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Background: Right ventricular (RV) pacing causes delayed activation of remote ventricular segments. We used the ultra‐high‐frequency ECG (UHF‐ECG) to describe ventricular depolarization when pacing different RV locations. Methods: In 51 patients, temporary pacing was performed at the RV septum (mSp); further subclassified as right ventricular inflow tract (RVIT) and right ventricular outflow tract (RVOT) for septal inflow and outflow positions (below or above the plane of His bundle in right anterior oblique), apex, anterior lateral wall, and at the basal RV septum with nonselective His bundle or RBB capture (nsHBorRBBp). The timings of UHF‐ECG electrical activations were quantified as left ventricular lateral wall delay (LVLWd; V8 activation delay) and RV lateral wall delay (RVLWd; V1 activation delay). Results: The LVLWd was shortest for nsHBorRBBp (11 ms [95% confidence interval = 5–17]), followed by the RVIT (19 ms [11–26]) and the RVOT (33 ms [27–40]; p <.01 between all of them), although the QRSd for the latter two were the same (153 ms (148–158) vs. 153 ms (148–158); p =.99). RV apical capture not only had a longer LVLWd (34 ms (26–43) compared to mSp (27 ms (20–34), p <.05), but its RVLWd (17 ms (9–25) was also the longest compared to other RV pacing sites (mean values for nsHBorRBBp, mSp, anterior and lateral wall captures being below 6 ms), p <.001 compared to each of them. Conclusion: RVIT pacing produces better ventricular synchrony compared to other RV pacing locations with myocardial capture. However, UHF‐ECG ventricular dysynchrony seen during RVIT pacing is increased compared to concomitant capture of basal septal myocytes and His bundle or proximal right bundle branch. [ABSTRACT FROM AUTHOR]

Introduction: We aimed to compare the acute differences in left ventricular (LV) function and mechanical synchrony during nonselective His bundle pacing (ns‐HBP) versus selective His bundle pacing (s‐HBP) using strain echocardiography. Methods and results: Consecutive patients with permanent His bundle pacing, in whom it was possible to obtain both s‐HBP and ns‐HBP, were studied in two centers. In each patient, echocardiography was performed sequentially during s‐HBP and ns‐HBP. Speckle‐tracking echocardiography parameters were analyzed: Global longitudinal strain (GLS), the time delay between peak systolic strain in the basal septal and basal lateral segments (BS‐BL delay), peak strain dispersion (PSD) and strain delay index. Right ventricle function was assessed using tricuspid annular plane systolic excursion (TAPSE) and tissue Doppler velocity of the lateral tricuspid annulus (S′). A total of 69 patients (age: 75.6 ± 10.5 years; males: 75%) were enrolled. There were no differences in LV ejection fraction and GLS between s‐HBP and ns‐HBP modes: 59% versus 60%, and −15.6% versus −15.7%, respectively; as well as no difference in BS‐BL delay and strain delay index. The PSD value was higher in the ns‐HBP group than in the s‐HBP group with the most pronounced difference in the basal LV segments. No differences in right ventricular function parameters (TAPSE and S′) were found. Conclusion: The ns‐HBP and s‐HBP modes seem comparable regarding ventricular function. The dyssynchrony parameters were significantly higher during ns‐HBP, however, the difference seems modest and clarification of its impact on LV function requires a larger long‐term study. [ABSTRACT FROM AUTHOR]

Introduction: The present study introduces a new ultra‐high‐frequency 14‐lead electrocardiogram technique (UHF‐ECG) for mapping ventricular depolarization patterns and calculation of novel dyssynchrony parameters that may improve the selection of patients and application of cardiac resynchronization therapy (CRT). Methods: Components of the ECG in sixteen frequency bands within the 150 to 1000 Hz range were used to create ventricular depolarization maps. The maximum time difference between the UHF QRS complex centers of mass of leads V1 to V8 was defined as ventricular electrical dyssynchrony (e‐DYS), and the duration at 50% of peak voltage amplitude in each lead was defined as the duration of local depolarization (Vd). Proof of principle measurements was performed in seven patients with left (left bundle branch block) and four patients with right bundle branch block (right bundle branch block) before and during CRT using biventricular and His‐bundle pacing. Results: The acquired activation maps reflect the activation sequence under the tested conditions. e‐DYS decreased considerably more than QRS duration, during both biventricular pacing (−50% vs −8%) and His‐bundle pacing (−77% vs −13%). While biventricular pacing slightly increased Vd, His‐bundle pacing reduced Vd significantly (+11% vs −36%), indicating the contribution of the fast conduction system. Optimization of biventricular pacing by adjusting VV‐interval showed a decrease of e‐DYS from 102 to 36 ms with only a small Vd increase and QRS duration decrease. Conclusions: The UHF‐ECG technique provides novel information about electrical activation of the ventricles from a standard ECG electrode setup, potentially improving the selection of patients for CRT and application of CRT. [ABSTRACT FROM AUTHOR]

Background: The ablation of cavotricuspid-isthmus (CTI) atrial flutter (AFL) dependent atrial flutter could be difficult in patients with complex anatomy of the CTI.The aim of the study was to assess whether the use of intracardiac echocardiography (ICE) was associated with less fluoroscopy time and faster ablations of cavotricuspid isthmus dependent atrial flutter (CTI-AFL). Methods: Patients with an indication for an ablation of a CTI-AFL were enrolled. Patients in which ablation of a CTI-AFLas part of an atrial fibrillation ablation were not included. Randomization was done using the envelope method. Standard techniques (i.e., coronary sinus, 20-polar halo catheter, and an ablation catheter), and criteria of success (bidirectional block through the CTI) were used. In patients randomized to the ablation with ICE, a 10F AcuNav ICE probe (Siemens, Germany)was used. Results: Seventy-nine patients were enrolled; 40 were randomized to ablation with ICE and 39 without ICE. The X-ray exposure was shorter (3.29±2.6 vs. 5.94±3.43 min, p<0.001) and total X-ray dose was reduced (3.30±1.98 vs. 6.68±5.25 Gy.cm2, p<0.001) in the ICE group. However, the total RF energy ablation time was not different between groups (ICE group: 604.56±380.46sec vs. 585.82±373.39 sec, p=0.8). The procedure duration was slightly longer in the ICE group (82.0±20.8 vs. 72.1±19.0 min, p=0.03). Procedural success was 100% (40/40) in the ICE group and 95% (37/39) in the control group. Two control patients required crossover to ICE at a prespecified point to achieve bidirectional block. There were two femoral hematomas in the ICE group and one in the control group. Conclusion: The use of ICE for atrial flutter ablation is associated with less fluoroscopy time and improved ability to achieve bidirectional block compared to traditional conventional flutter ablation methods. However, it is not asoociated with reduced ablation time or overall procedure duration. [ABSTRACT FROM AUTHOR]