Blood Plasma Circulating DNA-Protein Complexes: Involvement in Carcinogenesis and Prospects for Liquid Biopsy of Breast Cancer

Circulating DNA (cirDNA) is a promising tool in translational medicine. However, studies of cirDNA have neglected its association with proteins, despite ample evidence that this interaction may affect the fate of DNA in the bloodstream and its molecular functions. The goal of the current study is to shed light on the differences between the proteomic cargos of histone-containing nucleoprotein complexes (NPCs) from healthy female (HFs) and breast cancer patients (BCPs), and to reveal the proteins involved in carcinogenesis. NPCs were isolated from the blood samples of HFs and BCPs using affinity chromatography. A total of 177 and 169 proteins were identified in NPCs from HFs and BCPs using MALDI-TOF mass spectrometry. A bioinformatics analysis revealed that catalytically active proteins, as well as proteins that bind nucleic acids and regulate the activity of receptors, are the most represented among the unique proteins of blood NPCs from HFs and BCPs. In addition, the proportion of proteins participating in ion channels and proteins binding proteins increases in the NPCs from BCP blood. However, the involvement in transport and signal transduction was greater in BCP NPCs compared to those from HFs. Gene ontology term (GO) analysis revealed that the NPC protein cargo from HF blood was enriched with proteins involved in the negative regulation of cell proliferation, and in BCP blood, proteins involved in EMT, invasion, and cell migration were observed. The combination of SPG7, ADRB1, SMCO4, PHF1, and PSMG1 NPC proteins differentiates BCPs from HFs with a sensitivity of 100% and a specificity of 80%. The obtained results indirectly indicate that, in tandem with proteins, blood cirDNA is an important part of intercellular communication, playing a regulatory and integrating role in the physiology of the body.

Comparative Analysis of Molecular Functions and Biological Role of Proteins from Cell-Free DNA-Protein Complexes Circulating in Plasma of Healthy Females and Breast Cancer Patients

Cell-free DNA (cfDNA) circulates in the bloodstream packed in membrane-coated structures (such as apoptotic bodies) or bound to proteins. To identify proteins involved in the formation of deoxyribonucleoprotein complexes circulating in the blood, native complexes were isolated using affinity chromatography with immobilized polyclonal anti-histone antibodies from plasma of healthy females (HFs) and breast cancer patients (BCPs). It was found that the nucleoprotein complexes (NPCs) from HF plasma samples contained shorter DNA fragments (~180 bp) than BCP NPCs. However, the share of DNA in the NPCs from cfDNA in blood plasma in HFs and BCPs did not differ significantly, as well as the share of NPC protein from blood plasma total protein. Proteins were separated by SDS-PAGE and identified by MALDI-TOF mass spectrometry. Bioinformatic analysis showed that in the presence of a malignant tumor, the proportion of proteins involved in ion channels, protein binding, transport, and signal transduction increased in the composition of blood-circulating NPCs. Moreover, 58 (35%) proteins are differentially expressed in a number of malignant neoplasms in the NPCs of BCPs. Identified NPC proteins from BCP blood can be recommended for further testing as breast cancer diagnostic/prognostic biomarkers or as being useful in developing gene-targeted therapy approaches.

Comparative Analysis of Tumor-Associated microRNAs and Tetraspanines from Exosomes of Plasma and Ascitic Fluids of Ovarian Cancer Patients

Ovarian cancer (OC) is one of the most common and fatal types of gynecological cancer. In the early phase of OC detection, the current treatment and diagnostic methods are not efficient and sensitive enough. Therefore, it is crucial to explore the mechanisms of OC metastasis and discover valuable factors for early diagnosis of female cancers and novel therapeutic strategies for metastasis. Exosomes are known to be involved in the development, migration, and invasion of cancer cells, and their cargo could be useful for the non-invasive biopsy development. CD151- and Tspan8-positive exosomes are known to support the degradation of the extracellular matrix, and are involved in stroma remodeling, angiogenesis and cell motility, as well as the association of miR-24 and miR-101 with these processes. The objective of this study was to explore the relationship of these components of exosomal cargo, in patients with OC, to clarify the clinical significance of these markers in liquid biopsies. The levels of tetraspanins Tspan8+ and CD151+ exosomes were significantly higher in plasma exosomes of OC patients compared with healthy females (HFs). The relative levels of miR-24 and miR-101 in plasma exosomes of HFs were significantly higher than in plasma exosomes of OC patients, while the levels of these microRNAs in exosomes from plasma and ascites of ill females showed no difference. Our study revealed a strong direct correlation between the change in the ascites exosomes CD151+Tspan8+ subpopulation level and the expression levels of the ascites (R = 0.81, p < 0.05) and plasma exosomal miR-24 (R = 0.74, p < 0.05) in OC patients, which confirms the assumption that exosomal cargo act synergistically to increase cellular motility, affecting cellular processes and signaling. Bioinformatics analysis confirmed the involvement of CD151 and Tspan8 tetraspanins and genes controlled by miR-24-3p and miR-101 in signaling pathways, which are crucial for carcinogenesis, demonstrating that these tetraspanins and microRNAs are potential biomarkers for OC screening, and predictors of poor clinicopathological behavior in tumors.

The state of measles and rubella in the WHO European Region, 2013

Measles and rubella persist in the World Health Organization European Region despite long-standing and widespread use of vaccines against them. Our aim was to review the epidemiology of measles and rubella in relation to the goal of eliminating these diseases from the Region by 2015. We report on the number of measles and rubella cases by country in 2012 and present an analysis of preliminary measles and rubella surveillance data for 2013. We analysed data of these diseases for 2013 by age group, diagnosis confirmation (clinical, laboratory-confirmed and epidemiologically linked), and vaccination, hospitalization and importation status. We also report on measles-related deaths. For 2012, there were 26,785 [corrected] measles cases and 29,601 rubella cases reported in the Region. For 2013, these figures were 31,520 and 39,367 respectively. Most measles cases in 2013 (96%; n = 30,178) were reported by nine countries: Georgia (7830), Germany (1773), Italy (2216), the Netherlands (2499), Romania (1074), the Russian Federation (2174), Turkey (7404), Ukraine (3308) and the United Kingdom (1900). In 2013, most measles cases were among unvaccinated persons and over one in three patients were aged 20 years and older. For 2013, almost all rubella cases were reported by Poland (n = 38,585; 98%). High population immunity and high-quality surveillance are the cornerstones to eliminate measles and rubella. Without sustained political commitment and accelerated action by Member States and partners, the elimination of measles and rubella in the WHO European Region may not be achieved.

Determination of up-to-date vaccination status for preschool-aged children: how accurate is manual assessment conducted by paraprofessional staff?

BACKGROUND

Accurate identification of underimmunized children is needed to determine which children need vaccination. Previous studies have found the accuracy of manually determining the immunization status from a personal vaccination record to be low (<50%).

OBJECTIVE

To determine the accuracy of manual immunization status assessment for preschool-aged children.

SUBJECTS AND SETTING

Children </=32 months old (n = 21 263) seen over 1 year at 12 women, infants, and children (WIC) sites in San Diego, California. Age at evaluation was between 0 and 24 months.

METHODS

Paraprofessional immunization specialists conducted manual immunization status assessment using the WIC client's personal vaccination record. Immunization status as recorded in the WIC record was compared with computerized assessment (the gold standard).

MEASURES AND RESULTS

For all patient encounters, 29 078 (80%) of 36 368 were assessed correctly; manual assessment outcome was not recorded in the WIC record for 2171 (6%) of encounters. Accuracy varied by WIC site (range: 70%-90%). The sensitivity at correctly identifying an underimmunized child per encounter was 53.6%; the specificity at correctly identifying a fully vaccinated child per encounter was 89. 4%. The 3 most common vaccines that were incorrectly assessed in identifying an underimmunized child were Haemophilus influenzae type b (43%), hepatitis B (37%), and diphtheria-tetanus toxoids and (cellular or acellular) pertussis vaccine (24%). Children with no outcome as recorded in the WIC record were 5 times as likely to be up-to-date.

CONCLUSIONS

Manual immunization assessment was specific but only moderately sensitive at identifying underimmunized children. Thus, many underimmunized children will by missed but only 10% of children will be referred inappropriately.

Diphtheria epidemic in the Republic of Uzbekistan, 1993-1996

The Republic of Uzbekistan, like the other Newly Independent States in the 1990s, experienced epidemic diphtheria during the 1990s. The outbreak in Uzbekistan began in 1993 in southern regions that bordered areas of Tajikistan that were experiencing a very intense diphtheria epidemic. However, the Uzbek epidemic rapidly spread and threatened to involve the entire country. From 1993-1996, 1169 cases of diphtheria were reported, compared with 58 in 1990-1992. Unvaccinated or only partially vaccinated cases were more likely to have clinically severe forms of diphtheria than those who were fully vaccinated. Strong epidemiologic links with the Tajik diphtheria epidemic and the predominance of mitis biotype strains of Corynebacterium diphtheriae in Uzbekistan make it likely that the Uzbek outbreak arose independently of the predominantly biotype gravis epidemic that began in Russia. The epidemic appeared to be due to low population immunity and the large-scale reintroduction of toxigenic strains of C. diphtheriae. Several mass vaccination campaigns and general enhancement of routine immunization procedures led to control of the epidemic in 1996.

Missed opportunities to improve immunization status among high-risk children in the WIC program

An investigation of a recent pertussis outbreak in Idaho showed that WIC participants were less well immunized than non-WIC participants. Conducting immunization status assessment and referral to a provider for vaccination (A/R) in WIC has been shown to significantly improve immunization. WIC files were abstracted to obtain immunization and visit histories. More frequent A/R at WIC has potential to improve the immunization status of preschool age WIC participants.

Thermodynamic prediction of active ingredient loading in polymeric microparticles

The growing use of microparticles as a controlled-delivery system for pharmaceutical and non-pharmaceutical active ingredients (AIs) has prompted a costly trial-and-error development of new and effective microparticle systems. In order to facilitate a more rational design and optimization of AI loadings in microparticles, we have developed a molecular-thermodynamic theory to predict the loading of liquid AIs in polymeric microparticles that are manufactured by a solvent evaporation process. This process involves the emulsification of a liquid polymer solution (consisting of polymer and AI dissolved in a volatile solvent) in an aqueous surfactant solution. The theory describes the equilibrium distribution of the AI between the aqueous phase and the dispersed polymeric droplets. The universal functional activity coefficient (UNIFAC) and UNIFAC-Free Volume (FV) group-contribution methods are utilized to model the nonidealities in the water and polymeric droplet phases, respectively. The inputs to the theory are: (i) the chemical structures, densities and total masses of the manufacturing ingredients, (ii) the manufacturing temperature and (iii) the glass transition temperature of the polymer. Since surfactant concentrations exceeding the critical micellar concentration (CMC) are often required in order to stabilize the dispersed polymeric droplets during the emulsion manufacturing process, the theory also accounts for AI solubilization in surfactant micelles present in the manufacturing solution. To test the AI loading predictions, we compare theoretical predictions of AI loadings in poly(lactic acid), poly(methyl methacrylate) and polystyrene microparticles to experimentally measured ones for five model AIs with varying degrees of hydrophobicity (benzyl alcohol, n-octanol, geraniol, farnesol and galaxolide). We also demonstrate how the developed theory can be utilized to screen polymers with respect to their abilities to load a given AI, as well as to provide guidelines for manufacturing microparticles having the desired AI loading.

What mothers in the Women, Infants, and Children (WIC) program feel about WIC and immunization linkage activities. A summary of focus groups in Wisconsin

BACKGROUND

Although studies indicate that strategies to improve immunization coverage among preschool-age children enrolled in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) are effective, the attitudes of parents of children enrolled in WIC toward the linkage between WIC and immunization programs is unknown.

OBJECTIVE

To gain a better understanding of how parents using WIC resources feel about the association of WIC and immunization services, their attitudes toward WIC immunization activities, factors that may cause clients to drop out of the program, and the effects of racial background on parent attitudes.

PARTICIPANTS AND METHODS

We conducted 8 focus group sessions with mothers whose children receive WIC services in Milwaukee, Wis. Mothers were between 18 and 35 years old, with at least 1 child between 6 and 24 months of age. The 47 mothers participating were each assigned to 1 of 8 focus groups, including 2 groups each of Asian, white, African American, and Hispanic mothers. A systematic content analysis was conducted for themes and key points within and across ethnic groups.

RESULTS

Socially disadvantaged mothers reported their overall experiences in WIC to be very positive. Lengthy waiting time during a WIC visit was identified as the most important barrier to participation. Mothers believed strongly that it was the responsibility of parents to get their children vaccinated, but that WIC staff and the primary care provider should work together to remind parents when vaccinations were due. Mothers expressed very positive attitudes toward the linking of WIC and immunization activities. Telephone reminders and education were mentioned as the best ways to encourage mothers to get their child vaccinated on time. Immunization linkage activities and the requirement that a parent report to a WIC center more frequently if the child was underimmunized were not mentioned as reasons for dropping out of the WIC program; indeed, more frequent visits to a WIC center were actually viewed as a potentially effective strategy by several mothers. Some mothers found obtaining immunizations and WIC services at the same time and place to be very convenient. There did not seem to be any significant differences among ethnic groups in attitudes toward immunization linkage activities being performed in WIC.

CONCLUSIONS

Mothers with preschool-age children enrolled in WIC feel that the linkage of immunization activities with WIC services is a helpful way to improve the health of their children. This linkage was not identified as a contributing factor for leaving the WIC program.

Outbreak of drug-resistant tuberculosis with second-generation transmission in a high school in California

BACKGROUND

In spring 1993, four students in a high school were diagnosed with tuberculosis resistant to isoniazid, streptomycin, and ethionamide.

METHODS

To investigate potential transmission of drug-resistant tuberculosis, a retrospective cohort study with case investigation and screening by tuberculin skin tests and symptom checks was conducted in a high school of approximately 1400 students. Current and graduated high-school students were included in the investigation. DNA fingerprinting of available isolates was performed.

RESULTS

Eighteen students with active tuberculosis were identified. Through epidemiologic and laboratory investigation, 13 cases were linked; 8 entered 12th grade in fall 1993; 9 of 13 had positive cultures for Mycobacterium tuberculosis with isoniazid, streptomycin, and ethionamide resistance, and all 8 available isolates had identical DNA fingerprints. No staff member had tuberculosis. One student remained infectious for 29 months, from January 1991 to June 1993, and was the source case for the outbreak. Another student was infectious for 5 months before diagnosis in May 1993 and was a treatment failure in February 1994 with development of rifampin and ethambutol resistance in addition to isoniazid, streptomycin, and ethionamide. In the fall 1993 screening, 292 of 1263 (23%) students tested had a positive tuberculin skin test. Risk of infection was highest among 12th graders and classroom contacts of the two students with prolonged infectiousness. An additional 94 of 928 (10%) students tested in spring 1994 had a positive tuberculin skin test; 22 were classroom contacts of the student with treatment failure and 21 of these had documented tuberculin skin test conversions.

CONCLUSION

Extensive transmission of drug-resistant tuberculosis was documented in this high school, along with missed opportunities for prevention and control of this outbreak. Prompt identification of tuberculosis cases and timely interventions should help reduce this public health problem.

Fatiguing illness among employees in three large state office buildings, California, 1993: was there an outbreak?

The objective was to determine if a cluster of chronic fatigue syndrome (CFS)-like illness had occurred among employees in two large state office buildings in northern California, and to identify risk factors for and features of fatiguing illness in this population.

DESIGN

case-control study.

POPULATION AND SETTING

Over 3300 current employees in two state office buildings and employees in a comparable "control" building. Information was collected on demographic and occupational variables, the occurrence of fatiguing illness for at least one month in the previous year, and the presence of 36 symptoms. A total of 3312 (82%) of 4035 employees returned questionnaires. Overall, 618 (18.7%) persons reported fatigue lasting at least one month; including 382 (11.5%) with fatigue of at least six months' duration and 75 (2.3%) with symptoms compatible with a CFS-like illness. Independent risk factors for fatigue lasting one month or longer were found to be Native American ethnicity (OR 2.4, CI 1.1,5.3), Hispanic ethnicity (OR 1.7, CI 1.3,2.3), female sex (OR 1.5, CI 1.2,1.9), gross household incomes of less than $50,000 (OR 1.3, CI 1.1,1.6), and less than a college education (OR 1.3, CI 1.1,1.6). Similar risks were observed for persons who reported fatigue lasting six months or longer. Female sex (OR 3.2, CI 1.7, 6.4) was the only independent risk factor found for those persons classified as having a CFS-like illness. Case prevalence rates for all three categories of fatigue, as determined by multivariate analysis, were not significantly different among buildings. Despite finding a substantial number of employees with fatiguing illness in the two state office buildings, the prevalence was not significantly different than that for a comparable control building. Previously unidentified risk factors for fatigue of at least one month and at least six months identified in this population included Hispanic ethnicity, not having completed college, and income below $50,000.

Assessment and related immunization issues in the Special Supplemental Nutrition Program for Women, Infants and Children: a status report

This article reports the results of a survey undertaken to determine the current level of collaboration between Women, Infants and Children (WIC) programs and immunization services. While the results of this study are encouraging, WIC needs to continue to place emphasis on using written or computerized immunization records for client screening, utilize available computer hardware and software to assist assessments, and expand the use of food voucher incentives as a strategy to improve coverage.

The retropectoral transaxillary permanent pacemaker: description of a technique for percutaneous implantation of an "invisible" device

This report describes a percutaneous, transaxillary approach for implanting permanent pacemakers in the retropectoral space. This approach was used in 17 patients; indications for the procedure included the need to find a new implantation site in patients with infections and multiple previous pacemaker pocket sites (2 patients), emaciation and absence of sufficient adipose tissue (4 patients), and cosmetic considerations (11 patients). No complications were encountered during the implantation and the results were uniformly excellent in all patients. The pacemaker was "invisible" in each case. We conclude that a percutaneous approach for implanting permanent pacemakers in the retropectoral region is safe and feasible. This approach is likely to be applicable to the implantation of transvenous antitachycardia devices.

Thermal properties and physical ageing behaviour of tyrosine-derived polycarbonates

Tyrosine-derived polycarbonates are new carbonate-amide copolymers. These materials have been suggested for use in medical applications, but their thermal properties and their enthalpy relaxation kinetics (physical ageing behaviour) have so far not been evaluated in detail. Since structure-property correlations involving enthalpy relaxation are rarely investigated for biomedical polymers, a series of four tyrosine-derived polycarbonates was used as a model system to study the effect of pendant chain length on the thermal properties and the enthalpy relaxation kinetics. The chemical structure of the test polymers was identical except for the length of their respective pendant chains. This feature facilitated the identification of structure-property correlations. Quantitative differential scanning calorimetry was utilized to determine the thermal properties and to measure enthalpy relaxation kinetics. The glass transition temperature of this family of polymers decreased from 93 to 52 degrees C when the length of the pendant chain was increased from two to eight carbon atoms. Successive additions of methylene groups to the pendant chain made a fairly constant contribution to lowering the glass transition temperature. For pendant chains of four or more methylene groups, the rate of enthalpy relaxation was independent of the number of methylene groups in the pendant chain. The enthalpy relaxation data were fitted to the Cowie-Ferguson model and the relaxation times obtained were about 90 min. Dynamic mechanical analysis was employed to study the viscoelastic properties. The available observations indicate that the polymers become more flexible with increasing length of the pendant chain. The results suggest that the length of the pendant chain can be used effectively to control important material properties in this series of polymers.

Usefulness of a prototype directional catheter for excimer laser coronary angioplasty in narrowings unfavorable for conventional excimer or balloon angioplasty

We report clinical and angiographic results in 53 patients with 57 significant coronary or saphenous vein graft narrowings treated with directional excimer laser angioplasty. The target vessels were the left main (1%), anterior descending (32%), circumflex (19%), right coronary artery (39%), and vein grafts (9%). Lesions were morphologic class B1 (18%), B2 (79%), or C (3%), with 40 de novo and 17 restenotic lesions. Adjunctive balloon angioplasty was used in 53 lesions (93%). Mean pre- and postprocedural minimal lumen diameters were 0.6 +/- 0.3 and 1.9 +/- 0.7 mm (p < 0.001), corresponding to a mean diameter stenosis of 72 +/- 20% and 27 +/- 16%. Procedural success rate was 91%. Cumulative risk of death, Q-wave myocardial infarction, or emergency bypass operation was 9% (5 patients). Of patients who had a successful laser procedure, 28 (60%) with 30 lesions underwent angiographic follow-up at 6 +/- 3 months after the procedure. Restenosis rates (> 50% diameter restenosis or acute gain loss) were 37% and 23%, respectively. Four patients underwent bypass, 3 angioplasty, and 1 patient died from cancer. This study demonstrates the feasibility of directional application of laser energy to selected unfavorable narrowings for conventional excimer laser or balloon angioplasty. Further evaluation of this device using the now standard saline infusion technique is necessary to establish its ultimate role as a primary interventional device.

Use and safety of acellular pertussis vaccine among adult hospital staff during an outbreak of pertussis

During May and June 1993, 10 patients and 5 members of the clinical staff at a hospital in California were diagnosed with Bordetella pertussis infection. In addition to erythromycin prophylaxis, 630 (48%) of 1330 staff members received a half dose of acellular pertussis vaccine with tetanus and diphtheria toxoids (DTaP). To identify side effects of the vaccine, a questionnaire was completed by 344 (54%) of 630 vaccinated staff. Side effects were reported by 117 respondents (34%); 64 were classified as mild (local reaction at injection site) and 50 as moderate (systemic complaints or local reaction resulting in limitation of arm movement). Three vaccinees (< 1%) reported missing 1 or more days of work because of their symptoms. Local reactions at the injection site occurred in 100 (29%), systemic symptoms in 38 (11%), and limitation of arm movement in 18 (5%). This study indicates that use of half dose of DTaP in adults appears safe and should be considered as an adjunct to chemoprophylaxis during institutional outbreaks.

The effect of quinidine and myocardial ischemia on the isolated rat heart with fat-free diet

Fat-free diet changes the lipid content and the electrophysiological properties of the rat myocardium. Five percent fat supplementation to the diet does not alter the basic electrophysiological properties but still has a biochemical effect on the lipid content of the myocardium. The purpose of this work was to determine whether these biochemical alterations affect the response of the myocardium to quinidine and ischemia, both of which interact with the lipid component of the membrane. We used strength-duration, strength-interval and threshold of ventricular fibrillation to measure the electrophysiological properties of the isolated rat heart at baseline and after 30 minutes of quinidine perfusion or coronary artery ligation. The fatty acid composition of the myocardium was analyzed. We found that a fat-free diet caused essential fatty-acid deficiency, while 5% fat supplementation had a partial protective effect. Quinidine decreased excitability and increased refractoriness in both groups but had more effect on the fat-free diet hearts group. There was no difference in the ventricular fibrillation threshold. Ischemia increased myocardial excitability in the fat-free diet hearts group and had no effect on refractoriness or ventricular fibrillation threshold. These results support the theory that the lipid composition of the myocardial membrane affects its response to lipophilic drugs and ischemia.

Percutaneous excimer laser coronary angioplasty of lesions not ideal for balloon angioplasty

BACKGROUND

Excimer laser coronary angioplasty is a new, investigational technique for treating coronary artery stenoses. Initial reports have demonstrated acute efficacy and relative safety of this procedure, but have not addressed the effect of lesion type on acute success and complication rates.

METHODS AND RESULTS

In the first 100 patients undergoing percutaneous excimer laser coronary angioplasty at our institution, acute laser success was obtained in 84% and procedural success was obtained in 94%. There were six acute closures during laser angioplasty and one myocardial infarction. Two patients required emergency coronary bypass surgery. Sixty-five percent of patients had lesions not ideal for balloon angioplasty because of lesion morphology (tubular, diffuse, or chronic total occlusion) or ostial location. There were 10 tubular stenoses, 29 diffuse lesions, 18 chronic total occlusions, and eight ostial lesions, including five aorto-ostial lesions. In this nonideal subgroup, the acute success rate with laser was 86% (72% of chronic total occlusions and 91% of non-totally occluded lesions), and the procedural success rate was 94%. There were three acute occlusions during laser angioplasty but no myocardial infarctions, emergency bypass surgeries, or deaths. One coronary artery perforation occurred without clinical sequelae. Laser angioplasty was successful in four of six lesions (67%) in which balloon angioplasty had failed. Laser success was obtained in 10 of 11 (91%) moderately or heavily calcified stenoses. Eight eccentric lesions and two lesions on bends were successfully treated without dissection or perforation. No side branch occlusions occurred in the 15 patients in whom one or more major branches originated within the lesion treated. Adjunctive balloon angioplasty was performed in 47% of cases, usually to obtain a larger final luminal diameter. Need for adjunctive balloon angioplasty decreased to 36% after a larger (2.0 mm) laser catheter became available. Twenty-eight percent of the 105 lesions treated were American College of Cardiology/American Heart Association classification type A, 47% were type B, and 25% were type C. Laser and procedural successes were obtained in 83% and 97% of type A, 88% and 96% of type B, and 85% and 88% of type C lesions, respectively.

CONCLUSIONS

In our initial experience, excimer laser angioplasty was found to be acutely effective and safe therapy for lesions identified as not ideal for balloon angioplasty. This technique may provide a useful adjunct or alternative to balloon angioplasty in selected patients.

Nitrate tolerance in heart failure: differential venous, pulmonary and systemic arterial effects

The hemodynamic profile of tolerance to intravenous nitroglycerin was studied in 9 patients with New York Heart Association Class III to IV congestive heart failure. After rapid dosage build-up to the maximal tolerated dose (decrease in pulmonary wedge pressure to 10 mm Hg or systolic blood pressure to 90 mm Hg), nitroglycerin (525 +/- 548 micrograms/min) was administered at a constant continuous intravenous infusion for a total of 24 hours. The extent of nitrate tolerance at 24 hours was calculated as the percentage loss of the benefit achieved at time of peak effect of nitroglycerin. Tolerance had a different time course and magnitude in the venous, arterial and pulmonary circulations. At 24 hours, right atrial pressure and pulmonary vascular resistance returned to control values in most patients, while 40 to 50% of the effect on systemic vascular resistance, cardiac index and pulmonary wedge pressure was maintained. These findings emphasize the importance of precise definitions in studies relating to nitrate tolerance.

Predicting late restenosis after coronary angioplasty by very early (12 to 24 h) thallium-201 scintigraphy: implications with regard to mechanisms of late coronary restenosis

To examine whether late coronary restenosis may be predicted by abnormalities of myocardial perfusion in the early hours after successful percutaneous transluminal coronary angioplasty and to study in greater detail the mechanisms involved in the development of late coronary restenosis after angioplasty, a prospective study was undertaken in 90 consecutive patients. Thallium-201 scintigrams were recorded at rest and during the stress of atrial pacing, 12 to 24 h after angioplasty, and the results were related to the findings at angiography in 70 patients undergoing late cardiac catheterization. A reversible thallium-201 perfusion defect was found in 39 (38%) of 104 myocardial regions supplied by the dilated coronary vessel and identified a subset of patients at high risk of late (6 to 12 months) angiographic restenosis (sensitivity 77%, specificity 67%). In contrast, late coronary restenosis developed in only 7 (11%) of 65 vessels and in 5 (14%) of 37 patients with a nonischemic thallium-201 scintigram on day 1 (p less than 0.005). Multivariate logistic regression analysis of 14 possible preangioplasty and periangioplasty clinical and angiographic variables selected reversible perfusion defect on the thallium-201 scintigram on day 1 (p = 0.016) and immediate postangioplasty residual coronary narrowing (p = 0.004) as significant independent predictors of late restenosis, with younger patient age as an additional less powerful predictor (p less than 0.05). The findings have important implications regarding the pathogenesis of late coronary restenosis in patients undergoing successful angioplasty and they imply that in the majority of these patients pathophysiologic events in the early minutes and hours after angioplasty may determine the development of late restenosis.

Effect of the second-generation calcium channel blocking drug nisoldipine on diastolic left ventricular dysfunction in heart failure

The effect of intravenous nisoldipine (0.12 microgram/kg/min) on diastolic left ventricular (LV) dysfunction was studied from simultaneous hemodynamic and radionuclide measurements in 12 patients with New York Heart Association class II to IV cardiac failure. The initial LV filling fraction was low, the peak LV filling rate normalized for end-diastolic volume was decreased, and the pulmonary capillary wedge pressure (PCWP) was high and associated with clinical shortness of breath. Nisoldipine produced an increase in LV filling fraction from 36 +/- 17% to 43 +/- 20% (p = 0.003). The increase in filling took place in both early and late diastole: peak early filling rate (PFR) increased in 11 of the 12 patients (p = 0.02) and late diastolic filling rate (atrial [A] wave in eight of them (NS). When the determinants of these changes, were examined further, it was found that in the control state PFR was inversely related to LV end-systolic volume (r = 0.77), whereas the A wave was related in exponential fashion to PCWP (preload) (r = 0.79). Nisoldipine did not change the slope of these relationships, and it did not alter the end-diastolic pressure-volume relationship, implying that inherent myocardial relaxation and distensibility were unaltered by the drug. In summary, nisoldipine improved measurements of diastolic LV dysfunction in patients with cardiac failure. This study illustrates the importance of considering ventricular loading conditions when analyzing and interpreting measurements of diastolic ventricular dysfunction. The measured changes in diastolic LV function during infusion of nisoldipine appear to be due to alterations in ventricular loading conditions rather than to a direct myocardial effect of the drug.

Identifying patients at high risk for restenosis after percutaneous transluminal coronary angioplasty for unstable angina pectoris

To study the determinants of late restenosis after percutaneous transluminal coronary angioplasty (PTCA) performed in patients with unstable angina pectoris, a prospective study was undertaken in 90 patients. Primary PTCA success was achieved in 84 (93%) patients, dilating 116 of 118 coronary narrowings (1.4/patient), while major complications during PTCA occurred in only 1 patient (1 death). Eighty-two patients (114 dilated arteries) were followed for 25 +/- 11 months: 68 (83%) were in New York Heart Association functional class I or II, 11 (13%) in class III, and there were 3 deaths. Late restenosis was found in 16 (25%) of 65 lesions (29% of 49 patients) studied by angiography 9 +/- 7 months after PTCA. Restenosis was more frequent in left anterior descending coronary artery lesions (p = 0.07) and in those which at the time of PTCA had multiple irregularities (67 vs 14%, odds ratio 12.5, p = 0.002), decreased coronary perfusion (Thrombolysis in Myocardial Infarction grade less than 3) (50 vs 15%, odds ratio 5.7, p = 0.02) or intraluminal thrombus (67 vs 19%, odds ratio 8.7, difference not significant). Multiple irregularities (p = 0.003) and decreased flow (p = 0.02) remained independent predictors of restenosis (goodness of fit 0.88) after adjustment for 12 pre- and peri-PTCA clinical and angiographic variables by logistic regression analysis. These data underline the feasibility of early revascularization by PTCA in patients with unstable angina pectoris. Careful follow-up should be instituted in patients with multiple irregular lesions, decreased coronary perfusion or intraluminal thrombus at the time of PTCA. In such patients, late restenosis may be the rule rather than the exception.

[Percutaneous transluminal coronary angioplasty after coronary artery bypass]

Anginal syndrome may recur early of several years after coronary artery bypass surgery (CABS), and may be due to narrowing of a bypass graft, progression of pre-existing coronary artery lesions, or the appearance of new lesions. Repeat CABS is associated with considerable morbidity and mortality. We therefore performed percutaneous transluminal angioplasty (PTCA) in saphenous or internal mammary bypass grafts or native coronary arteries in 23 patients after CABS. We successfully dilated 35 of 37 lesions (95%) present in 33 of 35 vessels (94%) of 21 of 23 patients (91%). The mean vessel narrowing decreased from 86 +/- 22% to 13 +/- 19% (p less than 0.001) and in all 21 patients with angiographic evidence of success functional capacity improved. Single vein grafts were successfully dilated in 9 patients. None developed acute myocardial infarction or needed emergency surgery, but 1 had a cerebral embolism. PTCA is effective therapy for recurrent angina after CABS, and in many patients is preferable to another operation.

Persistent painless ST-segment depression after exercise testing and the effect of age

The relation between the duration of ischemic ST-segment depression (1 mm or more 60 ms after the J point) and the clinical awareness of chest pain was studied in 31 patients (aged 39-73 years) undergoing symptom-limited, graded treadmill exercise testing. The response of these patients to nitrate therapy (spray or sublingual tablet) given immediately on cessation of exercise was also studied. During exercise, angina pectoris appeared at an estimated workload of 4.6 +/- 2.2 metabolic equivalents (METS) (mean +/- SD), and pathological ST-segment depression at 4.9 +/- 1.9 METS (p = NS.) On cessation of exercise, angina disappeared after 3.0 +/- 1.9 min, but ST-segment depression persisted for more than twice as long (6.6 +/- 4.1 min) (p less than 0.0001). The ratio of time to ST-segment recovery/time to relief of pain (a quantitative measure of silent ischemia during recovery) increased with age (r = 0.49, p = 0.002), and in 16 patients over 60 years of age was higher than in 15 younger patients (3.6 +/- 2.5 vs. 2.1 +/- 1.4) (p less than 0.04). The silent ischemia ratio after exercise tended to decrease, although not significantly so (p = 0.2), in patients who received oral nitrates; there was no difference in the response to spray or tablet in this regard. We conclude that ST-segment depression frequently persists after relief of exercise-induced angina pectoris and more so in elderly patients.

Effect of the second-generation calcium channel blocker nisoldipine on left ventricular contractility in cardiac failure

We studied the acute effects of nisoldipine, a new second-generation calcium channel-blocking drug, on cardiac hemodynamics and left ventricular (LV) contractility in 10 patients with grade 2 to 4 cardiac failure. Pressures were measured from an arterial line and a flow-guided catheter in the pulmonary artery, cardiac output by thermodilution, and LV ejection fraction simultaneously by radionuclide ventriculography. Ventricular loading conditions were altered by sublingual nitroglycerin to facilitate construction of LV end-systolic pressure (radial stress)-volume and stress-shortening curves. Nisoldipine, given by continuous intravenous infusion (0.12 micrograms/kg/min), reduced mean arterial pressure (p = 0.001), systemic vascular resistance (p less than 0.05), and the double product, a measurement of myocardial oxygen demand (p less than 0.01). Cardiac index, stroke index, and LV ejection fraction increased in 8 of the 10 patients. LV contractility was initially greatly reduced and was unchanged or slightly decreased during the administration of nisoldipine. Emax, the slope of the end-systolic pressure-volume curve, was unaltered in half of the patients and decreased in the others (NS), whereas the end-systolic stress-shortening curve did not change. In summary, nisoldipine has a potentially useful acute hemodynamic profile in patients with cardiac failure; it increases forward blood flow in most patients, decreases the determinants of myocardial oxygen demand, and produces little measurable changes in the inotropic state of the left ventricle.

Dietary lipid intake and myocardial electrophysiology

We studied the effect of a fat-free diet on the cardiac electrophysiology of rats. Fourteen 2-week-old rats were maintained on a fat-free diet and 12 rats had a 5% soybean oil supplement to their diet. The rats were killed after 6 weeks and the hearts mounted on a Langendorff chamber. Atrioventricular (A-V) block was induced. Myocardial strength-duration (S-D) and strength-interval (S-I) curves were determined. A significant depletion of linoleic acid and elevation of palmitoleic, stearic, and oleic acids was found in the hearts obtained from rats on fat-free diet as compared with the hearts obtained from the rats on oil-supplemented diets. Hearts obtained from rats who had had the oil supplement had a shorter refractory period and an increased threshold for excitation; therefore, these hearts should be less vulnerable to cardiac dysrhythmias. Both S-D and S-I curves best fitted a logarithmic relationship. The intercepts and slopes of these curves were significantly different in the two groups. There were significant correlations between myocardial fatty acid composition (stearate and linoleate in particular) and the different electrophysiological parameters.

Prediction of atrial and ventricular fibrillation complicating myocardial infarction from admission data: a prospective study

This study set out to examine prospectively two logistic formulae based on admission clinical data to predict ventricular or atrial fibrillation complicating acute myocardial infarction. A prospective study of 87 consecutive patients with acute transmural myocardial infarction was conducted. The formula for predicting ventricular fibrillation from the diastolic blood pressure, degree of ST-segment elevation, and QTc had a sensitivity of 93%, specificity of 83%, and a predictive value for an abnormal test of 62% (13 of 14 patients who developed ventricular fibrillation were identified). The formula for predicting atrial fibrillation from the age of the patient, a history of heart failure, systolic blood pressure, and four electrocardiographic parameters had a sensitivity of 78%, specificity of 85%, and a predictive value of 67% (14 of 18 patients identified). Our study shows that patients with myocardial infarction who are liable to develop ventricular or atrial fibrillation can be identified on admission from simple clinical data.

Fat-free diet and myocardial excitability, refractoriness and ventricular fibrillation

The lipid composition of the sarcolemma influences its function. The purpose of this study is to investigate the electrophysiological alterations induced in the rat's heart by dietary manipulation of cardiac fatty-acid composition. Strength-duration and strength-interval relationships were used to study excitability and refractoriness respectively. Ventricular fibrillation threshold measured by short bursts of rapid stimulation was used to indicate ventricular vulnerability. Gas liquid chromatography was used to analyse cardiac fatty-acid-composition. We used two-week-old rats fed with fat-free diet and 5% and 10% soya bean oil-supplemented diets for 6-9 weeks. Fat-free diet only was associated with increased eicosatrienoic acid content, a marker of essential fatty-acid deficiency. A decrease in poly-unsaturated to saturated (P:S) fatty-acid ratio was also observed. Five percent oil supplementation was associated with a delay and attenuation of this effect. Fat-free diet was associated with increased excitability, decreased refractoriness and reduced ventricular fibrillation threshold. Ten percent oil supplementation prevented these effects while 5% oil supplementation had only a temporary protective effect. We conclude that manipulation of dietary fat content can affect cardiac fatty-acid composition and electrophysiology.

Effects of vitamin A and dexamethasone on capsule collagen metabolism in mouse mammary adenocarcinoma

It was previously shown that the administration of dexamethasone (Dex) to mice bearing mammary adenocarcinoma caused the collagen content of the tumor capsule to be decreased by 50%, but collagenase and other neutral protease activities of the tumor were the same as in the controls. These events occurred with distinctly increased tumor invasion and metastasis. The present communication reports on the characterization of capsule collagen and the effects of agents [vitamin A (VA) and Dex] on capsule collagen metabolism and presents further evidence concerning the possible mechanisms by which the collagen content of the capsule was decreased in the Dex-treated hosts. The collagen extracted from capsules of untreated controls and mice (C3H/HeJ) treated with VA or Dex was primarily type I, as judged by the migration of protein bands in sodium dodecylsulfate-polyacrylamide gel electrophoresis and by patterns of elution peaks from an octadecyl C-18 column. The amino acid compositions of type I collagen of the capsule of treated and untreated controls were similar but not identical to those of mouse skin and guinea pig skin type I collagens. The specific activity of intracellular free [14C] proline, the extent of hydroxylation of [14C]proline residues of collagen, and the specific activity of [14C]hydroxyproline and proline in each case were similar in treated and in untreated controls. These results suggest that the observed 45% decrease in the conversion of [14C]proline into protein-bound [14C]hydroxyproline of the Dex-treated hosts apparently was due to decreased collagen synthesis. The data also suggest that the most critical effects of Dex on tumor invasion and metastasis appeared to occur at an early stage before full formation of the collagenous extracellular matrix.

Left ventricular function during physiological cardiac pacing: relation to rate, pacing mode, and underlying myocardial disease

The hemodynamic effects of cardiac pacing at different rates and in different modes were studied in 21 patients who were candidates for permanent pacemaker implantation. Nine of these had primary conduction disturbances (PCD), ten had ischemic heart disease (IHD), seven with additional cardiac failure (CHF), and two had hypertrophic cardiomyopathy (HCM). In patients with PCD, atrial (AOO) and AV sequential (DVI) pacing did not change systolic blood pressure and pulse pressure but ventricular (VVI) pacing caused a progressive fall in these measurements, especially as heart rate increased. Ventricular volume and stroke volume (counts) derived from radionuclide ventriculography (RVG) decreased progressively with higher pacing rates, especially during VVI pacing. Cardiac output was maintained during VVI pacing by the increase in heart rate; during AOO and DVI pacing, cardiac output increased. Similar but more marked differences were observed in patients with IHD and CHF and the changes were even greater in the patients with HCM. Left ventricular (LV) ejection fraction changed little with increasing heart rate in PCD but decreased progressively with the onset of ischemia in IHD and CHF. There was no difference in ejection fraction in the different pacing modes. Graphs related to LV contractility (end-systolic pressure-volume relations) showed that AOO pacing produced the highest and VVI pacing produced the lowest curves of myocardial contractility in all patient groups, except that at higher rates the AOO curve shifted down again in patients with IHD and CHF, presumably with the onset of myocardial ischemia. This study showed that physiological pacing produced the best hemodynamic results in all patient groups. Higher pacing rates should be avoided in patients with ischemic heart disease while VVI pacing should not be used in patients with HCM. Blood pressure and RVG studies during temporary pacing are useful in selecting the optimal pacing system in an individual patient when the clinical choice is not clear.

Chronotropic effect of hydralazine and its mechanism of symptomatic sinus bradycardia

The positive chronotropic effect of hydralazine was studied in 9 patients with symptomatic sinus bradycardia. Hydralazine was given in an intravenous dose of 0.15 mg/kg and heart rate, blood pressure, sinoatrial conduction time (Narula method) and corrected sinus node recovery time were measured. The effect of hydralazine was also studied after total autonomic nervous system blockade using 0.04 mg/kg of atropine and 0.2 mg/kg of propranolol intravenously. In the control state hydralazine produced an increase of 28 +/- 15% (mean +/- standard deviation) in heart rate, and this was essentially due to a decrease in sinoatrial conduction time (by 32 +/- 32%, p less than 0.05). Corrected sinus node recovery time also tended to shorten (decrease of 21 +/- 34%, difference not significant). After total autonomic blockade intrinsic heart rate did not change or increased very little (9 +/- 14%) after administration of hydralazine and there was no consistent change in sinoatrial conduction and corrected sinus node recovery times. The small residual effect of hydralazine on heart rate was related to incomplete autonomic blockade, since the effect of postural change (standing) on heart rate was also not totally abolished. The study showed that the positive chronotropic effect of hydralazine was mainly due to a change in sinoatrial conduction with a smaller change in corrected sinus node recovery time, and the major chronotropic effect of the drug was mediated by the autonomic nervous system.

Left ventricular function from end-systolic stress-shortening relations in mitral valve prolapse

Left ventricular (LV) function was studied from end-systolic stress-shortening relations in 13 patients with mitral valve prolapse (MVP). Studies were made noninvasively using M-mode echocardiography with blood pressure measurements on the right arm from a Baumanometer cuff. Fifteen age and sex-matched normal subjects formed the control group. LV end-diastolic dimension was normal in MVP, while shortening fraction (p less than 0.05) and velocity of circumferential fiber shortening (mean Vcf) in the short axis of the ventricle were increased (p less than 0.05). Ventricular afterload, as measured by meridional end-systolic stress was reduced in MVP (p less than 0.01) but the slope of the stress-shortening curve was not different form normal. The decrease in end-systolic stress was related to the severity of prolapse (r = 0.63, p less than 0.05). The study implied that mid- or basal LV contractility was normal in MVP. The increased shortening fraction of the LV minor axis was in keeping with geometrical changes and a reduced ventricular afterload.

Left ventricular function in acute myocardial infarction: assessment by nuclear angiography

Left ventricular function was assessed in 38 patients two to six days after acute myocardial infarction using nuclear angiocardiography and the following parameters were measured: Left ventricular end-diastolic (LVEDV) and end-systolic volumes (LVESV), ejection fraction (LVEF), indices of left ventricular filling and emptying, right ventricular ejection fraction and ejection rate. Their clinical significance was assessed by their relationship to the patients site and size of infarction, functional capacity, morbidity and mortality. The most sensitive indices of depressed left ventricular function were the EF and ESV. Thus, function was preserved in patients with a small inferior infarction (LVEF = 0.57 +/- 0.07, LVESV = 69 +/- 14 ml) and in Killip Class I (LVEF = 0.48 +/- 0.13, LVESV = 80 +/- 20 ml). Function was disturbed most in patients with extensive anterior infarction (LVEF = 0.18 +/- 0.12, LVESV = 131 +/- 46 ml), Killip Class IV (LVEF = 0.13 +/- 0.07, LVESV = 160 +/- 35 ml), cardiogenic shock (LVEF = 0.14 +/- 0.07, LVESV = 160 +/- 35 ml), pulmonary edema (LVEF = 0.11 +/- 0.06, LVESV = 166 +/- 25 ml) and pulmonary capillary wedge pressure greater than 20 mm Hg (LVEF = 0.14 +/- 0.07, LVESV = 160 +/- 33 ml). Previous infarction was associated with LV dilatation and a greater LVEDV. A lower ejection fraction signified a large infarct and poor left ventricular function. If the ejection fraction was less than 0.15, the patients were unlikely to leave the hospital alive, or if less than 0.25, they were left with poor residual ventricular function and either had significant cardiac failure or high late mortality. Nuclear angiocardiography was a simple method of predicting the clinical pattern and prognosis in each patient and emphasized the importance of limiting infarct size in acute myocardial infarction.

Atrial fibrillation in acute myocardial infarction

Atrial fibrillation (AF) complicating acute myocardial infarction (AMI) is associated with increased morbidity and mortality. Early intervention with antiarrhythmic treatment and hemodynamic support in patients prone to develop AF may modify their course. The purpose of this study was to characterize on admission the patients with AMI who are prone to develop AF. The admission data of 45 consecutive patients who developed AF during the course of AMI, and the data of a control group of 45 consecutive patients with AMI who did not develop AF, were analyzed using logistic regression. The following characteristics of patients who developed AF were identified: old age, history of heart failure prior to admission, low systolic blood pressure on admission, wide P waves, presence of left bundle branch block or left anterior hemiblock, marked ST segment elevation, and PQ segment depression (admission ECG). The logistic regression formula correctly classified 80 of the 90 patients (89%) to their actual group. The study showed that the relative risk of a patient with AMI to develop AF can be estimated on admission from simple, readily available, clinical data.

Short-term effect of nifedipine on effort tolerance in patients with angina pectoris

The short-term effect of oral nifedipine on effort tolerance was tested in 10 patients with effort angina pectoris and a positive effort test (GXT). The patients had four symptom-limited GXTs, using the Bruce protocol, on each day of the study at 0800, 1000, 1400, and 1800 hours. They received four doses of 10 mg oral nifedipine on one day and four doses of placebo on the other, each dose given half an hour prior to each GXT. Values with nifedipine were compared to values with placebo at the same time during each day. Nifedipine improved effort tolerance by 0.5 +/- 0.6 min (p = NS) on the first GXT (mean +/- SEM), by 1.2 +/- 0.6 min (p = NS) on the second GXT, by 1.0 +/- 0.3 min (p less than 0.01) on third GXT, and by 1.3 +/- 0.3 min (p less than 0.01) on the fourth GXT. Improvement of effort tolerance was associated with a fall in resting blood pressure and less ST depression; these changes were statistically significant only on the fourth GXT, which may indicate a cumulative effect of subsequent doses of nifedipine.

The effects of m-AMSA on rat isolated heart

m-AMSA (4'[9-acridinylamino]methansulphon-m-anisidide) is a new cytoxic agent now under clinical trial. We used the rat isolated perfused heart model in order to investigate the cardiac effects of m-AMSA. The results of the dose-response study indicate that m-AMSA has an acute moderate negative inotropic effect. The 90% effect (25% decrease in developed force compared to the control) was observed at drug concentration of 1.5 micrograms/ml. The refractory period (as measured by stimuli of twice diastolic threshold intensity) increased progressively as the drug concentration was increased (up to 2.5 micrograms/ml). Measurements of the strength-duration and strength-interval relationship showed that m-AMSA induced a significant reduction (P less than 0.005) in excitability and prolongation of refactoriness. We suggest that m-AMSA has a membranal cardiotoxic effect in addition to its known intracellular cytotoxic effect.

Effect of sustained release isosorbide dinitrate on exercise performance

The duration of action and hemodynamic mechanisms of isosorbide dinitrate in a sustained release formula (ISDSR) were examined over a 24-hour period. 20 patients with effort angina pectoris were divided randomly into two groups, one group received a single dose of 40 mg ISDSR (at 07.30 h) and the other, two doses of 40 mg ISDSR (at 07.30 and 13.30 h). Every patient had four exercise tests on the first (placebo) day and second (ISDSR) day and a single test on the third (placebo) day. Effort tolerance was improved significantly (p less than 0.05) with ISDSR and this lasted for more than 10 h. The double product was compared to ISDSR. Improvement was achieved by a decrease in blood pressure and an increase in heart rate. There were no signs of increased ischemia (ST segment depression) with the prolongation of exercise time. The antianginal and hemodynamic effects of ISDSR were more pronounced in the patients who received two doses of ISDSR. Thus, ISDSR improved effort tolerance for a prolonged period by inducing a sustained decrease of blood pressure and increase in heart rate in patients with effort-induced angina pectoris.

Restoration and maintenance of sinus rhythm after mitral valve surgery for mitral stenosis

The preoperative clinical, echocardiographic, hemodynamic and surgical data were studied from 40 consecutive patients with pure mitral stenosis and chronic atrial fibrillation who underwent surgical correction of mitral stenosis. After surgery, the patients had cardioversion of atrial fibrillation. The data of 24 patients who maintained sinus rhythm (SR) for more than 3 months (success group) were compared with the data of the 16 patients who failed to maintain SR for more than 3 months (failure group). The patients in the success group were younger (mean age 38 +/- 12 vs 47 +/- 13 years, p less than 0.05), had symptoms for a shorter time (3.0 +/- 4.3 vs 6.4 +/- 5.0 years, p less than 0.02) and had a smaller preoperative echocardiographic left atrial (LA) size (4.9 +/- 0.9 vs 5.5 +/- 1.0 cm, p less than 0.03). The correlation between duration of SR after cardioversion (range 0 to 12 months) and the preoperative data were examined with the use of the "all-possible-subsets-regression" software. The best subset of predictors of successful cardioversion included echocardiographic LA size, functional capacity, duration of symptoms and echocardiographic left ventricular fractional shortening. Patients with symptoms for more than 3 years and echocardiographic LA size of more than 5.2 cm had low rate of successful cardioversion; in this subset of patients, postoperative cardioversion should be avoided.

Regional and global left ventricular function during intra-aortic balloon counterpulsation in patients with acute myocardial infarction shock

We evaluated the improvement in hemodynamic and left ventricular (LV) function in 15 patients with acute myocardial infarction and cardiogenic shock, who were treated with intraaortic balloon counterpulsation (IABP). They were studied by flow-directed right heart catheterization and nuclear angiography. IABP decreased LV end-diastolic volume from 134 to 114 ml and LV end-systolic volume from 100 to 72 ml. LV stroke volume increased from 34 to 42 ml and cardiac output from 3.0 to 3.6 L/min. Global LV ejection fraction increased from 27.6% to 36.1%, and this was due to improvement in regional ejection fraction in ischemic areas. Pulmonary capillary wedge pressure and pulmonary blood volume decreased. Right ventricular ejection fraction also increased significantly. IABP improved LV function in acute myocardial infarction.

Improvement in regional ventricular function after percutaneous transluminal coronary angioplasty

We performed atrial pacing and radionuclide ventriculography in 12 patients before and after percutaneous transluminal coronary angioplasty (PTCA). Successful dilatation was achieved in 9 patients while in 3 the procedure was unsuccessful. Atrial pacing before PTCA showed ischemic dysfunction of the region supplied by the narrowed coronary artery. Regional ejection fraction decreased by 36 +/- 12% during rapid atrial pacing, while global left ventricular ejection fraction fell by 11 +/- 7% with a secondary increase in end-diastolic and end-systolic ventricular volume with the onset of ischemia. After successful PTCA, ischemic dysfunction was ameliorated or abolished. Measurements made at identical heart rates showed that both global and in particular regional left ventricular ejection fraction were significantly higher after successful angioplasty and did not fall during the stress of atrial pacing. There was no improvement in regional or global LV function in patients in whom angioplasty was not successful. The study showed that nuclear ventriculography with the stress of graded atrial pacing was a useful method for analysing the immediate results of coronary angioplasty and for studying its effects on regional myocardial function.