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Hans E Comtet,1,2 Martina Keitsch,2 Karl-Arne Johannessen1,3 1The Intervention Centre, Oslo University Hospital, Oslo, 0424, Norway; 2Department of Design, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway; 3Department of Health Management and Health Economics, Faculty of Medicine, University of Oslo, Oslo, 0318, NorwayCorrespondence: Hans E Comtet, The Intervention Centre, Oslo University Hospital, Postboks 4950, Oslo, 0424, Norway, Email hanscomtet@gmail.comPurpose: Drones are an emerging technology with the potential to improve laboratory logistics. This study is based on the hypothesis that the implementation of drones will benefit from an understanding of the current system and that existing transport solutions should be optimized before drone solutions are considered. It focuses on carriers transporting biological material today by car along a traditional circular route. It aims to explore how the current transport service is organized, identify areas for improvement, and investigate carriers’ perceptions of how drones could be integrated into or substituted for their services.Methods: A mixed-methods approach was applied, combining a questionnaire, shadowing of nine transport trips, semi-structured interviews, and time assessments.Results: The carriers shared insights into how to optimize existing transport solutions in terms of structure, culture, attitudes, and overall functionality. Most carriers expressed in the questionnaire that they were little involved in innovation work. The time assessment revealed that not the driving times, but the loading times had the highest deviations from plans and thus represented the area with the greatest potential for simple improvements. Questions about the use and organizational impact of drones are generated, and their prospects are discussed from a broad sociotechnical perspective.Conclusion: Our concept was to broaden our understanding of implementing drones into existing systems in a fairly simple setting. Although improved logistics may take place without complex processes, future research opportunities such as the impact of drones on organizational processes and social dynamics in the adoption of drones may be needed if more complex systems are involved. The paper proposes experimenting with, and learning from, transport with “road vehicles” and drones in combination and suggests that improvements should be made to existing transport solutions before drones are implemented.Keywords: logistics, transportation of laboratory samples, reconfiguration, sociotechnical systems, participation

We present a model for drone transport of the complete annual analytic volume of 6.5 million analyses-(routine and emergency) between two inner-city university laboratories at Oslo University Hospital located 1.8 km apart and with a time restriction for the analyses of no more than 60 min. The total laboratory activity was analyzed per min for the complete year of 2018. The time from the clinical ordering of tests to the loading of the drone, drone transport time, and analysis time after the sample arrived at the analyzing laboratory were assessed using the lead time of emergency analyses of C-reactive protein, troponin, and the international normalized ratio. The activity had characteristic diurnal patterns, with the most intensive traffic between 8 and 12 a.m. on weekdays and there being considerably less traffic for the rest of the day, at night and on weekends. Drone schedules with departures 15-60 min apart were simulated. A maximum of 15 min between flights was required to meet the emergency demand for the analyses being completed within 60 min. The required drone weight capacity was below 3.5 kg at all times. In multiple simulations, the drone times were appropriate, whereas variations in the clinic- and laboratory-related time intervals caused violations of the allowed time 50% of the time. Drone transport with regular schedules may potentially improve the transport time compared with traditional ground transport and allow the merging of large laboratories, even when the demand for emergency analyses restricts the maximum transport time. Comprehensive economic evaluations and robust drone technology are needed before such solutions can be ready for implementation.

Drones have been suggested as an emerging technology that has the potential to disrupt and improve healthcare. The attitude among healthcare workers towards the use of drones is important for its successful implementation. Our aim was to examine individual and institutional variables among employees that may be relevant for the successful implementation of drones. This study used a self-administered questionnaire to investigate the expectations and beliefs among 400 employees at three Norwegian healthcare organizations regarding the future role of drones in the provision of healthcare. The results showed that the use of drones in healthcare is positively perceived across professional groups, age, and location. Working in an innovative environment, having experienced previous technological change in one's working environment, and having leadership that supports new ideas were identified as drivers of individual beliefs regarding the use of drones as an innovative solution in future healthcare services. Men had significantly higher scores than women, and this was associated with reporting innovative leadership. This may indicate that a future implementation of drone usage should focus on local system environments and may depend on the presence of innovative leadership. Our results are harvested from a developed health care system and should be applicable for similar technologically advanced systems where the full potential of drone solutions may benefit from the integration of drones into the overall socio-technical system.

Objective: Most of the previous studies of drone transport of blood samples examined normal blood samples transported under tranquil air conditions. We studied the effects of 1- and 2-hour drone flights using random vibration and turbulence simulation (10-30 g-force) on blood samples from 16 healthy volunteers and 74 patients with varying diseased., Methods: Thirty-two of the most common analytes were tested. For biochemical analytes, we used plasma collected in lithium heparin tubes with and without separator gel. Gel samples were analyzed for the effect of separation by centrifugation before or after turbulence. Turbulence was simulated in an LDS V8900 high-force shaker using random vibration (range, 5-200 Hz), with samples randomly allocated to 1- or 2-hour flights with 25 or 50 episodes of turbulence from 10 to 30 G., Results: For all hematologic and most biochemical analytes, test results before and after turbulence exposure were similar (bias < 12%, intercepts < 10%). However, aspartate aminotransferase, folate, lactate dehydrogenase and lipid index increased significantly in samples separated by gel and centrifugation prior to vibration and turbulence test. These changes increased form 10 G to 30 G, but were not observed when the samples were separated after vibration and turbulence., Conclusions: Whole blood showed little vulnerability to turbulence, whereas plasma samples separated from blood cells by gel may be significantly influenced by turbulence when separated by spinning before the exposure. Centrifugation of plasma samples collected in tubes with separator gel should be avoided before drone flights that could be subject to turbulence.

Background: Lack of resources is often cited as a reason for long waiting times and queues in health services. However, recent research indicates these problems are related to factors such as uncoordinated variation of demand and capacity, planning horizons, and lower capacity than the potential of actual resources. This study aimed to demonstrate that long waiting times and wait lists are not necessarily associated with increasing demand or changes in resources. We report how substantial reductions in waiting times/wait lists across a range of specialties was obtained by improvements of basic problems identified through value-stream mapping and unsophisticated analyses., Methods: In-depth analyses of current operational processes by value-stream mapping were used to identify bottlenecks and sources of waste. Waiting parameters and measures of demand and resources were assessed monthly from 12 months before the intervention to 6 months after the intervention. The effect of the intervention on reducing waiting time and number of patients waiting were evaluated by a difference-in-differences analysis., Results: Mean waiting time across all clinics was reduced from 162 + 69 days (range 74-312 days) at baseline to 52 + 10 days (range 41-74 days) 6 months after the intervention. The time needed to achieve a waiting time of 65 days varied from 4 to 21 months. The number of new patients waiting was reduced from 15,874 (range 369-2980) to 8922 (range 296-1650), and the number of delayed returning patients was reduced from 18,700 (310-3324) to 5993 (40-1337) (p < 0.01 for all). Improvement in waiting measures paralleled a significant increase in planning horizon., Conclusions: Significant improvements in accessibility for patients waiting for service may be achieved by applying unsophisticated methods and analyses and without increasing resources. Engagement of clinical management and involvement of front line personnel are important factors for improvement.

Background: Although health care reforms may improve efficiency at the macro level, less is known regarding their effects on the utilization of health care personnel. Following the 2002 Norwegian hospital reform, we studied the productivity of the physician workforce and the effect of personnel mix on this measure in all nineteen Norwegian hospitals from 2001 to 2013., Methods: We used panel analysis and non-parametric data envelopment analysis (DEA) to study physician productivity defined as patient treatments per full-time equivalent (FTE) physician. Resource variables were FTE and salary costs of physicians, nurses, secretaries, and other personnel. Patient metrics were number of patients treated by hospitalization, daycare, and outpatient treatments, as well as corresponding diagnosis-related group (DRG) scores accounting for differences in patient mix. Research publications and the fraction of residents/FTE physicians were used as proxies for research and physician training., Results: The number of patients treated increased by 47% and the DRG scores by 35%, but there were no significant increases in any of the activity measures per FTE physician. Total DRG per FTE physician declined by 6% (p < 0.05). In the panel analysis, more nurses and secretaries per FTE physician correlated positively with physician productivity, whereas physician salary was neutral. In 2013, there was a 12%-80% difference between the hospitals with the highest and lowest physician productivity in the differing treatment modalities. In the DEA, cost efficiency did not change in the study period, but allocative efficiency decreased significantly. Bootstrapped estimates indicated that the use of physicians was too high and the use of auxiliary nurses and secretaries was too low., Conclusions: Our measures of physician productivity declined from 2001 to 2013. More support staff was a significant variable for predicting physician productivity. Personnel mix developments in the study period were unfavorable with respect to physician productivity., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Physician dual practice, a combination of public and private practice, has attracted attention due to fear of reduced work supply and a lack of key personnel in the public system, increase in low priority treatments, and conflicts of interest for physicians who may be competing for their own patients when working for private suppliers. In this article, we analyze both choice of dual practice among hospital physicians and the dual practices' effect on work supply in public hospitals., Methods: The sample consisted of 12,399 Norwegian hospital physicians working in public hospitals between 2001 and 2009. We linked hospital registry data on salaries and hospital working hours with data from national income and other registries covering non-hospital income, including income from dual work, cohabiting status, childbirths and socioeconomic characteristics. Our dataset also included hospital variables describing i.e. workload. We estimated odds ratio for choosing dual practice and the effects of dual practice on public working hours using different versions of mixed models., Results: The percentage of physicians engaged in dual practice fell from 35.1% for men and 17.6% for women in 2001 to 25.0% and 14.2%, respectively, in 2009. For both genders, financial debt and interest payments were positively correlated and having a newborn baby was negatively correlated with engaging in dual practice. Larger family size and being cohabitating increased the odds ratio of dual practice among men but reduced it for women. The most significant internal hospital factor for choosing dual practice was high wages for extended working hours, which significantly reduced the odds ratio for dual practice. The total working hours in public hospitals were similar for both those who did and did not engage in dual practice; however, dual practice reduced public working hours in some specialties., Conclusion: Economic factors followed by family variables are significant elements influencing dual practice. Although our findings indicate that engagement in dual practice by public hospital physicians in a well-regulated market may increase the total labor supply, this may vary significantly between medical specialties.

Previous studies of gender differences in relation to medical specialization have focused more on social variables than hospital-specific factors. In a multivariate analysis with extended Cox regression, we used register data for socio-demographic variables (gender, family and having a child born during the study period) together with hospital-specific variables (the amount of supervision available, efficiency pressure and the type of teaching hospital) to study the concurrent effect of these variables on specialty qualification among all 2474 Norwegian residents who began specialization in 1999-2001. We followed the residents until 2010. A lower proportion of women qualified for a specialty in the study period (67.9% compared with 78.7% of men, p < 0.001), and they took on average six months longer than men did to complete the specialization qualification (p < 0.01). Fewer women than men entered specialties providing emergency services and those with longer working hours, and women worked shorter hours than men in all specialties. Hospital factors were significant predictors for the timely attainment of specialization: working at university hospitals (regional) or central hospitals was associated with a reduction in the time taken to complete the specialization, whereas an increased patient load and less supervision had the opposite effect. Multivariate analysis showed that the smaller proportion of women who qualified for a specialty was explained principally by childbirth and by the number of children aged under 18 years., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

In industrialized countries, female physicians have up to 10h lower labor supply a week than male physicians. At the same time, the number of female physicians is increasing. The question analyzed in this article is whether these differences in labor supply for female and male hospital physicians persist in a modern welfare society, such as Norway, where comprehensive welfare reforms aim to reduce gender inequality are implemented. Information on weekly working hours from all hospital physicians in Norway during the period 2001-2007 was merged with economic variables (wages, income from other sources, net personal dept), demographic variables (age, sex, marital status, children born in the year, number of children), managerial positions and variables describing the hospital, specialty and time (year). The estimation method employed both random and fixed-effects models. Labor supply for women was 10-11 percent or 4-4.5 h per week lower than among men. The effects of children diverged strongly between the sexes. For instance, childbirth in a given year reduced the supply of working hours by women by approximately 80% but had no effects for men. After controlling for children and other factors, female physicians worked some 3-4% or 1-1.5 fewer hours than comparable male physicians. Although significant, variation in labor supply between female and male physicians is much lower in Norway then in other advanced industrialized countries., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Background: Analysis of the future need for medical doctors necessitates an assessment of their productivity. The goals of this study were to analyze the relation between doctors' work force and the increased activity in hospitals, and to describe the development of working hours and salary for hospital doctors in a gender perspective., Material and Methods: Information about man-labour years, working time and salary for doctors in Norwegian somatic hospitals was retrieved for the period 2001-2008. Number of hospital stays, DRG points and outpatient consultations per man-labour year are used as measures of doctors' clinical productivity., Results: The percentage of female doctors increased from 34.7 % to 42.2 %. The mean annual salary increased more for men (14.4 % higher in 2001 and 16.6 % higher in 2008) than women. Total salary costs for doctors increased by 69.9 % (from 3.66 bill to 6.22 bill. NOK); 42.6 % of this increase was generated by new positions (1 306 man-labour years, + 21.2 %). Labour years from extended working hours increased by 6.8 % (constituting 1043 labour years in 2008; 12.2 % of the total), but the average extended labour time per doctor decreased (-16.7 % for women and -9.6 % for men). The number of hospital stays increased by 13.2 %, DRG points increased by 12.4 % and outpatient consultations increased by 9.3 % per doctor's work year in the period 2001-2008., Interpretation: Higher salaries for men may be explained by age, more men in senior positions and longer working hours than for women. The productivity of Norwegian doctors still increased from 2001 to 2008 (taking into account the increase in salary).

Heart rate variability (HRV) (SD of the RR interval), an index of parasympathetic tone, was measured at rest and during exercise in 13 healthy older men (age 60 to 82 years) and 11 healthy young men (age 24 to 32 years) before and after 6 months of aerobic exercise training. Before exercise training, the older subjects had a 47% lower HRV at rest compared with the young subjects (31 +/- 5 ms vs 58 +/- 4 ms, p = 0.0002). During peak exercise, the older subjects had less parasympathetic withdrawal than the young subjects (-45% vs -84%, p = 0.0001). Six months of intensive aerobic exercise training increased maximum oxygen consumption by 21% in the older group and 17% in the young group (analysis of variance: overall training effect, p = 0.0001; training effect in young vs old, p = NS). Training decreased the heart rate at rest in both the older (-9 beats/min) and the young groups (-5 beats/min, before vs after, p = 0.0001). Exercise training increased HRV at rest (p = 0.009) by 68% in the older subjects (31 +/- 5 ms to 52 +/- 8 ms) and by 17% in the young subjects (58 +/- 4 ms to 68 +/- 6 ms). Exercise training increases parasympathetic tone at rest in both the healthy older and young men, which may contribute to the reduction in mortality associated with regular exercise.

To assess possible factors affecting the variability of digitized left ventricular M-mode echocardiograms, the influence of respiration and the variability due to different beats and observers were analysed in 11 healthy subjects and 11 patients with repaired tetralogy of Fallot. Left ventricular end-diastolic dimension (LVEDD) decreased from end-expiration to end-inspiration in the healthy subjects, but not in the patients. The maximal rate of dimension change decreased in both healthy subjects and patients from end-expiration to end-inspiration. The beat-to-beat variability assessed by the coefficient of variation (CV,%) between measurements of one cardiac cycle was twice the CV for three cycles, whereas the CV for three and five cardiac cycles was not different. The CV for intraobserver variability was less than 5.0% for dimensions and less than 13.0% for the rates of dimension change, whereas the interobserver variability had CV of 17.1% for rates of dimension changes. The influence of respiration and different observers on the variability of LV end-systolic dimension and shortening fraction was larger in the patients than in the healthy subjects. Thus, to obtain optimal technique for analysis of digitized LV M-mode echocardiograms in serial patient studies, the number of observers should be kept at a minimum and at least 3 beats at end-expiration should be used.

Percutaneous transluminal coronary angioplasty (PTCA) was performed on 115 consecutive patients with angina pectoris and the results were evaluated after an average of 100 days by means of bicycle exercise test and coronary angiography. Complete revascularization was achieved in 75% of the patients. Restenosis occurred in 23%. A good symptomatic effect was found in 90% of the patients with complete revascularization and in 72% of the patients with partial revascularization. Recurrence of angina pectoris 4-8 weeks after PTCA is a predictor of restenosis. Absence of angina and a negative bicycle exercise test 3-4 months after PTCA are strong predictors of the absence of restenosis.

Myasthenia gravis is an autoimmune disorder with autoantibodies to acetylcholine receptors of skeletal muscle. Left ventricular diastolic function was studied with M-mode and Doppler echocardiography in 25 patients with myasthenia and in a group of age- and heart rate-matched control subjects. In the patients, diastolic peak filling rate was reduced by 37%, and Doppler peak early filling velocity (E) was reduced by 12% compared with the control subjects (2.7 +/- 0.7 vs 4.2 +/- 1.0 s-1, and 76 +/- 8 vs 85 +/- 15 cm/s, respectively; p less than 0.05). Peak atrial filling velocity (A) was increased by 38% (68 +/- 17 vs 48 +/- 9 cm/s; p less than 0.01), and consequently the E:A ratio in the group of patients was reduced by 33% (1.22 +/- 0.40 vs 1.81 +/- 0.33; p less than 0.001). End-diastolic dimension was 5.0 +/- 0.5 cm in both groups, heart rate was 70 +/- 12 vs 68 +/- 16 beats/min (p = not significant [NS]), M-mode ejection fraction was 76 +/- 8 vs 79 +/- 5% (p = NS), M-mode peak ejection rate was -1.9 +/- 0.4 vs -2.1 +/- 0.3 s-1 (p = NS), and peak aortic outflow velocity was 109 +/- 18 vs 98 +/- 13 cm/s (p = NS). Twenty-three patients and 15 control subjects were studied before and after intake of the acetylcholine-esterase inhibitor pyridostigmine.(ABSTRACT TRUNCATED AT 250 WORDS)

To define the quantitative relations between radionuclide and Doppler measures of systole during sympathetic activation with epinephrine, 10 young normal men were studied with simultaneous radionuclide angiography and M-mode and Doppler echocardiography during graded infusions of epinephrine (10, 25 and 50 ng/kg/min for 12 minutes each). During a nine-fold increase in circulating levels of epinephrine in arterialized plasma (94 +/- 59 to 879 +/- 310 pg/ml, P less than 0.001), the heart rate increased from 58 +/- 8 to 73 +/- 7 beats/min (P less than 0.01), whereas the mean arterial pressure fell from 82 +/- 3 to 75 +/- 6 mmHg (NS) and end-systolic wall stress decreased from 97 +/- 6 to 67 +/- 10 dynes/sec (P less than 0.01). The ejection fraction as estimated using radionuclide techniques increased from 68 +/- 6 to 83 +/- 6%, the peak ejection rate measured in this way increased from -3.36 +/- 0.3 to -5.10 +/- 0.5 end-diastolic volumes/sec, the ejection fraction as estimated with M-mode echocardiography increased from 66 +/- 5 to 83 +/- 5%, the echocardiographic ventricular dimension shortening increased from -1.78 +/- 0.2 to -2.7 +/- 0.4 sec-1, the peak aortic outflow velocity as measured with Doppler techniques increased from 98 +/- 13 to 147 +/- 25 cm/sec, and the aortic outflow acceleration velocity increased from 11 +/- 3 to 27 +/- 7 m/sec2 (all P less than 0.001). There was a significant correlation between the changes in radionuclide and M-mode estimations of ejection fractions (r = 0.82), between the radionuclide peak ejection rate and M-mode peak dimension shortening (r = 0.80) and between the radionuclide peak ejection rate and the Doppler peak aortic outflow velocity (r = 0.90) (all P less than 0.01). We conclude that corresponding radionuclide and Doppler echocardiographic measurements of systolic function are altered similarly during increased sympathetic activation with epinephrine.

Stress thallium scintigraphy was performed in 60 patients with chest pain of uncertain origin. Myocardial ischemia was identified in 91% of the 47 patients who had angiographically significant coronary artery stenoses. Sensitivity of thallium scintigraphy was highest in patients with stenosis in the left descending coronary artery (LAD); 91% of the patients had abnormal thallium as compared with 67% of the patients with normal LAD but significant stenoses in the circumflex artery and/or the right coronary artery. Perfusion defects in the circumflex in only 50% of the patients with multiple vessel disease. We conclude that stress thallium scintigraphy is a useful diagnostic procedure in patients with chest pain of uncertain origin and identifies the patients to be selected for coronary artery angiography.

To determine the effects of parasympathetic withdrawal or sympathetic stimulation on Doppler echocardiographic measures of left ventricular diastolic filling, we studied 10 young normal subjects aged 21 to 29 years during separate infusions of atropine (0.8 mg followed by 0.4 mg every 10 minutes until heart rate greater than 110 beats/min or a total dose of 2 mg was attained) and epinephrine (10, 25 and 50 ng/kg/min for 12 minutes each). At the highest atropine dose, heart rate increased from 60 +/- 9 to 105 +/- 8 beats/min (mean +/- standard deviation), the diastolic filling period decreased by 61% (573 +/- 141 to 222 +/- 34 ms), the peak early (E) filling decreased 23% (77 +/- 12 to 61 +/- 11 cm/s), the peak atrial (A) filling increased 103% (40 +/- 6 to 81 +/- 17 cm/s), and the E/A ratio decreased by 60% (2.0 +/- 0.5 to 0.8 +/- 0.3) (all p less than 0.001). These alterations were not correlated to changes in systolic function, preload, blood pressure or plasma catecholamines, all of which were unchanged. However, atropine-induced changes in diastolic filling period were highly correlated to changes in E peak (r = 0.64, p less than 0.01), A peak (r = -0.95, p less than 0.001) and the E/A ratio (r = 0.93, p less than 0.001). The effects of atropine on the E/A ratio were normalized by dividing the E/A ratio by the diastolic filling period (E/A/diastolic filling period).(ABSTRACT TRUNCATED AT 250 WORDS)

To assess the relation between myocardial infarction size and diastolic function as measured by radionuclide ventriculography and Doppler echocardiography, 83 patients (aged 58 +/- 9 years) without significant valvular disease were studied 8 to 12 weeks after an acute myocardial infarction. Myocardial infarction size was measured by resting thallium-201 tomography. Peak early filling rate (in end-diastolic volumes/s) was measured by gated blood pool scintigraphy. Doppler measures of mitral inflow were peak early (E) and atrial (A) filling velocities, slopes of E and A, percent E and A filling, E/A ratio and diastolic filling period. In univariate analyses, there was a significant inverse correlation between infarction size and the peak early filling rate (r = -0.59, p less than 0.001), and this remained significant (r = -0.63, p less than 0.0001) in an analysis that included 2 other determinants of the filling rate, age and diastolic filling period. Infarction size was directly correlated to the peak E velocity (r = 0.37, p less than 0.01), deceleration of E (r = 0.41, p less than 0.01) and percent E filling (r = 0.31, p less than 0.01), and was inversely correlated to peak A (r = -0.27, p less than 0.05) and percent A filling (r = -0.26, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

In 92 acute myocardial infarction (AMI) patients treated with tissue plasminogen activator 2.3 +/- 1.2 hours after the onset of chest pain, echocardiography was performed at 11 +/- 14 hours (early) and, in 49 patients, again at 13 +/- 7 weeks (late). Infarct location and the left ventricular wall motion score index--the average score (normal = 1, hypokinetic = 2, akinetic = 3, dyskinetic = 4) for 20 segments--were determined by 2 observers unaware of clinical, angiographic or electrocardiographic data. Concordance between noninvasive infarct location by electrocardiography or echocardiography and infarct-related artery at angiography 4 +/- 2 days later (n = 85) was 76 and 81%, respectively. The early wall motion score index was worse for anterior (1.8 +/- 0.4) versus inferior (1.3 +/- 0.2, p less than 0.0001) or posterior-lateral (1.6 +/- 0.2, p = 0.0003) infarcts. Overall, the wall motion score index improved from early to late echocardiography (n = 49, 1.5 +/- 0.3 to 1.3 +/- 0.3, p = 0.0008). However, improvement was confined to those with time to treatment less than or equal to 2 hours (n = 22, 1.4 +/- 0.3 to 1.2 +/- 0.2, p less than 0.0001), and evidence of reperfusion at angiography (n = 38, 1.5 +/- 0.3 to 1.2 +/- 0.3, p less than 0.0001). The decrease in the wall motion score index was related to a decrease in the number of adjacent involved segments (5.5 +/- 3.0 to 3.7 +/- 3.9/patient, p = 0.0006). Thus, echocardiography early after AMI identifies infarct location. Improvement in regional wall motion is seen after early treatment with intravenous tissue plasminogen activator.

To examine the effect of short-term, high-dose anticoagulation on the subsequent occurrence of left ventricular (LV) thrombi after a first anterior wall acute myocardial infarction (AMI), 21 patients received placebo and 21 high-dose anticoagulants during the first 10 days of the acute infarction. They were studied with cross-sectional echocardiography 10 days and 1.3 and 6 months post infarction. At 1 month, 6 of 7 thrombi present in the placebo group at 10 days were still visible. No thrombi were detected at 10 days in the anticoagulation group, but 6 patients had developed a LV thrombus at 1 month. These 12 patients with LV thrombi were subsequently treated with oral warfarin for 2 months, after which all thrombi had disappeared. Warfarin was then discontinued, and a thrombus had recurred in 5 patients after 6 months. Apical akinesis at 10 days was a predictor for thrombus with a sensitivity and specificity of 100% and 72.2%, respectively. Three of the 13 patients with LV thrombi suffered stroke in contrast to none without thrombi (P = 0.025). We conclude that after discontinuation of short-term high-dose anticoagulation therapy in anterior AMI, LV thrombi may develop rapidly and lead to embolic complications, particularly in patients with persisting apical akinesis.

In a prospective study, 20 patients with a first acute myocardial infarction and no current treatment with diuretics or cardioactive drugs were randomized to treatment with intravenous timolol (10 patients) or placebo (10 patients). Plasma adrenaline, noradrenaline, and serum potassium were estimated at baseline (mean +/- SD 3.6 +/- 0.8 hours after the onset of the infarction) and 4 hours after the start of treatment. The patient selection criteria embraced a low-risk study population. Before treatment, the serum potassium concentrations correlated inversely with plasma adrenaline but not with plasma noradrenaline concentrations. A rise of serum potassium (mean +/- SD mmol/L) from 4.1 +/- 0.3 to 4.4 +/- 0.4 (p less than 0.05) in the placebo group and from 4.0 +/- 0.4 to 4.5 +/- 0.5 (p less than 0.05) in the timolol group was in multivariate analysis associated with infarct size, estimated as cumulative creatine kinase release, in the placebo group, and with the mean individual plasma adrenaline concentrations in the timolol group. By reversing the effect of adrenaline from a decrease to an increase in the serum potassium concentrations, timolol changes the relationships between circulating adrenaline, potassium, and infarct size.

To examine whether early intervention with timolol influences the occurrence of left ventricular thrombi in acute anterior myocardial infarction, 40 patients with acute anterior myocardial infarction admitted to hospital within 6 hr of onset of symptoms were randomly assigned to receive intravenous followed by oral timolol maleate or placebo. Five (25%) of 20 patients in the placebo group and 14 (73.7%) of 19 patients with confirmed infarction in the timolol group developed a left ventricular apical thrombus as detected by two-dimensional echocardiography from 2 to 10 days after inclusion (p less than .005). Patients received anticoagulants only after a left ventricular thrombus had been diagnosed. Only one patient with thrombus suffered peripheral embolization (timolol group). The treatment groups were comparable with respect to location of regional left ventricular dysfunction, electrocardiographic changes, and infarct size estimated by creatine kinase release. However, computer-assisted regional wall motion analysis demonstrated significantly reduced apical wall motion in the timolol group compared with the placebo group (p less than .01). Also, the mean heart rate during the first 10 days after the acute infarction was reduced by 13% in the timolol group (p less than .001). The reduction in heart rate and left ventricular apical wall motion caused by timolol in patients with acute anterior myocardial infarction may increase the occurrence of left ventricular thrombi.

Risk factors for systemic embolisation in patients with ventricular thrombi caused by an acute myocardial infarction were studied in 150 consecutive patients with an infarction of the anterior wall. Serial echocardiograms were performed 2-10 days after the acute event and patients were followed up for three months. Anticoagulation treatment was started only after the detection of thrombi. Of the 55 patients in whom a thrombus developed, 15 (27%) had peripheral emboli between 6-62 days; but only two (2%) of 95 patients without thrombus had emboli. Among 15 variables, the best single predictors of embolisation were age greater than 68 years (80% sensitive, 85% specific), pendulous thrombus (60%, 93%), and independent thrombus mobility (60%, 85%). Logistic regression analysis showed that a formula that included patient age, thrombus area, and the length of thrombus in the ventricular lumen predicted embolisation (sensitivity 87%, specificity 88%). There was no correlation between age and the thrombus variables. The risk of embolisation from left ventricular thrombi in acute anterior myocardial infarction can be accurately assessed from patient age and echocardiographic features. The risk of peripheral emboli is high in patients with left ventricular thrombi and those aged greater than 68.

Fifty-three patients with a suspected first anterior wall acute myocardial infarction (AMI) were randomized to intervention with intravenous heparin followed by oral warfarin (26 patients) or matching placebo (27 patients). The regimen was started within 12 hours after the onset of AMI. Anticoagulation was maintained at a therapeutic level (for heparin, activated partial thromboplastin time 70 to 140 seconds; for warfarin, thrombotest 5 to 10%) for 10 days, and no bleeding episodes occurred. The baseline characteristics of the 2 study groups were well matched. In 7 patients in the placebo group and in none in the anticoagulant group, left ventricular thrombus developed during the study, as detected by serial 2-dimensional echocardiography. Early intervention with high-dose anticoagulant drugs may prevent the development of left ventricular thrombus in anterior wall AMI.

In a prospective study of 90 consecutive patients with acute myocardial infarction, 15 (28.3%) of 53 patients with an anterior wall infarction developed a left ventricular thrombosis diagnosed by cross sectional echocardiography. Patients received anticoagulants only after a left ventricular thrombosis had been diagnosed. Twenty eight patients had an inferior infarction, but none of these had a left ventricular thrombosis. Five (5.5%) of the 90 patients suffered a cerebrovascular accident, and all had an anterior wall infarction. In four of these five patients a left ventricular thrombosis was confirmed by echocardiography before the cerebrovascular accident. All patients with left ventricular thrombosis had apical akinesis. The incidence of a thrombosis did not differ in patients with a first anterior myocardial infarction and with reinfarctions. Among the 40 patients with a first anterior wall infarction, 12 with a thrombosis had a significantly higher incidence of enlarged heart on chest radiographs and significantly higher serum aspartate aminotransferase enzyme activity than those without. Thus patients with a large anterior wall infarction and with akinesis in the apical region are at high risk of developing a left ventricular thrombosis, which may be a source of peripheral emboli. Left ventricular thrombosis appears to be rare with infarctions in other locations.

Sixty patients with a first acute myocardial infarction and no current treatment with cardioactive drugs were included in a prospective study of the relationship between serum potassium concentration and the early occurrence of ventricular tachycardia and premature ventricular contractions (PVCs). Serum potassium level (range 2.5 to 5 mmol/liter) was estimated 3.8 +/- 2.5 hr (mean +/- SD) after the onset of the infarction, and Holter monitoring was performed during the subsequent 12 hr. In multivariate analysis, serum potassium level was negatively and age positively related to ventricular tachycardia. Among the subclasses of PVCs (frequent unifocal, multifocal, couplets, bigeminy), serum potassium concentration was negatively related to the frequent unifocal subclass; hypertension was related to couplets and to the presence of any of the subclasses, and serum aspartate aminotransferase concentration was related to multifocal PVCs. Heart failure leading to death was related to all subclasses of PVC. Serum potassium concentration is an independent inverse predictor of the occurrence of ventricular tachycardia and frequent unifocal PVCs early in acute myocardial infarction.

Although left ventricular thrombi that form acutely after myocardial infarction frequently resolve spontaneously or with anticoagulant therapy, the fate of left ventricular thrombi in patients with remote myocardial infarction or with idiopathic cardiomyopathy remains unknown. To determine the natural history of such chronic left ventricular thrombi, we performed serial echocardiograms on 51 patients with remote myocardial infarction (greater than or equal to 3 months; mean, 31 +/- 41 months) and on nine patients with idiopathic dilated cardiomyopathy. Mean follow-up was 24 +/- 22 months during which 3.5 +/- 1.4 echocardiograms were obtained. Studies were interpreted by blinded observers, and an increase or decrease of more than 5 mm in maximal thrombus thickness was defined as significant. Among all 60 patients left ventricular thrombi were unchanged in 24 (40%), completely resolved in 24 (40%), decreased in size in four (7%), increased in size in five (8%), and decreased and then increased in size in three (5%). Results in patients with remote infarction and idiopathic cardiomyopathy were similar. Warfarin therapy, which was at the discretion of the primary physician, was associated with a higher prevalence of thrombus resolution compared with no therapy (59% vs. 29%, p = 0.02). Definite systemic emboli occurred in seven patients (12%), all at times while they were not anticoagulated. Among the 48 thrombi that were present on two or more echocardiograms, changes in thrombus shape (classified as protruding or flat) occurred in only 16%, and changes in thrombus movement (classified as mobile or immobile) occurred in only 10%.(ABSTRACT TRUNCATED AT 250 WORDS)

In four patients with anterior wall acute myocardial infarction (AMI) and left ventricular thrombi diagnosed by two-dimensional (2-D) echocardiography, disappearance of left ventricular thrombi was demonstrated by 2-D echocardiography immediately after the patients had suffered peripheral emboli. Two thrombi were pendulous with free motion during the cardiac contractions; one of these consisted of two separated pendulous clots that disappeared after two episodes of embolization six and 16 days, respectively, after the onset of AMI. Two thrombi were initially broad based, flat, and without intracavitary motion. One thrombus caused two episodes of peripheral emboli; the other began as a flat thrombus without intracavitary motion but progressed to show central echolucency and, then, vigorous intracavitary motion of the margin prior to embolization. Five of six embolic episodes occurred when these patients were receiving high-dose anticoagulants. These anticoagulants were administered once the thrombi were diagnosed. Left ventricular thrombi of very different appearance on 2-D echocardiography may cause embolization, which may occur during therapeutic anticoagulation administered after thrombi have developed in patients with AMI.

One hundred and six patients with acute myocardial infarction admitted to hospital within four hours after the onset of symptoms were randomised to treatment with intravenous timolol (54 patients) or placebo (52 patients). Serum potassium concentrations were estimated at frequent intervals during the first 24 hours of admission. Patients in both treatment groups, who did not receive subsequent diuretic treatment, had a transient rise in serum potassium concentration, which was maximal after four hours. This rise was abolished by diuretic treatment in the placebo group but not in the timolol group, in which there was a pronounced and prolonged rise in serum potassium concentration. The change in serum potassium concentration in the first four hours after admission correlated with cumulative creatine kinase release in the placebo group, but not in the timolol group. Hypokalaemia (serum potassium concentration less than or equal to 3.5 mmol/l) occurred in 15 (28.8%) patients in the placebo group and in seven (13%) in the timolol group and was independent of infarct size. The frequency of hyperkalaemia was not increased in the timolol group. By increasing the serum potassium concentration and preventing hypokalaemia, the use of intravenous timolol early in acute myocardial infarction may have important clinical effects in addition to reducing infarct size.