Search PubMed⌕ Search

Biomedical subjects

K H Kuck

Publications and source records attributed to K H Kuck.

At least 37 records · Page 2Linked to original sources
PubMed2000

The defibrillator in acute myocardial infarction trial (DINAMIT): study protocol.

BACKGROUND: The implantable cardioverter/defibrillator (ICD) has been shown to be superior to antiarrhythmic drug therapy for the secondary prevention of sudden cardiac death. Its role in the primary prevention of sudden death after myocardial infarction is unknown. Methods and Results The Defibrillator in Acute Myocardial Infarction Trial (DINAMIT) is a randomized, open-label, parallel-group comparison of ICD therapy versus no ICD therapy in selected survivors of acute myocardial infarction. It will test the hypothesis that reduction of sudden arrhythmogenic death by means of the ICD will result in reduction of overall mortality rates in patients at high risk after acute myocardial infarction. Accordingly, this international multicenter study aims to enroll patients shortly after their infarction (day 6 to day 40) who have reduced left ventricular function (left ventricular ejection fraction </=0. 35) and impairment of cardiac autonomic function shown by depressed heart rate variability (standard deviation of normal-to-normal R-R intervals </=70 ms) or elevated average 24-hour heart rate (mean 24-hour R-R interval </=750 ms, assessed by Holter monitoring). Patients will be followed for approximately 3 years on average with subsequent data analysis based on the intent-to-treat principle. Primary outcome is all-cause death. The trial is expected to be completed in 2003. CONCLUSIONS: DINAMIT is the first prospective study to evaluate the benefit of ICD therapy for the primary prevention of sudden cardiac death in patients at high risk after acute myocardial infarction.

Defibrillators, Implantable↗
PubMed2000

Catheter ablation in the year 2000.

After its introduction in 1987, radiofrequency catheter ablation became established as a safe and effective therapy for the cure of many cardiac arrhythmias in people. The possibility of assessing the relationship between the anatomical target and the electrophysiologic changes produced by radiofrequency pulse delivery has also provided significant improvement in the physician's knowledge of the pathophysiology of the underlying rhythm disturbance. Nowadays, using this therapy, success rates well above 90% with recurrence rates lower than 5% are expected after treatment of most regular supraventricular arrhythmias. As catheter ablation techniques develop, success rates in the range of those obtained for regular supraventricular arrhythmias are expected in the future in the treatment of regular ventricular and irregular supraventricular arrhythmias.

Catheter Ablation↗
PubMed2000

Prevention of atrial fibrillation by complete compartmentalization of the left atrium using a catheter technique.

INTRODUCTION: Right atrial compartmentalization has been demonstrated to only reduce the number of atrial fibrillation (AF) episodes; left atrial (LA) fibrillation still occurs. METHODS AND RESULTS: We report successful LA compartmentalization resulting in isolation of all four pulmonary veins in a 51-year-old woman suffering from paroxysmal AF. Deployment of a complete encircling line resulted in dissociation of electrical activation within the isolated area from the remaining LA. Despite attempts at reinduction by pacing maneuvers inside and outside the isolated area, AF was no longer inducible. During 21-week follow-up, the patient remained in stable sinus rhythm with rare atrial extrasystoles. CONCLUSION: If reproducible, this ablation strategy could allow treatment of AF independent of suppression of any triggering event.

Atrial Fibrillation↗
PubMed1999

Modification of the substrate for maintenance of idiopathic human atrial fibrillation: efficacy of radiofrequency ablation using nonfluoroscopic catheter guidance.

BACKGROUND: Catheter ablative techniques to modify the substrate to maintain atrial fibrillation (AF) require the creation of continuous radiofrequency current-induced ablation lines. This study was designed to assess the efficacy and safety of nonfluoroscopic mapping in this setting. METHODS AND RESULTS: A total of 45 consecutive patients with idiopathic AF were studied. The first 13 underwent ablation confined to the left atrium by creating a circular line isolating the pulmonary vein ostia and a second line connecting the former with the mitral annulus. Subsequently, 12 of these patients underwent a procedure confined to the right atrium (RA), where attempts were made to create an isthmus line between the inferior vena cava and the tricuspid annulus, an anterior line connecting the tricuspid annulus with the superior vena cava, and an intercaval line between the ostia of the inferior and superior venae cavae. In the last 32 patients, only the RA approach was performed. Technical difficulties prevented the creation of the intended left atrial line pattern: all patients experienced recurrences. A 100% recurrence rate was also observed after subsequent RA ablation, despite creation of a complete line pattern in 4 of 12 patients. Of the final 32 patients, AF recurred in 94%; a complete ablation line pattern had been achieved in 18 patients (56%), 16 of whom had recurrences. CONCLUSIONS: The electroanatomically-guided creation of extended radiofrequency current lesions is technically feasible only in the RA. However, procedural success in the RA does not suppress recurrences of AF in the majority of patients.

Atrial Fibrillation↗
PubMed1999

Living anatomy of the atrioventricular junctions. A guide to electrophysiologic mapping. A Consensus Statement from the Cardiac Nomenclature Study Group, Working Group of Arrhythmias, European Society of Cardiology, and the Task Force on Cardiac Nomenclature from NASPE.

Current nomenclature for the atrioventricular (AV) junctions derives from a surgically distorted view, placing the valvar rings and the triangle of Koch in a single plane with antero-posterior and right-left lateral coordinates. Within this convention, the aorta is considered to occupy an anterior position, although the mouth of the coronary sinus is shown as being posterior. Although this nomenclature has served its purpose for the description and treatment of arrhythmias dependent on accessory pathways and atrioventricular nodal reentry, it is less than satisfactory for the description of atrial and ventricular mapping. To correct these deficiencies, a consensus document has been prepared by experts from the Working Group of Arrhythmias of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. It proposes a new anatomically sound nomenclature that will be applicable to all chambers of the heart. In this report, we discuss its value for description of the AV junctions, establishing the principles of this new nomenclature.

Atrioventricular Node↗
PubMed1999

Prospective evaluation of the coronary sinus anatomy in patients undergoing electrophysiologic study.

BACKGROUND: Previous retrospective studies could find a predominant incidence of coronary sinus (CS) anomalies in patients with accessory pathways and a characteristic anatomy of the CS ostium in patients with atrioventricular nodal reentrant tachycardias (AVNRT). HYPOTHESIS: In the present prospective study, CS angiograms were prospectively performed to analyze the incidence of CS anomalies and to measure the diameters of the CS ostium. METHODS: The study included patients referred for electrophysiologic study and catheter ablation of various tachyarrhythmias. The anatomy of the CS and its side branches was visualized [left anterior oblique (LAO) 30 degrees, right anterior oblique (RAO) 30 degrees] by retrograde angiography in 204 consecutive patients (82 women, 122 men, age 45 +/- 15 years); of these, 120 presented with 123 accessory pathways (45 left-sided, 33 right-sided, 45 septal). The diagnosis in the remaining patients was atrioventricular nodal reentrant tachycardia in 43 cases, atrial tachycardia or atrial fibrillation in 12, and ventricular tachycardia in 15. In 14 patients, the indication for the electrophysiologic study was an unexplained syncope. The CS angiogram was evaluated for anomalies and the size of the CS ostium was manually measured in both projections. RESULTS: Anomalies of the CS defined as diverticula, persistent left superior vena cava, or enlarged CS ostia were found in 18 patients (9%). Of those, CS diverticula were found in nine patients, all with a posteroseptal or left posterior manifest accessory pathway, which was abolished within the neck of the diverticulum in seven patients and at the posteroseptal tricuspid annulus in two patients. Persistence of the left superior vena cava was found in five patients, four had atrioventricular reentrant tachycardia secondary to five accessory pathways (left free wall in four, right midseptal in one), and one patient had atrioventricular nodal reentrant tachycardia (AVNRT). Enlargement of the CS ostium of > 25 mm width was detected in nine patients (5%), of whom four had AVNRT. However, the width of the CS ostium generally did not differ significantly between patients with AVNRT (LAO: 14.4 +/- 5.6; RAO 9.3 +/- 2.4 mm) compared with the control group (LAO 13.4 +/- 4.1; 8.2 +/- 1.9 mm). CONCLUSIONS: Anomalies of the CS as diverticula, persistent superior vena cava, or enlargement of the CS ostium are predominantly found in patients with accessory pathway-related tachycardias. Diverticula of the proximal CS were found in 7% of patients with accessory pathways; in these cases, ablation succeeded mostly by radiofrequency (RF) current delivery in the neck of the diverticulum. Enlargement of the CS ostium was more often seen in patients with AVNRT than in all other patients. However, in general the measurements of the coronary sinus ostium did not significantly differ in patients with AVNRT compared with the control group.

Adult↗
PubMed1999

[Arrhythmias in patients with congenital heart disease and their impact on prognosis].

Patients with congenital heart disease have an increased chance to suffer from brady- as well as tachyarrhythmias. The impact of these on quality of life, morbidity and mortality is more often imperative as compared to heart-healthy individuals. The substrate for these may be either congenital or acquired. Improvements of the surgical management of these patients have led, on the one hand, to improved survival rates with prolonged life expectancy within the last 2 decades, which on the other hand provided the basis for a higher rate of acquired cardiac arrhythmias. Together, this not only challenges diagnostics and therapy but also the prognostic relevance of these arrhythmias. The therapeutic strategies and prognostic markers have until now mostly been based on retrospective studies limited by the low number of patients and inhomogeneous patient selection. Despite these limitations, an increased risk of sudden cardiac death has been substantiated for certain patient groups, e.g., those operated on by the Mustard- or Senning procedures in patients with transposition of the great arteries and patients operated on with correction of the tetralogy of Fallot. However, until now it has not been possible to identify reliable markers for establishing the risk on an individual basis within these patient cohorts. For achieving reliable data on the symptomatic and prognostic effects of present-day--as well as new-coming--therapeutic strategies, it is mandatory to perform prospectively based, randomized multicenter studies. Furthermore, the well-appreciated synergism of hemodynamically and primarily of arrhythmia-based effects on prognosis could potentially be divided into their relative weight to better guide appropriate, substrate-related therapy. In addition, this should help to get better estimates of the risk for sudden cardiac death in different, etiologically homogeneous, groups of patients with congenital heart disease.

Arrhythmia, Sinus↗
PubMed1999

Laser angioplasty of restenosed coronary stents: results of a multicenter surveillance trial. The Laser Angioplasty of Restenosed Stents (LARS) Investigators.

OBJECTIVES: This study evaluated safety and efficacy of excimer laser angioplasty for treatment of restenosed or occluded coronary stents. BACKGROUND: Balloon angioplasty of in-stent restenosis is limited by a high recurrence rate. Debulking by laser angioplasty is a novel concept to treat in-stent restenosis. METHODS: A total of 440 patients with restenoses or occlusions in 527 stents were enrolled for treatment with concentric or eccentric laser catheters and adjunctive balloon angioplasty. RESULTS: Laser angioplasty success (< or =50% diameter stenosis after laser treatment or successful passage with a 2.0-mm or 1.7-mm eccentric laser catheter) was achieved in 92% of patients. Adjunctive balloon angioplasty was performed in 99%. Procedural success (laser angioplasty success followed by < or =30% stenosis with or without balloon angioplasty) was 91%. There was neither a significant difference in success with respect to lesion length, nor were there differences between small and large vessels or native vessels and vein grafts. Success was higher and residual stenosis lower using large or eccentric catheters. Serious adverse events included death (1.6%, not directly laser catheter related), Q-wave myocardial infarction (0.5%), non-Q-wave infarction (2.7%), cardiac tamponade (0.5%) and stent damage (0.5%). Perforations after laser treatment occurred in 0.9% of patients and after balloon angioplasty in 0.2%. Dissections were visible in 4.8% of patients after laser treatment and in 9.3% after balloon angioplasty. Reinterventions during hospitalization were necessary in 0.9% of patients; bypass surgery was performed in 0.2%. CONCLUSIONS: Excimer laser angioplasty with adjunctive balloon angioplasty is a safe and efficient technology to treat in-stent restenoses. These data justify a randomized comparison with balloon angioplasty.

Adult↗
PubMed1999

Evaluation of antiarrhythmic drug efficacy in patients with an ICD: unlimited potential or replete with complexity and problems?

There are a number of novel ways in which implantable cardioverter defibrillator (ICD) endpoints can be used in clinical trials to evaluate antiarrhythmic drugs. The advances in ICD technology (storage, retrieval, and accurate interpretation of ICD electrograms) expand the potential to include the use of an ICD endpoint as a clinical surrogate for sudden death. The ICD also provides the necessary safety net to test new drugs. The frequent need for antiarrhythmic drugs in patients already fitted with an ICD (e.g., for atrial fibrillation) necessitates knowledge of the drugs' effect on defibrillator threshold. There are interpretative problems and challenges associated with all types of ICD trials. A particular difficult issue is the degree to which the results of data on antiarrhythmic drug efficacy and safety acquired in the context of an ICD endpoint trial might be extrapolated to patient populations in which the device is not used. These and other challenging issues are discussed, with the goal of enhancing the design and interpretation of clinical trials featuring ICD endpoints.

Anti-Arrhythmia Agents↗
PubMed1999

ESCWGA/NASPE/P experts consensus statement: living anatomy of the atrioventricular junctions. A guide to electrophysiologic mapping. Working Group of Arrhythmias of the European Society of Cardiology. North American Society of Pacing and Electrophysiology.

Current nomenclature for the AV junctions derives from a surgically distorted view, placing the valvar rings and the triangle of Koch in a single plane with anteroposterior and right-left lateral coordinates. Within this convention, the aorta is considered to occupy an anterior position, whereas the mouth of the coronary sinus is shown as being posterior. Although this nomenclature has served its purpose for the description and treatment of arrhythmias dependent on accessory pathways and AV nodal reentry, it is less than satisfactory for the description of atrial and ventricular mapping. To correct these deficiencies, a consensus document has been prepared by experts from the Working Group of Arrhythmias of the European Society of Cardiology and from the North American Society of Pacing and Electrophysiology. It proposes a new, anatomically sound, nomenclature that will be applicable to all chambers of the heart. In this report, we discuss its value for description of the AV junctions and establish the principles of this new nomenclature.

Atrioventricular Node↗
PubMed1998

Ventricular tachycardia during follow-up in patients resuscitated from ventricular fibrillation: experience from stored electrograms of implantable cardioverter-defibrillators.

OBJECTIVE: The purpose of this study was to use the electrogram storage capabilities of the implantable cardioverter-defibrillator (ICD) to categorize any arrhythmic event during follow-up in a group of patients who had survived an episode of ventricular fibrillation (VF) and to possibly identify clinical predictors of future arrhythmic events. BACKGROUND: Little is known about the electrophysiologic characteristics of ventricular arrhythmias recurring during follow-up in survivors of VF as the sole documented arrhythmia at the time of resuscitation. METHODS: Forty patients (58+/-10 years; 73% men; left ventricular ejection fraction 42+/-18%; 70% with coronary artery disease) who had survived an episode of VF and subsequently received an ICD capable of intracardiac electrogram recording and storage were followed for 23+/-11 months. In all patients, the arrhythmogenic substrate was investigated by means of programmed electrical stimulation (PES). RESULTS: Among the 40 patients, 41 episodes of ventricular arrhythmias were documented in 13 patients (33%): 36 episodes of ventricular tachycardias (VT) were recorded in 11 patients (28%) and 5 episodes of VF were recorded in the remaining 2 patients (5%). Age, gender, cardiac disease and left ventricular ejection fraction failed to distinguish between patients with clinical recurrences and patients without. The sensitivity, specificity and positive accuracy of PES were 29%, 63% and 46%, respectively, for prediction of ventricular arrhythmia recurrence; 45%, 70% and 36%, respectively, for prediction of VT; and 50%, 98% and 50%, respectively, for prediction of VF during follow-up. CONCLUSIONS: In survivors of VF receiving ICD therapy, VT is the most common ventricular arrhythmia recorded on device-incorporated electrograms during follow-up. This finding, associated with the relatively well-preserved ventricular function, may account for the ability of these patients to survive at time of the index arrhythmia; the use of antitachycardia pacing as a modality to treat arrhythmia recurrences may contribute to reduce the incidence of shock during follow-up in these patients.

Aged↗
PubMed1998

[High frequency current ablation of supraventricular tachyarrhythmias in congenital heart defects].

Supraventricular tachycardia is a frequent cause of disease in patients with congenital heart defects and has a potentially high impact on quality of life, morbidity and mortality of this patient cohort. Conventional treatment often fails to avoid recurrences of tachycardia in a long-term perspective. Potential side effects of antiarrhythmic drugs include aggravation of heart disease related disturbances of impulse generation and conduction properties or negative inotropic effects on haemodynamically impaired ventricular chambers. For these reasons, interventional electrophysiology is increasingly used for the treatment of supraventricular tachycardias in patients with congenital heart disease. Until March 1998 a total of 83 patients with congenital heart defects underwent an attempt for radiofrequency current treatment of supraventricular tachycardias. Among these were 36 children with an age of 5 months to 15 years (8.2 +/- 4.6 years) and 4.7 grown ups with an age of 17 to 76 years (39.3 +/- 14.3 years). In a natural course or preoperative status of the congenital heart disease were 35 patients, while palliative or corrective surgery was performed in 48 patients. Supraventricular tachycardia was based on a total of 63 congenital arrhythmogenic substrates, among them were 53 accessory pathways, 4 Mahaim fibres, 5 functionally dissociated AV-nodes and an anatomically doubled specific conduction system including 2 distinct AV-nodes in one case. In the remaining patients with tachycardia based on acquired arrhythmogenic substrates there were 45 incisional atrial reentrant tachycardias, 15 atrial flutters of the common type and 6 ectopic atrial tachycardias. In a total of 105 sessions 78 of the 83 patients were successfully treated with the use of radiofrequency current ablation. There were no significant procedure related complications. Radiofrequency current ablation can be carried out safely and successfully for the treatment of supraventricular tachycardia in young and adult patients with congenital heart disease. As such therapeutic strategy meets the specific requirements of this patient cohort, early consideration for this therapy is recommended.

Adolescent↗
PubMed1998

[High frequency current ablation of ectopic atrial tachycardia. Different mapping strategies for localization of right- and left-sided origin].

UNLABELLED: Ectopic atrial tachycardia (EAT) is a rare form of supraventricular tachycardia and often drug-resistant. Radiofrequency catheter (RFC) ablation offers an alternative therapy suggesting a high efficacy rate. Localization of the EAT origin is proposed to be efficacious by various mapping strategies. We analyzed the efficacy of different mapping strategies for localization of right and left sided EAT foci. METHODS AND PATIENTS: In a cohort of 48 patients (25 female: age 35 +/- 18 years) RFC ablation of 40 right and 12 left sided EAT foci was performed. Mapping of the right atrium was achieved with 2 ablation catheters using the "encircling" technique (Figure 1). We looked for an early bipolar local electrogram in relation to the onset of the P-wave and a QS-complex in the unipolar electrogram. The bipolar local electrogram was retrospectively analyzed for a fragmented morphology and duration of more than 50 ms (Figure 3). In case of mechanical block of the EAT during mapping P-wave pace mapping over the mapping catheter was performed (Figure 4). RESULTS: RFC ablation succeeded in 44 patients with 46 EAT foci (Figure 5). Left sided EAT origin was in 40% in the region of the pulmonary veins. Two left sided foci were abladed within the coronary sinus. An anteroseptal location in vicinity to the bundle of His was found in 4 cases (Figure 6). There were no differences between left and right sided origin regrading session duration (304 +/- 131 vs 241 +/- 101 min) and fluoroscopic time (39 +/- 29 vs 31 +/- 19 min). The activation time related to the onset of the P-wave was at successful ablation site for left sided origin significantly earlier compared to a right sided origin (45 +/- 22 vs 30 +/- 18 ms). Fragmenation of the bipolar local electrogram was found before successful RFC application in 86% in the left and in 65% in the right atrium. The unipolar electrogram showed in 87% of all cases a QS-complex before the successful RFC pulse. In 16% a beat to beat change of the unipolar electrogram could be found at successful ablation site (Figure 7). Both criteria had a low specify and sensitivity. Mechanical block could be induced during mapping in 10 patients (20%). In these cases RFC application at a site with a perfect match of P-wave pace mapping succeeded in 8 patients. In 2 patients the same EAT occurred within the following 24 hours. During a follow-up of 4 to 58 months there were additionally recurrence of EAT in 3 patients (3 to 6 months after ablation). No influence of the AV nodal conduction was observed after ablation of anteroseptal EAT foci. Other acute or chronic complications were not observed. CONCLUSIONS: 1. RFC ablation of right and left sided EAT foci is a safe and efficacious treatment. There were no differences regarding session duration and fluoroscopic time between right and left sided foci. 2. Activation mapping showed an earlier activation time for left sided origin compared to right sided. 3. Mechanical block could be induced in 20% of cases. P-wave pace mapping might offer a strategy to localize the focus during mechanical block.

Adolescent↗
PubMed1998

Anatomy-guided linear atrial lesions for radiofrequency catheter ablation of atrial fibrillation.

The surgical atrial maze procedure has provided proof that atrial fibrillation can be cured by performing atrial incisions based on anatomical and electrophysiological principles. Preliminary reports of attempts at radiofrequency catheter ablation of atrial fibrillation utilizing an anatomy-based "linear incision" method have shown the feasibility of the method. However, postprocedural atrial fibrillation recurrence has been common and in addition new, uniform tachycardias have developed in some patients. Both of these outcomes may be in part due to incomplete or inconsistent lesion deployment. This article details the use of the CARTO system for deploying anatomy guided linear atrial lesions for the purpose of curing atrial fibrillation. The procedure is comprised of three phases, which are discussed in detail: (1) baseline map; (2) lesion deployment and; (3) lesion assessment. Using a single standard ablation electrode, lesions can be deployed safely, and complete lesions can be confirmed. Paradigms for right and left atrial incisions are proposed.

Animals↗
PubMed1998

Nonfluoroscopic endocardial catheter mapping of atrial fibrillation.

The treatment of drug-refractory atrial fibrillation (AF) remains one of the unsolved problems in cardiology. Surgical interventions have demonstrated that AF can be prevented by multiple incisions within both atria. Recently, this strategy has been translated into a catheter procedure. So far, the ablation approach is not based on individual electrophysiologic data, but constitutes only an anatomic approach. Further insight into the spatial and temporal distribution of the local electrograms during AF is needed. Electroanatomic maps acquired by sequential mapping over 45 seconds at each site during AF in six patients with paroxysmal AF were analyzed off-line. Electrograms were sampled at a mean of 36 +/- 12 sites in the left atrium of each patient. A total of 217 sites were sampled, of which 27.3% (59) represented type A (regular) AF, 9.7% (21) represented type B (totally irregular), and 63.1% (137) represented type C (mixture of type A and B) electrograms. The distribution was analyzed in 20 different segments of the left atrium, and a significantly higher incidence of type A electrograms was found in area 3 (upper lateral pulmonary vein) than at all other sites (P < 0.005). This observation needs further confirmation before any conclusion with regard to catheter ablation can be drawn, particularly because the analysis was based on bipolar recordings from a 4-mm tip electrode.

Aged↗
PubMed1998

Atrial fibrillation--maintaining sinus rhythm versus ventricular rate control: the PIAF trial. Pharmacological Intervention in Atrial Fibrillation.

INTRODUCTION: In patients with persistent atrial fibrillation, therapy can be directed toward restoration of sinus rhythm or control of ventricular rate only. There are no prospective data in the literature comparing both treatment strategies. METHODS AND RESULTS: Patients with symptomatic persistent atrial fibrillation (duration > or = 7 and < or = 360 days) will be randomized to control of ventricular rate only or to conversion therapy. All patients will be followed for 12 months. Diltiazem is used as the primary therapy for rate control, whereas amiodarone will be administered for restoration and maintenance of sinus rhythm. The primary endpoint of the trial is the recurrence of symptomatic tachyarrhythmic episodes in patients randomized to rate control and recurrent atrial fibrillation in the alternative treatment arm. A number of secondary endpoints also will be investigated. The trial is expected to end its follow-up in the summer of 1998. CONCLUSION: PIAF (Pharmacological Intervention in Atrial Fibrillation) is one of several trials designed to evaluate the optimal treatment strategy in patients with persistent atrial fibrillation. The results hopefully will help to improve care of patients with this common rhythm disorder.

Animals↗
PubMed1997

[Anatomic distribution, conduction properties and recurrences after ablation of multiple in comparison with single accessory conduction pathways].

In 1076 consecutive patients referred for radiofrequency current catheter ablation, the anatomical distribution and conduction properties of accessory pathways (APs) as well as the mode of recurrence after ablation were retrospectively analyzed and compared in patients with multiple and single APs. Except for 17 patients with Ebstein's anomaly, the prevalence of patients of multiple APs in this cohort was 5.4%. Patients with multiple APs. as opposed to patients with a single AP, had significantly more often APs located on the right free wall (23% versus 10%) and--since the prevalence of septal APs was identical in both groups--less frequently APs located on the left free wall (44% versus 56%). Also, concealed APs were significantly more often encountered in patients with multiple APs (45% versus 24%). Recurrence of conduction across an AP which had presumably been ablated was observed in both groups with statistically equal incidence of < 5%. In 11 patients with multiple APs, the additional AP was only found at the repeat session. These "new" APs were mostly concealed (9 out of 11) and necessitated an intervention predominantly late after the initial ablation session. Intermittent concealed conduction appears to be a likely explanation for this phenomenon. Patients with multiple APs exhibit a higher incidence of right free-wall and concealed APs, yet they stand the same, approximately 95%, chance of cure as do patients with a single AP. Nearly 25% percent of repeat sessions in patients initially thought to have a single AP are caused by the late manifestation of an additional AP.

Adolescent↗