Troubleshooting Programming of Conduction System Pacing

Conduction system pacing (CSP) comprises His bundle pacing and left bundle branch area pacing and is rapidly gaining widespread adoption. Effective CSP not only depends on successful system implantation but also on proper device programming. Current implantable impulse generators are not specifically designed for CSP. Either single chamber, dual chamber or CRT devices can be used for CSP depending on the underlying heart rhythm (sinus rhythm or permanent atrial arrhythmia) and the aim of pacing. Different programming issues may arise depending on the device configuration. This article aims to provide an update on practical considerations for His bundle and left bundle branch area pacing programming and follow-up.

Reduction in QRS area correlates with hemodynamic response during CRT-device implantation

Funding Acknowledgements Type of funding sources: None. Background Previous studies have shown that reduction in QRS area after cardiac resynchronization therapy (CRT) is associated with improved long-term clinical outcome. Purpose To investigate whether reduction in QRS area is associated with hemodynamic improvement and whether QRS area reduction could be used for CRT optimization, with respect to LV lead position and device programming in individual patients. Methods A total of 78 patients with indication for CRT were prospectively included in 4 hospitals. QRS area was calculated from vectorcardiograms that were synthesized from 12-lead ECG’s. Acute hemodynamic response was assessed invasively as the maximum rate of percentual left ventricular (LV) pressure (%LVdP/dtmax) rise. QRS area reduction was studied in relation to LV-lead position (n = 26), proximal versus distal LV lead position (n = 27), and VV-delay (n = 25). Results Combining all measurements in all patients showed a significant correlation between QRS area reduction and %LVdP/dTmax increase (R = 0.49, P < 0.0001). Also, when one fixed routine implantation setting was used for each patient (lateral lead position, distal, AV-delay 120-150ms, VV-delay 0ms) this correlation was present (R = 0.45, p < 0.0001, figure panel A). In 21 patients in which at least 3 lead positions were available there was also a significant correlation between QRS area reduction and %LVdP/dtmax increase (average R = 0.69, p < 0.0001, panel B). For VV-delay, 25 other patients as well showed a significant correlation (average R = 0.53, p < 0.0001). Conclusion Within patients, QRS area reduction is associated with %LVdP/dtmax increase with various LV lead positions and VV-intervals. Therefore, QRS area, which is an easily obtainable and objective parameter, might be a promising tool for optimization of LV lead position and device programming in CRT. Abstract Figure.

THE CHANGE OF CARDIOSTIMULATION DEVICE PROGRAMMING DUE TO DETECTION OF ELECTROMAGNETIC INTERFERENCE

The study deals with the interdisciplinary topic of the electromagnetic compatibility of the cardiac implantable electronic devices that are used in patients with a defect of heart conduction system. We are focusing on the detection of disturbing signals on electrodes of cardiostimulation device and its interpretation. The detection of electromagnetic interference (EMI) is related to electrode choice, device placement, its configuration and programming. The aim of the study is the analysis of the pacemaker response in the presence of an external source of the disturbance fields. We point to possible risks of its interaction and discuss mechanisms that can influence the pacemaker sensitivity to EMI. Due to improper signal detection, the device programming changes can occur. We present an experiment of the exposure of the cardiostimulation system to a low-frequency harmonic interference signals and finally we analyse similar clinical episode and discuss proper functioning of the pacemaker.

LOCALIZATION OF THE LEFT VENTRICULAR MYOCARDIAL SCARRING AND ITS ELECTRICAL ACTIVATION IN PATIENTS WITH HEART FAILURE AND DIFFERENT RESPONSE TO CARDIAC RESYNCHRONIZATION THERAPY

Introduction. As a significant number of patients with heart failure (HF) does not respond to cardiac resynchronization therapy (CRT), a lot of research has deservedly focused on optimization, and better patient selection. The ideal resynchronization depends on different factors, from device programming to heart features and left ventricle (LV) lead position. Analysis of the 12-lead electrocardiogram (ECG) is the most simple method which can provide important information on LV lead location, presence of scar at LV pacing site, and fusion of intrinsic activation or RV pacing with LV pacing.Purpose. To analyze the electrophysiological and structural heart features and their correlation with the ECG pattern during biventricular (BV) pacing in patients with HF and CRT devices.Methods. The study included 47 patients (mean age 62.3±8.9 years) with LBBB, QRS duration ≥ 130 ms, left ventricular ejection fraction (LVEF) ≤ 35%, heart failure (HF) NYHA II-IV despite optimal pharmacological therapy during months. All patients had undergone CRT-D implantation. Late-gadolinium enhancement-cardiovascular magnetic resonance (LGE-CMR), 12-lead ECG, non-invasive cardiac mapping (NICM) (with obtaining the zone of late LV activation (ZLA)) were undertaken prior to CRT devices implantation. NICM with cardiac CT and evaluation of LV lead position, ECG pattern during BV pacing (#1 - fusion complex with increased or dominant R wave, independent of QRS duration, #2- QS pattern with QRS duration normalization, and #3- QS pattern with increased QRS duration) were undertaken after CRT devices implantation. Response to CRT was estimated by echo and was defined as decrease in LV end-systolic volume by > 15% after 6 months of follow-up.Results. CRT was effective in 28 patients (59.5%). According to the results of NICM, zone of late LV activation more often was located at 5,6,11,12 segments, and LV pacing site - at 6,7,12 segments of LV. In the “response” group overlap of scar zone and zone of late LV activation was observed (p=0.005). The presence of scar tissue in the LV pacing site was associated with CRT non-response (p<0.001), and the pacing zone of late LV activation resulted in the best CRT response (p<0.001). The distance from the LV electrode to the zone of late LV activation was less in the “CRT response” group (33 [20;42] mm vs 83 [55;100] mm, p<0.001). The most beneficial ECG pattern during BV pacing was #2, and #3 was more often observed in the group “CRT non-response”; configuration #1 was intermediate between ECG patterns #2 and #3.Conclusions. A comprehensive examination, including the study of the structural and electrophysiological heart features is important for the optimal positioning the LV lead and subsequent CRT device programming. The simple analysis of the QRS pattern during BV pacing can show whether biventricular pacing is adequately performed and can reveal inadequate CRT programming and LV lead positioning.

P3802Electrophysiological and structural heart features in patients with heart failure and response to cardiac resynchronization therapy

Introduction As a significant number of patients with heart failure (HF) does not respond to cardiac resynchronization therapy (CRT), a lot of research has deservedly focused on optimization, and better patient selection. The ideal resynchronization depends on different factors, from device programming to heart features and left ventricle (LV) lead position. Analysis of the 12 lead electrocardiogram (ECG) is the most simple method which can provide important information on LV lead location, presence of scar at LV pacing site, and fusion of intrinsic activation or RV pacing with LV pacing. Purpose To analyze the electrophysiological and structural heart features and their correlation with the ECG pattern during biventricular (BV) pacing in patients with HF and CRT devices. Methods The study included 47 patients (mean age 62,3±8,9 yrs) with LBBB, QRS≥130 ms, LV ejection fraction (LVEF) ≤35%, heart failure (HF) NYHA II-IV despite optimal pharmacological therapy during 3 months. All patients had undergone CRT-D implantation. Late-gadolinium enhancement-cardiovascular magnetic resonance, 12 lead ECG, non-invasive cardiac mapping (NICM) (with obtaining the zone of late LV activation were undertaken prior to CRT devices implantation. NICM with cardiac CT and evaluation of LV lead position, ECG pattern during BV pacing (#1 - fusion complex with increased or dominant R wave, independent of QRS duration, #2- QS pattern with QRS duration normalization, and #3- QS pattern with increased QRS duration) were undertaken after CRT devices implantation. Response to CRT was estimated by echo and was defined as decrease in LV end-systolic volume by >15% after 6 months of follow-up. Results CRT was effective in 28 patients (59,5%). According to the results of NICM, zone of late LV activation more often was located at 5,6,11,12 segments, and LV pacing site – at 6,7,12 segments of LV. In the “response” group overlap of scar zone and zone of late LV activation was observed (p=0,005). The presence of scar tissue in the LV pacing site was associated with CRT non-response (p<0.001), and the pacing zone of late LV activation resulted in the best CRT response (p<0.001). The distance from the LV electrode to the zone of late LV activation was less in the “CRT response” group (33 [20; 42] mm vs 83 [55; 100] mm, p<0.001). The most beneficial ECG pattern during BV pacing was #2, which found more often found in case of pacing zone of late LV activation. Configuration #3 was more often observed in the group “CRT non-response”; #1 was intermediate between ECG patterns #2 and #3. Conclusions A comprehensive examination, including the study of the structural and electrophysiological heart features is important for the optimal positioning the LV lead and subsequent CRT device programming. The simple analysis of the QRS pattern during BV pacing can show whether biventricular pacing is adequately performed and can reveal inadequate CRT programming and LV lead positioning.