Refine
Year of publication
Document Type
- Conference Proceeding (58)
- Book (7)
- Article (unreviewed) (7)
- Article (reviewed) (5)
- Contribution to a Periodical (3)
- Part of a Book (1)
- Patent (1)
Conference Type
- Konferenz-Abstract (46)
- Konferenzartikel (10)
- Konferenz-Poster (1)
- Sonstiges (1)
Language
- English (63)
- German (18)
- Other language (1)
Is part of the Bibliography
- yes (82) (remove)
Keywords
- Abtragung (6)
- Defibrillator (5)
- Herz (5)
- Kardiale Resynchronisationstherapie (5)
- Elektrokardiogramm (4)
- Herzkrankheit (3)
- Herzschrittmacher (3)
- Hochfrequenztechnik (3)
- Katheter (3)
- Medizintechnik (3)
Institute
Open Access
- Open Access (36)
- Closed Access (27)
- Closed (4)
About 20% of those heart failure patients receiving cardiac resynchronization therapy (CRT) are in atrial fibrillation (AF). Current guidelines apply for patients in sinus rhythm only. Recent studies have shown again, that successful resynchronization is closely linked to a pre-existent ventricular desynchronization. In those studies, the interventricular conduction delay (IVCD) was determined prior to device implantation by ultrasound in patients with sinus rhythm (SR)only. In patients with AF this method ́s use is limited.
To implement left-heart electrogram (LHE) into standard programmers and to simplify IVCD measurement in heart failure patients with AF, LHE was recorded in 11 AF patients with heart failure by Biotronik ICS3000 programmer via a15Hz Butterworth high-pass filter. Therefore, TOslim esophageal electrode (Dr. Osypka GmbH, Rheinfelden, Germany) was perorally applied and fixed in position of maximal left ventricular defection. IVCD was measured between onset of QRS in surface ECG and left ventricular defection (LV) in LHE. In addition, intra-left ventricular conduction delay (ILVCD) was measured as duration of LV in LHE.
In all of the 11 AF patients, desynchronization was quantifiable by LHE. Mean QRS of 162 ± 27ms (120-206ms) was linked with IVCD of 62ms ± 27ms (37-98ms) and ILVCD of 110 ± 20ms (80-144ms), at mean. Correlation between IVCD and QRS was 0.39 (n. s.) with IVCD/QRS ratio of 0.38 ± 0.11 (0.22-0.81).
A 15Hz high-pass filtered LHE feature of the Biotronik ICS3000 programmer is feasible to quantify ventricular dyssynchrony in heart failure patients with AF in order to clearly indicate implantation of CRT systems. As relations between QRS duration, IVCD and ILVCD considerably differ interindividually, the predictive values of IVCD, ILVCD and IVCD/QRS ratio for individual CRT response or non-response shall be identified in follow-up studies.
Semi-invasive electromechanical target interval to guide left ventricular electrode placement
(2011)
Cardiac resynchronization therapy (CRT) with biventricular pacing (BV) is an established therapy for heart failure (HF) patients with inter- and intraventricular conduction delay. The aim of this pilot study was to test the feasibility of both transesophageal measurement of left ventricular (LV) electrical delay and transesophageal LV pacing prior to implantation, to better select patients for CRT.
ECG simulators, available on the market, imitate the electric activity of the heart in a simplified manner. Thus, they are suitable for education purposes but not really for testing algorithms to recognize complex arrhythmias needed for pacemakers and implantable defibrillators. Especially certain discrimination between various morphologies of atrial and ventricular fibrillation needs simulators providing native electrograms of different patients’ heart rhythm events. This explains the necessity to develop an ECG simulator providing high-resolution native intracardiac and surface electrograms of in-vivo rhythm events. In this paper we demonstrate an approach for an ECG simulator based on a consumer multichannel soundcard and a corresponding software application for a laptop computer. This Live-ECG Simulator is able to handle invasive electrogram recordings from electrophysiological studies and send the data to a modified external soundcard for subsequent digital to analog conversion. The hardware is completed with an electronic circuit providing level adjustment to adapt the output amplitude to the input conditions of several cardiac implants.
AV delay (AVD) optimization is mandatory in cardiac resynchronization (CRT) for heart failure. Several time consuming methods exist. We initialized development of left-atrial electrogram (LAE) feature for Biotronik ICS3000 programmer. It can be utilized to approximate optimal AV delay in CRT patients with pacing systems irrespective of make and model. Using this feature, we studied the share of interatrial conduction intervals (IACT) on individual echo AVD in 45 CRT patients (34m, 11f, mean age 69±6yrs.). The percentage of IACT on optimal echo AVD resulted in44.5±22.1% for VDD and 70.7±10.9% for DDD operation. In all patients, optimal echo AVDs exceeded the individual IACT by a duration of 52.5±33.3ms (p<0.001), at mean. Therefore, if AV delay optimization is not possible or not practicable in CRT patients, AVD should be approximated by individually measuring IACT and adding about 50ms.
AV delay (AVD) optimization can improve hemodynamics and avoid nonresponding to cardiac resynchronization therapy (CRT). AVD can be approximated by the sum of the individual implant-related interatrial conduction interval and a mean electromechanical interval of about 50ms. We searched for methods to facilitate automatic, implant-based AV delay optimization. In 25 patients (19m, 6f, age: 65±8yrs.) with Medtronic Insync III Marquis CRT-D series systems and left ventricular electrode at lateral or posterolateral wall, we determined interatrial conduction intervals by telemetric left ventricular tip versus superior vena cava coil electrogram (LVCE). Compared with esophageal measurements, the duration of optimal AV delay by LVCE showed good correlation (k=0.98, p=0.01) with a difference of 1.5±4.9ms, only. Therefore, LVCE is feasible to determine interatrial conduction intervals in order to automate AV delay optimization in CRT-D pacing promising increased accuracy compared to other algorithms.
Introduction: Cardiac resynchronization therapy (CRT) with biventricular pacing is an established therapy for heart failure (HF) patients with sinus rhythm and ventricular desynchronisation. The aim of this study was to evaluate interventricular conduction delay (IVCD) and interatrial conduction delay (IACD) before and after premature ventricular contractions (PVC) in HF patients.
Methods: 13 HF patients (age 68 ± 10 years; 2 females, 11 males) with New York Heart Association functional class 2,8 ± 0.5, left ventricular (LV) ejection fraction 28,6 ± 12,6 %, 154 ± 25 ms QRS duration and PVC were analysed with bipolar transesophageal LV and left atrial electrogram recording and National Instruments LabView 2009 software. The level of significance of the t-test is 0,005.
Results: QRS duration increases during PVC (188 ± 32 ms) in comparison to the beat before (154 ± 25 ms, P = ) and after PVC (152 ± 25 ms,). IVCD increases during PVC up to 65 ± 33 ms (51 ± 19 ms in the beat before PVC, P=0.18, 49 ± 19 ms after PVC, P = 0.12). Intra-LV delay of 90 ± 16 ms is not different in the beat before PVC, 90 ± 14 ms during PVC (P = 0.99) and 94 ± 16 ms in the beat after PVC (P = 0.38). IACD is not significantly PVC influenced (67 ± 12 ms before PVC and 65 ± 13 ms after PVC, P = 0.71). Intra-left atrial conduction delay is not significant longer during PVC (57 ± 28 ms) than in the beat before PVC (54 ± 13 ms, P = 0.51) or after PVC (54 ± 8 ms, P = 0.45). PQ duration increases significantly after PVC (224 ± 95 ms) in comparison to the beat before PVC (176± 29 ms, P =...).
Conclusion: Transesophageal left cardiac electrocardiography with LabView 2009 software can improve evaluation of IVCD and IACD before, during and after PVC in HF patient selection for CRT.
In cardiac resynchronization therapy (CRT) for heart failure, individualization of the AV delay is essential to improve hemodynamics and to minimize non-responder rate. In patients in sinus rhythm having additional disposition to bradycardia, optimization is necessary for both situations, atrial sensing and pacing. Therefore, echo-optimization is the goldstandard but time consuming. Unfortunately, it depends on the particular CRT systems parameter set if the resulting individually optimal AV delays can be programmed or not. Some CRT systems provide a set of AV delays for DDD operation combined with a set of the pace-sense-compensation to optimize the AV delay in DDD and VDD operation. The pace-sense-compensation (PSC) can be defined by the difference of implant-related interatrial conduction intervals in DDD and VDD operation measured in the esophageal left atrial electrogram. In a cohort of 96 CRT patients we found mean PSC of 59-35ms ranging between 0-143ms. As a consequence, allowing 10ms tolerance, AVD optimization is completely impossible in one of the two modes, VDD or DDD operation, in 34 (35%) or 5 (5%) patients with implants restricting the PSC range to 60ms or 100ms, respectively. Thus, we propose companies to provide CRT systems with programmable pace-sense- compensation between 0ms and 150ms.