Use of body-surface potential mapping and computer model simulations for optimal programming of cardiac resynchronization therapy devices

Abstract

It has been proposed that by optimizing the timing of activation between the ventricles (V-V interval), with the aid of body-surface potential mapping (BSPM), IntroductionMany patients with heart failure have an underlying abnormality in the cardiac conduction system [1], such that the timing of the ventricular contractions becomes dyssynchronous, which further impairs cardiac output [2]. In these cases, restoration of ventricular synchrony is accomplished by use of an implantable pacemaker, which activates both ventricles in a process known as cardiac resynchronization therapy (CRT) or biventricular pacing (BVP).While CRT is successful in many cases, at least 30% of patients do not respond to CRT [3]. Recently, it has been proposed that if the ventricles are paced sequentially (V-V timing), instead of simultaneously, the ventricular synchrony of the heart can be further improved. This could help to maximize the mechanical efficiency of the heart, allowing more patients to benefit from CRT [4].One possible non-invasive method for evaluating ventricular electrical synchrony during different pacing modes is body-surface potential mapping (BSPM). It requires the placement of at least 100 electrocardiographic leads on the patient torso, in a variety of configurations. Because of the increased spatial resolution, BSPM provides a comprehensive three-dimensional picture of cardiac electrical activity that is not possible with the conventional 12-lead electrocardiogram (ECG). Moreover, it is possible to incorporate patient-specific torso geometry from computed tomography (CT) scans and calculate activation sequences (depicted as isochrones of activation times) on the epicardial surface of the heart. Epicardial potential maps and isochrones can be used to asses the electrical synchrony of the ventricles and are, therefore, valuable tools for determining the optimal inter-ventricular pacing delay. MethodsBody-surface potential recordings were performed on two patients with implanted Medtronic CRT devices (InSync III and Concerto) at the QEII Health Sciences Centre in Halifax. Ethics approval was obtained from the Research Ethics Board. One hundred and twenty disposable radiolucent Ag/AgCl surface electrodes (FoxMed, Idstein, Germany) were attached to the patients' torso in the Dalhousie mapping configuration. The V-V timing was varied from L80R (indicating LV lead activation, 80 ms delay and then RV lead activation) to R80L. 15 seconds of recording was done for each setting. Data were acquired via a custom acquistion system (BioSemi, Amsterdam, The Netherlands) at 2000 Hz and digitized with 16-bit quantization. All recordings were stored off-line for later analysis.Axial CT scans of the upper torso were performed for each patient using a Siemens SOMATOM Sensations 64-slice CT scanner (Siemens Medical, USA) at the QEII Health Sciences Centre. The spacing between each scan was 1 mm and the resulting images were stored in the DI-COM format for analysis with Amira 4.0 software (Mer-

Computerized optimization of biventricular pacing using body surface potential map

“…This suggests that in patients with optimal lead placement, programming of the inter-ventricular (V-V) timing may not be necessary [3][4][5]. Ideally, a computerized optimization of BVP would use a model of the cardiac contraction in order to calculate the cardiac output.…”

“…Once a decision has been made to proceed with the CRT then appropriate placement of the leads and optimal programming of the device will maximize the therapeutic effect. A recent study by Mohindra et al [3] investigated the use of body surface potential mapping and computer model simulations to optimize the CRT device. The outcome was the influence of pacing locations on reducing dyssynchrony.…”

“…linical trials of CRT have demonstrated considerable improvements in quality of life and exercise capacity, but a significant number of non-responders have decreased the overall benefits [1][2][3]. The use of ECG criteria alone might result in selection of some patients who are unlikely to benefit and also exclusion of potential responders.…”

A Study of Mechanical Optimization Strategy for Cardiac Resynchronization Therapy Based on an Electromechanical Model

“…Their results showed the importance of individually adjusting the electrode position, beside the timing delays, to the patient's anatomy and pathology in accordance with current clinical studies. Mohindra et al recorded 120-electrode body-surface potential mapping (BSPM) data and calculated the epicardial potentials and isochrones of activation for different V-V intervals by means of an electrocardiographic inverse solution based on a ventricular computer model [17]. They used the area between the LV and RV percentage surface-activated curves as a measure of interventricular synchrony for a variety of V-V settings.…”

A Study of Electrode Locations for Design of ECG Monitoring Smart Clothing based on Body Mapping

“…(Jang, 2006;Jeong et al, 2010), 인체 밀착형 전극 디자인 연구 (Lee, 2010;Song et al, 2010 (Watkins, 1984). (Mohindra et al, 2007;Ornato et al, 2002;Self et al, 2006;Sobieszczanska et al, 2007;Tysler et al, 2007 (Cho et al, 2010;Cho et al, 2015b), 의류 소재에 따른 인체 밀착성에 관 한 연구 (Jang, 2006), 인체 밀착성을 위한 입체형 전극 개발 연 구 (Cömert et al, 2013;Kang, 2008), 생체 신호 측정을 위한 인체 밀착 의류 연구 (Jeong et al, 2010;Jeong et al, 2012) 등으로 다양하게 진행되고 있다. FD:4-6, FD:8-9, BC:6-7, BC:8-9, BD:4-5에서 20~30%의 변 화율이 나타났으며, 의복 FB:5-6, FB:7-9, FC:4-5, FC:6-7, FA:1-9, FB:1-3, BA:1-7, BB:1-2, BB:3-4, BC:1-3, BD:1-2에 서 수직 방향으로 10% 이하의 변화율이 나타났으며, FA-FB:5, FA-FD:6, FA-FD:7, FA-FB:8, FC-FD:8, FA-FD:9, BB-BD:5, BB-BD:6, BB-BC:7, BB-BD:8, BA-BD:9에서 수평 방향으로 10% 이하의 변화율을 갖는 것으로 분석되었다.…”