Right heart catherisation – a virtual reality

Introduction

Right heart catheterisation (RHC) is the gold standard for assessing patients with pulmonary hypertension. Doctors require training in this procedure in a safe and friendly environment with minimal risk to patients. Due to the Covid pandemic, formal RHC teaching workshops were cancelled in our country, so we sought to develop a Virtual Reality Right Heart Catheterisation (VRRHC) training program to fulfil this area of need without the need for face to face contact. The aim was to improve training, competency and confidence in this technique with improved diagnostic skills and reduction of procedural errors.

Method

We approached a health technology company to design a VRRHC training module based on our current RHC simulation workshops. Phase 1 required virtual insertion of RHC via the right internal jugular vein using micro-puncture, double Seldinger technique under ultrasound guidance, followed by insertion of the RHC to the right atrium, right ventricle and pulmonary artery with pulmonary artery occlusion using real time pressure tracings and fluoroscopy. Thermodilution cardiac outputs and chamber saturations were also performed.

The proprietary platform technology was delivered via a laptop and VR headset. Clinicians perform the VRRHC with imaging, monitoring and haptic feedback with the collection of real time performance tracking allowing user data (e.g. failed steps and proficiency scores) to be captured and subsequently visualised in the learning management system.

We collected analytics and data on user engagement, experience and retention, targeted learning outcomes and learning curve, reduction in operating costs, reduction in procedure times due to higher proficiency, early diagnosis of pulmonary hypertension, reduced complications, improved interpretation and diagnosis.

Results

The program was launched in October 2021. Preliminary data shows a learning curve is associated with both using VR (10–15 minutes) and the RHC procedure itself. Initial time to completion of the RHC was 30–40 mins, reducing to 20–30 minutes with experience and 15 minutes in experts. Completion rates increase with experience from 40–50% to 100% and error rates reduce with frequency of completion.

Conclusion

A Virtual Reality Right Heart Catheter training program is safe, feasible and non-invasive. Increased experience results in increased completion rates, reduced procedure time and reduced errors. Using this program will potentially have beneficial effects on doctor training, outcomes, patient safety and health economics with no risk to a real patient.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Janssen Pharmaceuticals

148 Superovulation and embryo production response in oestrus-synchronized Arunachali yak

The Arunachali breed of yak is reared by the Monpa pastoral community of Arunachal Pradesh in India for their livelihood and nutritional security on highland pastures. In addition to fulfilling the basic needs of highlanders, this animal is associated with poor production potential linked to its inherent reproductive problems, including silent oestrus, seasonality, and inbreeding, making yak rearing a less-profitable venture. In the recent past, efforts have been made to improve reproductive efficiency of Arunachali yak through assisted reproductive techniques. However, a few regimens for superovulation have been tried to date with limited success in terms of superovulatory response and embryo recovery. Therefore, the present study was undertaken to evaluate the efficacy of two different doses and regimes of superovulation: Stimufol (400 and 200µg per animal) and Folligon (1500 and 1000IU per animal) in Arunachali yak. Twenty-four yaks were allotted in 4 groups (of 6 animals each) and subjected to respective superovulation treatment. Thereafter, the treatment response was assessed in terms of expression of oestrus, interval between treatment and oestrus onset, duration of oestrous, number of corpora lutea and embryos recovered, and analysed using two-way statistical analysis between treatment groups. The results (Table 1) showed a significant (P<0.01) variation in onset of oestrus after the treatment, whereas other responses did not differ among the groups. Further, the recovered embryos were categorized as excellent, good, fair, and poor according to cell size, shape, texture, and number of vesicles present in the blastomeres; 58.33, 20.83, 8.33, and 12.5% embryos in these categories were recovered, respectively. The overall embryo recovery rate was 30.77%, ranging from 10.53 to 52.38% in different treatment groups. The numbers of embryos recorded were less than the numbers of CL present, showing the possibility of non-availability of all ovulated oocytes for fertilization in the oviduct due to untrapping by the fimbriae. The effectiveness of treatments depended upon the precision of oestrus detection and the time of ovulation. In our study, the variation in onset of oestrus might be associated with poor expression of behavioural oestrus in the treated animals. Based on the present findings, we conclude that all the treatments are effective in superovulation and embryo recovery. However, the use of Folligon at 1500IU seemed to be comparatively more effective in Arunachali yak. Table 1. Mean (n=6) average of treatment responses in yak following different superovulatory treatment Variable Treatment Stimufol Folligon 400 µg/animal 200 µg/animal 1500 IU/animal 1000 IU/animal Oestrus response (%) 100 100 100 100 Interval between treatment and oestrus onset (h) 17.67±0.56a 20.83±0.79b 21.17±0.79bc 23.67±1.43c Duration of oestrous (h) 30.33±1.09 28.50±0.99 31.50±1.50 28.83±1.25 Corpora lutea (n) 2.83±1.22 3.50±1.18 3.50±0.67 3.17±0.87 Embryo recovered (n) 0.83±0.83 1.00±0.81 1.83±0.98 0.33±0.21 Recovery rate (%) 29.41 28.57 52.38 10.53 a–cMeans within a row with different superscripts differ P<0.05.

Impregnation of catheters with anacardic acid from cashew nut shell prevents Staphylococcus aureus biofilm development

AIM

The effect of anacardic acid impregnation on catheter surfaces for the prevention of Staphylococcus aureus attachments and biofilm formations were evaluated.

METHODS AND RESULTS

Silicon catheter tubes were impregnated using different concentrations of anacardic acids (0·002-0·25%). Anacardic acids are antibacterial phenolic lipids from cashew nut (Anacardium occidentale) shell oil. Anacardic acid-impregnated silicon catheters revealed no significant haemolytic activity and were cytocompatible against fibroblast cell line (L929). Sustained release of anacardic acids was observed for 4 days. Anacardic acid-impregnated silicon catheters efficiently inhibited S. aureus colonization and the biofilm formation on its surface. The in vivo antibiofilm activity of anacardic acid-impregnated catheters was tested in an intraperitoneal catheter-associated medaka fish infection model. Significant reduction in S. aureus colonization on anacardic acid-impregnated catheter tubes was observed.

CONCLUSIONS

Our data suggest that anacardic acid-impregnated silicon catheters may help in preventing catheter-related staphylococcal infections.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study opens new directions for designing antimicrobial phytochemical-coated surfaces with ideal antibiofilm properties and could be of great interest for biomedical research scientists.

Adaptation strategies of yak to seasonally driven environmental temperatures in its natural habitat

The gradual increase of ambient temperature (TA) at high altitude can cause heat stress as an effect of climate change and may shift the traditional habitat of yak to further higher altitude. Therefore, an attempt has been made in this study to evaluate the thermo-adaptability of yaks to different seasons at high altitude. The adaptive capabilities of yaks were assessed based on different heat tolerance tests in relation to changes in rectal temperature (RT; °F), respiration rate (RR; breaths/min), pulse rate (PR; beats/min), and plasma heat shock protein (HSP) profile. The experiment was conducted in 24 yaks, divided into three groups based on age as calf (n = 8), adult (n = 8), and lactating cow (n = 8). Thermal adaptability was determined by temperature humidity index (THI), dairy search index (DSI), and Benezra's thermal comfort index (BTCI) along with HSP70 profile. The THI was higher (P < 0.01) in summer than winter which increased from lowest (40.87) to highest (61.03) in summer by 20 points, where yaks were under heat load beyond THI 52. The RT (100.09 ± 0.18 °F), RR (21.76 ± 0.18), and PR (59.78 ± 0.32) increased by 23-35%, and this was correlated to the higher values of DSI exceeding 1 in calves (1.35 ± 0.03), lactating cows (1.29 ± 0.04), and adults (1.23 ± 0.32) during summer in comparison to winter (0.98 ± 0.02). The BTCI also showed values greater (P < 0.01) than 2 in calves (3.47 ± 0.27), lactating cows (3.23 ± 0.28), and adults (2.98 ± 0.29) which reflected 49-75% increase in rectal temperature and respiration rate during summer. Further, heat stress was substantiated by threefold higher (P < 0.01) level of plasma HSP70 in calves (189.61 ± 3.90 pg/ml) followed by lactating cows (168.62 ± 3.03 pg/ml) and adults (155.33 ± 2.30 pg/ml) against the winter average of 87.92 ± 3.19 pg/ml. Present results revealed that yaks were experiencing heat stress in summer at an altitude of 3000 m above sea level and calves were more prone to heat stress followed by lactating cows and adults.

257 IN VITRO YAK EMBRYO PRODUCTION THROUGH CONVENTIONAL AND OVUM PICKUP METHODS

Yak is one of the most important economically useful animals for highlanders. The decline in the yak population demands effective measures for conservation and multiplication of elite germplasm. In vitro production of embryos and their cryopreservation and transfer to suitable recipients for production of elite calves may contribute to fulfill the objectives. The work was conducted at the National Research Center on Yak over a period of 3 years. The ovaries of slaughtered animals were used for collecting oocytes through aspiration of follicles followed by slicing of ovaries in the conventional method. Trials were conducted using 7 cyclic parous yaks for ultrasound-guided ovum pickup (OPU) at Nyukmadung farm (2700 m above mean sea level). The technique followed was similar to that in buffaloes with slight modification. Categories of oocytes classified A (2–3 layers of cumulus) and B (at least one layer of cumulus) obtained through the processes were subjected to in vitro maturation using standardized maturation medium (TCM-199 + 10% follicular fluid + sodium pyruvate + l-glutamine + 10% heat inactivated oestrus cow serum + pFSH + 17β oestradiol). The frozen-thawed yak sperm were capacitated using the swing-up method before their incubation with matured oocytes using BO medium. Oocytes matured for 24 h were washed 5 to 6 times with BO medium and then co-incubated with in vitro capacitated spermatozoa (0.1 to 0.25 million) for fertilization (8–10 oocytes per group) in 100-µL droplets of BO medium under mineral oil in 35-mm Petri dishes and placed in a CO2 incubator (5% CO2, 90% RH) at 38.5°C for 16 to 18 h. The presumed zygotes were washed several times in mCR2aa (modified Charles Rosenkrans) washing medium and then cultured in culture medium for 7 days on original beds of granulosa cells. The rates of maturation and fertilization of oocytes collected by conventional and OPU technique were comparable (Table 1). This may be attributed to greater numbers of good quality oocytes recovered in the conventional method. Embryos developed up to the stage of compact morula and blastocysts (24.66% through conventional and 22.73% through OPU) were cryopreserved using the vitrification method for further study. Thirteen embryos were transferred non-surgically to one each of 13 yak recipients; 5 became pregnant and only 1 recipient transferred with a cryopreserved-thawed embryo, developed through OPU, delivered one male calf, leading to the first successful production of an IVF yak calf in the world. The present findings are suggestive of using the OPU technique for in vitro embryo production, though resulting in lower numbers of transferable embryos (Table 1), because availability of ovaries for conventional IVF is a major constraint in yak. Table 1.Comparative in vitro yak embryo production rate with recovery of oocytes by conventional or ovum pickup (OPU) method

Lack of precision in HbA(1c) values on variant II in cases of hemoglobin Q India

This study was carried out to check the precision of HbA(1c) values on Bio-Rad Variant II in cases of a rare hemoglobin variant Q India. The study was carried out over a three month period on samples collected for HbA(1c) estimation. Seven out of eleven patients showed variable results of HbA(1c) with a very high and unacceptable intraday mean coefficient of variation (CV) of 9.93%. We conclude, that the results of HbA(1c) on Variant II can not be reported without adversely affecting HbA(1c) as a marker of long-term glycemic control in patients who have hemoglobin Q India. The HbA(1c) value of these patients needs to be assessed by a different instrument/method or the glycemic control be monitored by an alternate test like serum Fructosamine.

Physicians' attitudes towards self-treatment of latent tuberculosis

We conducted a cross-sectional study to assess physicians' attitudes towards self-treatment of latent tuberculosis infection (LTBI) based on real-time responses related to actual purified protein derivative (PPD) results, in addition to using hypothetical situations for those who were PPD-negative. We also obtained information on physicians' recommendations for their patients to treat this condition. Although the physicians claimed to recommend optimal treatment to their patients, the majority of them had different attitudes when considering treatment for themselves. There appears to be a discrepancy between physicians' attitudes to self-treatment and their management of patients with LTBI.

Tele-education vs classroom training of neonatal resuscitation: a randomized trial

OBJECTIVE

To compare gain in knowledge and skills of neonatal resuscitation using tele-education instruction vs conventional classroom teaching.

STUDY DESIGN

This randomized controlled trial was conducted in the tele-education facility of a tertiary care center. In-service staff nurses were randomized to receive training by tele-education instruction (TI, n=26) or classroom teaching (CT, n=22) method from two neonatology instructors using a standardized teaching module on neonatal resuscitation. Gain in knowledge and skill scores of neonatal resuscitation were measured using objective assessment methods.

RESULT

Age, educational qualification and professional experience of the participants in two groups were comparable. Pre-training mean knowledge scores were higher in TI group (8.3±1.7 vs 6.6±1.4, P=0.004). However, skill scores were comparable in the two groups (11.7±3 vs 10.3±2.9, P=0.13). Training resulted in a significant and comparable gain in knowledge scores (4.2±2.2 vs 5.3±1.7; P=0.06) and skills scores (4.5±3.3 vs 5.0±3.1, P=0.62) in both the groups. The post-training knowledge scores (TI: 12.5±1.7 vs CT: 12.0±1.7, P=0.37) and the post-training skill scores (TI: 16.0±0.5 vs CT: 15.6±2.5, P=0.55) were comparable in the two groups. However, the post-training scores, adjusted for baseline knowledge scores, were statistically higher in the in-person group compared with the telemedicine group (knowledge: 12.46±0.03 vs 12.16±0.01, P=0.00; skills: 15.6±2.5 vs 16.0±2.8, P=0.00). The quantum of lower scores in the telemedicine group was only 2% for knowledge and 6% for skills. This difference was felt to be of only marginal importance. Satisfaction scores among trainees and instructors were comparable in the two groups.

CONCLUSION

Tele-education offers a feasible and effective alternative to conventional training in neonatal resuscitation among health-care providers.

The evaluation of pulmonary vein isolation and wide-area left atrial ablation to treat atrial fibrillation in patients with implanted permanent pacemakers: the Previously Paced Pulmonary Vein Isolation Study

BACKGROUND

The practise of catheter ablation for atrial fibrillation (AF) is increasing rapidly and is recommended as the treatment of choice in many patient subgroups. At present, the efficacy of this procedure has been assessed by means of electrocardiographic recording, intermittent Holter monitoring and evaluation of patient symptoms. We sought to evaluate the true efficacy of this procedure in patients with sophisticated permanent pacemakers capable of continuous long-term cardiac rhythm monitoring.

METHODS

Twenty-five patients (aged 63.7 (9.4), 20 men), seven with persistent AF and 18 with prolonged paroxysmal AF, underwent a mean of 1.7 AF ablation procedures. All the patients had previously been implanted with a pacemaker or atrial defibrillator device. Data were downloaded from the device Holter before catheter ablation and at 2, 4, 6 and 8 months postprocedure(s). The primary outcome measure was AF burden. The secondary outcomes were patient symptom and quality-of-life measures.

RESULTS

Initial AF burden was 43.8 (35.5)%. After catheter ablation(s), this was significantly reduced at 2 months to 23.8 (35.4)% (p=0.023), at 4 months to 21.4 (34.1)% (p=0.008), at 6 months to 14.5 (28.1)% (p=0.002) and at 8 months to 15.0 (29.4%) (p=0.003). Only nine (36%) of 25 patients demonstrated no recurrence of arrhythmia during follow-up completion, consistent with a long-term cure. Quality-of-life indices showed significant improvement after ablation.

CONCLUSIONS

Catheter ablation for AF significantly improves patient symptoms and reduces AF burden after long-term beat-to-beat monitoring by implanted cardiac pacemaker and defibrillator devices. However, AF recurrence is common after these procedures.

Incidence of paroxysmal atrial tachycardias in patients treated with cardiac resynchronization therapy and continuously monitored by device diagnostics

AIMS

Little is known about the incidence of paroxysmal atrial tachycardias (PAT) in patients with heart failure (HF). The availability of cardiac resynchronization therapy (CRT) devices with extended diagnostics for AT enables continuous monitoring of PAT episodes. The aim of the study was to assess the incidence over time of PAT in HF patients treated with CRT.

METHODS AND RESULTS

Consecutive patients in NYHA functional class III or IV despite optimal drug therapy, QRS duration > or = 130 ms, left ventricular ejection fraction < or = 35%, and left ventricular end-diastolic dimension > or = 55 mm were eligible for enrolment. Patients with permanent or persistent atrial fibrillation (AF) were not included in the study. The first follow-up examination was performed 2 weeks after implantation, to optimize atrial sensing and CRT. Subsequent follow-up examinations were carried out 15 and 28 weeks after implantation, to collect the telemetric data. A total of 173 patients (67 +/- 11 years, M 116) were enrolled. Complete arrhythmia monitoring data were available from 120 patients over a mean follow-up of 183 +/- 23 days. Atrial tachycardia episodes were detected through telemetry in 25 of 120 patients (21%) during at least one follow-up examination. Atrial tachycardia episodes were recorded in 29 and 17% (P = NS) of patients with and without previous history of AF, respectively.

CONCLUSION

More than 20% of the overall HF patient population treated with CRT suffer PAT episodes. Paroxysmal atrial tachycardia may interfere with response to CRT. Therefore, telemetric data may be relevant to drive the appropriate therapy in each patient.

Effects of human chorionic gonadotropin on luteal blood flow and progesterone secretion in cows and in vitro-microdialyzed corpora lutea

To check human chorionic gonadotropin (hCG) effects on luteal blood flow (LBF) and progesterone (P(4)) synthesis, six cows received either 3000 IU hCG or saline (NaCl) on Day 7 (Day 1=ovulation) during two estrous cycles. Plasma P(4) and LBF were measured before (0h) and up to 48h after treatment. Luteal blood flow increased by 51% (P<0.05) at 1h after hCG administration and returned to baseline levels thereafter. Plasma P(4) levels were increased from pretreatment levels by 30% at 1h (P=0.05) and 81% at 48h (P=0.02) after hCG treatment. In contrast, NaCl did not cause changes in LBF and P(4) (P>0.05). Additionally, central and peripheral parts of 14 abattoir-derived corpora lutea of the mid-luteal phase (Day 8 to 12) were perfused with Ringer solution in an in vitro microdialysis system, supplemented with 50 or 150 IU/mL hCG for 1h. Application of 50 IU/mL hCG showed no influence on P(4) response (P>0.05) in both central and peripheral parts, whereas 150 IU/mL hCG resulted in an increase of P(4) synthesis (P=0.002) in the central parts only. In vivo, hCG provoked an immediate and long-term rise in P(4) but only a temporary elevation of LBF. Luteal blood flow itself does not seem to be the exclusive cause for an increase in P(4), because the in vitro data clearly showed direct effects of hCG on P(4) secretion. Interestingly, different P(4) secretion patterns could be found between central and peripheral parts of the corpus luteum in both control and hCG perfused corpora lutea.

Predicting mortality and rehospitalization in heart failure patients with home monitoring--the Home CARE pilot study

The increasing worldwide prevalence of heart failure is associated with numerous and protracted hospital admissions. The multidisciplinary team approach together with telemonitoring aims at reducing the number of rehospitalizations, length of hospital stay, and mortality rates. Novel cardiac resynchronization therapy (CRT) devices have a Home Monitoring capability, offering wireless, everyday transfer of the essential status and therapy data to the attending physician. The transmitted data include potential predictors of death or hospitalization, such as the onset of atrial and ventricular arrhythmias, duration of physical activity, mean heart rates over 24 h and at rest, percentage of CRT delivered, and lead impedances. We present here interim results of the prospective, longitudinal, multicenter Home CARE Phase 0 study, conducted in 123 patients (age: 67+/-9 years, 83% male) with clinical indication for CRT. Twenty-nine patients (24%) received a CRT pacemaker, 52 (42%) a prophylactic implantable cardioverter defibrillator (ICD), and 42 (34%) had other ICD indications. All devices have an integrated Home Monitoring feature. In a mean (interim) follow-up period of 3 months (9194 observational days), 11 unplanned rehospitalizations of cardiovascular etiology and 9 deaths occurred. In 70% of the rehospitalization events, the retrospective analysis of transmitted data via Home Monitoring revealed an increase in mean heart rate at rest and in mean heart rate over 24 h within 7 days preceding hospitalization. A decrease in the percentage of CRT was observed in 43% and a reduction in the patients' daily activity in 30% of rehospitalized patients. These interim findings suggest that Home Monitoring data may predict events leading to hospitalization and encourage further research.

Laser-assisted lead extraction: the European experience

AIMS

The aim of this study is to investigate the safety and effectiveness of Excimer laser-assisted lead extraction in Europe. The final European multi-centre study experience is presented.

METHOD AND RESULTS

The Excimer is a cool cutting laser (50 degrees C) with a wavelength of 308 nm. The energy is emitted from the tip of a flexible sheath and is absorbed by proteins and lipids, 64% of the energy is absorbed at a tissue depth of 0.06 mm. The sheath is positioned over the lead, and the fibrosis surrounding the lead is vaporized while advancing the sheath without damaging other leads. From August 1996 to March 2001, 383 leads (170 atrial, 213 ventricular) in 292 patients (mean age 61.6 years, range 13-96) were extracted at 14 European centres. Mean implantation time was 74 months (3-358). Most frequent indications were pocket infection (26%), non-functional leads (21%), patient morbidity (21%), septicaemia or endocarditis (14%), erosion (5%), and lead interference (8%). Median extraction time was 15 min (1-300). Complete extraction was achieved in 90.9% of the leads and partial extraction in 3.4%. Extraction failed in 5.7% of the leads. Major complications = perforations caused 10/22 (3.4/5.7%) of the failures. Most partially extracted patients were considered clinically successful, as only minor lead parts without clinical significance were left. Femoral non-laser technique was used to remove 8/12 of the non-complication failures. The total complication rate, including five minor complications (1.7%), was 5.1%. No in-hospital mortality occurred.

CONCLUSION

Pacing and implantable cardioverter-defibrillator leads can safely, effectively, and predictably be extracted. Open-heart extractions can be limited to special cases. The results indicate that the traditional policy of abandoning redundant leads, instead of removing them, may be obsolete in many patients.

Trial of low molecular weight heparin in the treatment of viper bites

AIM OF THE STUDY

To study the efficacy of low molecular weight heparin (LMWH) in the treatment of viper envenomation to combat the haematotoxicity and disseminated intravascular coagulation (DIC).

METHODOLOGY

Eighty patients with viper bite and incoagulable blood were randomized into two groups of 40 each. One group (Test group) received LMWH, in addition to the antisnake venom (ASV) and other routine measures received by the other group (Control group). Efficacy was assessed by monitoring the bleeding time (BT), whole blood clotting time (CT), prothrombin time (PT), platelet count, fibrinogen, blood urea (BU), serum creatinine, development of complications and overall outcome.

RESULTS

LMWH group showed favourable outcome in all the parameters except in the incidence of renal failure which was reversible in the majority of the cases. However the differences between the two groups were statistically not significant.

CONCLUSION

LMW heparin seems to have a beneficial role in the treatment of viper bites, but this needs to be confirmed by a larger trial using a higher dose of heparin.

Left Ventricular Pacing Minimizes Diastolic Ventricular Interaction, Allowing Improved Preload-Dependent Systolic Performance

Background— Left ventricular (LV) pacing improves hemodynamics in patients with heart failure. We hypothesized that at least part of this benefit occurs by minimization of external constraint to LV filling from ventricular interaction.

Methods and Results— We present median values (interquartile ranges) for 13 heart failure patients with LV pacing systems implanted for New York Heart Association class III/IV limitation. We used the conductance catheter method to measure LV pressure and volume simultaneously. External constraint was measured from the end-diastolic pressure-volume relation recorded during inferior vena caval occlusion, during LV pacing, and while pacing was suspended. External constraint to LV filling was reduced by 3.0 (4.6 to 0.6) mm Hg from 4.8 (0.6 to 7.5) mm Hg ( P <0.01) in response to LV pacing; effective filling pressure (LV end-diastolic pressure minus external constraint) increased by 4.0 (2.2 to 5.8) mm Hg from 17.7 (13.3 to 22.6; P <0.01). LV end-diastolic volume increased by 10 (3 to 11) mL from 238 (169 to 295) mL ( P =0.01), whereas LV end-systolic volume did not change significantly (−1 [−2 to 3] mL from 180 [124 to 236] mL, P =0.97), which resulted in an increase in stroke volume of 11 (5 to 13) mL from 49 (38 to 59) mL ( P <0.01). LV stroke work increased by 720 (550 to 1180) mL · mm Hg from 3400 (2110 to 4480) mL · mm Hg ( P =0.01), and maximum dP/dt increased by 120 (2 to 161) mm Hg/s from 635 (521 to 767) mm Hg/s ( P =0.03).

Conclusions— This study suggests a potentially important mechanism by which LV pacing may produce hemodynamic benefit. LV pacing minimizes external constraint to LV filling, resulting in an increase in effective filling pressure; the consequent increase in LV end-diastolic volume increases stroke volume via the Starling mechanism.

Biventricular pacing in heart failure

Optimal pharmacological therapy for heart failure improves patients' prognosis and symptoms. Despite this, the long-term prognosis for these patients is very poor and symptoms are debilitating. Biventricular pacing, or resynchronization therapy, should be considered for patients who remain symptomatic despite optimal therapy and have evidence of dyssynchrony.

High-dose anti-snake venom versus low-dose anti-snake venom in the treatment of poisonous snake bites--a critical study

OBJECTIVES

To asses the optimum dose of anti-snake venom to treat snake bites cases effectively. This is particulary relevant in the present scenario when the cost of anti-snake venom ( Serum Institute of India) has gone up to nearly Rs. 400 per vial and the cross-section of people usually affected belong to the poor socioeconomic class.

METHODOLOGY

One hundred snake bite cases with envenomation, irrespective of whether they were bitten by viper, cobra or krait, brought within 24 hours of the bite to Jubilee Mission Hospital, Trichur, Kerala State during the 15 months from August 2001 to October 2002 were randomized into two groups of 50 cases each, irrespective of the severity of the cases. One group received a fixed dose regime of six vials of anti-snake venom and the other 12 vials of the same.

RESULTS

In the low-dose group there were five deaths giving a mortality rate of 10%, nine (18%) required dialysis and three (6%) required ventilatory support. In the high-dose group there were seven deaths giving a mortality rate of 14%, 13 (26%) required dialysis and three (6%) required ventilatory support. The average hospital stay for the low-dose group was 8.42 days while that of the high-dose group was 9.02 days.

CONCLUSION

While there was no additional advantage in following a high-dose regime for snake bite cases, there was considerable financial gain by following the low-dose regime, Most of the parameters showed a beneficial trend for the low-dose group though the differences were not statistically significant.

210INCREASE IN OVULATION RATE AFTER IMMUNIZATION OF MALPURA EWES AGAINST A SYNTHETIC PEPTIDE SEQUENCE OF THE ±-SUBUNIT OF BOVINE INHIBIN

Unlike many other breeds of sheep (e.g. Boroola, Romney or Merino) which have high fecundity, the Malpura ewe, an Indian breed of sheep, is marked by an ovulation rate of one and a low incidence of twinning. Active immunization against a number of inhibin-based synthetic peptides has been reported to increase ovulation rates in these high fecundity breeds of sheep. The objective of the present study was to explore the possibility of increasing ovulation rates in Malpura ewes by active immunization against a synthetic peptide replica of the N-terminal sequence of the bovine inhibin. Adult Malpura ewes (n=5) were actively immunized against a synthetic peptide that corresponded to the N-terminus of the α-subunit of bovine inhibin [bIα(1–29)Tyr30]. The peptide was conjugated to ovalbumin, with a peptide-to-ovalbumin ratio of around 20 moles mole−1, to increase its antigenicity. Control ewes (n=5) were immunized against ovalbumin. On the day of primary immunization, 400μg of peptide-ovalbumin conjugate or ovalbumin were dissolved in 1mL of isotonic saline, emulsified with an equal volume of Freund’s complete adjuvant and injected at four sites in each ewe. Following this, boosters 1, 2 and 3 were given on Days 28, 56 and 84, respectively, of the experiment (Day 0=day of primary immunization); boosters were 200μg of peptide-ovalbumin conjugate or ovalbumin dissolved in 1mL of isotonic saline and emulsified with an equal volume of Freund’s incomplete adjuvant. Estrus was synchronized by a double injection schedule of PGF2α (7.5mg Lutalyse, once each on Days 35 and 45). The animals were subsequently allowed to undergo normal cyclicity until the end of the experiment. Ovulation rate was determined by counting the number of corpora lutea observed during laparoscopic examinations approximately 5 days after estrus during three estrous cyles following treatment. The ovulation rate between control and immunized groups was compared by repeated measures ANOVA. Immunization of the Malpura ewes against the synthetic peptide sequence of the α-subunit of bovine inhibin [bIα(1–29)Tyr30] increased ovulation rate over 5-fold compared to that of controls (Table 1). In conclusion, we have shown that inhibin-based fecundity vaccines have the potential of increasing ovulation rates in the Malpura breed of sheep. Table 1