Left Ventricular Electrical Delay Research Articles

Novel implant technique for septal pacing. A noninvasive approach to nonselective his bundle pacing

BackgroundHis Bundle pacing (HBP) preserves native ventricular activation through His Purkinje. Unfortunately, most current techniques for HBP implants require sheaths, special leads, and an electrophysiology setup for electrogram recording. MethodsWe developed an implantation technique guided by a non-invasive assessment of left ventricular electrical delay (LVED) as a measure of intraventricular dyssynchrony. The objective was to evaluate the usefulness and safety of this technique for implants of pacemakers and ICDs with right ventricular septal pacing (RVSP) using conventional screw-in leads and compare it with a reduced group of HBP (n = 32) guided by His potential mapping. 208 patients eligible for ventricular stimulation were implanted. Conventional screw-in leads were used in all cases. To ensure mechanical stability, stylets required a slight reshaping at the tip ResultsRVSP normalized electrical activity in patients with conduction disease, producing NS-HBP-like patterns. The parameters evaluated during implantation for the RVSP group were better than those of HBP and remained constant at a twelve months follow-up. In proportion, the number of dislodgments and the need for CRT upgrade was lower for RVSP than for HBP. Additionally, fluoroscopy time was significantly reduced in the RVSP group. ConclusionsThis technique successfully guided RVSP implants in a non-invasive way and represents a simple alternative to the implant of a cardiac stimulation device.

Application and efficacy of the adjustment on left ventricular electrical delay and the distance between right and left ventricular pacing polar in optimizing the left ventricular pacing polar

Objective: To investigate the application and efficacy of left ventricular (LV) electrical delay (LVED) and the distance of right ventricular(RV) pacing polar to LV(DRLV) in optimizing LV pacing polar. Methods: Heart failure (HF) patients who implanted cardiac resynchronization therapy (CRT) device with a LV quadripolar lead from January 2014 to January 2018 at General Hospital of Northern Theater Command were enrolled in the study. Measurements of LVED and DRLV of each polar of the lead were performed in patients with HF who underwent CRT with LV quadripolar lead. The principle in turn for polar selecting used for clinical LV pacing was the pacing polar: (1)without phrenic nerve stimulation(PNS); (2)with appropriate capture threshold; (3)not located in apical; (4)with maximal LVED; (5)with maximal DRLV. The LV pacing polar was selected for CRT according to the procedure. The distribution of target veins implanted with LV quadripolar lead were calculated. The percentage of biventricular pacing at 6-month follow-up was recorded. The following indexes were compared before and 6-month after surgery, including QRS duration, LV end-systolic volume(LVESV), LV ejection fraction(LVEF), LV end-diastolic dimension(LVEDD), 6 minute walking distance(6MWD), New York Heart Association(NYHA) class. The efficacy and echocardiographic efficacy of CRT was evaluated. Results: There were twenty-nine HF patients enrolled. The mean age of enrolled patients was(61.7±7.6)years old, nineteen (66%)of them were male. There were seventeen(59%) patients diagnosed as dilated cardiomyopathy and twelve(41%) patients as ischemic cardiomyopathy. All patients were successfully implanted with LV quadripolar lead into target veins, and all four pacing sites were also in target veins. Target veins were located in lateral veins in 15 patients (52%), anterior veins in 2 patients (7%), posterior veins in 11 patients (38%), and lateral branches of great cardiac veins in 1 patient (3%). After 6-month of follow-up, the percentage of biventricular pacing was greater than 95%.There were nineteen(66%) patients optimized LV pacing polar by the largest LVED and four (14%) patients by the DRLV. Of the 29 patients, 5(17%) patients used D1 as the pacing polar, 5(17%) patients used M2 as the pacing polar, 7(24%) patients used M3 as the pacing polar, and 12(41%) patients used P4 as the pacing polar. The pacing polars (D1, M2) of traditional bipolar lead were used in 10(34%) patients, and the LV quadripolar lead specific pacing polars (M3, P4) were used in 19(66%) patients.Compared to a LV quadripolar lead, the LV pacing polar (M3, P4) selected in 19(66%) patients were not achievable with the traditional LV bipolar lead (D1, M2). Preoperative QRS duration, LVESV, LVEF, LVEDD, 6MWD and NYHA class were (171±24)ms, (231±79)ml, (28±5)%, (74±11)mm, (294±103)m, (3.2±1.0)class and the postoperative 6-month were (130±12)ms, (158±73)ml, (36±10)%, (66±12)mm, (371±86)m, (1.9±0.5)class. These indexes were significantly improved after 6 months operation(P<0.001). 97% and 83% patients were responders of CRT as assessed by 6-month efficacy and echocardiographic efficacy. Conclusion: The maximal LVED and DRLV can be used to select LV pacing polar with a high rate of CRT response rate.

Coronary sinus and great cardiac vein electroanatomic mapping predicts the activation delay of the coronary sinus branches.

Implantation of left ventricular (LV) lead in segments with delayed electrical activation may improve response to cardiac resynchronization therapy (CRT). The search for the latest LV electrical delay (LVED) site can be time-consuming. To assess if electrical mapping of coronary sinus (CS) and magna cardiac vein can help to identify the latest activated CS branch. We retrospectively evaluated 48 consecutive patients who underwent electroanatomic mapping system-guided (EAMS)-CRT device implantation with ≥2 mapped CS branches. The activation mapping of the CS and relative branches were performed using an insulated guide wire. LVEDwas defined as the interval between the beginning of the QRS complex on the surface electrocardiogramand the local electrogram and expressed in milliseconds (ms). Thirty-two(67%) patients showed left bundle branch block (LBBB) and 16 (33%) non-LBBB electrocardiographic patterns. A total of 116 CS branches (mean, 2.4/patient;range, 2-5) were mapped. In the left oblique view, most patients (N = 39, 81%) showed the latest CS-LVED in lateral segments whilenine(19%) showed the latest CS-LVED in anterior or posterior segments. Specifically, 94% of patients with LBBB showed the latest CS-LVED in lateral segments while CS activation among non-LBBB patients was heterogeneous. In all patients, the CS branch that demonstrated the highest LVED originated from the latest activated segment of the CS. Electrical mapping of CS allows identifying the latest activated branches. This finding may contribute to simplify CRT device implantation compared to activation mapping of all the branches.

MEASURING LEFT VENTRICLE ELECTRICAL DELAY IN A CRT OPTIMIZATION CLINIC AND CORRELATING WITH CRT RESPONSE

Previously published research has indicated left ventricular electrical delay (QLV) as an independent predictor of patient response to cardiac resynchronization therapy (CRT) as measured by change in left ventricular end systolic volume (LVESV). We sought to validate this concept in our cohort of

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.

688Comparison of left ventricular electrical delay and mechanical contractions between intrinsic and right ventricular paced configurations during cardiac resynchronization therapy

688Comparison of left ventricular electrical delay and mechanical contractions between intrinsic and right ventricular paced configurations during cardiac resynchronization therapy

Coronary sinus activation patterns in patients with and without left bundle branch block undergoing electroanatomic mapping system–guided cardiac resynchronization therapy device implantation

Implantation of the left ventricular (LV) lead in segments with delayed electrical activation may improve response to cardiac resynchronization therapy (CRT). The purpose of this study was to evaluate the amount and regional distribution of LV electrical delay (LVED) in patients with or without left bundle branch block (LBBB). We enrolled 60 patients who underwent electroanatomic mapping system-guided CRT device implantation. Activation mapping of the coronary sinus (CS) branches was performed using an insulated guidewire. LVED was defined as the interval between the beginning of the QRS complex on the surface electrocardiogram (ECG) and the local electrogram and expressed in milliseconds or as percentage of the total QRS duration (LVED%). Forty-three patients showed a LBBB and 17 a non-LBBB electrocardiographic pattern. A total of 148 CS branches (mean 2.5 per patient; range 2-4 per patient) were mapped. Patients with LBBB showed higher maximum LVED (135 ms [108-150 ms] vs 100 ms [103-110 ms]; P < .001) and LVED% (86% [79%-89%] vs 72% [54%-80%]; P < .001) than did patients without LBBB. The maximum LVED was recorded in mid-basal anterolateral or inferolateral LV segments (traditional CRT targets), significantly more often in patients with LBBB than in patients without LBBB (85% vs 59%; P = .02). The number of CS branches showing LVED >50% of the total QRS duration, >75% of the total QRS duration, and >85 ms was significantly higher in patients with LBBB than in patients without LBBB. Patients without LBBB showed lower LVED and more heterogeneous electrical activation of the CS than did patients with LBBB. This finding may contribute to a lower rate of response to CRT of patients without LBBB and suggests the use of activation mapping to guide LV lead placement.

ECG parameters predict left ventricular conduction delay in patients with left ventricular dysfunction

Estimating left ventricular electrical delay (Q-LV) from a 12-lead ECG may be important in evaluating cardiac resynchronization therapy (CRT). The purpose of this study was to assess the impact of Q-LV interval on ECG configuration. One hundred ninety-two consecutive patients undergoing CRT implantation were divided electrocardiographically into 3 groups: left bundle branch block (LBBB), right bundle branch block (RBBB), and nonspecific intraventricular conduction delay (IVCD). The IVCD group was further subdivided into 81 patients with left (L)-IVCD and 15 patients with right (R)-IVCD (resembling RBBB, but without S wave in leads I and aVL). The Q-LV interval in the different groups and the relationship between ECG parameters and the maximum Q-LV interval were analyzed. Patients with LBBB presented a long Q-LV interval (147.7 ± 14.6 ms, all exceeding cutoff value of 110 ms), whereas RBBB patients presented a very short Q-LV interval (75.2 ± 16.3 ms, all <110 ms). Patients with an IVCD displayed a wide range of Q-LV intervals. In L-IVCD, mid-QRS notching/slurring showed the strongest correlation with a longer Q-LV interval, followed, in decreasing order, by QRS duration >150 ms and intrinsicoid deflection >60 ms. Isolated mid-QRS notching/slurring predicted Q-LV interval >110 ms in 68% of patients. The R-IVCD group presented an unexpectedly longer Q-LV interval (127.0 ± 12.5 ms; 13/15 patients had Q-LV >110 ms). Patients with LBBB have a very prolonged Q-LV interval. Mid-QRS notching in lateral leads strongly predicts a longer Q-LV interval in L-IVCD patients. Patients with R-IVCD constitute a subgroup of patients with a long Q-LV interval.

New strict left bundle branch block criteria reflect left ventricular activation differences

AimsPacing lead electrical delays and strict left bundle branch block (LBBB) criteria were assessed against cardiac resynchronization therapy (CRT) outcome. MethodsForty-nine patients with LBBB and QRS duration >130 milliseconds underwent CRT-implantation. Sensed right ventricular to left ventricular electrical delay (RV-LV-IED) was measured. Response to CRT was defined as ≥15% decrease in left ventricular end-systolic volume. ResultsEighteen of 20 (90%) patients with non-ischemic dilated cardiomyopathy (DCM) and 18 of 29 (62%) with ischemic heart disease (IHD) responded to CRT, p<0.01. When applying new strict ECG criteria subsequent rates of response in DCM were 18/19 (95%) and in IHD of 18/23 (78%) respectively, p<0.05 between IHD groups. Correspondingly, RV-LV-IED was longer in DCM compared to IHD patients and in responders compared to non-responders, p=0.017 and p<0.001, respectively. ConclusionInterventricular electrical delay predicts left ventricular remodeling after CRT and new, strict ECG criteria of LBBB are superior in predicting remodeling.

Determination of the Longest Intrapatient Left Ventricular Electrical Delay May Predict Acute Hemodynamic Improvement in Patients After Cardiac Resynchronization Therapy

Background— One of the reasons for patient nonresponse to cardiac resynchronization therapy is a suboptimal left ventricular (LV) pacing site. LV electric delay (Q-LV interval) has been indicated as a prognostic parameter of cardiac resynchronization therapy response. This study evaluates the LV delay for the optimization of the LV pacing site. Methods and Results— Thirty-two consecutive patients (23 men; mean age, 71±11 years; LV ejection fraction, 30±6%; 18 with ischemic cardiomyopathy; QRS, 181±25 ms; all mean±SD) underwent cardiac resynchronization therapy device implantation. All available tributary veins of the coronary sinus were tested, and the Q-LV interval was measured at each pacing site. The hemodynamic effects of pacing at different sites were evaluated by invasive measurement of LV d P /d t max at baseline and during pacing. Overall, 2.9±0.8 different veins and 6.4±2.3 pacing sites were tested. In 31 of 32 (96.8%) patients, the highest LV d P /d t max coincided with the maximum Q-LV interval. Q-LV interval correlated with the increase in LV d P /d t max in all patients at each site (AR1 ρ=0.98; P &lt;0.001). A Q-LV value &gt;95 ms corresponded to a &gt;10% in LV d P /d t max . An inverse correlation between paced QRS duration and improvement in LV d P /d t max was seen in 24 patients (75%). Conclusions— Pacing the LV at the latest activated site is highly predictive of the maximum increase in contractility, expressed as LV d P /d t max . A positive correlation between Q-LV interval and hemodynamic improvement was found in all patients at every pacing site, a value of 95 ms corresponding to an increase in LV d P /d t max of ≥10%.

The Effect of Left Ventricular Electrical Delay on the Acute Hemodynamic Response with Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) improves hemodynamic function, as well as reduces hospitalizations and mortality among patients with systolic dysfunction, QRS prolongation, and heart failure. The magnitude of the hemodynamic response is associated with improved outcomes, so optimization of this parameter is a goal of therapy. The purpose of this study was to evaluate the effect of left ventricular (LV) electrical delay, as assessed by the QLV interval, on the acute hemodynamic response to CRT. This study included 31 patients undergoing biventricular ICD placement. At implant, invasive LV dP/dt was measured by a micromanometer catheter during biventricular (BV) or LV only pacing. Both atrial sensing (AS) and atrial pacing (AP) modes were evaluated at 5 different AV delays, tested in randomized order. The QLV interval was measured at the LV pacing site. Compared with intrinsic rhythm, CRT increased LV dP/dtmax by 9.5 ± 8.8% with BV pacing and 10.0 ± 9.2% with LV pacing (P = 0.38) during AS. With AP, CRT increased LV dP/dtmax by 16.0 ± 10.8% and 15.3 ± 11.1%, respectively (P = 0.47). QLV was strongly correlated with the hemodynamic response in all pacing configurations. Multivariate analysis showed that with BV pacing QLV was an independent predictor of the hemodynamic response with a 1.7% increase in %LV dP/dt for every 10 milliseconds prolongation of QLV. LV electrical delay is a strong predictor of the acute hemodynamic response to CRT. This relationship is independent of pacing mode.

The anatomic and electrical location of the left ventricular lead predicts ventricular arrhythmia in cardiac resynchronization therapy

Both anatomic and electrical locations of the left ventricular (LV) lead have been identified as important predictors of clinical outcomes in cardiac resynchronization therapy (CRT). The impact of LV lead location on incident device-treated ventricular arrhythmia (VA), however, is not well understood. To assess the relationship between electrical and anatomic LV lead location and device treated VAs in CRT. Sixty-nine patients undergoing CRT implantation for standard indications were evaluated. Anatomic LV lead location was assessed by means of coronary venography and chest radiography and categorized as apical or nonapical. Electrical LV lead location was assessed by LV electrical delay (LVLED) and was calculated as the time between the onset of the native QRS on the surface electrocardiogram and sensed signal on the LV lead during implantation and corrected for native QRS. Incident appropriate device-treated VA was assessed via device interrogation. Apical lead placement was an independent predictor of VAs (hazard ratio 5.29; 95% confidence interval 1.69-16.5; P = .004). Among patients with a nonapical lead, LVLED<50% native QRS was an independent predictor of VAs (hazard ratio 6.90; 95% confidence interval 1.53-31.1; P = .012). Those with a nonapical lead and LVLED ≥ 50% native QRS were at substantially lower risk for first incident and recurrent VAs when compared to all other patients. The apical lead position is associated with an increased risk of VAs in CRT patients. Among patients with a nonapical lead position, an LVLED of<50% of the native QRS is associated with an increased risk of VAs.

Transesophageal left ventricular electrogram-recording and temporary pacing to improve patient selection for cardiac resynchronization

Cardiac resynchronization therapy (CRT) with biventricular pacing (BV) is an established therapy for heart failure (HF) patients with inter- and intraventricular conduction delay. The aim of this pilot study was to test the feasibility of both transesophageal measurement of left ventricular (LV) electrical delay and transesophageal LV pacing prior to implantation, to better select patients for CRT. Esophageal TO8 Osypka catheter was perorally applied in 30 HF patients in position of maximum LV deflection to measure LV electrical delay and to study arterial pulse pressure (PP) during transesophageal bipolar LV pacing. There were 15 responders with a PP increase of a mean 65 ± 24 mmHg to 79 ± 27 mmHg (P < 0.001) and a mean LV electrical delay of 86.8 ± 33 ms. The 15 non-responders with poor PP increase of a mean 63.5 ± 23.5 mmHg to 64.1 ± 23.9 mmHg (P = 0.065) had a significantly smaller LV electrical delay of 36 ± 21 ms (P < 0.001). During a 34 ± 26 month CRT follow-up, the responders New York Heart Association (NYHA) class improved from 3.1 ± 0.35 to 2.1 ± 0.35 (P < 0.001). Determination of left ventricular electrical delay by transesophageal electrogram recording and transesophageal left ventricular pacing may be additional useful techniques to improve patient selection for CRT.