Ventricular Automatic Capture Research Articles

Clinical use of automatic pacemaker algorithms: results of the AUTOMATICITY registry

Follow-up of the ever-increasing numbers of patients with implantable cardiac devices places a heavy burden on clinical departments. Device automaticity may alleviate the follow-up burden by minimizing the time for physician involvement. The aim of the prospective, multicentre AUTOMATICITY registry was to examine the performance of a subset of programmed automatic algorithms during patient follow-up and their acceptance by implanting physicians. The clinical use of automatic algorithms from the Insignia pacemakers (PM; Boston Scientific, St Paul, MN, USA) was evaluated: atrial and ventricular AutoSense (sensitivity adjustment), ventricular Automatic Capture (threshold verification and output setting), AutoLifeStyle (sensor settings adjustment). The objective of the study was to assess the reprogramming rates within 12 months of implant, the reasons for reprogramming and relationship to adverse events. A total of 960 patients were enrolled in the study. The proportion of patients free from any algorithm reprogramming at 12 months was 86.1%. A total of 2736 algorithms were activated at enrolment, with 156 (5.7%) being reprogrammed in 115 patients at 12 months for any reason. Forty-nine reprogrammings (1.8%) were unintentional or related to changes in device settings such that the algorithm was no longer available, 33 (1.2%) were due to suspected sensing issues, and 22 (0.8%) were assumed related to the algorithm. The individual 12-month reprogramming-free rates were: ventricular AutoSense 94.3%, Atrial AutoSense 93.3%, AutoLifeStyle 93.9%, and Automatic Capture 95.9%. The results of the AUTOMATICITY registry show that automatic measurement of key settings and automatic adjustment to optimal programming is feasible and safe. The simplicity of PM follow-up and avoidance of frequent reprogramming may contribute to a more effective use of hospital time and resources.

209 How automatic algorithms are used in daily medical practice in dual chamber pacemaker recipients? Intermediate results from a prospective registry

Automatic algorithms in pacemakers (PM) allow continuous adaptation of settings to patients’ clinical conditions. Some are dedicated to pacing and others to sensing. One of the objectives of BELUGA on-going, international, prospective registry was to evaluate the use of automatic algorithms available in Insignia™ PM in current medical practice. The percentage (%) of activation of atrio-ventricular search hysteresis algorithm (AVSH), dynamic AV delay (DynAVD), automatic atrial/ventricular sensing (AAS/AVS), ventricular automatic capture (VAC) and the % of use of automatic ventricular threshold test during patients assessment (AVT) are reported at enrolment (Enrol), 3-6 months (FU1) and 9-12 months (FU2) in patients with dual chamber PM (pts). Up to now 804 pts were enrolled and followed during 9.5±3.9 months (age 76±9 years, 57% male, PR interval 196±34 ms, 40% sinus node dysfunction, 27% bradycardia/tachycardia syndrome, 10% 1°AV block, 33% paroxysmal 2° or 3° AV block). PM programming was left to the discretion of the investigator. Atrial and ventricular automatic sensing algorithms were used in less than half of the pts without any increase over the time. During follow-up, ventricular automatic capture algorithm and ventricular automatic threshold test were increasingly used (p<0.01). DynAVD and AVSH were continuously activated in most of the pts (see table).ParameterAAS on (%)AVS on (%)VAC on (%)AVT (%)AVSH on (%)DynAVD on (%)Enrol464069648597FU1453974688797FU2464076718797p (Enrol vs FU2)nsns<0.01<0.01nsns Intermediate results of this study show that automatic algorithms were currently used by the investigators when directly dedicated to right ventricular pacing. However, automatic algorithms dedicated to sensing appeared to be less used in daily medical practice.

Acute performance evaluation of a new ventricular automatic capture algorithm

This study evaluated the acute clinical performance of a new ventricular automatic capture algorithm developed to work with all lead types and pacing vectors. 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 (33 DDD/20 VVI) from four medical centres were analysed. Tested leads included 43 BP and 10 UP from nine manufacturers, and seven had electrodes with low polarization. The rate of successful commanded and ambulatory AutoThreshold tests was 96 and 94%, respectively, with an average absolute threshold difference compared with manual threshold of < 0.1 V at 0.4 ms (commanded 0.07 +/- 0.07 V and ambulatory 0.08 +/- 0.07 V). There was no significant difference in performance between UP/BP pacing, polarization, and lead type. No loss-of-capture event was observed. When successful, the ventricular automatic capture algorithm accurately determined pacing thresholds in either a UP or BP pacing configuration among all leads tested.

Clinical Performance of a Ventricular Automatic Capture Verification Algorithm

This study was conducted to evaluate the clinical performance of the ventricular automatic capture feature as implemented in the Insignia I Ultra pacemaker system (Guidant) utilizing a variety of ventricular leads. Currently, the optimal programming of the pacemaker output considers both pacemaker efficiency (prolonging battery longevity) and patient safety (adequate safety margin). The ability of a pacemaker to automatically adjust the ventricular output above the pacing threshold while maintaining the appropriate safety margin has been explored since the early 1970s and is only available today in conjunction with a specific low polarization lead system. One hundred and five patients were enrolled from 17 European centers utilizing 31 different types of ventricular leads were followed through their 3-month follow-up visit. There were no restrictions on the type of ventricular leads used. The average mean difference between the commanded autothreshold test (0.652 + 0.335 V) and the manual threshold test (0.651 + 0.335 V) was 0.001 + 0.49 (P < 0.0001). The average mean difference between the ambulatory autothreshold test (0.696 + 0.322 V) and the commanded autothreshold test (0.682 + 0.315 V) was 0.002 + 0.74 (P < 0.0001). Holter recordings confirmed that there were no loss of capture incidences without a backup pulse being delivered. In addition, the mean number of backup pulses delivered in a 24-hour period was less than 0.1% of the total number of paced beats. This study provided that the automatic capture feature while using a variety of leads accurately determines the ventricular stimulation threshold and safely delivers a backup pulse when required.

514 Effects of ventricular automatic capture on device longevity in dual chamber rate responsive pacemakers

514 Effects of ventricular automatic capture on device longevity in dual chamber rate responsive pacemakers

514 Effects of ventricular automatic capture on device longevity in dual chamber rate responsive pacemakers

514 Effects of ventricular automatic capture on device longevity in dual chamber rate responsive pacemakers

Epicardial patch lead and ventricular automatic capture in permanent pacemakers: a case report

PURPOSE Permanent pacemakers implants with epicardial patch leads may give problems of high pacing threshold or threshold variability, often requiring a device programming with maximum energy output for adequate safety margin. An automatic capture algorithm, ensuring a “beat to beat” check of ventricular pacing threshold would be useful in these patients only if the signal characteristics of epicardial lead can warrant correct functioning of the system. These leads usually have lower impedance and lower sensing if compared to endocardial leads. METHODS One patient implanted with epicardial lead (Medtronic 4965) underwent pacemaker replacement and has been implanted with INSIGNIA pacemaker (GUIDANT Corp.) with automatic capture algorithm active. This algorithm is specifically designed for use with a wide range of polarization signals and with different lead types. RESULTS At 1 month follow up, daily data on ventricular threshold (T), impedance (I) and amplitude (A) were retrived from device diagnostics (T=1.3±0.3 V; I=320±10 . ; A=2.5±1.1 mV). Despite low amplitude signal and impedance, automatic capture detected correctly ventricular threshold during the whole follow up period. CONCLUSION Automatic capture algorithm may have a good opportunity of application in patients implanted with epicardial patches leads, allowing increased pacemaker lifetime and adequate pacing safety margin.

Evaluation of Fusion Beat Detection with a New Ventricular Automatic Capture Algorithm in ICDs

This study evaluated a newly developed automatic capture verification scheme for implantable cardioverter defibrillators (ICDs) regarding discrimination of capture, fusion, and noncapture beats, with an emphasis on fusion detection. The algorithm uses evoked response detection based on a sensing vector from right ventricular shocking coil to Can. Patients undergoing ICD implant or replacement were enrolled in this study. An external system was used for pacing and data acquisition. To provoke ventricular fusion beats, VVI patients were paced close to the rate of their intrinsic rhythm and DDD patients were paced close at their intrinsic PR interval. Surface ECG and wideband filtered intracardiac electrograms were recorded for off-line analysis. Each paced beat was independently classified visually by surface ECG and by the automatic detection algorithm. The algorithm performance was then evaluated by comparing the classification results. Twenty-seven patients (22 males, 5 females; 63.8 +/- 12.5 years) were analyzed. Device and lead demographics were: 18 DDD/9 VVI; 16 dedicated bipolar, 11 integrated bipolar leads; 18 acute, 9 chronic (3.7 +/- 2.0 years) leads. In total, 2064 beats were analyzed, including 1,477 fusion beats and 587 capture beats. Fusion detection sensitivity and specificity were 99.5% and 99.0%, respectively. Seven true-fusion beats (0.5%) were classified as capture and 6 capture beats (1.0%) were identified as fusions. Capture or fusion beats were never detected as non-capture beats. It is concluded that the algorithm was effective in detecting fusion beats. It could potentially be used in ICD applications that need accurate fusion detection.

P-376 A new algorithm for ventricular automatic capture detection in ICDS

P-376 A new algorithm for ventricular automatic capture detection in ICDS

P-376 A new algorithm for ventricular automatic capture detection in ICDS

P-376 A new algorithm for ventricular automatic capture detection in ICDS

Ventricular automatic capture algorithm. Assessment of the logos system in different temporary and implanted leads

Ventricular automatic capture algorithm. Assessment of the logos system in different temporary and implanted leads

Ventricular automatic capture algorithm. Assessment of the logos system in different temporary and implanted leads

Ventricular automatic capture algorithm. Assessment of the logos system in different temporary and implanted leads