128Non-invasive 3D mapping of earliest activation of premature ventricular complexes originating from intracardiac structures to guide catheter ablation

Funding Acknowledgements

Research funding from Catheter Precision, Inc.

Introduction

Catheter ablation for ventricular arrhythmias such as premature ventricular complexes and ventricular tachycardia is an established management approach.  Non-invasive mapping to localise the earliest activation (site of origin) on the myocardium may help guide ablation.  Established ECGi methods using the inverse solution to reconstruct epicardial electrograms are unable to accurately locate arrhythmias from the endocardium or from intracardiac structures.  VIVO™ (Catheter Precision) is a novel vectorcardiography based 3D mapping system that may be able to localise arrhythmias from any part of the ventricle.

Methods

We reviewed our initial experience utilising this mapping system to guide catheter ablation of ventricular ectopics from the inter-ventricular septum, coronary cusp or papillary muscle.  A patient-specific 3D heart and torso model was created using semi-automated segmentation of MRI or CT scan images.  A 3D topographic image of the patient’s torso was taken to accurately position surface ECG electrode locations onto the 3D heart-torso model.  An ECG of the PVC was imported from LabSystemPro (Bard) into VIVO™ for analysis prior to ablation.  The result was then compared with the site of earliest activation identified using invasive electro-anatomical (EA) mapping.

Results

VIVO™ was used in 12 cases where the PVC was localised to an intracardiac structure – six papillary muscle, four to the septum and two from the coronary cusp.  VIVO™ was able to accurately localise the earliest activation site when compared to the invasive map in 5/6 papillary muscle cases, 3/4 septal cases and 2/2 coronary cusp cases.  Ablation was acutely successful in all cases.  One additional patient had a PVC localised non-invasively to the postero-medial papillary muscle, however an invasive 3D electro-anatomical map or ablation was not performed.

In three cases we were able to merge the 3D geometry of the non-invasive map from VIVO™ into the Carto™ system to guide mapping and ablation in real time (see figure).

Conclusion

Our experience shows promising results for accurate non-invasive localisation of ventricular arrhythmias originating from intracardiac structures.  Non-invasive localisation is of particular value in cases where the arrhythmia is infrequent, difficult to induce or poorly tolerated haemodynamically.  The two cases where PVC localisation was inaccurate were performed using an older version of the software. With recent refinements, localisation is anticipated to be improved further.

We also present the first experience of combining the VIVO™ geometry with the real-time invasive EA map.  This has potential to significantly speed up mapping time and reduce the need for expensive multi-polar catheters by allowing the operator to see their target in real time 3D.  Further work is ongoing to validate the accuracy of VIVO™ prospectively and quantitatively.

Abstract Figure. VIVO map merged with Carto LV geometry

Cytological Studies in Cluster Bean by the Application of Physical and Chemical Mutagens (<i>Cyamopsis tetragonoloba</i> L.)

The miotic and meotic behaviour is considered to be one of the most dependable indices to estimate the potency of mutagen cytological aberrations in plants serve as an excellent monitoring system for the determination of mutagens that may cause a genetic hazard in the present study cluster bean contains 7 bivalents (24 = 14) for the present investigation the plant exposed to dolf concentration of 60, 80, and 100kr gamma rays and 0.4, 0.6 and 0.8 % Mm ( EMS ) the present study reveals various chromosomal aberration includes stickiness precocisus movement ,single and anaphasis bridge laggards and synchronized movement of chromosomes at anaphase

Cytological Studies in Cluster Bean by the Application of Physical and Chemical Mutagens (<i>Cyamopsis tetragonoloba</i> L.)

The miotic and meotic behaviour is considered to be one of the most dependable indices to estimate the potency of mutagen cytological aberrations in plants serve as an excellent monitoring system for the determination of mutagens that may cause a genetic hazard in the present study cluster bean contains 7 bivalents (24 = 14) for the present investigation the plant exposed to dolf concentration of 60, 80, and 100kr gamma rays and 0.4, 0.6 and 0.8 % Mm ( EMS ) the present study reveals various chromosomal aberration includes stickiness precocisus movement ,single and anaphasis bridge laggards and synchronized movement of chromosomes at anaphase

Renal function and aspirin resistance in patients with coronary artery disease

Aspirin resistance and chronic renal failure are both potentially important clinical issues in coronary artery disease. To test the hypothesis of a relationship between the two, we recruited 169 stable outpatients with proven coronary artery disease (myocardial infarction, coronary artery bypass grafting, intra-coronary stents) taking 75 mg aspirin daily. Blood was taken for light transmission aggregometry to agonists arachidonic acid (0.5mg/mL) and adenosine diphosphate (10 μmol/L), for platelet marker soluble P selectin (enzyme linked immunosorbent assay), resting and stimulated expression of CD62P (flow cytometry) and for renal function (estimated glomerular filtration rate). The estimated glomerular filtration rate was lower when aspirin resistance was defined by response to arachidonic acid after 3, 5 and 7 minutes (approximately 30% of patients) (p<0.021), and when defined by response to adenosine diphosphate after 3 minutes (approximately 17% of patients)(p=0.015) compared to those who were sensitive to aspirin. Mean [standard deviation] soluble P selectin levels were 57 [23] ng/mL in 49 patients with aspirin resistance, and 50 [15] ng/mL in the 119 aspirin sensitive patients (p=0.02). Estimated glomerular filtration rate correlated inversely with platelet CD62P expression at rest (r=-0.22, p=0.004), and when stimulated by arachidonic acid (r=-0.21, p=0.007) and by adenosine diphosphate (r=-0.17, p=0.023). Aspirin resistance was more than twice as prevalent in those with the greatest renal disease (50% of patients) compared to those with the best renal function (21.4%). Our data point to a weak relationship between worsening glomerular filtration rate and aspirin resistance. Nevertheless, we suspect that failure of patients to be fully responsive to aspirin may be important in the pathophysiology of thrombosis in renal dysfunction.

Performance enhancement of polysulfone ultrafiltration membrane by blending with polyurethane hydrophilic polymer

The aim of this work was to study the effect of two solvents such as N,N′-dimethylformamide (DMF) and dimethylacetamide (DMAc) used in the production of polysulfone (PSf) and polyurethane (PU) blend ultrafiltration membranes, influence permeability and selectivity. PSf/PU membranes were prepared by the phase inversion method using polymer concentrations of 100/0, 20/80 and 0/100 wt%. Permeation performance of the prepared membranes was evaluated in terms of pure water flux, water content and hydraulic resistance. It was found that the membrane composed of 20/80 wt% of PSf/PU in the presence of DMAc showed a water flux of 60.5 l m-2h-1 under transmembrane pressure of 345 kPa, and the water flux of 23.5 l m-2h-1 for 20/80 wt% of PSf/PU in the presence of DMF. With increasing the polarity of DMAc in the casting solution, an increase in porous layer thickness was observed, and then a good water flux of membranes can be obtained. It was found that the polar solvent caused the rapidly demixing of casting solution in coagulation bath and formed porous asymmetric membranes with defective skin layer. The permeation rates of proteins were measured with different molecular weights of the proteins.

Cytotoxic and antioxidant effects of methoxylated stilbene analogues on HepG2 hepatoma and Chang liver cells: Implications for structure activity relationship

Stilbenes possess a variety of biological activities including chemopreventive activity. This study was conducted to evaluate the structural activity relationships of six methoxylated stilbene analogues with respect to their cytotoxic effects and antioxidant activities on HepG2 hepatoma and Chang liver cells. The cytotoxic and total antioxidant activities of six stilbene analogues were determined by MTT and Ferric Reducing Antioxidant Power (FRAP) assays, respectively. We found that the cis-methoxylated stilbene: (Z)-3,4,4'-trimethoxystilbene was the most potent and selective antiproliferative agent (IC₅₀ 89 µM) in HepG2 cells. For the total antioxidant activity, compounds possessing hydroxyl groups at the 4' position namely (E)-3-methoxy-4'-hydroxystilbene, (E)-3,5-dimethoxy-4'-hydroxystilbene (pterostilbene), (E)-4-methoxy-4'-hydroxystilbene showed the highest antioxidant activity. Structure activity relationship studies of these compounds demonstrated that the cytotoxic effect and antioxidant activities of the tested compounds in this study were structurally dependent.

Structure-based approach to pharmacophore identification, in silico screening, and three-dimensional quantitative structure-activity relationship studies for inhibitors of Trypanosoma cruzi dihydrofolate reductase function

We have employed a structure-based three-dimensional quantitative structure-activity relationship (3D-QSAR) approach to predict the biochemical activity for inhibitors of T. cruzi dihydrofolate reductase-thymidylate synthase (DHFR-TS). Crystal structures of complexes of the enzyme with eight different inhibitors of the DHFR activity together with the structure in the substrate-free state (DHFR domain) were used to validate and refine docking poses of ligands that constitute likely active conformations. Structural information from these complexes formed the basis for the structure-based alignment used as input for the QSAR study. Contrary to indirect ligand-based approaches the strategy described here employs a direct receptor-based approach. The goal is to generate a library of selective lead inhibitors for further development as antiparasitic agents. 3D-QSAR models were obtained for T. cruzi DHFR-TS (30 inhibitors in learning set) and human DHFR (36 inhibitors in learning set) that show a very good agreement between experimental and predicted enzyme inhibition data. For crossvalidation of the QSAR model(s), we have used the 10% leave-one-out method. The derived 3D-QSAR models were tested against a few selected compounds (a small test set of six inhibitors for each enzyme) with known activity, which were not part of the learning set, and the quality of prediction of the initial 3D-QSAR models demonstrated that such studies are feasible. Further refinement of the models through integration of additional activity data and optimization of reliable docking poses is expected to lead to an improved predictive ability.

Ellis-van Creveld Syndrome

A 21 years old male with typical features of Ellis-Van Creveld Syndrome is presented for its rarity. This is the second living case being reported from India.

Two controlled studies of the efficacy of isoniazid alone in preventing relapse in patients with bacteriologically quiescent pulmonary tuberculosis at the end of one year of chemotherapy

An earlier report showed that, in patients with bacteriologically quiescent pulmonary tuberculosis at the end of 1 year of chemotherapy, isoniazid alone in a single daily dose of 150-200 mg, given as maintenance therapy in the second year, did not markedly prevent relapse over a 4-year period of follow-up in patients who had had residual cavitation (the "open-negative" syndrome) at 1 year, but was highly effective in patients who had not. As a result of these findings, two controlled studies, reported here, were undertaken.The first study was undertaken in patients with bacteriologically quiescent disease and residual cavitation at 1 year, and investigated the value of isoniazid in a higher daily dose (400 mg) throughout the second year; this is known to be the optimum therapeutic dose when isoniazid is prescribed alone for 1 year in the initial treatment of the disease. The second study was carried out in patients with bacteriologically quiescent disease and no residual cavitation at 1 year, and sought to determine the value of a shorter duration (6 months) of chemotherapy in the second year with a daily dose of 300 mg of isoniazid. Neither of the two isoniazid regimens was highly satisfactory, although both appeared to have had some effect in preventing relapse during the 4-year period of follow-up.

Attack rate of tuberculosis in a 5-year period among close family contacts of tuberculous patients under domiciliary treatment with isoniazid plus PAS or isoniazid alone

This report from the Tuberculosis Chemotherapy Centre, Madras, considers the risk, over a 5-year period, to close family contacts of sputum-positive patients treated at home for 1 year with a standard regimen of isoniazid plus PAS or one of 3 regimens of isoniazid alone. The attack rate of tuberculosis in the contacts did not appear to be influenced by the treatment received by the patients in the first year or by the duration in the 5-year period for which the patients had (1) positive sputum smears, (2) positive cultures, or (3) isoniazid-resistant cultures. Further, over half the cases of tuberculosis developed in the first year, many of these being in the first 3 months. These findings confirm the conclusions reached from an earlier study, namely, that the major risk to the contacts is from exposure to the infectious patient before diagnosis, and that the risks from the other possible sources of infection (the patient during treatment and the urban environment of Madras) are, in comparison, small.

A 5-year study of patients with pulmonary tuberculosis treated at home in a controlled comparison of isoniazid plus PAS with 3 regimens of isoniazid alone

This report from the Tuberculosis Chemotherapy Centre, Madras, describes the progress, over a 5-year period, of 341 patients with newly diagnosed, sputum-positive tuberculosis. All the patients were treated on a domiciliary basis. In the first year, the patients received, on the basis of random allocation, a standard regimen of isoniazid plus PAS or 1 of 3 regimens of isoniazid alone. Previous reports have shown that the response in the first year was substantially superior with the standard regimen, and that the bacteriological relapse rates in the second year were fairly similar for the 4 regimens. The findings in the present report extend the latter conclusion to the end of 5 years. Further, when considered together with the findings in an earlier study, they have shown that isoniazid, given as maintenance chemotherapy in the second year, was highly effective in preventing bacteriological relapse in patients who, at 1 year, had bacteriologically quiescent disease and no residual cavitation; the effect was, however, less marked in patients with residual cavitation at 1 year.Patients who were clear-cut failures of the allocated chemotherapy and those who had a bacteriological relapse in the second or subsequent years were usually re-treated with streptomycin plus PAS or streptomycin plus pyrazinamide, and if this was ineffective, with cycloserine plus thioacetazone or cycloserine plus ethionamide.Considering the findings over the 5-year period for all patients, 16 died from non-tuberculous causes and 1 took his discharge prematurely. Of the remainder, 86% had bacteriologically quiescent disease at 5 years, 6% had bacteriologically active disease and 8% had died of tuberculosis. These findings confirm the value of well-organized domiciliary chemotherapy, which was established by an earlier report from the Centre, and are particularly encouraging for developing countries such as India, where tuberculosis is a major problem and resources are limited.

A controlled study of the influence of segregation of tuberculous patients for one year on the attack rate of tuberculosis in a 5-year period in close family contacts in South India

This report is the last of a series of nine publications from the Tuberculosis Chemotherapy Centre, Madras, concerning various aspects of an investigation of the role of ambulatory chemotherapy for pulmonary tuberculosis. It presents the attack rates of tuberculosis over a 5-year period of follow-up of close family contacts of patients, all of whom were treated for one year with isoniazid plus PAS, half (selected at random) in sanatorium and half at home. The incidence of active tuberculosis and of tuberculous infections was no greater in the contacts of patients treated at home than in the contacts of patients treated in sanatorium, either in the first year or over the subsequent four years. The major risk to the contacts resulted from exposure to the patient before diagnosis. These findings reaffirm that close family contacts of patients treated at home were at no additional risk of developing tuberculosis, provided the patients received effective chemotherapy. Finally, this study has shown that it is possible in South India to obtain extremely good co-operation from a group of families over a period of several years.

A 5-year study of patients with pulmonary tuberculosis in a concurrent comparison of home and sanatorium treatment for one year with isoniazid plus PAS

This report from the Tuberculosis Chemotherapy Centre, Madras, summarizes the progress over a 5-year period of 193 patients with newly diagnosed, sputum-positive pulmonary tuberculosis who were admitted to a concurrent comparison of home and sanatorium treatment for one year with isoniazid plus PAS. Previous reports have shown that, despite the traditional advantages of sanatorium treatment-rest, adequate diet, nursing and supervised drug-administration-the home patients responded nearly as well as the sanatorium patients in the first year; further, the relapse rates over a 2-year period of follow-up were similar. The findings in the present report are based on a 4-year period of follow-up and extend these conclusions, the relapse rates over the period being 7% for the home patients and 10% for the sanatorium patients.Patients who failed to respond to treatment in the first year and those who had a bacteriological relapse in the second or subsequent years were usually re-treated with reserve regimens, first with streptomycin plus pyrazinamide and, if this was ineffective, with cycloserine plus ethionamide. Considering the findings over the entire 5-year period, five home patients and three sanatorium patients died from non-tuberculous causes. Of the remainder, 5% of the home patients and 6% of the sanatorium patients died of tuberculosis, 4% in each series had bacteriologically active disease at five years and 90% and 89%, respectively, had bacteriologically quiescent disease at that time. These findings are very encouraging, particularly for developing countries such as India, where tuberculosis is a major problem and sanatorium beds are very few.