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Introduction: Left bundle branch area pacing (LBBAP) comprises pacing at the left ventricular septum (LVSP) or left bundle branch (LBBP). The aim of the present study was to investigate the differences in ventricular electrical heterogeneity between LVSP, LBBP, right ventricular pacing (RVP) and intrinsic conduction with different dyssynchrony measures using the ECG, vectorcardiograpy, ECG belt, and Ultrahigh frequency (UHF‐)ECG. Methods: Thirty‐seven patients with a pacemaker indication for bradycardia or cardiac resynchronization therapy underwent LBBAP implantation. ECG, vectorcardiogram, ECG belt and UHF‐ECG signals were recorded during RVP, LVSP and LBBP, and intrinsic activation. QRS duration (QRSd) was measured from the ECG, QRS area was calculated from the vectorcardiogram, LV activation time (LVAT) and standard deviation of activation time (SDAT) from ECG belt and electrical dyssynchrony (e‐DYS16) from UHF‐ECG. Results: Both LVSP and LBBP significantly reduced ventricular electrical heterogeneity as compared to underlying LBBB and RV pacing in terms of QRS area (p <.001), SDAT (p <.001), LVAT (p <.001) and e‐DYS16 (p <.001). QRSd was only reduced as compared to RV pacing(p <.001). QRS area was similar during LBBP and normal intrinsic conduction, e‐DYS16 was similar during LVSP and normal intrinsic conduction, whereas SDAT was similar for LVSP, LBBP and normal intrinsic conduction. For all these variables there was no significant difference between LVSP and LBBP. Conclusion: Both LVSP and LBBP resulted in a more synchronous LV activation than LBBB and RVP. Especially LBBP resulted in levels of LV synchrony comparable to normal intrinsic conduction. [ABSTRACT FROM AUTHOR]

Aims: An appropriate left ventricular (LV) lead position is a pre-requisite for response to cardiac resynchronization therapy (CRT) and is highly patient-specific. The purpose of this study was to develop a non-invasive pre-procedural CRT-roadmap to guide LV lead placement to a coronary vein in late-activated myocardium remote from scar.Methods and Results: Sixteen CRT candidates were prospectively included. Electrocardiographic imaging (ECGI), computed tomography angiography (CTA), and delayed enhancement cardiac magnetic resonance imaging (DE-CMR) were integrated into a 3D cardiac model (CRT-roadmap) using anatomic landmarks from CTA and DE-CMR. Electrocardiographic imaging was performed using 184 electrodes and a CT-based heart-torso geometry. Coronary venous anatomy was visualized using a designated CTA protocol. Focal scar was assessed from DE-CMR. Cardiac resynchronization therapy-roadmaps were constructed for all 16 patients [left bundle branch block: n = 6; intraventricular conduction disturbance: n = 8; narrow-QRS (ablate and pace strategy); n = 1; right bundle branch block: n = 1]. The number of coronary veins ranged between 3 and 4 per patient. The CRT-roadmaps showed no (n = 5), 1 (n = 6), or 2 (n = 5) veins per patient located outside scar in late-activated myocardium [≥50% QRS duration (QRSd)]. Final LV lead position was outside scar in late-activated myocardium in 11 out of 14 implanted patients, while a LV lead in scar was unavoidable in the remaining three patients.Conclusion: A non-invasive pre-implantation CRT-roadmap was feasible to develop in a case series by integration of coronary venous anatomy, myocardial-scar localization, and epicardial electrical activation patterns, anticipating on clinically relevant features. [ABSTRACT FROM AUTHOR]

Synchronous ventricular electrical activation is a prerequisite for adequate left ventricular (LV) systolic function. Conduction abnormalities such as left bundle branch block, and ventricular pacing lead to a dyssynchronous electrical activation sequence, which may have deleterious consequences. The present review attempts to connect the various processes involved in the development of 'dyssynchronopathy', and its correction by cardiac resynchronization therapy (CRT). Abnormal electrical impulse conduction leads to abnormal contraction, characterized by regional differences in timing as well as shortening patterns and amount of external work performed. Early activated regions may show 'wasted work', which leads to inefficient action of the entire left ventricle. Moreover, both the development of heart failure (HF) in general and the regional differences in mechanical load lead to structural, electrical, and contractile remodelling processes. These have been demonstrated at the level of the myocardium (asymmetric hypertrophy, fibrosis, prolongation of activation and reduction in repolarization forces, decrease in LV ejection fraction), cell (gap junctional remodelling, derangement of the T-tubular structure), and molecule (under or overexpression of ion channels and contractile proteins subtypes and abnormal calcium handling). The myocardial adaptations to dyssynchrony are 'maladaptive'. This also explains why CRT, unlike most pharmacological treatments, continues to increase its therapeutic effect over time. Finally, better understanding of all processes involved in dyssynchrony and CRT may also lead to new pharmacological agents for treating HF and to novel pacing strategies. [ABSTRACT FROM AUTHOR]

Aims: The aim of this study was to investigate the influence of the activation sequence on voltage amplitudes by evaluating regional voltage differences during a left bundle branch block (LBBB) activation sequence vs. a normal synchronous activation sequence and by evaluating pacing-induced voltage differences.Methods and Results: Twenty-one patients and three computer models without scar were studied. Regional voltage amplitudes were evaluated in nine LBBB patients who underwent endocardial electro-anatomic mapping (EAM). Pacing-induced voltage differences were evaluated in 12 patients who underwent epicardial EAM during intrinsic rhythm and right ventricular (RV) pacing. Three computer models customized for LBBB patients were created. Changes in voltage amplitudes after an LBBB (intrinsic), a normal synchronous, an RV pacing, and a left ventricular pacing activation sequence were assessed in the computer models. Unipolar voltage amplitudes in patients were approximately 4.5 mV (4.4-4.7 mV, ∼33%) lower in the septum when compared with other segments. A normal synchronous activation sequence in the computer models normalized voltage amplitudes in the septum. Pacing-induced differences were larger in electrograms with higher voltage amplitudes during intrinsic rhythm and furthermore larger and more variable at the epicardium [mean absolute difference: 3.6-6.2 mV, 40-53% of intrinsic value; interquartile range (IQR) differences: 53-63% of intrinsic value] compared to the endocardium (mean absolute difference: 3.3-3.8 mV, 28-30% of intrinsic value; IQR differences: 37-40% of intrinsic value).Conclusion: In patients and computer models without scar, lower septal unipolar voltage amplitudes are exclusively associated with an LBBB activation sequence. Pacing substantially affects voltage amplitudes, particularly at the epicardium. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the relationship between vectorcardiography (VCG) and myocardial scar on cardiac magnetic resonance (CMR) imaging, and whether combining these metrics may improve cardiac resynchronization therapy (CRT) response prediction.Methods: Thirty-three CRT patients were included. QRSarea, Tarea and QRSTarea were derived from the ECG-synthesized VCG. CMR parameters reflecting focal scar core (Scar2SD, Gray2SD) and diffuse fibrosis (pre-T1, extracellular volume [ECV]) were assessed. CRT response was defined as ≥15% reduction in left ventricular end-systolic volume after six months' follow-up.Results: VCG QRSarea, Tarea and QRSTarea inversely correlated with focal scar (R = -0.44--0.58 for Scar2SD, p ≤ 0.010), but not with diffuse fibrosis. Scar2SD, Gray2SD and QRSarea predicted CRT response with AUCs of 0.692 (p = 0.063), 0.759 (p = 0.012) and 0.737 (p = 0.022) respectively. A combined ROC-derived threshold for Scar2SD and QRSarea resulted in 92% CRT response rate for patients with large QRSarea and small Scar2SD or Gray2SD.Conclusion: QRSarea is inversely associated with focal scar on CMR. Incremental predictive value for CRT response is achieved by a combined CMR-QRSarea analysis. [ABSTRACT FROM AUTHOR]

Background: Previous studies indicated the importance of the intrinsic left ventricular (LV) electric delay (QLV) for optimal benefit to cardiac resynchronization therapy. We investigated the use of QLV for achieving optimal acute hemodynamic response to cardiac resynchronization therapy with a quadripolar LV lead.Methods and Results: Forty-eight heart failure patients with a left bundle branch block were prospectively enrolled (31 men; age, 66±10 years; LV ejection fraction, 28±8%; QRS duration, 176±14 ms). Immediately after cardiac resynchronization therapy implantation, invasive LV pressure-volume loops were recorded during biventricular pacing with each separate electrode at 4 atrioventricular delays. Acute cardiac resynchronization therapy response, measured as change in stroke work (Δ%SW) compared with intrinsic conduction, was related to intrinsic interval between Q on the ECG and LV sensing delay (QLV), normalized for QRS duration (QLV/QRSd), and electrode position. QLV/QRSd was 84±9% and variation between the 4 electrodes 9±5%. Δ%SW was 89±64% and varied by 39±36% between the electrodes. In univariate analysis, an anterolateral or lateral electrode position and a high QLV/QRSd had a significant association with a large Δ%SW (all P <0.01). In a combined model, only QLV/QRSd remained significantly associated with Δ%SW (P<0.05). However, a direct relation between QLV/QRSd and Δ%SW was only seen in 24 patients, whereas 24 patients showed an inverse relation.Conclusions: The large variation in acute hemodynamic response indicates that the choice of the stimulated electrode on a quadripolar lead is important. Although QLV/QRSd was associated with acute hemodynamic response at group level, it cannot be used to select the optimal electrode in the individual patient. [ABSTRACT FROM AUTHOR]

Late complications of an atrial septal occluder device (ASO) are rare but may be serious. We report a case with extensive hemopericardium five years after ASO implantation most likely triggered by anticoagulant therapy. Although not surgically confirmed, indirect clues for erosion of the atrial wall by the device were the exclusion of other etiologies, lack of recurrence after pericardial drainage and withdrawal of anticoagulants. In addition, multimodality imaging using echocardiography, computed tomography, and cardiac magnetic resonance imaging were helpful to elucidate this unusual cause. Initiation of anticoagulant treatment in patients with an ASO should be carefully balanced and may warrant more frequent echocardiographic follow-up. < Learning objective: Late complications of an atrial septal occlude device (ASO) are rare. Initiation of anticoagulant therapy in patients with an ASO may lead to late hemopericardium, suggesting that more frequent echocardiographic follow-up is warranted.> [ABSTRACT FROM AUTHOR]

Background: Validation of voltage-based scar delineation has been limited to small populations using mainly endocardial measurements. The aim of this study is to compare unipolar voltage amplitudes (UnipV) with scar on delayed enhancement cardiac magnetic resonance imaging (DE-CMR). Methods: Heart failure patients who underwent DE-CMR and electro-anatomic mapping were included. Thirty-three endocardial mapped patients and 27 epicardial mapped patients were investigated. UnipV were computed peak-to-peak. Electrograms were matched with scar extent of the corresponding DE-CMR segment using a 16-segment/slice model. Non-scar was defined as 0% scar, while scar was defined as 1–100% scar extent. Results: UnipVs were moderately lower in scar than in non-scar (endocardial 7.1 [4.6–10.6] vs. 10.3 [7.4–14.2] mV; epicardial 6.7 [3.6–10.5] vs. 7.8 [4.2–12.3] mV; both p<0.001). The correlation between UnipV and scar extent was moderate for endocardial (R = -0.33, p<0.001), and poor for epicardial measurements (R = -0.07, p<0.001). Endocardial UnipV predicted segments with >25%, >50% and >75% scar extent with AUCs of 0.72, 0.73 and 0.76, respectively, while epicardial UnipV were poor scar predictors, independent of scar burden (AUC = 0.47–0.56). UnipV in non-scar varied widely between patients (p<0.001) and were lower in scar compared to non-scar in only 9/22 (41%) endocardial mapped patients and 4/19 (21%) epicardial mapped patients with scar. Conclusion: UnipV are slightly lower in scar compared to non-scar. However, significant UnipV differences between and within patients and large overlap between non-scar and scar limits the reliability of accurate scar assessment, especially in epicardial measurements and in segments with less than 75% scar extent. [ABSTRACT FROM AUTHOR]