Acute performance evaluation of a new ventricular automatic capture algorithm

Aims This study evaluated the acute clinical performance of a new ventricular automatic capture algorithm developed to work with all lead types and pacing vectors. Methods and results During regular pacemaker implant or replacement, AutoThreshold and manual threshold tests were performed in ventricular unipolar (UP) and bipolar (BP, if applicable) pacing using a customized external prototype INSIGNIA™ pacemaker. The success rate and accuracy of two different modes (commanded and ambulatory) of the automatic capture algorithm were used to evaluate the performance. Loss-of-capture events (two consecutive non-captured beats without backup pacing) were used to assess safety. Data of 53 patients…

Ist eine ICD-Programmierung auf eine Schockenergie der doppelten intraoperativen Defibrillationsschwelle im Langzeitverlauf sicher effektiv? Ergebnisse einer prospektiven randomisierten Multizenterstudie (Low Energy Endotak Trial – LEET)

Ziel dieser kontrollierten, prospektiven, randomisierten Studie war die Untersuchung der Effektivitat und der Sicherheit einer reduzierten Defibrillationsenergie mit biphasischer Schockform und einem endokardialem ICD-Sondensystem. 176 Patienten, die klinisch ein typisches ICD-Patientenkollektiv darstellten, wurden im Rahmen der Studie untersucht. Alle Patienten erhielten ein ICD-Aggregat mit der Moglichkeit der Episodenspeicherung (Ventak TM PRx II, PRx III) in Verbindung mit einem rein endokardialem Sondensystem (Endotak TM Serie 0070; 0090, CPI). Die intraoperative Defibrillationsschwelle (DFT) sollte ≤15 J betragen. Die DFT wurde in einem Protokoll mit absteigenden Energiemengen (15, 10…

Paroxysmal atrial fibrillation and high degree AV block: use of single-lead VDDR pacing with mode switching.

Dual chamber rate responsive pacing incorporating a mode switching option is increasingly used in patients with chronic paroxysmal atrial fibrillation and high degree AV block. Single-lead VDDR pacemakers have rarely used for this indication. The purpose of this study was to determine their reliability of atrial sensing during atrial fibrillation, the percentage of atrial synchronous ventricular pacing, and the behavior of the sinus rate outside the phases of atrial fibrillation. We studied ten patients with a single-lead VDDR pacemaker implanted for this indication. Follow-up visits were performed at predischarge and after 1, 3, 6, 12, 18, and 24 months. During the mean follow-up period of…

Reduction of ICD Shock Burden by Eliminating Back-Up Pacing Induced Ventricular Tachyarrhythmias

ICD Shock Reduction by Subthreshold Pacing Introduction Implantable cardioverter defibrillators (ICD) may have the capacity to provoke or worsen ventricular tachyarrhythmias (VT). It has been reported that ICD shocks by itself can increase mortality. This study aimed to determine the role of back-up pacing-induced VT (PIT) in the overall ICD shock burden by avoiding pause-related ventricular back-up pacing. Methods and Results A population of 550 single-chamber ICD patients was studied. Of them, 17 (3%, 69 ± 16 years, 14 male) patients had documented episodes of PIT. A total of 431 VT episodes were documented including 89 (21%) due to PIT. In 3 patients, VT events were exclusively PITs. Aft…

A simple method for preoperative assessment of the best fitting electrode length in single lead VDD pacing.

For single lead VDD pacing, electrodes with various distances between the lead tip and the floating atrial dipole (AV distance) are available. Using different AV distances allows positioning of the atrial dipole in the mid- to high right atrium, regardless of the size of the right heart. In this position, reliable atrial sensing and rejection of ventricular far-field potentials can be expected. A simple test for the preoperative assessment of the best fitting AV distance in the individual patient was tested. We studied 24 consecutive patients prior to implantation of a VDD pacemaker. With the patient in supine position, a test electrode with an AV distance of 13 cm was taped onto the thorax…

European Clinical Experience with a Dual Chamber Single Pass Sensing and Pacing Defibrillation Lead

Dual chamber ICDs are increasingly implanted nowadays, mainly to improve discrimination between supraventricular and ventricular arrhythmias but also to maintain AV synchrony in patients with bradycardia. The aim of this study was to investigate a new single pass right ventricular defibrillation lead capable of true bipolar sensing and pacing in the right atrium and integrated bipolar sensing and pacing in the right ventricle. The performance of the lead was evaluated in 57 patients (age 61 +/- 12 years; New York Heart Association 1.9 +/- 0.6, left ventricular ejection fraction 0.38 +/- 0.15) at implant, at prehospital discharge, and during a 1-year follow-up. Sensing and pacing behavior of…

Cardiac output in single-lead VDD pacing versus rate-matched VVIR pacing.

The importance of atrioventricular synchronous pacing compared with single-chamber rate-responsive pacing is still under discussion, especially for low-intensity workload representing daily life activities. We evaluated hemodynamics in single-lead VDD pacing versus VVIR pacing in 11 patients (8 men and 3 women, aged 58.6 +/- 13.8 years) with normal left ventricular function and a previously implanted single-lead VDDR pacemaker. A low-intensity steady-state treadmill test at 1 to 2.5 mph with a gradient of 2% to 4% was performed. Cardiac output was determined using a standard carbon dioxide rebreathing technique. Initially, the VDD mode was programmed, and after 5 minutes of exercise, cardia…

Die Spätpotentialanalyse in der Diagnostik nach akutem Myokardinfarkt:¶Risikomarker für den Arrhythmie-gefährdeten und klinisch symptomatischen Patienten (Late potentials in postinfarction patients: arrhythmogenic risk and clinical characteristics)

Ziel der prospektiven Studie ist die Korrelation ventrikularer Spatpotentiale mit klinischen Parametern bei Patienten nach akutem Myokardinfarkt. Es wurde die prognostische Wertigkeit dieser Methode hinsichtlich der Risikostratifizierung bezuglich des plotzlichen Herztodes in der spaten Postinfarktphase im Vergleich mit herkommlichen diagnostischen Moglichkeiten uberpruft. Zudem wurde untersucht, welche klinischen Symptome die potentiell gefahrdeten Patienten charakterisieren.

Kurzzeitmessung der Herzfrequenzvariabilität bei Postinfarktpatienten -

Hintergrund: In der Risikostratifizierung fur einen PHT bzw. das Auftreten eines arrhythmogenen Ereignisses nach AMI wurden bisher eine hohe Spezifitat und ein hoher negativ pradiktiver Wert durch Kombination mehrerer Methoden erreicht. Sensitivitat und positive Pradiktion sind jedoch weiterhin nicht ausreichend. Eine dieser Methoden ist die Messung der HRV, die als unabhangiger Pradiktor eines solchen Ereignisses gilt. Sie wird genutzt, um einen schnellen Uberblick uber den Zustand des autonomen Nervensystems zu bekommen, wird jedoch insbesondere in der Kardiologie bisher nur aus dem 24-Stunden-Langzeit-EKG bestimmt.¶   Studienziel: Die Kurzzeitmessung der HRV bei Postinfarktpatienten als …

How Can We Identify the Best Implantation Site for an ECG Event Recorder?

ZELLERHOFF, C., et al.: How Can We Identify the Best Implantation Site for an ECG Event Recorder? The aim of this study was to show how to find the preferable implantation site for an ECG event recorder (ECG-ER). We compared the quality of bipolar ECG recordings (4-cm electrode distance, vertical position) in 65 patients at the following sites: left and right subclavicular, left and right anterior axillary line (4th-5th interspace), left and right of the sternum (4th-5th interspace), heart apex, and subxyphoidal. The results were compared to the standard ECG lead II. In 30 patients, an additional comparison between vertical and horizontal ECG registrations was done using the same sites. ECG…

Hypoxia and myocardial remodeling in human cardiac allografts: a time-course study.

Background: Cardiac allografts are known to develop myocardial fibrosis, which may be a cause of progressive cardiac dysfunction. Apart from the renin‐angiotensin and transforming growth factor- system, hypoxia has been proposed as an important player in the pathogenesis of fibrosis, but its significance remains unclear. This study examines the degree of myocardial fibrosis, cellular remodeling and hypoxic signaling over a time-course of 10 years after human cardiac allograft transplantation. Methods: Serial right ventricular biopsies of 57 patients were collected in 6-month intervals after cardiac transplant surgery for a total of 10 years to allow a retrospective longitudinal analysis. Ov…

VDD(R)-Stimulation mit Mode-Switch bei paroxysmalem Vorhofflimmern und AV-Block: Verlauf über 2 Jahre

Safety and efficacy of implantable defibrillator therapy with programmed shock energy at twice the augmented step-down defibrillation threshold: results of the prospective, randomized, multicenter Low-Energy Endotak Trial.

Whether the safety and efficacy of implantable cardioverter defibrillator (ICD) therapy can be assured with lower output devices is an important question. The purpose of this study was to evaluate whether programming the device output at twice the augmented defibrillation threshold was as safe and effective as using the maximum energy. Patients indicated for ICD therapy, but without slow monomorphic ventricular tachycardia (MVT), who achieved an augmented defibrillation threshold (DFT plus)or = 15 joules (J) with a single endocardial lead system and a biphasic defibrillator were included in the study. Prior to ICD implantation, patients were randomized into 2 groups. The shock energies in t…

A26-5 Electrical performances of a 2MM2 steroid electrode

Patient Alert to detect ICD lead failure: efficacy, limitations, and implications for future algorithms.

Aims An algorithm that alerts implantable cardioverter-defibrillator (ICD) patients, in case of abnormal lead impedance (Patient Alert™, Medtronic), may help to recognize lead dysfunction. We aimed to determine the utility of Patient Alert for ICD lead-failure detection in a prospective study. Methods and results Three hundred and sixty ICD patients were followed for 22±14 months. Patient Alert was active for pacing impedance 2000–3000 Ω, and high-voltage conductor impedance 200 Ω. Ten alert events and a total of 29 severe system complications occurred. Patient Alert detected three of 10 ICD lead failures, with a positive predictive value (PPV) of 77.8% for any severe system complication. R…

The Incidence of Audible Steam Pops Is Increased and Unpredictable With the ThermoCool® Surround Flow Catheter During Left Atrial Catheter Ablation: A Prospective Observational Study

Audible Steam Pops During Left Atrial Catheter AblationIntroduction Open irrigated radiofrequency (RF) ablation catheters with a porous tip (56 holes, TC-SF) permit delivering RF energy in a temperature-controlled mode without temperature rise. This prospective observational study investigated the association of different catheter parameters on the occurrence of audible steam pops during left atrial (LA) ablation. Methods and Results A total of 226 patients underwent TC-SF catheter ablation for atrial fibrillation. RF power delivery, impedance and catheter tip temperature were continually recorded throughout the ablation. Pulmonary vein isolation was performed with a maximum of 27 W and LA …

Prävention von Vorhofarrhythmien durch Overdrive-Stimulation und Automatische Ruhefrequenz — Die PROVE-Studie

Im Rahmen der PROVE-Studie werden Patienten mit klas-sischer Schrittmacherindikation bzgl. atrialer Arrhythmien untersucht. Patienten mit und ohne Vorhofarrhythmien werden in verschiedene Subgruppen unterteilt. In der Gruppe mit atrialen Arrhythmien zeigen die bisherigen Daten einen praventiven antiarrhythmischen Effekt der Overdrive — Stimulation in Kombination mit der Automatischen Ruhefrequenz

Arrhythmia Termination Versus Elimination of Dormant Pulmonary Vein Conduction as a Procedural End Point of Catheter Ablation for Paroxysmal Atrial Fibrillation: A Prospective Randomized Trial.

Background— Pulmonary vein isolation (PVI) is still associated with a substantial number of arrhythmia recurrences in paroxysmal atrial fibrillation (AF). This prospective, randomized study aimed to compare 2 different procedural strategies. Methods and Results— A total of 152 patients undergoing de novo ablation for paroxysmal AF were randomized to 2 different treatment arms. The procedure in group A consisted of PVI exclusively. In this group, all isolated PVs were challenged with adenosine to reveal and ablate dormant conduction. In group B, PVI was performed with the patient either in spontaneous or in induced AF. If AF did not terminate with PVI, ablation was continued by targeting ex…

Reproduzierbarkeit der Defibrillationseffektivität zur Terminierung von induziertem Kammerflimmern unter Verwendung der intraoperativ gemessenen Defibrillationsschwellenenergie bei Patienten mit implantierbarem Kardioverter-Defibrillator

Ziel vorliegender Untersuchung war es, die Reproduzierbarkeit der Effektivitat der nach einem modifizierten Protokoll intraoperativ bestimmten Defibrillationsschwellenenergie im Langzeitverlauf zu uberprufen. Hierzu wurden im Rahmen einer Substudie einer prospektiven, randomisierten Multizenterstudie (“Low Energy Endotak Trial” LEET)) zwischen Dezember 1993 und Januar 1996 83 Patienten, die im Rahmen einer Erstversorgung mit einem implantierbaren Kardioverter-Defibrillator (ICD) in Kombination mit einem transvenosen Einzelelektrodensystem eine intraoperativ bestimmte Defibrillationsschwelle (DFT) ≤15 J aufwiesen, eingeschlossen. Zur Bestimmung der DFT wurde ein Protokoll mit absteigenden En…

[Is ICD-programming for double intraoperative defibrillation threshold energy safe and effective during long-time follow-up? Results of a prospective randomized multicenter study (Low-Energy Endotak Trial--LEET)].

The aim of this prospective and randomized study was to evaluate the safety and efficacy of a reduced shock strength in transvenous implantable defibrillator therapy. So far clinical data concerning the safety margin of the shock energy in ICD therapy do not exist. The shock energy tested during long-term follow-up in this study was twice the intraoperatively measured defibrillation threshold (DFT). A total number of 176 consecutive patients representing a typical cohort of ICD patients were evaluated. All patients received a non-thoracotomy lead system (CPI, Endotak 0070, 0090) and a biphasic cardioverter-defibrillator with the ability to store episodes (Cardiac Pacemakers Inc., Ventac TM …

Device-Therapie nach akutem Koronarsyndrom

AV-Blocke sind beim akuten Koronarsyndroms selten. Nur wenige Patienten benotigen eine Schrittmacherimplantation. Besonders beim Hinterwandinfarkt ist die Prognose gut. Die Haufigkeit anhaltender AV-Blockierungen hat durch die Akut-PTCA abgenommen. Ventrikulare Tachyarrhythmien sind in der Akutphase des Infarktes haufig. Treten sie als anhaltende Kammertachykardien oder Kammerflimmern > 48 Stunden nach Infarkt auf, konnen sie eine Indikation zur sekundarprophylaktischen ICD-Implantation darstellen. Primarprophylaktisch sollte ein Defibrillator implantiert werden, wenn die LV-EF auch > 40 Tage nach Infarkt ≤ 35 % betragt. Ist fruh nach Infarkt eine Aggregatimplantation erforderlich, sollte b…

Schrittmachertherapie bei Frühgeborenen mit AV-Block: Erstmaliger Einsatz von „Autocapture” mit epikardialer Elektrode

Förderung und Optimierung der intrinsischen AV-Überleitung bei Patienten mit DDD(R)-Schrittmachern

Experimentelle Untersuchungen zum Einsatz verschiedener atrialer Dipolkonfigurationen für die Vorhof-Stimulation mit VDD-Elektroden

Fourier-Analyse der P-Welle bei der VDD-Stimulation. Ein intra-individueller Vergleich verschiedener atrialer Dipolkonfigurationen

Der Frequenzinhalt der wahrgenommenen P-Welle wird bei der VDD-Stimulation sowohl von der Dipollokalisation, als auch von der Dipolkonfiguration beeinflust. Eine Vergroserung der Dipoloberflache resultiert in der Detektion tieferer Frequenzen.

Pacemaker therapy in premature children with high degree AV block.

The smallest pacemaker pulse generator and a steroid-eluting bipolar epicardial lead were implanted in two premature children with symptomatic AV block. Stable capture threshold and high amplitude evoked response electrogram resulted in normal function of the pacemaker Autocapture algorithm, which adjusts output 0.3 V above the measured capture threshold. Autocapture had previously been used only with endocardial leads. Longer-term observation is required.