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The prevalence of aortic valve stenosis is increasing due to the continuously growing geriatric population. Data on procedural success and mortality of very old patients are sparse, raising the question of when this population may be deemed as "too old even for transcatheter aortic valve replacement (TAVR)." We, therefore, sought to evaluate the influence of age on outcome after TAVR and the impact of direct implantation.The data of 394 consecutive patients undergoing TF-TAVR were analyzed. Patients were divided into four age groups: ≤75 (group 1, n = 28), 76-80 (group 2, n = 107), 81-85 (group 3, n = 148), and85 (group 4, n = 111) years. Direct implantation was performed when possible according to current recommendations. Survival was evaluated by Kaplan-Meier analysis.Mortality at 30 days and 1 year was not significantly different between the four age groups (3.6 vs. 6.7 vs. 5.4 vs. 2.7% and 7.6 vs. 17 vs. 14.5 vs. 13%m respectively, log-rank p = 0.59). Direct implantation without balloon aortic valvuloplasty was more frequently performed on patients aged85 vs. ≤85 years (33.3 vs. 14.1%, p 0.001). the incidence of procedural complications frequently associated with advanced age (stroke, vascular complications) was not significantly increased in group 4.Outcome after TF-TAVR is comparable among different age cohorts, even in very old patients. Direct implantation simplifies the procedure and could therefore play a role in reducing the incidence of peri-interventional complications in patients of advanced age.HINTERGRUND: Die Prävalenz der Aortenklappenstenose steigt durch eine kontinuierlich wachsende geriatrische Bevölkerung. Daten über prozeduralen Erfolg sowie Mortalität von sehr alten Patienten sind gering, sodass sich die Frage stellt, wann diese Population „als bereits zu alt“ für einen Transkatheter-Aortenklappenersatz (TAVR) anzusehen wäre. Ziel dieser Studie war es, den Einfluss der direkten Implantation auf die Ergebnisse nach transfemoraler (TF-)TAVR bei Patienten in fortgeschrittenem Alter zu evaluieren.Dazu wurden die Daten von 394 konsekutiven Patienten nach TF-TAVR ermittelt. Die Patienten wurden in 4 Altersgruppen eingeteilt: ≤75 Jahre (Gruppe 1, n = 28), 76–80 Jahre (Gruppe 2, n = 107), 81–85 Jahre (Gruppe 3, n = 148) und85 Jahre (Gruppe 4, n = 111). Sofern es die aktuellen Empfehlungen erlaubten, wurde eine direkte Implantation durchgeführt. Das Überleben wurde mittels Kaplan–Meier-Analyse evaluiert.Zwischen den 4 Altersgruppen waren keine signifikanten Unterschiede der Mortalität nach 30 Tagen und nach einem Jahr zu verzeichnen (entsprechend 3,6 vs. 6,7 vs. 5,4 vs. 2,7 % und 7,6 vs. 17 vs. 14,5 vs. 13 %; p = 0,59 für Log-Rank-Test). Eine direkte Implantation ohne Ballonvalvuloplastie wurde bei Patienten85 Jahre häufiger durchgeführt als ≤85 Jahre (33,3 vs. 14,1 %; p 0,001). Die Inzidenz von häufig mit fortgeschrittenem Patientenalter assoziierten prozeduralen Komplikationen (Schlaganfall, vaskuläre Komplikationen) war in der Gruppe 4 nicht signifikant erhöht.In verschiedenen Alterskollektiven zeigen sich vergleichbare Ergebnisse nach TF-TAVR, dies gilt sogar für Patienten sehr hohen Alters. Die direkte Implantation kann die Prozedur vereinfachen und zu einer konsekutiven Reduktion der Inzidenz von periprozeduralen Komplikationen bei Patienten mit fortgeschrittenem Alter führen.

Fehlfunktionen bei implantierten Schrittmacher- und Defibrillatorsystemen konnen alle Bauteile des Gerats betreffen (Batterie, Kondensator, „central processing unit“ (CPU), Konnektor, Lotstellen, Elektroden). Die daraus entstehenden Probleme konnen sich als inadaquate Therapie, eine unterbleibende Therapie trotz Notwendigkeit einer Stimulation oder Schockabgabe bei aufgetretener ventrikularer Tachyarrhythmie oder als eine ineffektive Therapieabgabe manifestieren. Die hohe Anzahl von implantierten Schrittmacher- und Defibrillatorsystemen, die gestiegene Lebenserwartung sowie der technische Fortschritt der kardialen Device-Therapie konfrontiert den nachsorgenden Arzt mit zunehmend komplexeren Problemen im Follow-up. Neben der Kenntnis der basalen Funktion dieser Gerate wird ein strukturiertes Vorgehen gefordert, um Fehlfunktionen rechtzeitig zu erkennen und zu behandeln. In dieser Ubersicht werden haufige Fehlfunktionen von Schrittmachern und Defibrillatoren dargestellt, auf einzelne Probleme hingewiesen und Losungsansatze sowie Therapieoptionen gezeigt.

AIMS: The objective of this paper is to assess whether cardiac contractility modulation (via the Optimizer System) plus standard of care (SoC) is a cost-effective treatment for people with heart failure [New York Heart Association (NYHA) III, left ventricular ejection fraction of 25-45%, and narrow QRS] compared against SoC alone from the perspective of the English National Health Service. METHODS AND RESULTS: We developed a regression equation-based cost-effectiveness model, using individual patient data from three randomized control trials (FIX-HF-5 Phases 1 and 2, and FIX-HF-5C) to populate the majority of parameters. A series of regression equations predicted NYHA class over time, mortality, all-cause hospitalization rates, and health-related quality of life. We conducted the analysis in line with the National Institute for Health and Care Excellence reference case, modelling costs from an English National Health Service perspective, and considering outcomes in quality-adjusted life years (QALYs) over a patient lifetime perspective. Our base case analysis produced an incremental cost per additional QALY of GBP22 988 (€25 750) when comparing Optimizer + SoC to SoC alone. This result was not sensitive to parameter uncertainty but was sensitive to the time horizon over which costs and QALYs were captured and the duration over which a survival benefit with Optimizer + SoC can be assumed to apply. CONCLUSIONS: Cardiac contractility modulation is likely to be cost-effective in people with heart failure with reduced ejection fraction, NYHA III, and narrow QRS, provided that the treatment benefit can be maintained beyond the duration of the existing clinical trial follow-up. This analysis supports the current recommendations of the European Society of Cardiology that this therapy may be considered for such patients. peerReviewed

BACKGROUND Optimization of cardiac resynchronization therapy (CRT) is often time-consuming and therefore underused in a clinical setting. Novel device-based algorithms aiming to simplify optimization include a dynamic atrioventricular delay (AVD) algorithm (SyncAV, Abbott) and multipoint pacing (MPP, Abbott). This study examines the acute effect of SyncAV and MPP on electrical synchrony in patients with newly and chronically implanted CRT devices. METHODS Patients with SyncAV and MPP enabled devices were prospectively enrolled during implant or scheduled follow-up. Blinded 12-lead electrocardiographic acute measurements of QRS duration (QRSd) were performed for intrinsic QRSd (Intrinsic), bi-ventricular pacing (BiV), MPP, BiV with SyncAV at default offset 50 ms (BiVSyncAVdef ), BiV with SyncAV at patient-specific optimised offset (BiVSyncAVopt ), MPP with SyncAV at default offset 50 ms (MPPSyncAVdef ), and MPP with SyncAV at patient-specific optimised offset (MPPSyncAVopt ). RESULTS Thirty-three patients were enrolled. QRSd for Intrinsic, BiV, MPP, BiVSyncAVdef , BiVSyncAVopt , MPPSyncAVdef , MPPSyncAVopt were 160.4 ± 20.6 ms, 141.0 ± 20.5 ms, 130.2 ± 17.2 ms, 121.7 ± 20.9 ms, 117.0 ± 19.0 ms, 121.2 ± 17.1 ms, 108.7 ± 16.5 ms respectively. MPPSyncAVopt led to greatest reduction of QRSd relative to Intrinsic (-31.6 ± 11.1%; p

Multipoint pacing [Multipoint™ Pacing (MPP), Abbott] via a single left ventricular lead (Quartet™ LV lead, Abbott) improves acute left ventricular (LV) function and response to cardiac resynchronization therapy (CRT). Aim of this study was to examine additional benefits in terms of LV reverse remodeling and CRT response by activating MPP in responders and non-responders to conventional biventricular pacing (CONV). 43 consecutive patients receiving CRT (Quadra Assura MP™, Abbott) received LV dP/dtmax optimized CONV programming for 6 months. MPP programming with large anatomical electrode separation (> 30 mm) and basal LV1 pacing location was activated afterwards. Echocardiographic and clinical parameters were obtained at baseline, 6- and 12-month follow-up (FU). The response was defined as an improvement of LVESV ≥ 15% and super-response as improvement ≥ 30% relative to baseline. 41 patients completed FU (one died of non-cardiac cause and one was lost to FU) and after 6 months CONV, 26 patients (63%) were classified as CRT responders. With MPP, the response rate increased to 90% (p

Highlights • Transcatheter heart valve size selection is still challenging. • The overlap between two different prosthesis sizes for borderline annuli remains. • Undersizing but overfilling improves sizing in borderline annulus cases. • Undersizing but overfilling decreases the postprocedural THV-pressure gradient. • Prospective studies are needed considering the TAVR expansion to younger patients., Background Current recommendations for valve size selection are based on multidimensional annular measurements, yet the overlap between two different transcatheter heart valve (THV) sizes remains. We sought to evaluate whether undersizing but overfilling eliminates the gray zones of valve sizing. Methods Data of 246 consecutive patients undergoing transcatheter aortic valve replacement (TAVR) with the balloon-expandable bioprosthesis with either conventional sizing and nominal filling (group 1 (NF-TAVR), n = 154) or undersizing but overfilling under a Less Is More (LIM)-Principle (group 2 (LIM-TAVR), n = 92) were compared. Paravalvular leakage (PVL) was graded angiographically and quantitatively using invasive hemodynamics. Results Annulus rupture (AR) occurred only in group 1 (n = 3). Due to AR adequate evaluation of PVL was possible in 152 patients of group 1. More than mild PVL was found in 13 (8.6%) patients of group 1 and 1 (1.1%) patient of group 2 (p = 0.019). Postdilatation was performed in 31 (20.1%) patients of group 1 and 6 patients (6.5%) of group 2 (p = 0.003). For patients with borderline annulus size in group 1 (n = 35, 22.7%) valve size selection was left to the physiciańs choice resulting in selection of the larger prosthesis in 10 (28.6%). In group 2 all patients with borderline annulus (n = 36, 39.1%) received the smaller prosthesis (LIM-TAVR). The postprocedural mean transvalvular pressure gradient was significantly higher in the NF-TAVR-group (11.7 ± 4 vs. 10.1 ± 3.6 mmHg, p = 0.005). Conclusion LIM-TAVR eliminates the gray zones of sizing and associated PVL, can improve THV-performance, reduce incidence of annular rupture and simplify the procedure especially in borderline cases.

Malfunctions in implanted pacemaker and defibrillator systems can affect all components of the device (battery, capacitor, central processing unit (CPU), connector, soldering points, electrodes). The resulting problems can manifest themselves as inadequate therapy, a lack of therapy despite the need for stimulation or shock release in case of ventricular tachyarrhythmia, or as an ineffective delivery of therapy. The high number of implanted pacemaker and defibrillator systems, the increased life expectancy and the technical progress of cardiac "device" therapy mean that the treating physician is confronted with increasingly complex problems in the follow-up. In addition to the knowledge of the basic function of these devices, a structured procedure to detect and treat malfunctions in a timely manner is required. In this review, frequent malfunctions of pacemaker and defibrillators are presented, individual problems are pointed out, and solutions and treatment options are shown.

Introduction The Medtronic Attain Stability Quad lead is a quadripolar left ventricular (LV) lead with an active fixation helix assembly designed to fixate the lead within the coronary sinus and pace nonapical regions of the LV. The primary objective of this study was to determine the safety and effectiveness of this novel active fixation quadripolar LV lead. Methods Patients with standard indications for cardiac resynchronization therapy (CRT) were enrolled. All patients were followed at 3 and 6 months post-implant and every 6 months thereafter until study closure. Pacing capture thresholds (PCTs) were measured at implant and each follow-up and adverse events (AEs) were recorded upon occurrence. Results Of the 440 patients who underwent implant procedures, placement of the Attain Stability Quad lead was successful in 426 (96.8%). LV lead-related complications occurred in 10 patients (2.3%), including LV lead dislodgement in three patients (0.7%). The percentage of patients with at least one LV pacing vector with a PCT ≤2.5 V at a 6-month follow-up was 96.3%. The LV lead was successfully fixated to the prespecified pacing location in 97.4% of cases. Conclusions This large, multinational study of the Attain Stability Quad lead demonstrated a high rate of implant success with a low complication rate. The active fixation mechanism allowed precise placement of the pacing electrodes at the desired target region with good PCTs and a very low dislodgement rate.

Objectives This study sought to evaluate the effects of programming a long detection in single-chamber (VVI) implantable cardioverter-defibrillators (ICDs) in the multicenter prospective ADVANCE III (Avoid DeliVering TherApies for Non-sustained Arrhythmias in ICD PatiEnts III) trial. Background Programming strategies may reduce unnecessary ICD shocks and their adverse effects but to date have been described only for dual-chamber ICDs. Methods A total of 545 subjects (85% male; atrial fibrillation 25%, left ventricular ejection fraction 31%, ischemic etiology 68%, secondary prevention indications 32%) receiving a VVI ICD were randomized to long detection (30 of 40 intervals) or standard programming (18 of 24 intervals) based on device type, atrial fibrillation history, and indication. In both arms, antitachycardia pacing (ATP) therapy during charging was programmed for episodes with cycle length 320 to 200 ms and shock only for cycle length Results A total of 267 patients were randomized to long detection and 278 to the control group. Median follow-up was 12 months. One hundred twelve therapies (shocks and ATP) occurred in the long detection arm versus 257 in the control arm, for a 48% reduction with 30 of 40 intervals (95% confidence interval [CI]: 0.36 to 0.76; p = 0.002). In the long detection arm, overall shocks were reduced by 40% compared to the control arm (48 vs. 24; 95% CI: 0.38 to 0.94; p = 0.026) and appropriate shocks by 51% (34 vs. 74; 95% CI: 0.26 to 0.94; p = 0.033). Syncopal events did not differ between arms, but survival improved in the long detection arm. Conclusions Among patients implanted with a VVI ICD, programming with the long detection interval significantly reduced appropriate therapies, shocks, and all-cause mortality. (Avoid DeliVering TherApies for Non-sustained Arrhythmias in ICD PatiEnts III [ADVANCEIII]; NCT00617175)

This article provides a technical description of common implant practice for delivery of cardiac contractility modulation (CCM) therapy to heart failure patients. As of September 2016, the authors of this article collectively have been involved with more than 400 system implantations in five medical centers, beginning with the advent of CCM therapy approximately 12 years ago. CCM therapy has been evaluated in a variety of studies, and was shown to be safe and effective and of benefit to patient quality of life and exercise capacity. As the use of CCM therapy continuously expands among medical centers in Europe, this article describes the technical and practical aspects of the implant procedure, and additional special technical cases based on our cumulative experience.

Introduction Cardiac Contractility Modulation (CCM) is a treatment for patients with heart failure with reduced ejection fraction (HFrEF) providing improved myocardial molecular and biochemical characteristics and thus improved exercise tolerance and quality of life by application of electrical signals during the absolute refractory period. Cardiopulmonary exercise testing is an integrative method to assess exercise tolerance in heart failure patients providing insights in circulatory, respiratory and metabolic reactions during exercise. The VE/VCO2-Slope (minute ventilation/carbon dioxide production) and an oscillatory breathing pattern have widely been demonstrated to have strong prognostic value for patients with chronic heart failure. Methods Between February 2017 and January 2019 15 patients (mean age 64.4±7.9 years, NYHA 2.93±0.58) with standard indication for CCM-therapy have been enrolled in a single center in Germany. Prior to implantation of the Optimizer Smart System, symptom-limited cardiopulmonary exercise testing was performed using a bicycle ramp protocol (25W+10W/min). The Follow-up was conducted 6 weeks post implantation. The control group consisted of 45 patients (mean age 64.8±7.9 years, NYHA 2.2±0.72) with stable systolic heart failure and reduced ejection fraction. Statistical Analysis was performed by paired and unpaired t tests. Results 6 weeks after CCM-implantation the VE/VCO2-Slope showed a significant decrease (39.6±11.1 vs. 36.6±8.9, p In contrast, subjects showed no significant changes in watt-measurements (72.67 W ± 19.2 W vs. 76.57 W ± 18.5 W) or maximal oxygen uptake (1034 ml/min ± 247 ml/min vs. 1104 ml/min ± 256 ml/min) compared to baseline. Similarly, the control-group showed stable measurements for external load (79.9 W ± 16.4 W vs. 77.1 W ± 17.5 W) and peak oxygen uptake (1097 ml/min ± 225 ml/min vs. 1116 ml/min ± 330 ml/min). Conclusion Cardiac Contractility Modulation provides improved ventilatory efficiency measures by VE/VCO2-slope and reduces oscillatory breathing pattern during exercise at follow up. As the low ventilatory efficiency observed in patients with heart failure constitutes an important predictor of cardiovascular mortality these results provide an interesting insight of therapeutic effects of Cardiac Contractility Modulation apart from VO2-measurements.

The transfemoral approach for transcatheter aortic valve implantation (TF-TAVI) is associated with a significant survival benefit for intermediate and high-risk patients. Due to the increased procedural risk, many operators avoid TF-TAVI in patients with aortic disease. Moreover, significant peri-interventional device interaction may occur in patients with previous endovascular aortic repair (EVAR). We evaluated the feasibility of TF-TAVI in patients with aortic disease in combination with simultaneous or sequential EVAR.Data from 15 TF-TAVI patients with concomitant aortic disease treated between 2009 and 2019 in three German heart centers representing 4410 TAVI procedures were analyzed.Two patients with progressive penetrating atherosclerotic ulcers (PAUs) in the descending thoracic aorta underwent sequential and simultaneous thoracic EVAR (TEVAR), respectively. One patient with stable PAU and 4 patients with not yet relevant abdominal aortic aneurysm (AAA) underwent isolated TF-TAVI. One patient with relevant AAA underwent TF-TAVI and sequential EVAR. Seven patients with previous EVAR due to an AAA underwent TF-TAVI (5 with a bifurcated graft and 2 with a straight graft). TF-TAVI and sequential or simultaneous TEVAR were technically successful in all patients. Vascular complications occurred in 1 patient. One patient died within 30 days and 2 patients died within 12 months.TF-TAVI can be performed successfully in patients with aortic disease or previous endovascular aortoiliac intervention. Simultaneous and sequential (T)EVAR is feasible.

ObjectiveIn implantable cardiac defibrillators (ICDs), long-detection times safely reduce unnecessary and inappropriate therapies. We aimed to evaluate ICD treatment of ventricular arrhythmias in women, compared with men, also taking into account ICD detection.MethodsThe Advance III trial randomised patients implanted with an ICD for primary or secondary prevention in two arms—long and nominal ventricular arrhythmias detection times before therapy delivering (number of intervals needed to detect (NID) 30/40 and 18/24, respectively). The main endpoint of this post hoc analysis was the incidence of ICD therapies evaluated through Kaplan-Meier method and univariate Cox regression models.ResultsOverall, 1902 patients (304 women, 65±11 years) were randomised. Women showed a lower risk of ICD therapy (HR 0.63, 95% CI 0.43 to 0.93, p=0.022); this difference was observed only in the long-detection arm (HR 0.37, p=0.013) and not in the short detection arm (HR 0.82, p=0.414). No significant sex differences were observed concerning inappropriate therapies and mortality rate. Long-detection settings significantly reduced overall ICD therapies and appropriate ICD therapies, both in women (overall HR 0.31, p=0.007; appropriate HR 0.33, p=0.033) and in men (overall HR 0.69, p=0.006; appropriate HR 0.73, p=0.048).ConclusionsIn patients with ICDs, the strategy of setting a long-detection time to treat ventricular arrhythmias (NID 30/40) reduces overall delivered therapies, both in women and men, when compared with nominal setting (NID 18/24). The reduction was significantly higher in women. Overall, women were less likely to experience ICD therapies than men; this result was only observed in the long-detection arm.Clinical trial registrationNCT00617175.

Aims A long-detection interval (LDI) (30/40 intervals) has been proved to be superior to a standard-detection interval (SDI) (18/24 intervals) in terms of reducing unnecessary implantable cardioverter defibrillator (ICD) therapies. To better evaluate the different impact of LDI and anti-tachycardia pacing (ATP) on reducing painful shocks, we assessed all treated episodes in the ADVANCE III trial. Methods and results A total of 452 fast (200 ms < cycle length ≤ 320 ms) arrhythmic episodes were recorded: 284 in 138 patients in the SDI arm and 168 in 82 patients in the LDI arm (106/452 inappropriate detections). A total of 346 fast ventricular tachycardias (FVT) were detected in 169 patients: 208 in 105 patients with SDI and 138 in 64 patients with LDI. Setting LDI determined a significant reduction in appropriate but unnecessary therapies [208 in SDI vs. 138 in LDI; incidence rate ratio (IRR): 0.61 (95% CI 0.45–0.83), P = 0.002]. Anti-tachycardia pacing determined another 52% reduction in unnecessary shocks [208 in SDI with hypothetical shock-only programming vs. 66 in LDI with ATP; IRR: 0.37 (95% CI 0.25–0.53, P < 0.001)]. The efficacy of ATP in terminating FVT was 63% in SDI and 52% in LDI ( P = 0.022). No difference in the safety profile (acceleration/degeneration and death/cardiovascular hospitalizations) was observed between the two groups. Conclusion The combination of LDI and ATP during charging is extremely effective and significantly reduces appropriate but unnecessary therapies. The use of LDI alone yielded a 39% reduction in appropriate but unnecessary therapies; ATP on top of LDI determined another 52% reduction in unnecessary shocks. The strategy of associating ATP and LDI could be considered in the majority of ICD recipients.

Aims Cardiac Contractility Modulation (CCM) is a treatment for heart failure based on electrical signals applied during the absolute refractory period. CCM improves myocardial molecular and biochemical characteristics of heart failure and improves exercise tolerance and quality of life. However, the long term impact on survival has not been described. Methods and results Survival was determined retrospectively from a cohort of 68 consecutive heart failure cases with NYHA II or III symptoms and QRS duration ≤130ms, implanted with a CCM device between May 2002 and July 2013 in either Bochum or Ludenscheid, Germany. Results were compared with predicted survival (Seattle Heart Failure Model; SHFM) pre-implant for each patient. Mean follow-up was 4.5years (range 0.25–10.3years). Baseline characteristics were as follows: mean age 61years, 88% male, 68% with ischemic heart disease, 78% with an ICD, mean NYHA class 2.9±0.3, LVEF 26%±6% (range 15–40%) and mean QRS duration 106±11ms. Mortality rates (Kaplan–Meier analysis) at 1-, 2- and 5-years were lower with CCM than predicted by SHFM for the cohort (0% with CCM vs. 6.1% per SHFM, 3.5% vs. 11.8%, and 14.2% vs. 27.7%, respectively, p=0.007). Conclusions Long-term mortality rates in heart failure patients with NYHA (II–III) and QRS≤130ms are lower when treated by CCM than predicted for the cohort. These findings warrant substantiation in a prospective study.

Background The impact of right ventricular (RV) lead location on clinical end points in patients undergoing cardiac resynchronization therapy (CRT) is unclear. We evaluated the impact of different RV lead locations on clinical outcome in CRT patients enrolled in the Septal Positioning of ventricular implantable cardioverter-defibrillator (ICD) Electrodes (SPICE) trial, which randomized recipients of implantable cardioverter defibrillators to apical versus midseptal RV lead positioning. Methods Ninety-eight CRT recipients were included in the multicenter SPICE trial and followed for 12 months: Fifty-three patients were randomized to receive an apical (A) and 45 to receive a midseptal (S) lead position. We compared echocardiographical and electrocardiographical parameters and outcome. Results Echocardiographic response with respect to improvement of left ventricular ejection fraction (A: +15.8 ± 14.6%, S: +9.7 ± 12.6%, P = 0.156) and reduction of left ventricular end-diastolic diameter (A: −4.2 ± 10.7 mm, S: −7.5 ± 10.7 mm, P = 0.141) was comparable in apical and midseptal groups. Paced QRS width neither differed at prehospital discharge (A: 129 ± 21 ms, S: 135 ± 21 ms, P = 0.133) nor at 12-month follow-up (A: 131 ± 23 ms, S: 134 ± 28 ms, P = 0.620). No differences were found with respect to the risk of ventricular tachyarrhythmia or ICD therapy. Septal RV lead position, however, was associated with a significant longer time to a first heart failure event (P = 0.040) and a longer survival time (P = 0.019). Conclusions In CRT recipients, midseptal RV lead position was not superior with respect to improvement of echocardiographic parameters or paced QRS width. It did not predispose to ventricular arrhythmias or ICD therapy. The finding that midseptal lead position was associated with a longer time to first heart failure event and a longer survival time deserves further investigation.

Aims Right ventricular (RV) septum is a non-apical site targeted during lead implantation. Electrocardiographic (ECG) recognition of mid-septal lead location is challenging. The aim of the study is to determine ECG correlates of RV mid-septal pacing. Methods and results The present study is a pre-specified analysis of a prospective, multicenter study, which randomized recipients of an implantable cardioverter defibrillator to an apical vs. mid-septal RV lead positioning. Following implantation, a 12-lead ECG was recorded during intrinsic rhythm and RV pacing. In total, 227 patients, 121 in the apical group (76.9% males, 67.1 ± 11.3 years) and 106 in the mid-septal group (82.1% males, age 64.7 ± 12.7 years) were included. Apically as compared with septally paced patients had significantly longer paced QRS duration (177.0 ± 25.0 vs. 170.4 ± 21.7, respectively, P = 0.03) and significantly more leftward paced QRS axis (−71.6 ± 33.3° vs. 9.4 ± 86.5°, respectively, P < 0.001). A significantly higher proportion of patients in the mid-septal as compared with the apical group displayed predominantly positive QRS in lead V6 (62.3 vs. 4.1%, P < 0.001), predominantly positive QRS in any of the inferior leads (53.8 vs. 4.1%, P < 0.001), and a QR pattern in lead aVL (53.3 vs. 3.3%, P < 0.001). These ECG correlates were incorporated in a stepwise algorithm with total sensitivity of 87% and specificity of 90% for the identification of a mid-septal lead location. Conclusion A mid-septal lead location may be identified using a simple stepwise algorithm, based on the presence of positive QRS in lead V6, positive QRS in any of the inferior leads, and a QR pattern in lead aVL.

Background Left bundle branch block (LBBB) and QT prolongation both are associated with a worse prognosis. LBBB lengthens the QT interval. To date it is not known whether QT prolongation during LBBB differs in repolarization from QT prolongation during narrow QRS. Objective The purpose of the present proof-of-concept-study was to develop a formula that allows comparison of the adjusted QT interval during LBBB with reference values and thereby allows interpretation of the QT interval irrespective of QRS widening. Methods Sixty consecutive patients with sinus rhythm (SR) and narrow QRS underwent electrophysiologic study for ablation. In all patients, the intrinsic QRS ,QT, and JT times were measured during SR, and ventricular pacing from both the right ventricular apex (RVA) and the right ventricular outflow tract (RVOT) caused LBBB. We determined prolongation of the QT during as compared to SR (ΔQT). ΔQT was then divided by the QRS length during pacing QRS (QRSb). This describes the percentage of the QRS duration at LBBB, which must be subtracted from the measured QT (QTb) to determine the modified QT interval (QTm). Results The ratio of ΔQT to paced QRS was calculated as 48.3% (RVA) and 48.8% (RVOT) (mean 48.5%). The ratio intrinsic of JTi to paced JT was 1.0055 (RVA) and 1.0087 (RVOT). There was no significant difference in intrinsic JT vs paced JT (P = .2). Conclusion Right ventricular pacing causes prolongation of the QT due to a paced LBBB without prolongation of the JT time. In our study, we showed that QT prolongation caused by LBBB constitutes 48.5% of the QRS width. This is the value that must be subtracted from the measured QT in LBBB in order to estimate the modified QT. Thus, the resulting formula for "modified QT" estimation in LBBB is QTm=QTb – 48.5% * (QRSb).

Electrocardiographic (ECG) identification of prior myocardial infarction (MI) during right ventricular (RV) pacing is of clinical importance. Proposed ECG criteria have been evaluated only during apical pacing. We evaluated the effect of pacing site on the predictive performance of ECG signs of prior MI.The present study is a secondary analysis of a prospective, multicenter study which randomized recipients of an implantable cardioverter defibrillator to an apical versus septal RV lead positioning. ECGs of patients with or without prior MI were analyzed for the presence of the following criteria: Cabrera sign, Chapman sign, QR pattern in leads I, aVL, V5 or V6, QR in inferior leads and notching in the descending slope of the QRS complex in inferior leads.The MI group included 89 patients (55.1% apically paced), while 99 patients had no prior MI (50.5% apically paced). In the total population, the Cabrera sign presented the highest specificity (97%) and diagnostic accuracy (62.2%), with a sensitivity of 23.6%. The Cabrera sign was the only significant predictor of a prior MI [OR=9.9, (95%CI:2.8-34.5), p0.001], among all ECG markers. Pacing site did not significantly influence the sensitivity and specificity of the Cabrera sign for detection of prior MI.In our study, the Cabrera sign was the only ECG marker that predicted the presence of prior MI during ventricular paced rhythm. Septal RV lead positioning did not affect the predictive performance of the Cabrera sign.

This study sought to evaluate the effects of programming a long detection in single-chamber (VVI) implantable cardioverter-defibrillators (ICDs) in the multicenter prospective ADVANCE III (Avoid DeliVering TherApies for Non-sustained Arrhythmias in ICD PatiEnts III) trial.Programming strategies may reduce unnecessary ICD shocks and their adverse effects but to date have been described only for dual-chamber ICDs.A total of 545 subjects (85% male; atrial fibrillation 25%, left ventricular ejection fraction 31%, ischemic etiology 68%, secondary prevention indications 32%) receiving a VVI ICD were randomized to long detection (30 of 40 intervals) or standard programming (18 of 24 intervals) based on device type, atrial fibrillation history, and indication. In both arms, antitachycardia pacing (ATP) therapy during charging was programmed for episodes with cycle length 320 to 200 ms and shock only for cycle length 200 ms. Wavelet and stability functions enabled. Therapies delivered were compared using a negative binomial regression model.A total of 267 patients were randomized to long detection and 278 to the control group. Median follow-up was 12 months. One hundred twelve therapies (shocks and ATP) occurred in the long detection arm versus 257 in the control arm, for a 48% reduction with 30 of 40 intervals (95% confidence interval [CI]: 0.36 to 0.76; p = 0.002). In the long detection arm, overall shocks were reduced by 40% compared to the control arm (48 vs. 24; 95% CI: 0.38 to 0.94; p = 0.026) and appropriate shocks by 51% (34 vs. 74; 95% CI: 0.26 to 0.94; p = 0.033). Syncopal events did not differ between arms, but survival improved in the long detection arm.Among patients implanted with a VVI ICD, programming with the long detection interval significantly reduced appropriate therapies, shocks, and all-cause mortality. (Avoid DeliVering TherApies for Non-sustained Arrhythmias in ICD PatiEnts III [ADVANCEIII]; NCT00617175).

Background Detrimental effects of right ventricular (RV) apical pacing have directed the interest toward alternative pacing sites such as the RV mid-septum. As safety data are scarce for implantable cardioverter defibrillator (ICD) recipients the study aims to evaluate ICD lead performance in the mid-septal position. Methods and results A total of 299 ICD recipients (79% male, aged 65.2±12.1years, 83% primary prevention of sudden cardiac death) were randomized to receive the RV ICD electrode either in a mid-septal (n=145) or apical (n=154) location. Event-free survival was evaluated at 3 (primary endpoint) and 12months (secondary endpoint). Events included a composite of lead revision, suboptimal right ventricular electrode performance (including defibrillation thresholds (DFT)>25J) or lead position not in accordance with randomized location. Event-free survival at 3 (12) months was observed in 80.6% (72.3%) of patients randomized to a mid-septal and in 82.2% (72.1%) of patients randomized to an apical lead position, p=0.726 (p=0.969). Pre-defined margins for non-inferiority were not reached at 3 or 12months. High DFT was found in 7 patients (5.0%) of the mid-septal and in 3 (2.2%) patients of the apical group (p=0.209). Conclusion In ICD recipients electrode positioning to the RV mid-septum or the RV apex results in slightly different rates concerning the survival free of lead revision, suboptimal right ventricular electrode performance or non-randomized lead position. Non-inferiority of the mid-septal lead location cannot be concluded. This should be taken into consideration when a mid-septal lead position is pursued. Clinical trial registration ClinicalTrials.gov identifier NCT00745745.

Background The survival of in-hospital cardiac arrest (8–25%) has not changed substantially in the past. Until now, most hospitals in Germany had no standardized protocols available for a course of action in case of emergency, and there are no continuous registry data for in-hospital cardiac arrest and survival. Objective Our aim was to improve survival and receive outcomes data, so we implemented a structured hospital-wide automated first-responder system in the hospital. Here our 5-year experience with 443 emergency calls is outlined. Methods Throughout the hospital, 15 automated external defibrillator (AED) “access spots,” which can be easily reached within 30 s, were identified. AEDs were then installed at these locations (Lifepak 500 and Lifepak 1000, Medtronic equipped with a Biolog 3000i portable ECG monitor). At the same time, a training program was initiated in which the employees of the hospital participated once a year. Participants learned how to apply and activate an AED in case of cardiac arrest even before the designated Cardiac Arrest Team arrived at the scene. Results A witnessed cardiac arrest event was confirmed in 126 cases. In 56 of the 126 cases, the primary arrest rhythm was either ventricular tachycardia or ventricular fibrillation and the AED delivered a shock. In this group, spontaneous circulation was reached in 44 cases (79%) and 23 patients (41%) were discharged. In 44% (24 from 55 patients) of the cases, a shock was recommended by AED and delivered by the first responders before the rescue team arrived. Conclusions The first-responder AED program successfully gave training lessons to the hospital staff. The training included how to initiate the cardiac arrest call, how to use the AED, and how to start immediate resuscitation. As a result, a higher survival rate after in-hospital cardiac arrest can be accomplished.

Cardiac contractility modulation (CCM) is an electrical stimulation treatment for symptomatic heart failure (HF) patients. The procedure involves implantation of two ventricular leads for delivery of CCM impulses. The purpose of this study is to compare the efficacy and safety of CCM when the signal is delivered through one vs. two ventricular leads.This prospective blinded randomized trial enrolled 48 patients. Eligible subjects had symptoms despite optimal HF medications, left ventricular ejection fraction40% and peakVOFollowing 6 months, similar and significant (p0.05) improvements from baseline in NYHA (-0.7±0.5 vs. -0.9±0.7) and MLWHFQ (-14±20 vs. -16±22) were observed in Group A and in Group B. PeakVOThe efficacy and safety of CCM in this study were similar when the signal was delivered through either one or two ventricular leads. These results support the potential use of a single ventricular lead for delivery of CCM.

Aims Cardiac resynchronization therapy (CRT) requires effective left ventricular (LV) pacing (i.e. sufficient energy and appropriate timing to capture). The AdaptivCRT™ (aCRT) algorithm serves to maintain ventricular fusion during LV or biventricular pacing. This function was tested by comparing the morphological consistency of ventricular depolarizations and percentage effective LV pacing in CRT patients randomized to aCRT vs. echo-optimization. Methods and results Continuous recordings (≥20 h) of unipolar LV electrograms from aCRT ( n = 38) and echo-optimized patients ( n = 22) were analysed. Morphological consistency was determined by the correlation coefficient between each beat and a template beat. Effective LV pacing of paced beats was assessed by algorithmic analysis of negative initial EGM deflection in each evoked response. The %CRT pacing delivered, %effective LV pacing (i.e. % of paced beats with effective LV pacing), and overall %effective CRT (i.e. product of %CRT pacing and %effective LV pacing) were compared between aCRT and echo-optimized patients. Demographics were similar between groups. The mean correlation coefficient between individual beats and template was greater for aCRT (0.96 ± 0.03 vs. 0.91 ± 0.13, P = 0.07). Although %CRT pacing was similar for aCRT and echo-optimized (median 97.4 vs. 98.6%, P = 0.14), %effective LV pacing was larger for aCRT [99.6%, (99.1%, 99.9%) vs. 94.3%, (24.3%, 99.8%), P =0.03]. For aCRT vs. echo-optimized groups, the proportions of patients with ≥90% effective LV pacing was 92 vs. 55% ( P = 0.002), and with ≥90% effective CRT was 79 vs. 45%, respectively ( P = 0.018). Conclusion AdaptivCRT™ significantly increased effective LV pacing over echo-optimized CRT.

Right bundle branch block (RBBB) configuration is an unexpected finding during right ventricular (RV) pacing that raises the suspicion of inadvertent left ventricular lead positioning. The aim of this study was to evaluate the prevalence of paced RBBB pattern in relation to RV lead location. This is a secondary analysis of a prospective, multicenter study, which randomized implantable cardioverter defibrillator recipients to an apical versus midseptal defibrillator lead positioning. A 12-lead electrocardiogram was recorded during intrinsic rhythm and RV pacing. Paced RBBB-like pattern was defined as positive (0.05 mV) net amplitude of QRS complex in leads V1 and/or V2. In total, 226 patients (65.6 ± 12.0 years, 20.8% women, 53.1% apical site) were included in the study. The prevalence of paced RBBB pattern in the total population was 15.5%. A significantly lower percentage of patients in the midseptal group demonstrated RBBB-type configuration during RV pacing compared with the apical group (1.9% vs 27.5%, p0.001). Baseline RBBB, prolonged QRS duration during intrinsic rhythm, and reduced ejection fraction were not associated with increased likelihood of paced RBBB. In the subgroup of patients with RBBB type during pacing, 91.4% of patients had a paced QRS axis from -30° to -90°, whereas 100% of patients displayed a negative QRS vector at lead V3. In conclusion, RBBB configuration is encountered in a considerable percentage of device recipients during uncomplicated RV pacing. Midseptal lead positioning is associated with significantly lower likelihood of paced RBBB pattern compared with apical location.

Modern pacemakers and implantable defibrillators provide a multitude of technical algorithms and parameters, which can be programmed individually and can treat different forms of arrhythmias. Stored electrograms offer the possibility to obtain valuable information during follow-up (but also in real-time) about arrhythmias and device function or malfunction. This results in improved treatment of cardiac arrhythmias and heart disease. Due to constant innovation and development of these systems, it requires, however, profound biomedical and technical knowledge, since stored electrograms may display complex arrhythmias and device reactions that are not easy to interpret. Understanding of stored device information improves follow-up and facilitates individual care for the patient.

After implanting a CRT device, consistent and scheduled patient follow-up is mandatory. Besides determining electrode parameters and reviewing arrhythmic episodes, these follow-ups focus on monitoring and optimizing congestive heart failure therapy. Therefore new CRT devices present methods for heart failure surveillance and telemetric transmission of the acquired data, which allows the physician to respond immediately to the varying needs of the respective heart failure patient. In addition to cardiac resynchronization, optimization of atrioventricular (AV) and interventricular (VV) delay provide major hemodynamic benefits. As echocardiographic optimization of AV and VV delay is time consuming it is often not feasible during daily clinical practice. Therefore implemented algorithms that automatically determine and adapt AV and VV delays with respect to the fluctuating needs of the patients are essential. This article presents the current state of monitoring and optimization methods in CRT devices.

Background: Cardiac contractility modulation (CCM) signals are non-excitatory electrical signals delivered during the absolute refractory period intended to improve contraction and cardiac function. Clinical trials have shown that CCM treatment significantly improves exercise tolerance and quality of life in symptomatic heart failure patients. Studies with CCM therapy typically include CCM delivery for 3, 5 or 7 h per day, although other configurations are also commonly used. Each has been associated with improved outcomes in heart failure, but it is not clear whether different application durations are associated with the various degrees of benefit. The purpose of the current pilot evaluation study was to evaluate the quality of life, exercise tolerance, and cardiac function, over a 6-month period when CCM was delivered for 5 h/day vs. 12 h/day. Increasing the daily CCM therapy duration is safe and as good as the standard CCM periods of application per day. Methods: This single center pilot evaluation study involved 19 medically refractory symptomatic patients with heart failure and reduced left ventricular function who underwent implantation of an Optimizer™ system (Impulse Dynamics, Orangeburg, NY, USA). Patients were randomized into one of two treatment groups; 5 h/day CCM treatment or 12 h/day CCM treatment. Subjects and evaluating physicians were blinded to the study group. Subjects returned to the hospital after 12 and 24 weeks. Efficacy evaluations included changes from baseline to 24 weeks in Minnesota Living With Heart Failure Questionnaire score (MLWHFQ), maximal oxygen consumption in the cardio-pulmonary stress test (peak VO2), New York Heart Association classification (NYHA), 6-min walk distance (6MWD), and ejection fraction (EF). Results: At the end of 24 weeks, clinical improvement was observed in the entire cohort in all efficacy measures (mean change from baseline of –17.1 in MLWHFQ, –0.86 in NYHA, and improvement trend of 1.48 mL O2/kg/min in peak VO2, 31.3 m in 6MWD, and 2.25% in EF). There were no significant differences, either clinically or statistically, between the groups receiving CCM for 5 h/day vs. 12 h/day. Three subjects were voluntarily withdrawn before completing the study. One subject died from pneumonia after 125 days, and 6 serious adverse events were reported, none of which was classified as related to either the device or the procedure. Conclusions: Together with previously reported experience with CCM, delivery of CCM therapy is equally safe and appears similarly effective over the range of shorter (5 h) to longer (12 h) daily periods of application. Given the small sample size, further studies are warranted.

The impact of right ventricular (RV) lead location on clinical end points in patients undergoing cardiac resynchronization therapy (CRT) is unclear. We evaluated the impact of different RV lead locations on clinical outcome in CRT patients enrolled in the Septal Positioning of ventricular implantable cardioverter-defibrillator (ICD) Electrodes (SPICE) trial, which randomized recipients of implantable cardioverter defibrillators to apical versus midseptal RV lead positioning.Ninety-eight CRT recipients were included in the multicenter SPICE trial and followed for 12 months: Fifty-three patients were randomized to receive an apical (A) and 45 to receive a midseptal (S) lead position. We compared echocardiographical and electrocardiographical parameters and outcome.Echocardiographic response with respect to improvement of left ventricular ejection fraction (A: +15.8 ± 14.6%, S: +9.7 ± 12.6%, P = 0.156) and reduction of left ventricular end-diastolic diameter (A: -4.2 ± 10.7 mm, S: -7.5 ± 10.7 mm, P = 0.141) was comparable in apical and midseptal groups. Paced QRS width neither differed at prehospital discharge (A: 129 ± 21 ms, S: 135 ± 21 ms, P = 0.133) nor at 12-month follow-up (A: 131 ± 23 ms, S: 134 ± 28 ms, P = 0.620). No differences were found with respect to the risk of ventricular tachyarrhythmia or ICD therapy. Septal RV lead position, however, was associated with a significant longer time to a first heart failure event (P = 0.040) and a longer survival time (P = 0.019).In CRT recipients, midseptal RV lead position was not superior with respect to improvement of echocardiographic parameters or paced QRS width. It did not predispose to ventricular arrhythmias or ICD therapy. The finding that midseptal lead position was associated with a longer time to first heart failure event and a longer survival time deserves further investigation.

The aim of this prospective study was to determine the impact of plasma B-type natriuretic peptide (BNP) on long-term outcome in patients undergoing transcatheter aortic valve implantation (TAVI).TAVI was performed either transfemorally or transaxillary using either the CoreValve prosthesis or Edwards SAPIEN prosthesis in 226 patients with symptomatic severe aortic valve stenosis and at high surgical risk. The examinations included measurements of plasma BNP and echocardiography before and at 30 days after TAVI. The primary study end-point was death from any cause after TAVI; the secondary end-point was defined as cardiovascular death.During a mean follow up of 728 ± 549 days, 72 patients died; 52 deaths were cardiovascular-related. Those patients who died had higher preprocedural plasma BNP levels compared to those who survived (1,305 ± 1,238 pg/ml versus 716 ± 954 pg/ml; p0.001). Plasma BNP was the strongest independent predictor of all-cause mortality (BNP475 pg/ml, hazard risk [HR] 3.049; 95% confidence interval [CI] 1.804-5.151; p0.001) and cardiovascular mortality (BNP475 pg/ml, HR 3.479; 95% CI 1.817-6.662; p0.001). In surviving patients, plasma BNP levels were decreased by 30 days after TAVI (pre-TAVI 874 ± 1,122 pg/ml; post TAVI 471 ± 569 pg/ml; p0.001). A plasma BNP level328 pg/ml at 30 days postoperatively was also associated with all-cause mortality (HR 8.125; 95% CI 3.097-21.318; p0.001).In patients undergoing TAVI, plasma BNP is the strongest independent predictor of all-cause mortality and cardiovascular mortality. Plasma BNP levels at 30 days after TAVI may provide prognostic information that should, potentially, lead to a more intensive therapy of these patients.

In order to obtain a better physiological performance and a closer restoration of the regular rhythm of failing hearts, a new fiber optical sensor system for the measurement of cardiac contraction has been developed. It consists of an opto-electrical unit and a sensing fiber which has to be positioned in the heart. The objective of this new fiber optic sensor system is to use the inotropic information to adjust a stimulation algorithm in single or multichamber pacing or to detect arrhythmia in insufficient heart function. In this study, the mechanical and optical characteristics of different fibers are investigated. The relationship between the attenuation (with an achieved numerical maximum of 0.3 dB), the bending diameter and the angle of bending is determined in a range of 20-160 mm. The most suitable fiber for the application in cardiological problems is determined (WT8 fiber), for which the sensitivity is analyzed. Additionally, power spectra are calculated from WT8 fiber signals obtained from pig hearts, working under physiological conditions. The maximal frequency response was 23 Hz. It is concluded that the fiber optical measurement of cardiac contraction is not only feasible and reproducible, but the WT8 fiber also shows optimal behavior in the range of parameters occurring in the heart chambers. Nevertheless, in order to restrict the measured signal reliably to bending processes within the chambers only, it is concluded that a special combined fiber has to be constructed with a high sensitivity only at its terminal section within the heart.

The cardio-circulatory system of chronotropic incompetent patients is unable to adapt heart rate adequately to the level of strain. A common therapy is the implantation of a pacemaker that stimulates the heart at a rate derived from a strain related sensor signal. The paper describes a new pacemaker concept that uses a well-defined time interval in the electrogram as a sensor parameter, the atrioventricular conduction time (AVCT). Identification experiments with patients delivered the stationary and dynamic behaviour of AVCT subject to variations in the exercise rate and the pacing frequency. Furthermore, it was demonstrated that AVCT is perturbed by respiratory activity. The new rate-responsive algorithm, which uses the internal model control principle, explicitly takes into account the closed-loop nature of the underlying system. The major design objectives were: extended range of the individual heart rate; effective attenuation of the respiratory-related disturbance; and stability. Seven patients undergoing incremental exercise were paced with this AVCT-based algorithm. The experiments confirmed the suitability of this concept with respect to the design goals. The patients' peak intrinsic heart rate at exercise was 100 +/- 20min(-1). When paced with the AVCT algorithm, the paced heart rate was 126 +/- 12min(-1). The increase was significant (26 +/- 13min(-1); 15 to 53 min(-1)), which clearly demonstrated the potential of this concept to restore chronotropic competence.

Ergänzend zum intrakardialen EKG sollten hämodynamische Größen zur Steuerung von Herzschrittmachern und implantierbaren Defibrillatoren genutzt werden. Zu diesem Zweck wurde ein faseroptisches Messsystem entwickelt, welches über die optische Biegedämpfung die mechanische Herzkontraktion misst. Bei Untersuchungen an einem isoliert schlagenden Schweineherzen wurde eine gute Korrelation des Sensorsignals mit dem linksventrikulären Schlagvolumen nachgewiesen.

Commercially available cardiac pacemakers and implantable cardioverters/defibrillators (ICD) predominantly use the intracardiac derived electrocardiogram (ECG) for detection of arrhythmias. To achieve an automatic control of the heart frequency in accordance with cardiovascular strain and an improved detection of life-threatening arrhythmias, it is desirable to monitor the heart by an input signal correlated with the hemodynamic state. One possible approach to derive such a signal, is to measure the inotropy (mechanical contraction strength of the heart muscle). For this purpose an optoelectronic measurement system has been designed. The fundamental function of the system has been shown in earlier investigations using an isolated beating pig heart. In this paper further results showing the correlation of the fiberoptic sensor signal with the left ventricular stroke volume are presented. To make the system useful for implantable devices, further improvements with regard to power consumption and signal quality were achieved.

Patients suffering from chronotropic incompetence are generally treated with a rate-responsive pacemaker that stimulates the heart at a rate derived from a strain related sensor signal. The pacemaker concept described here uses a well-defined time interval in the electrogram as sensor parameter (AVCT: atrio-ventricular conduction time). AVCT is directly controlled by the autonomic nervous system. The design of the new algorithm was based on a thorough experimental analysis of AVCT subject to variations of the exercise rate and the pacing frequency. There it was demonstrated that AVCT is disturbed by the respiratory activity. The new rate-responsive algorithm which uses the internal model control principle explicitly takes into account the closed-loop nature of the underlying system. The major design objectives were: a) extended range of the individual heart rate, b) effective attenuation of the respiratory related disturbance and c) dynamic stability. Seven patients undergoing an incremental exercise test were paced with the new AVCT-based algorithm. When paced with this algorithm the paced heart rate was 126 +/- 12 min(-1) whereas the peak intrinsic heart rate was only 100 +/- 20 min(-1). The increase which was significant (26 +/- 13 min(-1); 15.53 min(-1)) clearly demonstrated the potential of this concept to restore chronotropic competence. A reanalysis of the experiments was undertaken in order to facilitate the individual parameterization in clinical practice. It could be demonstrated that a rather simple screening test is sufficient to gain the knowledge necessary for the individual parameterisation.

Innovative fibre-optic sensor technology for measuring the movement of the myocardial walls, and from this the heart chamber volumes, was developed. An optical fibre, with a mirror at its end, is inserted into a catheter located in the heart. An opto-electrical control unit positioned outside the heart contains both the light source and the signal receiver. It generates and couples the light into the fibre and transforms and analyses the reflected signal. With such a system, the movement of the cardiac wall can be continuously measured during each cycle, because the fibre moves synchronously with the heart, and this movement bends the fibre, changing the optical attenuation. Experiments where the fibres were wound around metal cylinders of different diameters revealed a maximum sensitivity of 4% mm(-1), diameter. The noise signal corresponded to about 1% of the diameter. First tests in a working pig heart showed a high correspondence of the fibre signal with cardiac parameters. Although these tests are promising, further long-term, extensive experiments in preclinical test devices, and later in clinical tests, must be carried out before the new sensor is used in clinical practice. The fibre-optic technique could be used in monitoring devices, assist devices, pacemaker systems or cardioverter defibrillators.