Malignant hyperthermia in a 6-month-old infant

Malignant hyperthermia (MH) is a rare hypermetabolic disorder of skeletal muscles that manifests as a life-threatening crisis in susceptible individuals, after exposure to triggering agents, most commonly halothane and succinylcholine. MH presents with multiple nonspecific signs and laboratory findings such as tachycardia, hyperthermia, hypercarbia, acidosis, and muscle rigidity. Caffeine halothane contracture test is not available at most centers in India. Larach et al. have described a clinical grading scale for determining the MH raw score based on clinical findings and biochemical tests. The high degree of suspicion, early recognition and aggressive treatment should commence immediately. It is imperative to avoid triggering agents, such as volatile anesthetics and succinylcholine, and promote the use of total intravenous anesthesia in MH susceptible patients. We report a case of 6-month-old child undergoing laparotomy under general anesthesia, who presented with signs and symptoms of MH, had MH rank 5 and raw score 36.

Effect of Fractionated Dose of Radiotherapy on Oral Mucosa in Head and Neck Cancer Patients: A Cytological Assessment

BACKGROUND

Cancer therapy couples with it a plethora of complications of short and long term effects which can be so distressing that patient may tolerate only lower less-effective doses of therapy, may postpone treatments or will discontinue treatment entirely. Fractionated dose of radiotherapy coupled with therapy induce local or systemic infections due to high cellular turnover rates of the oral mucosa, diverse and complex microflora and trauma to oral tissues. Several mucosal abnormalities often results in epithelial and glandular destruction and inflammation, which can be so devastating that it may cause atypical changes on the area exposed to radiation. Thus, the aim of this study was to investigate the feasibility of using cytological evaluation to detect oral epithelial atypia among Head and Neck cancer patients receiving fractionated dose of radiotherapy.

METHODS

Study was conducted on 125 head and neck cancer patients receiving radiotherapy. Subjects were divided into 5 study groups on the basis of fractionated dose of radiotherapy from 10th-50th fractions respectively. Mucosal changes were evaluated by exfoliative cytology and atypical changes and inflammatory cell infiltration were assessed.

RESULTS

Without prior knowledge of the subjects' group, oral epithelial atypia was detected with increase fractionated dose of radiation. Dense inflammatory nfiltrate were identified in nearly all study groups irrespective of dose of radiotherapy.

CONCLUSION

Cytological atypia and inflammatory infiltrates were detected after exposure to radiotherapy.

Chronic Inflammation and Cancer: Paradigm on Tumor Progression, Metastasis and Therapeutic Intervention

As early as the 19th century, inflammation has been perceived to have a link with cancer but this perception has waned through the passing of time. In recent years however a renewed interest on inflammation and cancer connection stemming from different lines of work has been evolved that leads to a generally-accepted paradigm. In the tumor microenvironment, smouldering inflammation contributes to the proliferation and survival of malignant cells, angiogenesis, metastasis, subversion of adaptive immunity, reduced response to hormones and chemotherapeutic agents. Thus, this review will try to unravel and explain molecular events, mediators and regulators linking inflammation to cancer.

Spatially varying selection shapes life history clines among populations of Drosophila melanogaster from sub-Saharan Africa

Clines in life history traits, presumably driven by spatially varying selection, are widespread. Major latitudinal clines have been observed, for example, in Drosophila melanogaster, an ancestrally tropical insect from Africa that has colonized temperate habitats on multiple continents. Yet, how geographic factors other than latitude, such as altitude or longitude, affect life history in this species remains poorly understood. Moreover, most previous work has been performed on derived European, American and Australian populations, but whether life history also varies predictably with geography in the ancestral Afro-tropical range has not been investigated systematically. Here, we have examined life history variation among populations of D. melanogaster from sub-Saharan Africa. Viability and reproductive diapause did not vary with geography, but body size increased with altitude, latitude and longitude. Early fecundity covaried positively with altitude and latitude, whereas lifespan showed the opposite trend. Examination of genetic variance-covariance matrices revealed geographic differentiation also in trade-off structure, and QST -FST analysis showed that life history differentiation among populations is likely shaped by selection. Together, our results suggest that geographic and/or climatic factors drive adaptive phenotypic differentiation among ancestral African populations and confirm the widely held notion that latitude and altitude represent parallel gradients.

Knowledge, Attitude, and Practices about Biomedical Waste Management among Healthcare Personnel: A Cross-sectional Study

BACKGROUND

The waste produced in the course of healthcare activities carries a higher potential for infection and injury than any other type of waste. Inadequate and inappropriate knowledge of handling of healthcare waste may have serious health consequences and a significant impact on the environment as well.

OBJECTIVE

The objective was to assess knowledge, attitude, and practices of doctors, nurses, laboratory technicians, and sanitary staff regarding biomedical waste management.

MATERIALS AND METHODS

This was a cross-sectional study.

SETTING

The study was conducted among hospitals (bed capacity >100) of Allahabad city.

PARTICIPANTS

Medical personnel included were doctors (75), nurses (60), laboratory technicians (78), and sanitary staff (70).

RESULTS

Doctors, nurses, and laboratory technicians have better knowledge than sanitary staff regarding biomedical waste management. Knowledge regarding the color coding and waste segregation at source was found to be better among nurses and laboratory staff as compared to doctors. Regarding practices related to biomedical waste management, sanitary staff were ignorant on all the counts. However, injury reporting was low across all the groups of health professionals.

CONCLUSION

The importance of training regarding biomedical waste management needs emphasis; lack of proper and complete knowledge about biomedical waste management impacts practices of appropriate waste disposal.

Generic drug approval: a US perspective

OBJECTIVE

Generic drugs are identical or bioequivalent versions of the brand name drugs. They are the economic alternative of the costlier brand name drugs. This article presents a general overview of the procedure and regulatory aspects relating to generic drug approval in the US.

METHODS

A computerized search was conducted to find literature on generic drug approval in the US. The literature was searched using the following key words: generic drug, brand name drug, Hatch-Waxman Act, Medicare Act, NDA, ANDA, CTD and exclusivity.

FINDINGS

The search results were filtered for the literature describing and analyzing the procedure and regulatory provisions for generic drug approval in the US. After the screening total 19 applicable literature remained.

CONCLUSION

In the US standardized procedures for the recognition of generic drugs have been laid down under the Drug Price Competition and Patent Term Restoration Act, 1984 (the Hatch-Waxman Act). Provisions of this Act such as patent challenge, patent term extension and data exclusivity have created profound effects on the approval, sale and distribution of the pharmaceuticals in the US. The Hatch-Waxman Act is an excellent piece of legislation that takes care of the rights of both the brand name and generic drug companies. This article presents only an overview of generic drug approvals and for all practical purposes official resources should be referred.

Role of Transpupillary Thermotherapy in Central Serous Chorio-Retinopathy

BACKGROUND

To assess the efficacy of transpupillary thermo therapy (TTT) in cases of chronic central serous chorio- retinopathy (CSCR).

METHODS

A prospective evaluation was carried out on 25 cases of chronic CSCR who were subjected to TTT. Resolution of CSCR and improvement in visual acuity was noted after six weeks of therapy.

RESULT

Out of 25 patients, 13 (52%) had complete success (resolution of CSCR and improvement in visual acuity > 2 lines on Snellen's chart), 10 (42%) had qualified success (resolution of CSCR but no improvement in visual acuity) and two (8%) had failure to therapy (no resolution of CSCR or improvement in visual acuity).

CONCLUSION

TTT maybe a good modality in aiding resolution of subretinal fluid in cases of chronic CSCR. However, improvement in visual function is dependent upon integrity of photo receptor layer of retina which is not influenced by this modality. A controlled study could be undertaken to compare outcome of TTT with conservative management in cases of early CSCR such that deleterious effects of chronic CSCR on the retinal photoreceptor layer are avoided.

Balancing the role of the dental school in teaching, research and patient care; including care for underserved areas

Inequalities within dentistry are common and are reflected in wide differences in the levels of oral health and the standard of care available both within and between countries and communities. Furthermore there are patients, particularly those with special treatment needs, who do not have the same access to dental services as the general public. The dental school should aim to recruit students from varied backgrounds into all areas covered by the oral healthcare team and to train students to treat the full spectrum of patients including those with special needs. It is essential, however, that the dental student achieves a high standard of clinical competence and this cannot be gained by treating only those patients with low expectations for care. Balancing these aspects of clinical education is difficult. Research is an important stimulus to better teaching and better clinical care. It is recognized that dental school staff should be active in research, teaching, clinical work and frequently administration. Maintaining a balance between the commitments to clinical care, teaching and research while also taking account of underserved areas in each of these categories is a difficult challenge but one that has to be met to a high degree in a successful, modern dental school.

Androgens in women with anorexia nervosa and normal-weight women with hypothalamic amenorrhea

CONTEXT

Anorexia nervosa and normal-weight hypothalamic amenorrhea are characterized by hypogonadism and hypercortisolemia. However, it is not known whether these endocrine abnormalities result in reductions in adrenal and/ or ovarian androgens or androgen precursors in such women, nor is it known whether relative androgen deficiency contributes to abnormalities in bone density and body composition in this population.

OBJECTIVE

Our objective was to determine whether endogenous androgen and dehydroepiandrosterone sulfate (DHEAS) levels: 1) are reduced in women with anorexia nervosa and normal-weight hypothalamic amenorrhea, 2) are reduced further by oral contraceptives in women with anorexia nervosa, and 3) are predictors of weight, body composition, or bone density in such women.

DESIGN AND SETTING

We conducted a cross-sectional study at a general clinical research center.

STUDY PARTICIPANTS

A total of 217 women were studied: 137 women with anorexia nervosa not receiving oral contraceptives, 32 women with anorexia nervosa receiving oral contraceptives, 21 normal-weight women with hypothalamic amenorrhea, and 27 healthy eumenorrheic controls.

MAIN OUTCOME MEASURES

Testosterone, free testosterone, DHEAS, bone density, fat-free mass, and fat mass were assessed.

RESULTS

Endogenous total and free testosterone, but not DHEAS, were lower in women with anorexia nervosa than in controls. More marked reductions in both free testosterone and DHEAS were observed in women with anorexia nervosa receiving oral contraceptives. In contrast, normal-weight women with hypothalamic amenorrhea had normal androgen and DHEAS levels. Lower free testosterone, total testosterone, and DHEAS levels predicted lower bone density at most skeletal sites measured, and free testosterone was positively associated with fat-free mass.

CONCLUSIONS

Androgen levels are low, appear to be even further reduced by oral contraceptive use, and are predictors of bone density and fat-free mass in women with anorexia nervosa. Interventional studies are needed to confirm these findings and determine whether oral contraceptive use, mediated by reductions in endogenous androgen levels, is deleterious to skeletal health in such women.

Improvized pneumatic dilator for achalasia cardia

The indigenous pneumatic dilator for achalasia cardia reported previously by the authors was being placed alongside the endoscope to perform dilatation under direct vision. It has now been improvised to make the procedure wire-guided and fluoroscopy-assisted as well. The improvization includes insertion of a central Teflon tube for passage of a guidewire and presence of three radio-opaque markers, which define the proximal, central and distal ends of the dilator and help in precise positioning under fluoroscopy. Dilatation for achalasia cardia using the improvized pneumatic dilator with fluoroscopic guidance was performed successfully on 10 patients at our center. All patients had clinical response with greater than 50% improvement in total symptom score. Barium swallow examination after dilatation showed improvement in esophageal transit in all patients. None of the patients developed any complication. Cost of the dilator is approximately 50 times less than that of commercially available dilators. The dilator can be re-used by sterilizing it, which further reduces the cost.

Herpes simplex encephalitis in North West India

All patients admitted with provisional diagnosis of an encephalitic illness over a period of 30 months, were studied. Special investigations included CSF analysis, EEG, CT scan and MRI. Herpes simplex virus (HSV) antibody estimation in CSF and blood was done simultaneously using ELISA. Patients with diagnosis of cerebral venous thrombosis, cerebral malaria, tubercular meningitis etc, who resembled herpes simplex encephalitis (HSE), were excluded systematically with relevant investigations. 28 patients showed electroencephalographic, serologic and/or neuroradiological evidence of herpes simplex encephalitis. Males were affected more than females. Age ranged from 4 years to 65 years. Main clinical features included altered sensorium (100%) and seizures (89%). Serological test for HSV antibody in CSF and blood was positive in 14 patients. Fronto-temporal localisation was seen in EEG of 18 patients. CT and MRI were fairly characteristic with bilateral asymmetric fronto-temporal lesions. Patients with mild disease and who reported earlier responded well to treatment with acyclovir. Mortality was higher if treatment was delayed or if the disease was severe. Delayed treatment even in less severe cases produced neurological deficit in many survivors. Despite limitations of non-availability of CSF-PCR and serial estimation of HSV antibodies, the study is an attempt to highlight the value of high index of suspicion of HSE on clinical grounds, systematically excluding cases with different aetiologies resembling HSE and planning early antiviral therapy to reduce both mortality and morbidity associated with this fatal disease.

Use of fenoldopam to prevent radiocontrast nephropathy in high-risk patients

We evaluated the ability of fenoldopam, a newly available renal vasodilator, to prevent radiocontrast nephropathy in high-risk patients undergoing interventional diagnostic and therapeutic angiographic procedures. We reviewed the results from 46 consecutive procedures in patients with serum creatinine > or = 1.5 mg/dL if diabetic and > or = 1.7 mg/dL if nondiabetic. We compared our results to a previously published cohort of similarly at-risk patients. The incidence of radiocontrast nephropathy, defined as an increase in serum creatinine of > or = 25% at 48 hr following the procedure, was 13% in the group treated with fenoldopam, compared to an expected 38%. The percentage change in serum creatinine at 48 hr was +16% vs. +118%, respectively, in the two groups. In this preliminary experience, the use of fenoldopam in high-risk patients appears to minimize the likelihood of radioncontrast nephropathy. Cathet Cardiovasc Intervent 2001;53:341-345.

Fenoldopam, a dopamine agonist, for hypertensive emergency: a multicenter randomized trial. Fenoldopam Study Group

Despite successful therapies for chronic hypertension, hospital admissions for hypertensive emergency more than tripled between 1983 and 1992.

OBJECTIVE

To examine the safety and efficacy of fenoldopam, the first antihypertensive with selective and specific action on vascular dopamine (DA1) receptors, in a clinical trial involving emergency department patients with true hypertensive emergencies.

METHODS

Patients with a sustained diastolic blood pressure (DBP) of > or =120 mm Hg and evidence of target organ compromise were randomized in a double-blinded manner to one of four fixed doses of intravenous fenoldopam (0.01, 0.03, 0.1, or 0.3 microg/kg/min) for 24 hours. The primary endpoint was the magnitude of DBP reduction in each of the three higher-dose groups after four hours of fenoldopam treatment compared with the lowest-dose group.

RESULTS

One hundred seven participants from 21 centers were enrolled, and 94 patients received fenoldopam. Evidence of acute target-organ damage included new renal dysfunction or hematuria (50%), acute congestive heart failure or myocardial ischemia (48%), and papilledema or grade III-IV hypertensive retinopathy (34%). The DBP decreased in a dose-dependent fashion, with significant differences between the 0.1- and 0.3-microg/kg/min groups compared with the lowest-dose group. Treatment was well tolerated, and there were no deaths or serious adverse events during follow-up, up to 48 hours. All patients were successfully transitioned to oral or transdermal antihypertensives with maintenance of blood pressure control.

CONCLUSIONS

Fenoldopam safely and effectively lowers blood pressure in a dose-dependent manner in patients with hypertensive emergencies. Observations supporting potential risk factors for hypertensive emergency are discussed.

Pharmacokinetics of mycophenolate mofetil and intravenous ganciclovir alone and in combination in renal transplant recipients

STUDY OBJECTIVES

To evaluate the pharmacokinetics of mycophenolic acid and its glucuronide metabolite alone and in the presence of ganciclovir, and to determine the pharmacokinetics of ganciclovir alone and in combination with mycophenolate mofetil.

DESIGN

Randomized, open-label, three-way crossover study.

PATIENTS

Twelve kidney transplant recipients.

INTERVENTIONS

Mycophenolate mofetil 1500 mg orally and ganciclovir 5 mg/kg intravenously were each given alone and in combination with at least a 1-week washout period between treatment arms.

MEASUREMENTS AND MAIN RESULTS

Blood samples were obtained to measure mycophenolic acid and ganciclovir by high-performance liquid chromatography. Mean (+/-SD) oral plasma clearance for mycophenolic acid alone and with ganciclovir was 3.11 +/- 0.72 and 3.19 +/- 0.72 ml/min/kg (p = 0.64). The overall disposition of the major metabolite, MPA-glucuronide, was unchanged, with approximately 70% of the administered dose eliminated as the glucuronide conjugate for both arms of the study. Mean genciclovir serum clearance was 1.80 +/- 0.58 ml/min/kg for ganciclovir and 1.70 +/- 0.55 ml/min/kg for ganciclovir plus mycophenolate mofetil (p = 0.11; 10 patients). Renal clearance of ganciclovir was decreased when the drugs were administered in combination, 1.43 +/- 0.54 (ganciclovir) and 1.26 +/- 0.44 (both drugs) ml/min/kg (p = 0.02; 10 patients).

CONCLUSION

The single-dose pharmacokinetics of mycophenolic acid and its glucuronide metabolite were unchanged by the addition of ganciclovir. Total serum clearance of ganciclovir was unchanged by the addition of mycophenolate mofetil, however, renal clearance was slightly decreased.

Immunologic and patient selection strategies for successful utilization of less than 15 kg pediatric donor kidneys--long term experiences with 40 transplants

Renal transplantation using infant donors is associated with significantly less graft survival (GS) and increased morbidity, especially from very young and small donors. We report our results using specific strategies to determine which age and size donor require en bloc renal transplant reconstruction and associated immunologic protocols for optimization of subsequent GS. Forty cadaveric pediatric en bloc renal transplants were performed. Mean donor age was 23.6+/-18.4 months with subgroups: 2-12 months, n=14; 13-24 months, n=19; and 25-60 months, n=7. Mean donor weight was 14.4+/-4.5 kg. All kidneys were placed in primary, nonsensitized (peak PRA = 7.9+/-5.6%) adult (41.6+/-16 years) recipients. Low weight was preferred (62.4+/-12.8 kg). Mean cold ischemia time was 26.9+/-8.6 hr. Immunosuppression consisted of quadruple immunosuppression (QI) with OKT3 induction. All patients had ureteral stents placed intraoperatively. Mean follow-up was 16.9 months. Actuarial GS at 12, 24, and 33 months were 100% (n=13), 85% (n=20), and 71% (n=7), respectively. Total GS was 35/40=88%. All grafts functioned immediately and there were no technical losses. Biopsy proven rejections occurred in 12 (30%) patients, developing at 16-167 days postoperatively (mean = 50.3 days). Mean serum creatinine at one week and 1, 6, 12, and 18 months were 2.1+/-2.0, 1.5+/-0.8, 1.3+/-0.5, 1.1+/-0.4, and 0.9+/-0.4 mg/dl, respectively. Functional isotopic renography, as well as sonographic monitoring reflected rapid initial and continued growth in these kidneys. Mean BP at 12 and 24 months postoperatively were 145/83+/-18/13 and 122/76+/-20/10 mmHg, respectively, with no significant proteinuria noted. Excellent results with minimal complications utilizing very small and young infant donors can be achieved with QI immunosuppression, and selection of low immune reactive and noncomplicated adult recipients. Additionally, maximal renal dosing by minimizing recipient weight may prevent future hyperfiltration damage.

Joseph H. Boyes Award. Dispersion of regenerating axons across enclosed neural gaps

Tubular prostheses support peripheral axon regeneration across gaps of up to 3 cm in the primate. However, the precision with which axons cross a gap and reinnervate the periphery remains controversial. These experiments use continuous tracing of regenerated rat sciatic nerve axons with HRP-WGA to examine the dispersion of axons as they cross a gap, and the effects on this dispersion of gap distance and fascicular orientation. Proximal and distal tibial and peroneal fascicles were precisely oriented about the longitudinal midplane of a silicon tube, with correct or reversed fascicular alignment and gaps of 2 mm and 5 mm. After 6 weeks of regeneration, HRP-WGA was applied to the distal peroneal fascicle to continuously label its reinnervating axons. These axons tended to grow straight across the tube, with dispersion increasing as a factor of distance when correct fascicular alignment was maintained. However, when fascicular alignment was reversed, axonal dispersion was determined by fascicular size rather than fascicular identity. These experiments provide no evidence for neurotropic interactions promoting "correct" fascicular reinnervation. Progressive axonal dispersion and the absence of factors to promote fascicular specificity should result in an increase of random reinnervation and functional disruption with larger gaps. An enclosed gap is not an acceptable substitute for nerve graft when reconstructing a nerve that serves multiple functions.

Sequential MTX-5 FU chemotherapy in pallination of advanced cancer cervix

Twenty four patients with advanced cancer of cervix were submitted to sequential chemotherapy 5FU and MTX. The response rate was 85% in stage III and 50% in stage IV. Overall response rate was 75%. Patients who had not received radiotherapy earlier responded better than those who had received it earlier. This easy and economical modality has importance in view of late reporting and advanced stage of disease encountered in our set up.

Utilisation of psychotropic drugs in patients of the long stay ward

A survey of the prescribing of psychotropic drugs was carried out at the Psychiatric Hospital of Bahrain. This retrospective study on 60 inpatients of the Long Stay Ward revealed a man:woman ratio of 2.7. 91% of the men and 88% of the women were over 40 years old. 44 of the 60 patients had a diagnosis of schizophrenia, the rest had dementia, depression, schizoaffective disorders, drug-induced psychosis, general paralysis or Huntington's chorea. 95% of patients received antipsychotic drugs. Thioridazine was the most common drug followed by chlorpromazine. The mean number of drugs/patient was 1.7, with 41.7% of patients receiving only 1 drug. Tardive dyskinesia was observed in 11 patients and 9 experienced varying degrees of tremor. The findings confirm that psychiatric illness treated by psychiatrists need not lead to polypharmacy. As a consequence, its treatment may be less likely to result in adverse reactions than when patients are treated by general practitioners.

A new manifestation and treatment alternative for heparin-induced thrombosis

We treated a coronary artery bypass patient whose postoperative course was complicated by heparin-induced thrombocytopenia and resultant pulmonary artery and saphenous vein graft thromboses. The pulmonary thromboemboli were found first, and pulmonary blood flow was restored with intravenously administered tissue plasminogen activator (tPA). A short time later, the vein grafts were found to be occluded, and we subsequently performed multivessel percutaneous transluminal coronary angioplasty (PTCA) using tPA as an adjuvant to oral warfarin sodium therapy with excellent results. We conclude that heparin-induced thromboses in the pulmonary arteries are amenable to thrombolytic therapy, including tPA, whereas this regimen appears to have little effect on saphenous vein grafts. We also found that a combination of warfarin and thrombolytic therapy is an alternative regimen for heparin-intolerant patients who require PTCA.

Serum immunoglobulin status of psychiatric in-patients

In view of the fact that substantial evidence today links psyche, brain, stress and immune system, the serum immunoglobulin (viz. IgG, IgA, IgM) levels in 40 patients with psychiatric disorders (viz. Schizophrenia, Affective disorder and generalized Anxiety disorders) have been investigated. With the exception of IgA, all psychiatric patients had significantly elevated IgG, IgM levels (p less than 0.001) when compared with healthy controls. Surprisingly these immunoglobulin levels irrespective of prevalent psychiatric disorder were almost similar to those of the hospitalized surgical patients pre-operatively (preferable controls), suggestive of no direct linear causal relationship between the psychiatric disorder and serum immunoglobulin levels. Factors affecting immunoglobulins have been discussed. Considering a probable viral association in Schizophrenia it is felt that simultaneous monitoring of viruses (affecting the nervous system) in the form of antigen/antibodies may be more informative.

Effect of prior X-irradiation on ultraviolet light-induced sister-chromatid exchange

Induction of sister-chromatid exchanges (SCEs) by ultraviolet light at 2.6 J/m2 in Chinese hamster ovary cells was significantly inhibited by pretreatment with 3 and 5 Gy of X-rays. No inhibition was observed when cells were treated first with ultraviolet light and subsequently X-irradiated with 5 Gy.

Post-exercise potentiation of wall motion to identify myocardial viability

Resting left ventricular wall motion abnormalities may represent myocardial scars or areas of viable muscle which are ischemic and may thus benefit from revascularization surgery. Improvement in wall motion in the 3-6 minute post-exercise recovery period as compared to the resting state was investigated as a possible criterion to predict myocardial viability in 168 patients with coronary artery disease. Of 125 patients with abnormal resting wall motion, 14 of 14 who improved regional function post-exercise also improved following coronary bypass surgery. However, wall motion improved postoperatively in an additional 55 patients who had not demonstrated post-exercise improvement. An increase in ejection fraction post-exercise occurred in patients with coronary disease as well as an additional group of 24 normal subjects. Thus in the post-exercise period, improvement in resting wall motion is a highly specific but insensitive predictor of myocardial viability.

Electromechanical correlations in hypertrophic subaortic stenosis

Six of 14 patients with hemodynamically proven subaortic stenosis (SAS) showed electrocardiographic patterns consistent with myocardial infarction. Analysis of the 0.02-sec horizontal plane vector allowed discrimination between true myocardial infarction and SAS. In SAS this vector was shifted anteriorly and to the right consistent with septal hypertrophy and increased left-to-right early septal forces.

Cineangiographic studies of left ventricular contraction revealed a unique pattern also consistent with septal hypertrophy disproportionately greater than that of the ventricular free wall.

No correlation existed between maximal instantaneous vectorial voltage, and either the peak left ventricular pressure or the pressure gradient within the left ventricular outflow tract. Striking increases in vectorial forces in SAS may be related to dystrophic changes within the myocardial mass and may not be attributable to simple hypertrophy secondary to hemodynamic obstruction.