagnostic benefit could not be demonstrated. In 41 patients (48%) histopathologic and intraoperative results confirmed echocardiographic findings. Motion patterns could be reproduced independently of the heart rate by model experiments. This study demonstrates that TDE expedites the detection of vegetations in infective endocarditis. Diagnostic certainty can be increased as well for thrombus formations.

Pacing in distal left ventricular hypertrophic cardiomyopathy.

We report the case of an 85-year-old woman with distal LV hypertrophy resulting in an intraventricular pressure gradient and incomplete systolic emptying who benefited from permanent DDD pacing. Our experience based on this case suggests that permanent dual chamber pacing might be a safe and effective therapy also in symptomatic patients with the rare form of hypertrophic cardiomyopathy with left mid-ventricular obstruction resulting in incomplete emptying of the apical portion of the LV and a significant intraventricular pressure gradient that was not responding to pharmacological therapy.

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.

Determination of prestenotic flow volume using an automated method based on colour Doppler imaging for evaluating orifice area by the continuity equation: validation in a pulsatile flow model.

OBJECTIVE: To evaluate, in a pulsatile flow model simulating flow conditions in valvar stenoses, whether accurate determination of orifice area can be achieved by the continuity equation using automated determination of flow volumes based on spatiotemporal integration of digital colour Doppler flow velocities. METHODS: A method for automated determination of flow volumes which takes into account the velocity distribution across a region of interest was examined using flow through a tube and various restrictive outlet orifices with areas ranging between 0.2 and 3.1 cm2. The sampling rectangle of the Doppler method was positioned proximal to the obstructions within the flow convergence zone for evaluating prestenotic flow volume. Stenotic jet velocities were recorded by continuous wave Doppler to obtain the integral under the velocity curve. Prestenotic flow volume was then divided by the velocity integral to calculate functional orifice area according to the continuity equation. RESULTS: The presence of parabolically shaped velocity profiles across the prestenotic region was demonstrated by the Doppler method. Excellent agreement was found between prestenotic flow volumes measured by the Doppler technique and actual values (r = 0.99, SEE = 1.35 ml, y = 0.99x-0.24). Use of the continuity equation led to a close correlation, with a systematic underestimation of geometric orifice sizes. Correction of Doppler data for flow contraction yielded an excellent agreement with actual orifice areas. CONCLUSIONS: The study validated the accuracy of a Doppler method for automated determination of flow volumes for quantifying orifice area by the continuity equation. Prestenotic flow volume and functional orifice area could be evaluated reliably in the presence of non-flat velocity profiles. Thus the method contributes to the non-invasive assessment of valvar stenoses.

[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.

Tomographic three-dimensional echocardiographic determination of chamber size and systolic function in patients with left ventricular aneurysm: comparison to magnetic resonance imaging, cineventriculography, and two-dimensional echocardiography.

BACKGROUND: Two-dimensional (2D) echocardiographic approaches based on geometric assumptions face the greatest limitations and inaccuracies in patients with left ventricular (LV) aneurysms. Three-dimensional (3D) echocardiographic techniques can potentially overcome these limitations; to date, however, although tested in experimental models of aneurysms, they have not been applied to a series of patients with such distortion. The purpose of this study was therefore to validate the clinical application of tomographic 3D echocardiography (3DE) by the routine transthoracic approach to determine LV chamber size and systolic function without geometric assumptions in patients with LV aneurysms. METHODS AND RESULTS: In 23 patients with chronic stable LV aneurysms, LV end-systolic and end-diastolic volumes (LVEDV, LVESV) and ejection fraction (LVEF) by tomographic 3DE were compared with results from 3D magnetic resonance tomography (3DMRT) as an independent reference as well as with the conventional techniques of single plane and biplane 2D echocardiography and biplane cineventriculography. Dynamic 3DE image data sets were obtained from a transthoracic apical view with the use of a rotating probe with acquisition gated to control for ECG and respiration (Echoscan, TomTec). Volumes were calculated from the 3D data sets by summating the volumes of multiple parallel disks. 3DE results correlated and agreed well with those by 3DMRT, with better correlation and agreement than provided by other techniques for LVEDV (3DE: r=.97, SEE=14.7 mL, SD of differences from 3DMRT=14.5 mL; other techniques: r=.84 to .93, SEE=30.7 to 41.6 mL [P<.001 versus 3DE by F test], SD of differences=31.5 to 40.7 mL [P<.001 versus 3DE by F test]). The same also pertained to LVESV (3DE: r=.97, SEE=12.4 mL, SD of differences=12.9 mL; other techniques: r=.81 to .90, SEE=24.7 to 37.2 mL [P<.001], SD of differences=27.6 to 36.8 mL [P<.005]) and LVEF (3DE: r=.74, SEE=5.6%, SD of differences=6.7%; other techniques: r=.14 to .59, SEE=9.5% to 10.1% [P<.01], SD of differences=9.5% to 12.6% [P<.05]). Compared with 3DMRT, 3DE was less time consuming and patient discomfort was less. CONCLUSIONS: Tomographic 3DE is an accurate noninvasive technique for calculating LV volumes and systolic function in patients with LV aneurysm. Unlike current 2D methods, tomographic 3DE requires no geometric assumptions that limit accuracy.

[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.