Nonselective His Research Articles

Highlights From the Circulation Family of Journals.

Highlights From the Circulation Family of Journals.

HIS BUNDLE PACING INSIGHTS FROM ELECTRO-ANATOMICAL MAPPING: TOPOGRAPHY AND PACING TARGETS

Visualization of selective (S) and non-selective (NS) His bundle (HB) capture areas by 3D electro-anatomical mapping (EAM) has not been described and may help to guide HB pacing (HBP). The objective was to conduct EAM of the AV septum by using pace- and activation mapping. EAM was performed with

Programmed His Bundle Pacing: A Novel Maneuver for the Diagnosis of His Bundle Capture.

During permanent nonselective His bundle (ns-HB) pacing, it is crucial to confirm HB capture/exclude that only right ventricle (RV) myocardial septal pacing is present. Because the effective refractory period (ERP) of the working myocardium is different than the ERP of the HB, we hypothesized that it should be possible to differentiate ns-HB capture from RV myocardial capture using programmed extrastimulus technique. In consecutive patients during HB pacemaker implantation, programmed HB pacing was delivered from the screwed-in HB pacing lead. Premature beats were introduced at 10-ms steps during intrinsic rhythm and also after a drive train of 600 ms. The longest coupling interval that resulted in an abrupt change of QRS morphology was considered equal to ERP of HB or RV myocardium. Programmed HB pacing was performed from 50 different sites in 32 patients. In 34 of 36 cases of ns-HB pacing, the RV myocardial ERP was shorter than HB ERP (271.8±38 versus 353.0±30 ms; P<0.0001). Programmed HB pacing using a drive train resulted in a typical abrupt change of paced QRS morphology: from ns-HB to RV myocardial QRS (34 of 36 cases) or to selective HB QRS (2 of 36 cases). Programmed HB pacing delivered during native conduction resulted in obtaining selective HB QRS in 20 of 34 and RV myocardial QRS in 14 of 34 of the ns-HB cases. In RV myocardial-only pacing cases (false ns-HB pacing, n=14), such responses were not observed-the QRS morphology remained stable. Therefore, the programmed HB pacing correctly diagnosed all ns-HB cases and all RV myocardial pacing cases. A novel maneuver for the diagnosis of HB capture, based on the differences in ERP between HB and myocardium, was formulated, assessed, and found as diagnostically valuable. This method is unique in enabling to visualize selective HB QRS in patients with otherwise obligatory ns-HB pacing (RV myocardial capture threshold <HB capture threshold).

Novel Method for Assessment of His Bundle Pacing Morphology Using Near Field and Far Field Device Electrograms.

The 12-lead ECG is considered the gold standard to differentiate between selective (S), nonselective (NS) His bundle pacing (HBP), and right ventricular septal capture in routine clinical practice. We sought to assess the utility of device EGM recordings as a tool to identify the type of HBP morphology. One hundred forty-eight consecutive patients underwent HBP with a 3830 Select Secure lead (Medtronic, Inc) at 3 centers between October 2016 and October 2017. The near field V-EGM morphology (NF EGM), near field V-EGM time to peak (NFTime to peak), and far-field EGM QRS duration (QRSd) were recorded while pacing the His lead with simultaneous 12-lead ECG rhythm strips. Indications for HBP were sinus node dysfunction, atrioventricular conduction disease, and cardiac resynchronization therapy in 68 (46%), 56 (38%), and 24 (16%) patients, respectively. Baseline QRSd was 108±38 ms with QRSd >120 ms in 57 (39%) patients (27 right bundle branch block, 18 left bundle branch block, and 12 intraventricular conduction delay). S-HBP was noted in 54 (36%) patients. A positive NFEGM and NFTime to peak >40 ms were highly sensitive (94% and 93%, respectively) and specific (90% and 94%) for S-HBP irrespective of baseline QRSd. All 3 parameters (+NFEGM, NFTime to peak >40 ms, and far-field EGM QRSd <120 ms) had high negative predictive value (97%, 95%, and 92%). A novel device-based algorithm for S-HBP was proposed. EGM transitions correlated with ECG transitions during threshold testing and can help accurately differentiate between S-HBP, NS-HBP, and right ventricular septal pacing with a cumulative positive predictive value of 91% (positive predictive value =100% in patients with baseline QRSd <120 ms). We propose a novel and simple criteria for accurate differentiation between S-HBP, NS-HBP, and right ventricular septal capture morphologies by careful analysis of device EGMs alone. This study paves the way for future studies to assess autocapture algorithms for devices with HBP.

ECG parameters to predict left ventricular electrical delay

AimsLeft ventricular (LV) dyssynchrony lengthens the left ventricular electrical delay (LVED), measured from QRS onset to the first peak of the LV electrogram. We constructed an ECG model to predict LVED noninvasively. MethodsIntrapatient LVED was measured during a baseline vs nonselective His bundle pacing (nHBP) protocol. This setup provided paired synchronic/non-synchronic LVEDs, allowing intrapatient comparisons. Crosscorrelation of leads II and V6 was accomplished and extracted features together with age and gender fed a linear mixed effects model to predict LVED. ResultsHemodynamic increments were consistent with LVED advances under nHBP in a subset of 17 patients (dP/dtmax, baseline: 938.82 ± 241.95 mm Hg/s vs nHBP: 1034.94 ± 253.63 mm Hg/s, p = 6.24e-4). The inclusion of the area under V6 (AV 6) and the time shift of R-peaks obtained from the crosscorrelation signal (CorS) grouped by patient significantly improved LVED estimation with respect to the model based only on QRS duration, age and gender (p = 1.7e-5). ConclusionsInterlead ECG changes explained LVED, providing clues about the electrical impulse conduction within the left ventricle noninvasively.

Permanent nonselective His bundle pacing in an adult with L-transposition of the great arteries and complete AV block.

We report the placement of a permanent transvenous nonselective His bundle pacing lead in conjunction with a transvenous pacemaker/implantable cardioverter-defibrillator in an adult with Levo-Transposition of the Great Arteries (L-TGA) and a stenotic coronary sinus (CS) ostium, which would not accommodate a transvenous left ventricular (LV) pacing lead. Nonselective His bundle pacing provided a nearly identical ventricular activation pattern in this previously unpaced patient. Many L-TGA patients will have an eventual need for permanent pacing and, given the challenges of CS cannulation, His bundle pacing may represent a preferred modality rather than pure morphologic LV pacing or surgical systemic ventricular lead placement to achieve optimal electrical synchrony.

Permanent His Bundle Pacing in Intra-Hisian Conduction Block: Mechanistic Insights

We are reporting a patient with discrete intra-His conduction block and describe a refined technique of permanent His bundle pacing assuring reliable ventricular capture. Meticulous mapping of the site of block with lead placement distal to the site of block and non-selective His bundle pacing with local myocardial capture as an additional safety back up appears to be the technique of choice.

Non-selective His bundle pacing with a biphasic waveform: enhancing septal resynchronization.

His bundle pacing has shown to prevent detrimental effects from right ventricular apical pacing (RVA) and proved to resynchronize many conduction disturbances cases. However, the extent of His bundle pacing resynchronization is limited. An optimized stimulation waveform could expand this limit when implemented in His bundle pacing sets. In this work, we temporarily implemented RVA and Non-selective His bundle pacing with a biphasic anodal-first waveform (AF-nHB) and compared their effects against sinus rhythm (SR). Fifteen patients referred for electrophysiologic study with conduction disturbances, cardiomyopathy and ejection fraction below 35% were enrolled for the study. The following acute parameters were measured: QRS duration, left ventricular activation (RLVT), time of isovolumic contraction (IVCT), ejection fraction (EF), and dP/dtmax. QRS duration and RLVT decreased markedly under AF-nHB (SR: 169 ± 34 ms vs. nHB: 116 ± 31 ms, P < 0.0005) while RVA significantly increased QRS duration (SR: 169 ms vs. RVA: 198 ms, P < 0.05) and did not change RLVT (P = NS). Consistently, IVCT moderately decreased under AF-nHB (SR: 238 ms vs. RVA: 184 ms, P < 0.05 vs. SR) and dP/dtmax showed a 93.35 [mmHg] average increase under AF-nHB against SR. Also, T-wave inversions were observed during AF-nHB immediately after SR and RVA pacing suggesting the occurrence of cardiac memory. AF-nHB corrected bundle branch blocks in patients with severe conduction disturbances, even in those with dilated cardiomiopathy, outstanding from RVA. Also, the occurrence of cardiac memory during AF-nHB turned up as an observational finding of this study.

9-05: Both Selective And Non-Selective His Pacing Preserve Left Ventricle Activation

Purpose: His pacing provides physiological pacing by preserving ventricular activation via the His-Purkinjie system. The characteristics of selective and non-selective His capture have not been well established. Methods: The CardioInsight ECVUE(TM) system uses a 252-electrode vest to non-invasively map epicardial electrical activity from the entire myocardium in single beat. Vests were applied to four patients with heart failure undergoing His pacing. Mapping of ventricular activation was performed during selective and non-selective His pacing (as determined by the 12 lead surface ECG and intra-cardiac His signal) as well as during intrinsic ventricular activation. Results: Non-Selective His pacing resulted in early activation in the mid and basal right ventricle (RV), but subsequent RV activation matched that occurring during intrinsic activation. The epicardial ventricular activation pattern of selective His pacing was the same as activation observed during un-paced sinus rhythm. The left ventricular activation pattern observed with non-selective His pacing was identical to that seen during selective His pacing and intrinsic activation. Figure 1 depicts the activation maps derived from one patient with ischaemic cardiomyopathy (Ejection Fraction 35%) with a prolonged PR interval of 280ms but a normal QRS duration of 114ms. Left ventricular total activation time (LVTAT) did not differ significantly with non-selective His pacing compared to selective His pacing or intrinsic activation, mean change in LVTAT -0.8ms and -8ms, respectively, p = 0.8 & 0.4 in paired t-tests.

Selective versus non-selective His bundle pacing.

His bundle pacing was achieved in 10 anaesthetized open chest dogs by stimulation from bipolar electrode catheters positioned in the aortic root and right heart. Recordings were taken directly through plunge wires from the right atrium, high ventricular septum, and epicardial sites on the right and left ventricles. Six types of response were seen during A-V junctional stimulation: (1) low atrial pacing; (2) combined atrial and His bundle pacing; (3) His bundle pacing; (4) combined atrial, ventricular septal, and His bundle pacing; (5) combined septal and His bundle pacing; and (6) ventricular pacing. Pacing of the His bundle in combination with the atrium and/or ventricular septum is designated as non-selective, whereas stimulation of the His bundle alone is considered selective pacing. Non-selective His bundle pacing can be recognized from the surface leads by changes in onset and amplitude of the QRS with appreciable T-wave alterations. Although electrode position was an important determinant of the type of pacing achieved, a variety of patterns of stimulation resulted from variation in the modalities of the pacing stimulus, ie, polarity, intensity, and duration. Unless these factors are considered, selective His bundle pacing may not be achieved.