Incidents of potential public health significance identified using national surveillance of US poison center data (2008-2012).

BACKGROUND: The Centers for Disease Control and Prevention (CDC) and the American Association of Poison Control Centers conduct national surveillance on data collected by US poison centers to identify incidents of potential public health significance (IPHS). The overarching goals of this collaboration are to improve CDC's national surveillance capacity for public health threats, identify early markers of public health incidents and enhance situational awareness. The National Poison Data System (NPDS) is used as a surveillance system to automatically identify data anomalies. PURPOSE: To characterize data anomalies and IPHS captured by national surveillance of poison center data over 5 years. METHODS: Data anomalies are identified through three surveillance methodologies: call-volume, clinical effect, and case-based. Anomalies are reviewed by a team of epidemiologists and clinical toxicologists to determine IPHS using standardized criteria. The authors reviewed IPHS identified by these surveillance activities from 2008 through 2012. RESULTS: Call-volume surveillance identified 384 IPHS; most were related to gas and fume exposures (n = 229; 59.6%) with the most commonly implicated substance being carbon monoxide (CO) (n = 92; 22.8%). Clinical-effect surveillance identified 138 IPHS; the majority were related to gas and fume exposures (n = 58; 42.0%) and gastrointestinal complaints (n = 84; 16.2%), and the most commonly implicated substance was CO (n = 20; 14.4%). Among the 11 case-based surveillance definitions, the botulism case definition yielded the highest percentage of identified agent-specific illness. CONCLUSIONS: A small proportion of data anomalies were designated as IPHS. Of these, CO releases were the most frequently reported IPHS and gastrointestinal syndromes were the most commonly reported illness manifestations. poison center data surveillance may be used as an approach to identify exposures, illnesses, and incidents of importance at the national and state level.

Characterizing concentrations of diethylene glycol and suspected metabolites in human serum, urine, and cerebrospinal fluid samples from the Panama DEG mass poisoning.

CONTEXT: Diethylene glycol (DEG) mass poisoning is a persistent public health problem. Unfortunately, there are no human biological data on DEG and its suspected metabolites in poisoning. If present and associated with poisoning, the evidence for use of traditional therapies such as fomepizole and/or hemodialysis would be much stronger. OBJECTIVE: To characterize DEG and its metabolites in stored serum, urine, and cerebrospinal fluid (CSF) specimens obtained from human DEG poisoning victims enrolled in a 2006 case-control study. METHODS: In the 2006 study, biological samples from persons enrolled in a case-control study (42 cases with new-onset, unexplained AKI and 140 age-, sex-, and admission date-matched controls without AKI) were collected and shipped to the Centers for Disease Control and Prevention (CDC) in Atlanta for various analyses and were then frozen in storage. For this study, when sufficient volume of the original specimen remained, the following analytes were quantitatively measured in serum, urine, and CSF: DEG, 2-hydroxyethoxyacetic acid (HEAA), diglycolic acid, ethylene glycol, glycolic acid, and oxalic acid. Analytes were measured using low resolution GC/MS, descriptive statistics calculated and case results compared with controls when appropriate. Specimens were de-identified so previously collected demographic, exposure, and health data were not available. The Wilcoxon Rank Sum test (with exact p-values) and bivariable exact logistic regression were used in SAS v9.2 for data analysis. RESULTS: The following samples were analyzed: serum, 20 case, and 20 controls; urine, 11 case and 22 controls; and CSF, 11 samples from 10 cases and no controls. Diglycolic acid was detected in all case serum samples (median, 40.7 mcg/mL; range, 22.6-75.2) and no controls, and in all case urine samples (median, 28.7 mcg/mL; range, 14-118.4) and only five (23%) controls (median, < Lower Limit of Quantitation (LLQ); range, < LLQ-43.3 mcg/mL). Significant differences and associations were identified between case status and the following: 1) serum oxalic acid and serum HEAA (both OR = 14.6; 95% C I = 2.8-100.9); 2) serum diglycolic acid and urine diglycolic acid (both OR > 999; exact p < 0.0001); and 3) urinary glycolic acid (OR = 0.057; 95% C I = 0.001-0.55). Two CSF sample results were excluded and two from the same case were averaged, yielding eight samples from eight cases. Diglycolic acid was detected in seven (88%) of case CSF samples (median, 2.03 mcg/mL; range, < LLQ, 7.47). DISCUSSION: Significantly elevated HEAA (serum) and diglycolic acid (serum and urine) concentrations were identified among cases, which is consistent with animal data. Low urinary glycolic acid concentrations in cases may have been due to concurrent AKI. Although serum glycolic concentrations among cases may have initially increased, further metabolism to oxalic acid may have occurred thereby explaining the similar glycolic acid concentrations in cases and controls. The increased serum oxalic acid concentration results in cases versus controls are consistent with this hypothesis. CONCLUSION: Diglycolic acid is associated with human DEG poisoning and may be a biomarker for poisoning. These findings add to animal data suggesting a possible role for traditional antidotal therapies. The detection of HEAA and diglycolic acid in the CSF of cases suggests a possible association with signs and symptoms of DEG-associated neurotoxicity. Further work characterizing the pathophysiology of DEG-associated neurotoxicity and the role of traditional toxic alcohol therapies such as fomepizole and hemodialysis is needed.

Characterizing risk factors for pediatric lamp oil product exposures.

UNLABELLED: Poisonings from lamp oil ingestion continue to occur worldwide among the pediatric population despite preventive measures such as restricted sale of colored and scented lamp oils. This suggests that optimal prevention practices for unintentional pediatric exposures to lamp oil have yet to be identified and/or properly implemented. OBJECTIVE: To characterize demographic, health data, and potential risk factors associated with reported exposures to lamp oil by callers to poison centers (PCs) in the US and discuss their public health implications. STUDY DESIGN: This was a two part study in which the first part included characterizing all exposures to a lamp oil product reported to the National Poison Data System (NPDS) with regard to demographics, exposure, health, and outcome data from 1/1/2000 to 12/31/2010. Regional penetrance was calculated using NPDS data by grouping states into four regions and dividing the number of exposure calls by pediatric population per region (from the 2000 US census). Temporal analyses were performed on NPDS data by comparing number of exposures by season and around the July 4th holiday. Poisson regression was used to model the count of exposures for these analyses. In the second part of this project, in order to identify risk factors we conducted a telephone-based survey to the parents of children from five PCs in five different states. The 10 most recent lamp oil product exposure calls for each poison center were systematically selected for inclusion. Calls in which a parent or guardian witnessed a pediatric lamp oil product ingestion were eligible for inclusion. Data on demographics, exposure information, behavioral traits, and health were collected. A descriptive analysis was performed and Fisher's exact test was used to evaluate associations between variables. All analyses were conducted using SAS v9.3. RESULTS: Among NPDS data, 2 years was the most common patient age reported and states in the Midwestern region had the highest numbers of exposure calls compared to other regions. Exposure calls differed by season (p < 0.0001) and were higher around the July 4th holiday compared to the rest of the days in July (2.09 vs. 1.89 calls/day, p < 0.002). Most exposures occurred inside a house, were managed on-site and also had a "no effect" medical outcome. Of the 50 PC-administered surveys to parents or guardians, 39 (78%) met inclusion criteria for analysis. The majority of ingestions occurred in children that were 2 years of age, that were not alone, involved tiki torch fuel products located on a table or shelf, and occurred inside the home. The amount of lamp oil ingested did not appear to be associated with either the smell (p = 0.19) or the color of the oil (p = 1.00) in this small sample. Approximately half were asymptomatic (n = 18; 46%), and of those that reported symptoms, cough was the most common (n = 20, 95%) complaint. CONCLUSIONS: Lamp oil product exposures are most common among young children (around 2 years of age) while at home, not alone and likely as a result of the product being in a child-accessible location. Increasing parental awareness about potential health risks to children from these products and teaching safe storage and handling practices may help prevent both exposures and associated illness. These activities may be of greater benefit in Midwestern states and during summer months (including the period around the July 4th holiday).

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis: an etiology worth considering in the differential diagnosis of delirium.

BACKGROUND: Medical toxicologists are frequently consulted when young patients present with delirium attributed to suspected poisoning. Medical toxicologists should be aware of non-toxicological mimics of delirium. We describe two patients ultimately diagnosed with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis for which a toxicological consultation was requested to evaluate for neuroleptic malignant syndrome (NMS). CASE 1: A 21 year old male was sent from a psychiatric facility for new, worsening psychotic symptoms. He had autonomic instability, confusion, and hyper-reflexia. He was treated for NMS without improvement, and after an extensive workup was unrevealing, he was discharged home with significant cognitive dysfunction. Stored CSF later tested positive for anti-NMDAR antibodies. CASE 2: A 27 year old female was sent from a psychiatric facility for a seizure and new psychiatric symptoms. She was agitated and had violent, alternating extremity flexion and extension along with autonomic instability. She was treated for NMS, rhabdomyolysis, and rabies before analysis of CSF demonstrated anti-NMDAR antibodies. Treatment included surgical resection of a suspicious ovarian cyst, steroids and IVIG, with moderate improvement. DISCUSSION: Autoimmune syndromes of the central nervous system result from receptor dysfunction after an antibody response to extracellular or intracellular antigens, such as subunits of the NMDA receptor. The NMDA subunits NR2b and NR2a, in addition to the N-terminal region of the glycine binding NR1 subunit, have been implicated. Typical features such as memory loss, movement disorders, and hallucinations reflect the density and distribution of neuronal NDMA receptors. As young people, particularly young women, are predominantly affected, initial symptoms may be attributed to encephalopathy from drug abuse or schizophrenia. Toxicologists may be consulted as many features mimic NMS. Serum and cerebrospinal fluid can be checked for anti-NMDAR antibodies as part of a paraneoplastic or meningioencephalitis panel. Effective treatments have been described and include surgical resection and immunosuppressive medications.

A link between prompt optical and prompt gamma-ray emission in gamma-ray bursts.

The prompt optical emission that arrives with the gamma-rays from a cosmic gamma-ray burst (GRB) is a signature of the engine powering the burst, the properties of the ultra-relativistic ejecta of the explosion, and the ejecta's interactions with the surroundings. Until now, only GRB 990123 had been detected at optical wavelengths during the burst phase. Its prompt optical emission was variable and uncorrelated with the prompt gamma-ray emission, suggesting that the optical emission was generated by a reverse shock arising from the ejecta's collision with surrounding material. Here we report prompt optical emission from GRB 041219a. It is variable and correlated with the prompt gamma-rays, indicating a common origin for the optical light and the gamma-rays. Within the context of the standard fireball model of GRBs, we attribute this new optical component to internal shocks driven into the burst ejecta by variations of the inner engine. The correlated optical emission is a direct probe of the jet isolated from the medium. The timing of the uncorrelated optical emission is strongly dependent on the nature of the medium.

Endoscopic and traditional saphenous vein harvest: a histologic comparison.

BACKGROUND: Vein trauma after saphenectomy by endoscopic or longitudinal techniques may influence the progression of medial and intimal hyperplasia and ultimately affect graft patency. This study compared the histologic characteristics of saphenous veins after endoscopic and longitudinal harvest. METHODS: One hundred seventy patients who underwent elective coronary artery bypass grafting had saphenectomy performed endoscopically (n = 88) or by a longitudinal incision (n = 82). Cross-sectional specimens from endoscopically (n = 151) and longitudinally (n = 158) harvested veins were submitted for hematoxylin-eosin, trichrome, and elastin staining. Blinded histologic evaluation involved graded analysis of endothelial, smooth muscle, and elastic lamina continuity in addition to medial and adventitial connective tissue uniformity. RESULTS: Regardless of harvest technique, endothelial, elastic lamina, and smooth muscle continuity as well as medial and adventitial connective tissue uniformity were not significantly different. CONCLUSIONS: Minor histologic alterations occur during saphenectomy, however, endoscopically and longitudinally harvested saphenous veins are histologically similar.

Risk factors for leg wound complications following endoscopic versus traditional saphenous vein harvesting.

BACKGROUND: Risk factors for leg wound complications following traditional saphenectomy have included: obesity, diabetes, female gender, anemia, age, and peripheral vascular disease. Use of an endoscopic saphenectomy technique may modify the risk factor profile associated with a traditional longitudinal incision. METHODS: From September 1996 to May 1999, 276 consecutive patients who underwent elective isolated coronary artery bypass grafting performed by a single surgeon (K.B.A.) had their greater saphenous vein harvested endoscopically. During the period from January 1999 to May 1999, the surgical records of 643 patients who underwent the same operation and had a traditional longitudinal saphenectomy were reviewed for postoperative leg wound complications. Group demographics were similar regarding preoperative risk stratification and traditionally identified wound complication risk factors (diabetes, gender, obesity, preoperative anemia, and peripheral vascular disease). Leg wound complications were defined as: hematoma, dehiscence, cellulitis, necrosis, or abscess requiring dressing changes, antibiotics and/or debridement prior to complete epithelialization. Follow-up was 100% at six weeks. RESULTS: Leg wound complications following endoscopic harvest occurred in 3% (9/276) of patients versus 17% (110/643) of traditional harvest patients (p < 0.0001). No univariate risk factors for wound complications were associated with endoscopic saphenectomy. Univariate predictors of wound complications following traditional saphenectomy included: diabetes (p = 0.001), obesity (p = 0.0005), and female gender (p = 0.005). Multivariable risk factors for leg wound complications following saphenectomy were traditional harvest technique (OR 7.56, CI 3.8-17.2, p < 0.0001), diabetes (OR 2.10, CI 1.4-3.2, p = 0.0006) and obesity (OR 1.82, CI 1.2-2.8, p = 0.007). CONCLUSIONS: Traditional longitudinal saphenectomy is a multivariable risk factor for development of leg wound complications. Endoscopic saphenectomy modifies the risk factor profile for wound complications and should be the standard of care, particularly for obese and/or diabetic patients who require venous conduit during coronary artery bypass grafting.

Endoscopic versus traditional saphenous vein harvesting: a prospective, randomized trial.

BACKGROUND: Saphenous vein harvested with a traditional longitudinal technique often results in leg wound complications. An alternative endoscopic harvest technique may decrease these complications. METHODS: One hundred twelve patients scheduled for elective coronary artery bypass grafting were prospectively randomized to have vein harvested using either an endoscopic (group A, n = 54) or traditional technique (group B, n = 58). Groups A and B, respectively, were similar with regard to length of vein harvested (41 +/- 8 cm versus 40 +/- 14 cm), bypasses done (4.1 +/- 1.1 versus 4.2 +/- 1.4), age, preoperative risk stratification, and risks for wound complication (diabetes, sex, obesity, preoperative anemia, hypoalbuminemia, and peripheral vascular disease). RESULTS: Leg wound complications were significantly (p < or = 0.02) reduced in group A (4% [2 of 51] versus 19% [11 of 58]). Univariate analysis identified traditional incision (p < or = 0.02) and diabetes (p < or = 0.05) as wound complication risk factors. Multiple logistic regression analysis identified only the traditional harvest technique as a risk factor for leg wound complications with no significant interaction between harvest technique and any preoperative risk factor (p < or = 0.03). Harvest rate (0.9 +/- 0.4 cm/min versus 1.2 +/- 0.5 cm/min) was slower for group A (p < or = 0.02) and conversion from endoscopic to a traditional harvest occurred in 5.6% (3 of 54) of patients. CONCLUSIONS: In a prospective, randomized trial, saphenous vein harvested endoscopically was associated with fewer wound complications than the traditional longitudinal method.

Atrial fibrillation/flutter induced by implantable ventricular defibrillator shocks: difference between epicardial and endocardial energy delivery.

INTRODUCTION: We evaluated the incidence and energy dependence of atrial fibrillation/flutter (AF) induced by implantable ventricular defibrillator shocks in 63 patients tested in the operating room or electrophysiology laboratory. METHODS AND RESULTS: Defibrillator shocks were epicardial monophasic in 32 patients, and through an Endotak lead endocardial monophasic in 19 and biphasic in 12 patients. The epicardial and endocardial patient groups had similar clinical characteristics. A total of 517 defibrillator shocks were given. The epicardial group received 336 total defibrillator shocks and 10 +/- 6 shocks (mean +/- SD) per patient compared with the endocardial group, which received 181 total shocks and 6 +/- 4 defibrillator shocks per patient (P = 0.004). In the epicardial group, AF occurred in 13 (41%) patients and in 17 (5%) of the 336 shocks. No AF was induced with endocardial defibrillator shocks. The epicardial mean energy was 16 +/- 9 J, lower than the endocardial mean energy of 20 +/- 9 J (P < 0.004). In the epicardial monophasic group, energy correlated with AF induction. Each patient received 7 +/- 6 defibrillator shocks < 15 J and 4 +/- 2 shocks > or = 15 J, yet AF occurred in only 2.3% versus 9.6% (P < 0.05) of defibrillator shocks < 15 J and > or = 15 J, respectively. Of note, AF was not induced with energy < 4 J or > 31 J. CONCLUSIONS: In the epicardial configuration, AF induction is energy dependent, with an apparent lower and upper limit of vulnerability. AF induction by defibrillator shocks delivered through an Endotak lead is very rare, possibly related to an apparent upper limit of vulnerability of less energy, avoidance of thoracotomy, or different energy field distribution.

Prognosis of patients with frequent premature ventricular complexes and nonsustained ventricular tachycardia after coronary artery bypass graft surgery.

BACKGROUND: Previous studies in small groups of predominantly nongeriatric patients showed that complex ventricular arrhythmias occurring after coronary artery graft (CABG) surgery are of no prognostic significance. The purpose of this study was to compare the prognosis of patients with and without advanced grade ventricular arrhythmias (AGVA) after CABG in a large group of patients. [In this paper, AGVA is used as an abridged definition of frequent premature ventricular complexes (PVCs) and nonsustained ventricular tachycardia (NSVT) which represent advanced grade ventricular arrhythmias.] METHODS: Twenty-four hour ambulatory electrocardiographic (ECG) monitoring was performed 3 days after CABG in 185 consecutive patients with 185 closely matched control patients without AGVA. Of 185 patients with AGVA, 77 had frequent PVCs, 45 had NSVT, and 63 patients had both. The average age of both groups was 65 +/ 9.7 years. Patients were followed for 34 +/ 10 months, and in 30 patients ambulatory monitoring was repeated at the end of the follow-up. RESULTS: Fifteen AGVA and nine control patients died. In each group seven deaths were noncardiac. Six nonsudden and two sudden cardiac deaths (SCD) occurred in the AGVA group at 2-36 months after CABG and two nonsudden cardiac deaths in the control group at 3 and 35 months after CABG (p = 0.053). Both SCDs occurred 33 months after CABG after new events known to predispose to SCD. In 18 of 30 patients AGVA was no longer present when ambulatory ECG monitoring was repeated 36 +/ 11 months after CABG. CONCLUSION: AGVA after CABG was not a marker of an early sudden cardiac death. In 60% of patients not treated with antiarrhythmic drugs, AGVA was no longer present late after operation.

[Subcutaneous emphysema of the anterior chest wall as the only symptom of spontaneous rupture of the esophagus]. / Odma podskórna przedniej sciany klatki piersiowej jako jedyny objaw samoistnego pekniecia przelyku.

A diagnostically difficult case of Boerhaave's syndrome is reported. The patient gave a history of subcutaneous emphysema of the anterior chest wall as the only sign. Aspiration drainage through thoracotomy opening and artificial alimentation through jejunostomy were used with success.

Nonpharmacologic treatment of the Wolff-Parkinson-White syndrome and other supraventricular tachycardias.

Nonpharmacologic treatment using surgery or intracardiac catheter ablation can be used for several forms of supraventricular tachycardia. Surgery is highly successful in preventing recurrent tachyarrhythmias in patients with the Wolff-Parkinson-White syndrome and can be recommended as first-line treatment in several situations. Catheter ablation of the atrioventricular conduction system combined with an implanted ventricular pacemaker can offer substantial relief to selected patients with drug-refractory atrial fibrillation. Technical advances in catheter ablation will undoubtedly lead to more widespread use of this form of therapy in supraventricular tachycardia.

Thrombolytic therapy for acute arterial occlusion.

To evaluate the role of selective intra-arterial low-dose thrombolytic therapy (SILDT) as an alternative to the surgical management of acute arterial occlusion, the hospital records of 40 patients who underwent 43 SILDT treatments with either streptokinase (36) or urokinase (7) between December 1979 and March 1984 were reviewed. Twenty-eight patients underwent 30 treatments (group 1) for native arterial occlusion and 12 patients underwent 13 treatments (group 2) for prosthetic or autogenous graft occlusions. Therapy was deemed successful if subsequent surgical therapy was obviated. In group 1, SILDT was successful in 13 of 28 (45%) patients with 12 of 25 lower extremity occlusions and one of three upper extremity occlusions. Successful lysis in the native artery occlusion group fell into three categories: five patients were successfully treated for arterial thrombosis complicating percutaneous transluminal angioplasty (PTA); four patients required PTA after complete lysis revealed an underlying arterial stenosis; and only three required no further therapy after SILDT. SILDT failed in all three patients with the aortoiliac occlusions. Eleven patients with femoral artery occlusions and unsuccessful SILDT required six bypass procedures, three amputations, one embolectomy, and one PTA. In group 2 only 3 of 14 treatments (21%) were successful. Bypass revision was not possible in 11 patients and all required amputation. Systemic fibrinolysis was seen in 20 (59%) of 34 patients with available data. Neither fibrinogen levels nor fibrin degradation products predicted the occurrence of complications. Minor complications occurred in 18 of 43 (43%) treatments; small hematomas at the catheter entry site were most common. Minor complications occurred in 20 of 43 treatments (44%) and included severe local hemorrhage (four), distant bleeding (three), pulmonary embolism (four), myocardial infarction (three), unmasking of an aortoduodenal fistula (one), and clot migration requiring emergency thrombectomy (four). SILDT is most effective in acute arterial thrombosis complicating arteriography or percutaneous angioplasty. It may play a role in the patient in whom thrombolysis can reveal an underlying stenosis amenable to percutaneous angioplasty. This experience shows SILDT to be of limited value in the management of prosthetic autogenous graft occlusions. Finally, thrombolytic therapy is associated with significant morbidity and mortality rates and requires cautious monitoring to detect arterial thrombus migration, worsening tissue ischemia, venous thromboembolism, intracerebral hemorrhage, and local or systemic bleeding.

Experimental investigations on the influence of stroma-free haemoglobin solution on kidney function in exchange transfusion models.

In the continuing search for promoting the bio-pharmacological characteristics of an excellent oxygen carrier, the Stroma-free Haemoglobin Solution (SFHS), in the presented work, the authors were investigating the composition changes of SFHS infused to dogs. In 10 mongrel dogs a total exchange of the circulating blood was done for replacing it with SFHS. For the observing the physico-chemical changes in circulating and excreted fluids electron spectroscopy was used in view of good spectral characteristics of haemoglobin, and a high sensitivity of this method to changes taking place in the analyzed molecule. Comparing the spectral curves characterizing the solution used for exchange transfusion with the spectral curves obtained from circulating SFHS samples and haemoglobin excreted in the urine, and from the ascites, during the 6 hours course of the experiment, no essential structural changes were observed in the hemin molecule, in the visible range.

Mitral valve replacement after closed mitral commissurotomy.

Closed mitral commissurotomy (CMC) was performed at the National Heart Institute in 303 patients (73% women, 27% men; mean age 40 years) with acquired isolated mitral stenosis between 1954 and 1980. The average mean mitral valve gradient decreased from 14.2 +/- 0.4 to 5.3 +/- 0.4 mm Hg (p less than 0.001), and mitral valve area index increased from 0.7 +/- 0.03 to 1.4 +/- 0.9 cm2/m2 (p less than 0.001). The perioperative mortality was 2%. Ninety-two percent of patients improved one or more functional classes after CMC. Actuarial survival was 95%, 82% and 70% at 5, 10 and 15 years after CMC, respectively. Fifty-four patients (18%) required mitral valve replacement (MVR) a mean of 9.6 years after commissurotomy (range 1-26 years). Before CMC, factors associated with later MVR included preoperative functional class, calcification of the mitral valve, and the absence of an opening snap. After CMC, poor functional improvement, congestive heart failure, atrial fibrillation, and the necessity for a repeat CMC were associated with late MVR. Catheterization after CMC showed that patients who later required MVR had a smaller decrease in left atrial pressure (p less than 0.001), more mitral regurgitation (p less than 0.001), and were more likely to have pulmonary hypertension (p less than 0.05). The indications for MVR were residual stenosis with or without mild mitral regurgitation in 33 patients (61%), restenosis in 15 (28%), and moderate-to-severe regurgitation in six (11%). Perioperative mortality for valve replacement was 13%. Among survivors, 88% improved at least one functional class after valve replacement. Actuarial survival was estimated to be 95% at 5 years and 74% at 10 years after MVR. This study confirms that CMC provides excellent long-term hemodynamic and clinical improvement in appropriately selected patients. When symptomatic deterioration occurs late after CMC, MVR restores clinical and hemodynamic improvement in many patients. CMC continues to be performed at the National Heart Institute in selected patients with acquired mitral stenosis.

Structural and enzymatic comparison of human cardiac muscle myosins isolated from infants, adults, and patients with hypertrophic cardiomyopathy.

Human cardiac ventricular myosins were prepared from autopsy samples from nine adults, seven infants, and from surgical specimens from seven patients undergoing left ventricular septal myectomy for obstructive hypertrophic cardiomyopathy. Infant myosin differed from adult myosin in two important characteristics: (a) approximately 30% of the 27,000-dalton myosin light chain is replaced by a 28,000-dalton light chain, and (b) the actin-activated myosin MgATPase activity of infant myosin is significantly lower than that of adult myosin (64 nmol phosphate released/mg myosin per min vs. 124 nmol/mg per min at 37 degrees C). The K(+)-EDTA ATPase activity of the myosin measured in 0.5M KCl is also lower in infants (1,210 nmol/mg per min vs. 620 nmol/mg per min at 37 degrees C), but the Ca(++)-activated ATPase is not significantly different. There were no differences in enzymatic activity between the normal adult and cardiomyopathic myosins.A detailed study was performed to investigate possible variations in the structure of the myosin heavy chain in infant, adult, and cardiomyopathic samples. There were no significant differences between infant and normal adult, or between normal adult and cardiomyopathic myosins seen in pyrophosphate polyacrylamide gel electrophoresis, or peptide mapping using alpha-chymotrypsin, papain, or cyanogen bromide to generate peptides. These results suggest that isoenzymes of human ventricular myosin do not exist for the myosin heavy chain in the specimens examined from infants, adults, and patients with obstructive hypertrophic cardiomyopathy. The decreased actin-activated MgATPase activity found for infant myosin appears to be due solely to a partial replacement of the 27,000-dalton light chain of myosin with a 28,000-dalton light chain.