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Termination of atrial flutter (AFL) is not possible in all AFL patients (P) with transesophageal left atrial pacing (TLAP) with undirected electrical pacing field (EPF) and high atrial pacing threshold. Purpose of the study was to evaluate bipo-lar transesophageal left atrial electrocardiography (TLAE) and TLAP with directed EPF for evaluation and termination of AFL with and without simultaneous transesophageal echocardiography (TEE).
Methods: AFL P were analysed using either a TO electrode with one cylindrical (CE) and three or seven hemispherical electrodes (HE) or TEE electrode with four HE (Osypka, Rheinfelden, Germany). Burst TLAP cycle length was between 200msand 50ms.
Results: AFL cycle length was 233±30 ms with mean ventricular cycle length of 540±149 ms. AFL could be terminated by rapid bipolar TLAP with directed EPF using HE-HE and CE-HE with induction of atrial fibrillation (AF), induction of AF and spontaneous conversion to sinus rhythm and direct conversion to sinus rhythm. Directed EPF was simulated with finite element method.
Conclusions: AFL can be evaluated by bipolar TLAE. AFL can be terminated with rapid TLAP with directed EPF with and without simultaneous TEE. Bipolar TLAE with rapid TLAP is a safe, simple and useful method for evaluation and termination of AFL.
Introduction: Cardiac resynchronization therapy (CRT) with left ventricular (LV) pacing is an established therapy for heart failure (HF) patients (P) with ventricular desynchronisation and reduced LV ejection fraction (EF). The aim of this study was to test the utilization of the transesophageal approach to measure arterial pulse pressure (PP) during LV pacing and electrical interventricular conduction delay (IVCD), to better select patients for CRT.
Methods: 32 HF patients (age 64 ± 10 years; 5 females, 27 males) with New York Heart Association (NYHA) class 2.8 ± 0.6, 27 ± 11 % LV EF and 155 ± 35 ms QRS duration were analysed with semi-invasive left cardiac pacing and electrocardiography. Esophageal TO8 Osypka catheter of 10.5 F diameter was perorally applied to the esophagus and placed in the position of maximum left atrial (LA) deflection and maximum LV deflection to measure PP with VAT or D00 pacing modes.
Results: Temporary transesophageal LV pacing was possible with VAT mode (n=16) and D00 mode (n=16) in all patients. In 15 Δ-PP-responders, PP was higher during LV pacing on than LV pacing off (78.3 ± 26.6 versus 65.9 ± 23.7 mmHg, P < 0.001) and NYHA class improved from 3.1 ± 0.35 to 2.1 ± 0.35 (P < 0.001) during 29 ± 26 month biventricular (BV) pacing follow-up (6 Medtronic and 9 Boston BV pacing devices). In 17 Δ-PP-non-responders, PP was not higher during LV pacing on than LV pacing off (61.5 ± 23.9 versus 60.9 ± 23.5 mmHg, P = 0.066). IVCD was significant longer in Δ-PP-responders than in Δ-PP-non-responders (87 ± 33 ms versus 37± 29 ms, P < 0.001).
Conclusion: Semi-invasive transesophageale LA and LV pacing with D00 and VAT mode and LV electrogram recording may be useful techniques to predict CRT improvement.
Introduction: Cardiac resynchronisation therapy (CRT) with atrioventricular (AV) and interventricular (VV) optimized biventricular pacing (BV) is an established therapy for heart failure (HF) patients with electrical interventricular conduction delay (IVCD). The aim of the study was to compare AV and VV delay optimization with cardiac output (CO) and acceleration index (ACI) impedance cardiographic (ICG) methods.
Methods: HF patients with IVCD 86.8 ± 33 ms (n=15, age 66 ± 10 years; 2 females, 13 males), New York Heart Association (NYHA) functional class 3.1 ± 0.4, left ventricular (LV) ejection fraction 21.3 ± 7.8 % and QRS duration 176.1 ± 31.7 ms underwent AV and VV delay optimization with CO and ACI methods (Cardioscreen, Medis GmbH, Ilmenau, Germany). After evaluation of optimal AV delay, we evaluated optimal VV delay during simultaneous LV and right ventricular (RV) pacing (LV=RV), LV before RV pacing (LV-RV) and RV before LV pacing (RV-LV).
Results: Optimal VV delay was -12.3 ± 25.9 ms LV-RV pacing with VV delay range from -80 ms LV-RV pacing to +20 ms RV-LV pacing and RV=LV pacing. Optimal AV delay after atrial sensing was 108.6 ± 20.3 ms (n=14) and optimal AV delay after atrial pacing 190 ± 14.1 ms (n=2) with AV delay range from 80 ms to 200 ms. RV versus BV pacing mode resulted in improvement of CO from 3.4 ± 1.2 l/min to 4.4 ± 1.4 l/min (p<0.001) and ACI from 0.667 ± 0.227 1/s² to 0.834 ± 0.282 1/s² (p<0.002). During 34 ± 26 month BV pacing, the NYHA class improved from 3.1 ± 0.4 to 2.1 ± 0.4 (p<0.001).
Conclusion: AV and VV delay optimized BV pacing acutely improve ICG CO and ACI and their NYHA class during long-term follow-up. ICG may be a simple and useful technique to optimize AV and VV delay in CRT.
Introduction: Cardiac resynchronisation therapy (CRT) with atrioventricular (AV) and interventricular (VV) optimized biventricular pacing (BV) is an established therapy for heart failure (HF) patients. The aim of the study was to compare AV and VV delay optimization with cardiac output (CO), cardiac index (CI), contractility index (IC) and acceleration index (ACI) impedance cardiographic (ICG) methods in CRT.
Methods: 15 HF patients (age 66 ± 10 years; 2 females, 13 males) in New York Heart Association (NYHA) class 3.1 ± 0.4, left ventricular (LV) ejection fraction 21.3 ± 7.8 % and QRS duration 176.1 ± 31.7 ms underwent AV and VV delay optimization with CO, CI, IC and ACI (Cardioscreen ®, Medis GmbH, Ilmenau, Germany) at different AV and VV delay BV pacing settings versus right ventricular (RV) pacing one day after implantation of a CRT device.
Results: Optimal AV delay after atrial sensing was 108.6 ± 20.3 ms (n=14) and optimal AV delay after atrial pacing 190 ± 14.1 ms (n=2) with AV delay range from 80 ms to 200 ms. Optimal VV delay was -12.3 ± 25.9 ms left ventricular before RV pacing. RV versus BV pacing mode resulted in improvement of CO from 3.4 ± 1.2 l/min to 4.4 ± 1.4 l/min (p<0.001), CI from 1.8 ± 0.64 l/min/m² to 2.4 ± 0.78 l/min/m² (p<0.001), IC from 0.028 ± 0.011 1/s to 0.036 ± 0.013 1/s (p<0.001) and ACI from 0.667 ± 0.227 1/s² to 0.834 ± 0.282 1/s² (p<0.002). During 34 ± 26 month BV pacing, the NYHA class improved from 3.1 ± 0.4 to 2.1 ± 0.4 (p<0.001).
Conclusion: AV and VV delay optimized BV pacing acutely improve hemodynamic parameters of transthoracic ICG and their NYHA class during long-term follow-up. ICG may be a simple and useful technique to optimize AV and VV delay in CRT.
Using guideline parameters for indication of cardiac resynchronization therapy (CRT), only about two thirds of the patients improve clinically. Unfortunately both, surface ECG and echo are uncertain to predict CRT response. To better characterize cardiac desynchronization in heart failure, interventricular (IVCD) and intra-leftventricular conduction delays (ILVCD) were measured by esophageal left ventricular electrogram (LVE). Recordings in 43 CRT patients (34m, 9f, age: 64.7 ± 9.5yrs) evidenced only weak correlation between IVCD and QRS of 0.53 and between ILVCD and QRS of 0.33. This demonstrated that QRS duration is not a reliable indicator of desynchronization. Therefore, the study resulted into development of LVE feature for a programmer with implant support device. It can be used interoperatively to guide the left ventricular electrode location in order to increase responder rate in CRT.
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.
Electrical velocimetry to optimize VV delay in biventricular VVIR and DDD pacing for heart failure
(2011)
Introduction: VV delay (VVD) is the only parameter to hemodynamically optimize cardiac resynchronization therapy (CRT) for patients with atrial fibrillation (AF). Electrical velocimetry (EV) has been established to monitor thoracic electrical conductivity and to calculate hemodynamic surrogate parameters. We compared the response of this method to hemodynamic parameter changes between CRT patients with sinus rhythm (SR) and patients with AF.
Methods: VVD was individualized in 17 CRT patients in SR (12m, 5f, 67.0±7.2yrs.) after echo AV delay optimization and in 11 CRT patients in AF (10m, 1f, 69.8±9.6yrs.) using the Aesculon Cardiovascular Monitor (Osypka Medical, Berlin, Germany). Serial 30s EV recordings were accomplished, decreasing the VVD stepwise by 10ms from +60ms to -60ms between right and left ventricular stimulus. Optimal VVD was determined by the maximum of at least two of the three averaged parameters stroke volume (SV), cardiac output (CO) and cardiac index (CI). The response of SV, CO and CI was tested comparing their values in optimal VVD and suboptimal VVD. Suboptimal VVD was defined by optimal VVD±20ms.
Results: In all 28 patients in SR and AF, EV recordings resulted in optimal VVD. Between suboptimal and optimal mean VVD of 18.6±30.8ms between left and right ventricular stimulus, SV increased by 7.2±6.8%, CO by 7.8±7.2% and CI by 10.0±13.3% (all p<0.02). In the SR group with VVD of 18.8± 29.6ms, SV increased by 4.6±2.9%, CO by 5.0±2.9% and CI by 4.9±2.9% (all p<0.02). In the AF group with VVD of 18.2±4.0ms, SV increased by 10.4±8.9%, CO by 11.3±9.5% and CI by 16.4±18.2% (all p<0.02). Significant differences were not found between optimal VVD in SR and AF patients.
Conclusion: EV is a feasible serial method to individualize VVD in DDD and VVIR pacing for heart failure. Its response to hemodynamic changes demonstrates the value of EV for VVD fine-tuning.
Responder-rate in cardiac resynchronization therapy (CRT) of patients in sinus rhythm (SR) or atrial fibrillation (AF) mainly depends on accurat selection, optimal position of the left ventricular electrode and individualization of hemodynamical parameters of the implanted biventricular pacing system during follow-up. High resolution esophageal left heart electrocardiography offers a quick and semi-invasive approach to the electrical activity of left atrium and left ventricle. It was used in 62 heart failure patients in sinus rhythm and 11 in atrial fibrillation after implantation of CRT systems to compare the semi-invasive interventricular conduction delay (IVCDE) with QRS width. In all of the patients, guideline decision for CRT was linked with IVCDE of about 40ms and up. From logical point of view, IVCDE provides the minimal target interval for the left ventricular electrode placement in order to exclude non-responders. Esophageal measurement of interatrial conduction intervals in VDD and DDD pacing was utilized to individualize the AV delay and to exclude adverse hemodynamic effects.
Significance of new electrocardiographic parameters to improve cardiac resynchronization therapy
(2011)
Introduction: Oesophageal left heart electrogram (LHE) is a valuable tool providing electrocardiographic parameters for cardiac resynchronization therapy (CRT). It can be utilized to measure left ventricular (LVCD) and intra-leftventricular conduction delays (ILVCD) in heart failure patients to justify implantation of CRT systems. In the follow-up, LHE enables measurement of implant-related interatrial conduction times (IACT) which are the key intervals defining the hemodynamically optimal AV delay (AVD).
Methods: By TOSlim oesophageal electrode and Rostockfilter (Osypka AG, Rheinfelden, Germany), LHE was recorded in 39 heart failure patients (10f, 29m, 65±8yrs., QRS=163±21ms) after implantation of CRT systems according to guidelines. In position of maximal left ventricular deflection, LVCD and ILVCD were measured and compared with QRS width. In position of maximal left atrial deflection (LA), IACT was determined in VDD and DDD operation as interval As-LA and Ap-LA between atrial sense event (As) or stimulus (Ap), resp., and onset of LA. AVD was individualized using SAV =As-LA + 50ms for VDD and PAV=Ap-LA + 50ms for DDD operation.
Results: The CRT patients were characterized by minimal transoesophageal LVCD of 40ms but 73±20ms, at mean, ILVCD of 90±24ms and QRS/LVCD ratio of 2.4±0.6. The measured As-LA of 39±24ms and Ap-LA of 124±26ms resulted into SAV of 89±24ms and PAV of 174±26ms. In case of empirical AVD programming using 120ms for SAV and 180ms for PAV, the LHE revealed inverse sequences of LA and Vp in 4 patients (10%) during VDD and 13 patients (33%) in DDD pacing. In these patients, Vp preceded LA as IACT exceeded the programmed AVD.
Conclusion: Guideline indication of CRT systems is associated with LVCD of 40ms or more. Therefore, individual LVCD offers the minimal target interval that should be reached during left ventricular electrode placement to increase responder rate. Postoperatively, AV delay optimization respecting implant-related IACTs excludes adverse hemodynamic effects.