Right Ventricular Septum Research Articles

The usefulness of a delivery catheter system for right ventricular "true" septal pacing.

Right ventricular (RV) septum is an alternate site for the placement of RV lead tip instead of RV apex. Recent studies have demonstrated that less than half of the RV leads targeted for septal implantation are placed on the RV septum using a conventional stylet system; new guiding catheter systems have become available for RV lead placement. This study aimed to investigate the usefulness of the delivery catheter system in lead placement on the RV septum when compared with the stylet system. We retrospectively evaluated 198 patients who underwent fluoroscopically guided pacemaker implantation with RV leads targeted to be placed in the RV septum and in whom computed tomography was incidentally and subsequently performed. A delivery catheter was used in 16 patients, and a stylet in 182 patients. The primary endpoint of this study was the success rate of RV lead placement on the RV septum. The proportion of RV lead placement on the RV septum was higher in the delivery catheter group than in the stylet group (100% vs. 44%; p < 0.001). In the stylet group, the lead tips were placed at the hinge in 92 cases (51%) and on the free wall in 9 cases (5%). Paced QRS duration was narrower in the delivery catheter group than in the stylet group (128 ± 16 vs. 150 ± 21ms, p < 0.01). The delivery catheter system designated for pacing leads may aid in selecting RV septal sites and achieve good physiologic ventricular activation.

TRICUSPID VALVE REGURGITATION IN PATIENTS UNDERGOING ENDOCARDIAL LEADS PLACEMENT

Objective: To assess prospectively the presence and degree of tricuspid regurgitation (TR) after right ventricular (RV) lead placement utilizing 2-dimensional and doppler echocardiography in a group of patients implanted with Permanent pace-maker or implantable cardioverter defibrillator (ICD).&#x0D; Study Design: Descriptive cross sectional study.&#x0D; Place and Duration of Study: Study was conducted at OPD of AFIC/NIHD Rawalpindi from Jan to Jun 2019.&#x0D; Methodology: One hundred patients after cardiac stimulation system implantation were included in this study. Patients with severe valve disease, heart failure, congenital heart disease, pre-existing pulmonary hypertension and presence of moderate or severe tricuspid regurgitation were excluded. M-mode, 2 –dimensional and doppler echocardiographic studies were performed. Continuous-wave doppler measurements were made from apical four-chamber view in order to obtain maximum tricuspid flow velocities. A complete echocardiographic study was performed following device implantation. Echocardiographic measurements were repeated at 6-months of follow-up period. Those patients who developed tricuspid regurgitation were further assessed by color doppler, taking into account density and contour of the jet on continuous-wave doppler. Tricuspid regurgitation severity was classified into three groups: mild, moderate and severe according to the recommendations for non-invasive evaluation of native valvular regurgitation by the American Society of Echocardiography. The collected data was analysed by using SPSS-23.&#x0D; Results: Out of 100 patients, 67 (67%) were males and 33(33%) were females with the mean age of 65.29 ± 12.02 years. All the patients had normal chambers dimensions before the procedure. 65 (65%) had leads screwed to RV apex while 35 (35%) had through RV septum. 83 (83%) patients received a dual chamber device, while 17 (17%) patients got single chamber (ventricular) device implanted. Following device implantation after 6 months mild TR was noted in 4 (4%), moderate TR in 4 (4%) and severe TR 2 (2%) in cases.&#x0D; Conclusion: Tricuspid incompetence following endocardial leads implantation is not rare and occurred in approximately 10% of our patients. This complication may be preventable, because it is likely due to the interference of the endocardial lead with the TV.

Abstract 12947: Development of Molecular Targeted Therapy Against Right Ventricular Failure: Involvement in A Network of Immunocompetent Cells

Backgrounds: Right ventricular (RV) failure plays a critical role in right heart failure and left heart failure. However, there is no specific therapy developed for RV failure. To elucidate a novel therapeutic target against RV failure, we focus on differentially expressed genes in RV to develop novel therapeutics for RV failure. Methods: Microarray analysis using several parts of adult murine heart was conducted and differentially expressed genes (DEGs) were applied to pathway analysis by Ingenuity Pathway Analysis R . Molecular mechanism was examined by using neonatal rat ventricular cardiomyocyte (NRVM) in vitro . To understand the function of target molecule in vivo , we induced RV failure by pulmonary artery constriction (PAC) in mice and inhibition experiments were performed using these RV failure model mice. Results: In microarray analysis for RV, left ventricle and ventricular septum, 995 genes were extracted as DEGs in RV. Pathway analysis revealed that alternative complement pathway-related genes were significantly up-regulated in RV. Moreover, complement factor D (Cfd) and C3a was a potential upstream factor attributable to unique feature of RV. Administration of C3a recombinant protein to NRVM phosphorylated several MAP kinases. Moreover, in C3KO PAC mice, RV dysfunction was significantly suppressed, and histological study suggested that RV fibrosis was significantly suppressed by comparing to wild type PAC mice. Furthermore, administration of C3a receptor antagonist to wild type PAC mice dramatically improved RV dysfunction and reduced RV fibrosis. Additionally, in vivo electrophysiological study revealed that the inducibility of ventricular arrhythmia was increased in wild type PAC mice, but ventricular arrhythmia was significantly attenuated in C3KO PAC mice. Conclusion: We revealed that complement C3a was highly produced in RV, and genetic or chemical blockade of C3a ameliorates RV dysfunction and RV fibrosis in RV failure model mice. C3a was to be a potent bioactive protein for immunocompetent cells that played an important role in modulating RV function. Accordingly, we demonstrated that the blockade of C3a had a potential role for novel therapeutic target of RV failure.

Activation pattern during his pacing: how close are we to normal physiology?

Abstract Background His bundle pacing aims to mimic the activation pattern of normal conduction to maintain ventricular synchrony. However, selective His capture can be challenging, and the activation sequence during His pacing may not replicate normal conduction. Purpose Compare the right ventricular (RV) and left ventricular (LV) activation pattern in sinus rhythm and His bundle pacing. Methods Baseline LV and RV map was created in sinus rhythm using Rhythmia mapping system (Boston Scientific Corporation) in canine animal model. Medtronic 3830 lead was placed near the bundle of His under fluoroscopic, intracardiac echocardiogram, and electroanatomic guidance. Conduction system capture was confirmed by observing a QRS duration &amp;lt;120ms and an isoelectric segment between pacing artifact and QRS on surface ECG. Repeat LV and RV activation map was obtained during His pacing. Average QRS, HV and pacing to V intervals were calculated with standard deviation. Results Mapping was performed successfully in four animals. At baseline, the average QRS duration was 44±2.6ms and HV interval was 32±4.2ms. Earliest site of myocardial activation was in the mid-septal LV region. The earliest RV myocardial activation was also at the septum closer to the apex, but later than the LV (Figure1A). With His pacing, the average QRS duration was 70±17.0ms and the average stim to V interval was 31±8.7ms. During His pacing, the earliest site of activation was in the RV septum, with an activation pattern from base to apex in both the RV and LV. Conclusion Unlike normal physiology, the activation pattern during conduction system pacing is from base to apex with earliest site in the RV. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): Mayo Clinic

Electrical characteristics of deep septal vs. left bundle branch (area) pacing

Abstract Background/Introduction Recent studies have described transvenous left bundle branch (LBB) pacing as a new conduction system pacing strategy. However, information on effect of pacing depth within the septum and the additional effect of LBB capture is unknown. Purpose To investigate the relation of electrocardographic characteristics with transseptal LV lead implantation depth and LBB capture. Methods 20 consecutive patients referred for pacemaker implantation were enrolled. The right atrial (RA) lead was positioned according to routine practice. The LV septal pacing lead (Medtronic 3830) was transvenously positioned against the right side of the interventricular septum and advanced in small steps of 1–2mm towards the left side of the septum. At each depth in the septum 12-lead ECG's were recorded during pacing, from which vectorcardiograms (VCG) were calculated. QRS duration and QRS area were measured, the latter being the integral of the QRSarea in X, Y and Z directions. Successful LBB capture was defined as paced right bundle branch block (RBBB) morphology, stable and short stimulus to LV activation time (LVAT; R in V5) and recorded LBB potential. Differences were compared among pacing conditions using repeated measures ANOVA with Bonferroni multiple comparisons procedure applied to pairwise comparisons. Statistical significance was assumed at p&amp;lt;0.05. Results LV septal lead implantation was successful in all patients. Left bundle branch capture was achieved in 10/20 patients (50%). Post-procedural LV pacing threshold, impedance and sensing was 0.7±0.1 V at 0.5 ms pulse width, 658±5 Ω and 13±10 mV, respectively. Compared to intrinsic rhythm, QRS duration was significantly increased by both RV septum (RVS; 124±5 vs. 161±3 ms) and LV septum pacing (LVS; 142±3 ms). QRS area increased significantly during RVS pacing as compared to intrinsic rhythm but decreased when moving from RVS to LVS to values close to intrinsic rhythm (panel A &amp; B). LVS-pacing derived QRS area was significantly lower in patients with LBB capture (36±6 mV*ms) compared to patients without LBB capture (deep septal pacing; 46±12 mV*ms). The reduction in QRS area between RVS and LVS pacing coincided with normalization of the QRS vector in the transverse plane (panel C), which is characterized electrocardiographically by predominantly negative-to-positive inversion of the QRS complex in the precordial leads (V1-V3). Conclusions Compared to RV septal pacing, LV septal pacing restores ventricular electrical synchrony, as determined by QRS area, and normalizes the activation vector in the transverse plane to a level comparable to intrinsic rhythm. Differences in resynchronization between left bundle branch pacing and deep septal pacing are small. LBBAP restores ventricular synchrony Funding Acknowledgement Type of funding source: None

Salvage DC ablation of ventricular tachycardia following failed RF attempts

Abstract Background Ablation of ventricular tachycardia (VT) is a frequent clinical necessity. Modification of ventricular substrate can usually be achieved by radiofrequency ablation (RF). We present 4 cases of failed RF for recurrent VT. Two patients had multiple RF failures, one patient had in-procedure failure, and one patient had multiple RF attempts and a failed alcohol ablation (pt4). Objective To evaluate success of DC ablation after failed RF Methods A 6 Fr 4mm tip steerable ablation catheter, was placed at the site felt to be critical for the circuit following mapping (earliest activation, mid-diastolic, fractionated, site of concealed entrainment, or ventricular breakout). Two connection cables were utilized, one to the recording/mapping system, and one connected to an external biphasic defibrillator (DC). The DF was connected with one pad anterior chest and the other connected by the cable to electrode pins 1 and 2 folded within the second pad. The electrodes were secured by placing a hemostat on the pad. DC energy (360j) was delivered synchronized by electrodes 1–2 Results During follow-up 3 months to 1 year, no recurrent VT was observed. 3 patients received a total of 4 DC pulses, while the pt4 received 16 (RV and LV septum), complicated by prolonged hypotension. No other complications were observed. Figure shows broad RV breakout from the septum in pt4. Conclusion In patients with RF refractory VT, DC ablation may be safely used and in this limited series, provides long-term success. Interestingly, biphasic energy did not induce transient hypotension in 3 of 4 pts. DC ablation should be considered following failed RF, especially when mid-myocardial origin suspected. Funding Acknowledgement Type of funding source: None

Left Ventricular Dysfunction Correlates With Mortality in Pulmonary Embolism.

Risk stratification of patients with pulmonary embolism (PE) is essential to guide advanced interventional management and proper disposition. In this study, we sought to assess individual echocardiographic markers of right ventricular (RV) strain and left ventricular (LV) function in patients with high-risk PE and identify their association with the need for advanced intervention (such as thrombolysis) and 30-day mortality. This was a retrospective study of ED patients with PE who were subject to a pulmonary embolism response team activation over a 5-year period. Cardiac point-of-care ultrasound studies were performed as part of patient care and later assessed for septal bowing, RV hypokinesis, McConnell sign, RV enlargement, tricuspid annular place systolic excursion, and LV systolic dysfunction. Outcome variables included need for advanced intervention and 30-day mortality. The pulmonary embolism response team was activated in 893 patients, of which 718 had a confirmed PE. Of these, 90 had adequate cardiac point-of-care ultrasound images available for review. Patients who needed an advanced intervention were more likely to have septal bowing (odds ratio [OR] 8.69, 95% confidence interval [CI] 2.37-31.86), RV enlargement (OR 4.02, 95% CI 1.43-11.34), and a McConnell sign (OR 2.79, 95% CI 1.09-7.13). LV dysfunction was the only statistically significant predictor of 30-day mortality (OR 9.63, 95% CI 1.74-53.32). In patients with PE in the ED, sonographic findings of RV strain that are more commonly associated with advanced intervention included septal bowing, McConnell sign, and RV enlargement. LV dysfunction was associated with a higher 30-day mortality. These findings can help inform decisions about ED management and disposition of patients with PE.

Novel mesh-derived right ventricular global longitudinal strain predicts ICU outcomes in patients undergoing coronary artery bypass grafting

Introduction Right ventricular (RV) strain analysis proved to be prognostically relevant in various cardiac diseases. However, data regarding outcome prediction by RV strain analysis during surgical coronary revascularization are limited. Three-dimensional (3D) transesophageal echocardiography-based (TEE) methods dedicated to the RV might be advantageous over established measures of cardiac function. Methods 87 patients undergoing coronary artery bypass grafting with (CABG, n=49) or without cardiopulmonary bypass (off-pump coronary artery bypass grafting, OPCAB, n=38) were enrolled retrospectively if suitable 3D-TEE was performed after anesthesia induction. Post-hoc offline analysis using 3D-STE software (4D RV-Function 2.0, Tomtec) was used to generate RV meshes. Regional and RV global longitudinal and circumferential strain analysis on the surface of the meshes was performed using a custom-made software algorithm based on the Visualization Toolkit (www.vtk.org). Global RV and left ventricular (LV) ejection fraction (EF) as well as LV global longitudinal strain (LV-GLS) were assessed using commercially available 3D-STE software packages (4D RV-Function 2.0 and 4D LV-Analysis, Tomtec). Prolonged (>48 hours) post-operative mechanical ventilation was used as the primary end-point. Results RV strain analysis was feasible in all patients (100%). Mean RV global longitudinal strain (RV-GLS) and mean RV global circumferential strain (RV-GCS) was -14.1±4.6% and -15.7±4.7% respectively. Between CABG and OPCAB patients, neither RV-GLS (-14.3±4.6% vs. 13.8±4.7%, p=0.62) nor RV-GCS (-15.9±4.4% vs. -15.4±5.1%, p=0.60) was significantly different. In univariate regression models, septal longitudinal RV strains (p Discussion In patients undergoing coronary artery bypass surgery, right ventricular global longitudinal strain analysis on meshes derived from transesophageal 3D-STE is superior in predicting short-term ICU outcomes compared to conventional parameters of right or left ventricular function and might be helpful to identify patients at higher risks for post-operative complications.

When The “Genes” No Longer Fit: An Unusual Presentation of LMNA-related Cardiomyopathy

Introduction The diagnosis of dilated cardiomyopathy from genetic mutation of Lamin A/C (LMNA) is quite challenging in absence of known family disease or signs of skeletal myopathy. We present a case of high-grade AV block and septal ventricular tachycardia (VT) requiring orthotopic heart transplantation with post-transplant genetic testing showing LMNA-related dilated cardiomyopathy. Case A 58-year-old man with history of orthotopic liver transplant (OLT) for Hepatitis C cirrhosis and no familial cardiac history initially presented with symptomatic, sustained left bundle left superior axis ventricular tachycardia at 230 bpm. Baseline ECG after DCCV demonstrated a LBBB with periods of 2:1 AV block. Patient underwent an ischemic evaluation which was unremarkable. Cardiac MRI was negative for infiltrative disease but did show midmyocardial late gadolinium enhancement at the inferoseptal and apical right ventricle. He underwent secondary prevention CRT-D implantation. He had recurrent VT requiring radiofrequency ablation for inducible bundle-branch reentry VT. One year later, he presented with recurrent VT and underwent attempted radiofrequency ablation of numerous septal VT morphologies resulting in shock-refractory sustained VT complicated by cardiogenic shock requiring VA-ECMO and ultimately orthotopic heart transplantation. Pathology of the explanted heart showed scarring and fatty infiltration of the RV septum and free wall suggestive of a variant of arrhythmogenic right ventricular cardiomyopathy (ARVC). However, despite suspicion for ARVC on pathology, genetic testing showed a genetic mutation in Lamin A/C Gene, suggestive of laminopathy. Conclusion Our case shows that LMNA-related dilated cardiomyopathy can present with phenotypic appearance similar to patients with pathologic suspicion of ARVC. Although LMNA-related dilated cardiomyopathy contributes to 6-8% of familial related cardiomyopathy, it is often difficult to diagnose due to its inheritance and penetrance. Patients presenting with unclear etiology of dilated cardiomyopathy and malignant ventricular arrhythmias should prompt a suspicion for LMNA-related cardiomyopathy.

Abstract 297: Development of Molecular Targeted Therapy Against Right Ventricular Failure: Involvement in a Network of Immunocompetent Cells

Backgrounds: Right ventricular (RV) failure plays a critical role in right heart failure and left heart failure. However, there is no specific therapy developed for RV failure. To elucidate a novel therapeutic target against RV failure, we focus on RV specific genes to develop novel therapeutics for RV failure. Methods: Microarray analysis using several parts of adult murine heart was conducted and differentially expressed genes (DEGs) were applied to pathway analysis. Molecular mechanism was examined by using neonatal rat ventricular cardiomyocyte (NRVM) in vitro. To understand the function of target molecule in vivo, we induced RV failure by pulmonary artery constriction (PAC) in mice and inhibition experiments were performed using RV failure model. Results: In microarray analysis for RV, left ventricle and ventricular septum, 995 genes were extracted as DEGs in RV. Pathway analysis showed that alternative complement pathway-related genes were significantly up-regulated in RV. Moreover, complement factor D (Cfd) and C3a was a potential upstream factor attributable to unique feature of RV. Administration of C3a recombinant protein to NRVM phosphorylated several MAP kinases. In vivo, in C3KO PAC mice, RV dysfunction was significantly suppressed, and histological study showed that RV fibrosis was significantly suppressed. In wild type mice with PAC, administration of C3a receptor antagonist dramatically improved RV dysfunction and reduced RV fibrosis. Additionally, in vivo electrophysiological study revealed that the inducibility of ventricular arrhythmia was increased in wild type PAC mice, but ventricular arrhythmia was significantly attenuated in C3KO PAC mice. Furthermore, the expression of chemokine Ccl5 was enhanced in RV of wild type PAC mice, while Ccl5 was significantly attenuated in C3KO PAC mice. Conclusion: We revealed that complement C3a was highly produced in RV and chemical or genetical blockade of C3a ameliorates RV dysfunction and RV fibrosis in PAC mice. C3a was to be a potent bioactive protein for immunocompetent cells that played an important role in modulating cardiac function. Accordingly, we demonstrated that the blockade of C3a had a potential role for novel therapeutic target to RV failure.

His-bundle pacing is the best approach to physiological pacing.

His-bundle pacing is the best approach to physiological pacing.

62: High posterior wall defects: A laparoscopic approach

To demonstrate a laparoscopic technique for repairing high defects in the posterior vaginal wall. High defects in the posterior vaginal wall may result from apical detachment of the fascia of the posterior vaginal wall and resist repair by a traditional colporrhaphy because there is little or no lateral connective tissue that can be brought together over the defect. Instead, it is frequently effective to re-suspend the posterior wall fascia from the apex using the uterosacral ligaments as an attachment point. We identify the upper edge of the “RV septum” connective tissue by finding the point at which the ruggae disappear. An Alice clamp is placed to mark the top of the septum. Laparoscopy is then performed, and the top of the RV septum can be identified by manipulating the clamp. Sutures are placed attaching the RV septum to the uterosacral ligaments. Kinking of the ureters is prevented by opening the peritoneum between the ureters and the uterosacral ligaments. A traditional colporrhaphy or perineorrhaphy may be performed to address laxity in the distal posterior vaginal wall if needed. Laparoscopic resuspension of the posterior wall fascia from the uterosacral ligaments provides a sturdy and anatomic repair for high defects in the posterior vaginal wall.

Right Ventricular Electrogram Characteristics in a T1 Mapping-Validated Normal Population: Implications for Unipolar Voltage Mapping.

The aim of this study was to define normal ventricular electrographic characteristics in T1 mapping-validated normal patients using a contemporary contact force catheter. Reference values for human endocardial ventricular electrographic characteristics have not been defined using contemporary mapping equipment in patients without heart disease or ventricular arrhythmias. Fourteen patients undergoing SVT ablation underwent mapping of the right ventricle and cardiac magnetic resonance imaging with T1 mapping. Electrograms (EGMs) from sites with >10 g of contact force from the right ventricular free wall (RVFW) and right ventricular septum (RVS) were analyzed. Values<5th percentile or >95th percentile were defined as abnormal. The median age was 27 years, 64% of patients were men, and the mean left ventricular ejection fraction was 60%. Native T1 values (mean 979ms) of the study population were comparable with that of a normal volunteer population. Ninety-five percent of bipolar EGMs had<6 (RVFW) or<7 (RVS) deflections and duration<37ms. Ninety-five percent of unipolar EGMs had a maximum dV/dt >0.23mV/ms (RVFW) or >0.24mV/ms (RVS). Ninety-five percent of unipolar EGMs had a peak-to-peak voltage >3.8mV (RVFW) or >4.5mV (RVS). In structurally normal hearts, the threshold for abnormal endocardial unipolar voltage in the RVFW (3.8mV) is lower than that of the current standard (5.5mV). The unipolar voltage characteristics of the RVS is distinct from that of the RVFW and left ventricle. This has implications for the detection of intramural or epicardial and especially midseptal scar.

Surface ECG criteria can discriminate post-septal pacing cardiac memory from ischemic T wave inversions

Cardiac memory (CM) refers to transient T wave changes that appear after cessation of a period of abnormal ventricular activation, such as right ventricular (RV) pacing. ECG criteria for differentiating post-pacing CM from ischemia-induced T wave changes were previously published only for apical, but not for septal RV pacing. AimTo find ECG criteria for discriminating post-septal pacing CM from ischemic T wave inversions. MethodsECGs were analyzed in 2 groups: CM (n = 23) and ischemia (n = 26). CM was induced by 2 weeks of DDD pacing with a short AV delay. Ischemic patients were grouped by culprit vessel: left anterior descending (LAD), circumflex (Cx), right coronary artery (RCA). ResultsCM was visible on the ECG after 1 week of ventricular pacing, started to disappear in <1 week after pacing cessation and was completely reversible within 4 weeks of pacing cessation. T wave axis differed between CM (75.8 ± 18.5°) and Cx (−25.2 ± 25.5°, p < 0.01) and RCA (−18.3 ± 18.9°, p < 0.01) groups, but not compared to LAD group (96.4 ± 65.0°, p = 0.17). The combination of (1) positive T wave in aVF; and (2) (i) T wave amplitude in aVF ≥ the absolute value of the most negative precordial T wave, or (ii) positive T wave in V5 and positive or isoelectric T wave in lead I identified CM from all ischemia with a sensitivity of 91% and a specificity of 92%. ConclusionECG criteria can discriminate post-septal RV pacing CM from ischemic changes with high sensitivity and specificity.

P2567First experience of non-invasive and invasive activation maps merge in carto system for topical diagnosis of focal arrhythmias

Abstract Background Correct preoperative topical diagnostics of atrial and ventricular arrhythmias allows for operation time reduction by facilitating the ablation target localization, especially in case of several ectopic sources. Purpose To implement a non-invasive electrocardiographic imaging (ECGI) technique in CARTO system for aiming at topical diagnostics of focal arrhythmias improving. Methods Twelve patients (m/f – 10/2, age (min–max) – 50,5 (32–71)) with focal arrhythmias underwent ECGI in combination with CT or MR imaging. Two subjects had atrial premature contractions (PAC), while ten patients suffered from ventricular premature contractions (PVC) with indications for ablation. Before the ablation procedure Carto LAT mapping was performed in all patients. Using ECGI epi-/endocardial polygonal models of the heart were created, isopotential and activation maps were calculated, uploaded into the Carto system and merged with the CARTO FAM models (Figure 1). Results For six patients with PVC and two patients with PAC, earliest activation zones (EAZs) anatomical locations obtained by invasive and non-invasive methods were the same (RVOT septum, RVOT lateral-anterior and RV lateral-basal walls, right aortic cusp, LVOT, coronary sinus (CS), CS ostium, RA posterior wall), and arrhythmias ablation was successful. Two patients featured coherent EAZs (RV lateral-basal wall and RVOT septum) but a negative ablation outcome. In one patient, EAZs were situated in different anatomical regions: CARTO showed the PVC EAZ in RV septum, whereas Amycard system identified endocardial surface of lateral-basal RV wall. In this patient, PVC was ablated partially. For another patient with MRI late enhancement area in LV lateral wall the EAZs were in the same LV segment but with mismatch in epi/endocardial surface. Conclusion Non-invasive and invasive activation maps merge can improve localization of ablation targets in focal arrhythmias, potentially increasing effectiveness of the EP procedure and reducing operation time.

P1496Use of strain, strain rate, tissue velocity imaging and endothelial function for early detection of cardiovascular involvement in young diabetics

Abstract Background Subtle structural and functional changes may precede the onset of overt global left ventricular dysfunction and obvious reduction of ejection fraction (EF), especially in young diabetics. Data pertaining to tissue velocity indices (TVI) and strain imaging to assess regional myocardial function and flow mediated vasodilatation is limited in young patients with diabetes. Purpose To evaluate conventional echocardiography parameters, tissue doppler indices, global and regional strain, carotid intimal medial thickness (CIMT), endothelial dependent (FMD) and independent function (NMD) of brachial artery in young patients (age &lt;18 years) with type 1 diabetes and compare them with matched controls. Methods Conventional echocardiography parameters, tissue velocity indices (TVI) parameters along with strain (S), and strain rate (SR) in basal and mid left ventricular (LV) lateral wall, right ventricular (RV) lateral wall and septum were measured in 50 young diabetics (age 15.16±2.95 years, mean HBA1c 8.15±1.37 gm %) and 25 controls (age 15.60±2.51 years). Flow-mediated dilatation (FMD), nitrate mediated dilatation and carotid intimal media thickness (CIMT) were also estimated. Results Conventional echocardiography parameters were similar in patients and controls however deceleration time of the mitral inflow velocity (EDT) was significantly shorter in patients when compared with controls (149.06±31.66 vs. 184.56±19.27 ms, p&lt;0.05). Lateral early diastolic myocardial velocity (LV-Em) was significantly lower (10.30±0.99 vs. 11.67±3.21, p&lt;0.05) whereas lateral late diastolic myocardial velocity (LV-Am) was significantly higher than controls (11.73±1.44 vs. 8.82±1.69, p&lt;0.05), thus a significantly lower ratio of early/late diastolic velocity at the basal segment of lateral LV (LV-Em/Am). Lower strain values at the basal lateral LV (21.39±4.12 vs. 23.78±2.02; p&lt;0.05), mid lateral LV (21.43±4.27 vs. 23.17±1.92; p&lt;0.05), basal septum (20.59±5.28 vs. 22.91±2.00; p&lt;0.05), and mid septum (22.06±4.75 vs. 24.10±1.99; p&lt;0.05) as compared to controls. SR at the basal and mid segments of the lateral LV wall and at the basal septum were also significantly lower in diabetic subjects. Strain rate (SR) in mid septal, basal and mid RV were lower than controls although not statistically significant. Patients also had significantly lower flow mediated dilatation (FMD) (8.36±4.27 vs. 10.57±4.12, p&lt;0.05) implying endothelial dysfunction. Strain rate in diabetic patient Conclusion Left ventricular strain indices are impaired in asymptomatic children and adolescents with type 1 DM despite absence of overt heart failure and normal ejection fraction. Early detection of subclinical regional myocardial dysfunction by deformation analysis including strain and strain rate may be useful in the asymptomatic diabetic population. In addition, evidence of endothelial dysfunction in the form of impaired flow mediated vasodilatation was observed in the diabetic children. Acknowledgement/Funding None

Differential effect with septal and apical RV pacing on ventricular activation in patients with left bundle branch block assessed by non-invasive electrical imaging and in silico modelling

PurposeIt is uncertain whether right ventricular (RV) lead position in cardiac resynchronization therapy impacts response. There has been little detailed analysis of the activation patterns in RV septal pacing (RVSP), especially in the CRT population. We compare left bundle branch block (LBBB) activation patterns with RV pacing (RVP) within the same patients with further comparison between RV apical pacing (RVAP) and RVSP.MethodsBody surface mapping was undertaken in 14 LBBB patients after CRT implantation. Nine patients had RVAP, 5 patients had RVSP. Activation parameters included left ventricular total activation time (LVtat), biventricular total activation time (VVtat), interventricular electrical synchronicity (VVsync), and dispersion of left ventricular activation times (LVdisp). The direction of activation wave front was also compared in each patient (wave front angle (WFA)). In silico computer modelling was applied to assess the effect of RVAP and RVSP in order to validate the clinical results.ResultsPatients were aged 64.6 ± 12.2 years, 12 were male, 8 were ischemic. Baseline QRS durations were 157 ± 18 ms. There was no difference in VVtat between RVP and LBBB but a longer LVtat in RVP (102.8 ± 19.6 vs. 87.4 ± 21.1 ms, p = 0.046). VVsync was significantly greater in LBBB (45.1 ± 20.2 vs. 35.9 ± 17.1 ms, p = 0.01) but LVdisp was greater in RVP (33.4 ± 5.9 vs. 27.6 ± 6.9 ms, p = 0.025). WFA did rotate clockwise with RVP vs. LBBB (82.5 ± 25.2 vs. 62.1 ± 31.7 op = 0.026). None of the measurements were different to LBBB with RVSP; however, the differences were preserved with RVAP for VVsync, LVdisp, and WFA. In silico modelling corroborated these results.ConclusionsRVAP activation differs from LBBB where RVSP appears similar.Trial registration(ClinicalTrials.gov identifier: NCT01831518)

Efficacy of the current of injury in envisaging the dislodgement of leads implanted in the right atrial septum or the right ventricular septum.

The implantation of leads in the right atrial septum (RAS) or the right ventricular septum (RVS) is technically challenging, and dislodgement occurs occasionally. This study aims to determine a predictor for the dislodgement of leads implanted in the RAS or RVS. This retrospective cohort study enrolled 137 consecutive patients who underwent the cardiac implantable electronic devices implantation, using active fixation leads in the RAS and RVS. We compared the pacing threshold, R- or P-wave amplitude, slew rate, and presence of the current of injury (COI) between dislodged and nondislodged leads. We performed lead fixation for 74 and 125 times in the RAS and RVS, respectively. Atrial lead dislodgement occurred five times (6.8%) intraoperatively and five times (6.8%) postoperatively, whereas ventricular lead dislodgement occurred eight times (6.4%) intraoperatively and three times (2.4%) postoperatively. Although there were no lead parameters that showed a significant difference common to RAS lead and RVS lead, the presence of the COI was significantly different between nondislodged and dislodged leads in both the RAS and RVS (atrial leads: 57.8%vs 0%, P<0.001; ventricular leads: 67.5%vs 9.1%, P<0.001). The positive predictive value of COI presence for predicting no lead dislodgement was 100% and 98.7% in the RAS and RVS, respectively. Lead dislodgement is more likely when the COI is absent; documentation of COI should be pursued during lead implantation in challenging sites as the RAS and RVS.

Dynamic unipolar voltage criteria of right ventricular septum for identifying left ventricular septal scar.

The right ventricular (RV) septal unipolar voltage (UV) for predicting left ventricular (LV) septal scar wall thickness (WT) remains to be elucidated. From 2013 to 2015, data obtained from RV and LV electroanatomic maps of 28 patients (mean age, 53 ± 16years; 19 men [67.9%]) with/without identified LV septal scars were reviewed. Patients with an RV septal scar were excluded (n = 90). Direct measurement of septal WT was conducted (mean distance, 10.4 ± 3.3mm). Patients in group 1 had a normal LV substrate, while those in group 2 had an LV septal scar. Fisher's linear discriminant formula was used to determine the dynamic UV criteria. A total of 552 points were collected: 323 in 12 patients from group 1 and 229 in 16 patients from group 2. The UV of the RV septum is capable of identifying the opposite LV endocardial bipolar scar and is proportional to the WT of the interventricular septum. In the absence of an RV endocardial scar, the formula of "RV septal cut-off value = 0.736 × WT - 0.117mV" has better sensitivity and specificity for predicting the LV septal scar (0.96 vs. 0.68 and 0.91 vs. 0.80, respectively) than the predefined fixed criteria of 8.3mV with a net reclassification improvement of 25.7% (P < 0.001). The combined measurement of UV and WT is more sensitive than the predefined fixed UV criteria for defining deep scars.

Contemporary practice of CRT implantation in scandinavia compared to Europe

Objectives: To compare the contemporary practice of CRT implantation in Scandinavia and Europe. Design: We used data from The European CRT Survey II to highlight similarities and differences in the practice of CRT implantation between Europe (EUR) and Scandinavia (SCAND) and between the Scandinavian countries Denmark, Norway and Sweden. Implant data from the national pacemaker registries were used to calculate coverage. Results: The coverage was 24% in SCAND and 11% in EUR. SCAND patients were more often referred from another centre and follow-up was less often to be performed at the operating centre. Telemonitoring was more commonly used. More patients had AV-block or pacemaker dependency/expected high RV pacing percentage as indication for CRT. A CRT-P was more commonly used, and ischaemic aetiology was slightly less common. Echocardiography was more often used to determine LVEF, as well as occlusive venography and placing the RV lead first. In DK implanters tended to choose a septal RV position. Quadripolar leads were more often and a test shock less often used. The paced QRS duration was slightly longer and the narrowing of QRS with CRT more limited. Procedure times and preoperative LVEF were similar. Conclusions: In Scandinavia AV-conduction disturbance and/or a ventricular pacing indication was a more common indication for CRT, suggesting adaptation of the most recent guidelines ahead of their publication. A test shock was almost never performed, in agreement with recent scientific evidence. CRT-P was more often used, the procedures seem more centralized and quadripolar leads were preferred.