Project description:A 69-year-old woman with isolated cardiac sarcoidosis was hospitalized for frequent appropriate implantable converter defibrillator therapies for ventricular tachycardia (VT) despite of favorably controlled condition with oral prednisolone. The patient underwent urgent catheter ablation with CARTO 3D mapping system. Although the voltage map, activation map, and propagation map during VT could not visualize the tachycardia circuit, the coherent map clarified entrance and exit sites of the tachycardia circuit with slow or nonconducting (SNO) zones, which seemed like a figure-of-eight circuit. Considering the risk of VT termination or acceleration to rapid unstable VT, neither entrainment nor pacing studies were performed. The VT was terminated near the exit site of the isthmus where tiny pre-systolic potential was detected. Any diastolic potentials could not be detected. This meant that the critical isthmus might be located at the epicardium or deep incite of the left-ventricular myocardium where the coherent map showed as SNO zones. We should recognize coherent map as artificial that may represent VT circuit as if complete endocardial reentry even if not. The procedural time from mapping to termination of VT was only 22 minutes. The patient has been free from any cardiovascular events after the procedure. Coherent map might be feasible for revealing the critical isthmus of hemodynamically stable VTs without using electrophysiological techniques, including entrainment, pacing study, and voltage map during own beats, and would enable us to achieve successful VT ablation in a short time.
Project description:BackgroundAlthough premature ventricular complexes and ventricular tachycardia (VT) from outflow tracts are easy to map and ablate, some foci create the greatest challenges for the electrophysiologist. One such example is the 'Bermuda triangle' of the heart.Case summaryIn this article, we describe the rarely used but acceptable approach to the 'Bermudian' focus. We present a case of a 38-year-old male patient with sustained monomorphic VT, who underwent radiofrequency ablation of arrhythmogenic myocardium. After unsuccessful ablation through the posterior right ventricular outflow tract (RVOT), left coronary cusp (LCC), and distal coronary sinus, tachycardia was eliminated from the left atrial appendage (LAA). Complaints such as palpitations and weakness disappeared after the procedure.DiscussionRadiofrequency ablation of VT might be performed using LAA. This approach is used when the epicardial location of arrhythmia-causing tissue is suspected and ablation through the RVOT, LCC, and great cardiac vein fails.
Project description:Computational models have become essential in predicting medical device efficacy prior to clinical studies. To investigate the performance of a left-ventricular assist device (LVAD), a fully-coupled cardiac fluid-electromechanics finite element model was developed, incorporating electrical activation, passive and active myocardial mechanics, as well as blood hemodynamics solved simultaneously in an idealized biventricular geometry. Electrical activation was initiated using a simplified Purkinje network with one-way coupling to the surrounding myocardium. Phenomenological action potential and excitation-contraction equations were adapted to trigger myocardial contraction. Action potential propagation was formulated within a material frame to emulate gap junction-controlled propagation, such that the activation sequence was independent of myocardial deformation. Passive cardiac mechanics were governed by a transverse isotropic hyperelastic constitutive formulation. Blood velocity and pressure were determined by the incompressible Navier-Stokes formulations with a closed-loop Windkessel circuit governing the circulatory load. To investigate heart-LVAD interaction, we reduced the left ventricular (LV) contraction stress to mimic a failing heart, and inserted a LVAD cannula at the LV apex with continuous flow governing the outflow rate. A proportional controller was implemented to determine the pump motor voltage whilst maintaining pump motor speed. Following LVAD insertion, the model revealed a change in the LV pressure-volume loop shape from rectangular to triangular. At higher pump speeds, aortic ejection ceased and the LV decompressed to smaller end diastolic volumes. After multiple cycles, the LV cavity gradually collapsed along with a drop in pump motor current. The model was therefore able to predict ventricular collapse, indicating its utility for future development of control algorithms and pre-clinical testing of LVADs to avoid LV collapse in recipients.
Project description:ObjectivesIn this study the authors determined the extent of cellular infiltration and dispersion, and regional vascularization in electrophysiologically (EP) defined zones in post-myocardial infarction (MI) swine ventricle.BackgroundThe critical isthmus (CI) in post-MI re-entrant ventricular tachycardia (VT) is a target for catheter ablation. In vitro evidence suggests that myofibroblasts (MFB) within the scar border zone (BZ) may increase the susceptibility to slow conduction and VT, but whether this occurs in vivo remains unproven.MethodsSix weeks after mid-left anterior descending coronary artery occlusion, EP catheter-based mapping was used to assess susceptibility to VT induction. EP data were correlated with detailed cellular profiling of ventricular zones using immunohistochemistry and spatial distribution analysis of cardiomyocytes, fibroblasts, MFB, and vascularization.ResultsIn pigs with induced sustained monomorphic VT (mean cycle length: 353 ± 89 ms; n = 6) the area of scar that consisted of the BZ (i.e., between the normal and the low-voltage area identified by substrate mapping) was greater in VT-inducible hearts (iVT) than in noninducible hearts (non-VT) (p < 0.05). Scar in iVT hearts was characterized by MFB accumulation in the CI (>100 times that in normal myocardium and >5 times higher than that in the BZ in non-VT hearts) and by a 1.7-fold increase in blood vessel density within the dense scar region extending towards the CI. Sites of local abnormal ventricular activity potentials exhibited cellularity and vascularization that were intermediate to the CI in iVT and BZ in non-VT hearts.ConclusionsThe authors reported the first cellular analysis of the VT CI following an EP-based zonal analysis of iVT and non-VT hearts in pigs post-MI. The data suggested that VT susceptibility was defined by a remarkable number of MFB in the VT CI, which appeared to bridge the few remaining dispersed clusters of cardiomyocytes. These findings define the cellular substrate for the proarrhythmic slow conduction pathway.
Project description:Background Sarcoidosis is a granulomatous disease usually affecting the lungs, although cardiac morbidity may be common. The risk of these outcomes and the characteristics that predict them remain largely unknown. This study investigates the epidemiology of heart failure, atrioventricular block, and ventricular tachycardia among patients with and without sarcoidosis. Methods and Results We identified California residents aged ≥21 years using the Office of Statewide Health Planning and Development ambulatory surgery, emergency, or inpatient databases from 2005 to 2015. The risk of sarcoidosis on incident heart failure, atrioventricular block, and ventricular tachycardia were each determined. Linkage to the Social Security Death Index was used to ascertain overall mortality. Among 22 527 964 California residents, 19 762 patients with sarcoidosis (0.09%) were identified. Sarcoidosis was the strongest predictor of heart failure (hazard ratio [HR], 11.2; 95% CI, 10.7-11.7), atrioventricular block (HR, 117.7; 95% CI, 103.3-134.0), and ventricular tachycardia (HR, 26.1; 95% CI, 24.2-28.1) identified among all risk factors. The presence of any cardiac involvement best predicted each outcome. Approximately 22% (95% CI, 18%-26%) of the relationship between sarcoidosis and increased mortality was explained by the presence of at least 1 of these cardiovascular outcomes. Conclusions The magnitude of risk associated with sarcoidosis as a predictor of heart failure, atrioventricular block, and ventricular tachycardia, exceeds all established risk factors. Surveillance for and anticipation of these outcomes among patients with sarcoidosis is indicated, and consideration of a sarcoidosis diagnosis may be prudent among patients with heart failure, atrioventricular block, or ventricular tachycardia.
Project description:Differentiating between sarcoidosis and giant cell myocarditis (GCM) based on clinical presentation is difficult. We present the case of a 57-year-old woman who was initially diagnosed with GCM based on endomyocardial biopsy. The patient was refractory to standard management for GCM and went on to develop bidirectional ventricular tachycardia, a finding suggestive of sarcoidosis. Unfortunately, the patient eventually needed cardiac transplantation. The explanted heart demonstrated cardiac sarcoidosis. Bidirectional ventricular tachycardia has not been demonstrated in GCM, and its presence may help in distinguishing between GCM and cardiac sarcoidosis.
Project description:Data on relative safety, efficacy, and role of different percutaneous left ventricular assist devices for hemodynamic support during the ventricular tachycardia (VT) ablation procedure are limited.We performed a multicenter, observational study from a prospective registry including all consecutive patients (N=66) undergoing VT ablation with a percutaneous left ventricular assist devices in 6 centers in the United States. Patients with intra-aortic balloon pump (IABP group; N=22) were compared with patients with either an Impella or a TandemHeart device (non-IABP group; N=44). There were no significant differences in the baseline characteristics between both the groups. In non-IABP group (1) more patients could undergo entrainment/activation mapping (82% versus 59%; P=0.046), (2) more number of unstable VTs could be mapped and ablated per patient (1.05±0.78 versus 0.32±0.48; P<0.001), (3) more number of VTs could be terminated by ablation (1.59±1.0 versus 0.91±0.81; P=0.007), and (4) fewer VTs were terminated with rescue shocks (1.9±2.2 versus 3.0±1.5; P=0.049) when compared with IABP group. Complications of the procedure trended to be more in the non-IABP group when compared with those in the IABP group (32% versus 14%; P=0.143). Intermediate term outcomes (mortality and VT recurrence) during 12±5-month follow-up were not different between both groups. Left ventricular ejection fraction ?15% was a strong and independent predictor of in-hospital mortality (53% versus 4%; P<0.001).Impella and TandemHeart use in VT ablation facilitates extensive activation mapping of several unstable VTs and requires fewer rescue shocks during the procedure when compared with using IABP.
Project description:Catheter ablation of ventricular tachycardia (VT) can be technically challenging due to difficulty with catheter positioning in the left ventricle (LV) and achieving stable contact. The Hansen Sensei Robotic system (HRS) has been used in atrial fibrillation but its utility in VT is unclear.The purpose of this study was to test the technical feasibility of robotic catheter ablation of LV ventricular tachycardia (VT) using the HRS.Twenty-three patients underwent LV VT mapping and ablation with the HRS via a transseptal, transmitral valve approach. Nineteen patients underwent substrate mapping and ablation (18 had ischemic cardiomyopathy, 1 had an apical variant of hypertrophic cardiomyopathy). Four patients had focal VT requiring LV VT mapping and ablation. Procedural endpoints included substrate modification by endocardial scar border ablation and elimination of late potentials, or elimination of inducible focal VT.Mapping and ablation were entirely robotic without requiring manual catheter manipulation in all patients and reaching all LV regions with stable contact. Fluoroscopy time of the LV procedure was 22.2 ± 11.2 minutes. Radiofrequency time was 33 ± 21 minutes. Total procedural times were 231 ± 76 minutes. Complications included a left groin hematoma (opposite to the HRS sheath), 1 pericardial effusion without tamponade that was drained successfully, and transient right ventricular failure in a patient with previous left ventricular assist device. At 13.4 ± 6.7 months of follow-up (range 1-19 months), recurrence of VT occurred in 3 of 23 patients.Our initial experience suggests that the HRS allows successful mapping and ablation of LV VT.