Search

Background and aims: The discordance between QRS voltages on electrocardiogram (ECG) and left ventricle (LV) wall thickness (LVWT) on echocardiogram (echo) is a recognized red flag (RF) of amyloid cardiomyopathy (AC) and can be measured by specific indexes. No head-to-head comparison of different ECG/echo indexes among subjects with echocardiographic suspicion of AC has yet been undertaken. The study aimed at evaluating the performance and the incremental diagnostic value of different ECG/echo indexes in this subset of patients. Methods: Electrocardiograms of subjects with LV hypertrophy, preserved ejection fraction and ≥ 1 echocardiographic RF of AC participating in the AC-TIVE study, an Italian prospective multicenter study, were independently analyzed by two cardiologists. Low QRS voltages and 8 different ECG/echo indexes were evaluated. Cohort specific cut-offs were computed. Results: Among 170 patients, 55 (32 %) were diagnosed with AC. Combination of low QRS voltages with interventricular septum ≥ 1,6 cm was the most specific (specificity 100 %, positive predictive value 100 %) ECG/echo index, while the ratio between the sum of all QRS voltages and LVWT <7,8 was the most sensitive and accurate (sensitivity 94 %, negative predictive value 97 %, accuracy 82 %). When the latter index was added to a model using easily-accessible clinical variables, the diagnostic accuracy for AC greatly increased (AUC from 0,84 to 0,95; p = 0,007). Conclusions: Among patients with non-dilated hypertrophic ventricles with normal ejection fraction and echocardiographic RF of AC, easily-measurable ECG/echo indexes, mainly when added to few clinical variables, can help the physician orient second level investigations. External validation of the results is warranted.

Aim: To investigate the prevalence of amyloid cardiomyopathy (AC) and the diagnostic accuracy of echocardiographic red flags of AC among consecutive adult patients undergoing transthoracic echocardiogram for reason other than AC in 13 Italian institutions. Methods and results: This is an Italian prospective multicentre study, involving a clinical and instrumental work-up to assess AC prevalence among patients ≥55 years old with an echocardiogram suggestive of AC (i.e. at least one echocardiographic red flag of AC in hypertrophic, non-dilated left ventricles with preserved ejection fraction). The study was registered at ClinicalTrials.gov (NCT04738266). Overall, 381 patients with an echocardiogram suggestive of AC were identified among a cohort of 5315 screened subjects, and 217 patients completed the investigations. A final diagnosis of AC was made in 62 patients with an estimated prevalence of 29% (95% confidence interval 23%–35%). Transthyretin-related AC (ATTR-AC) was diagnosed in 51 and light chain-related AC (AL-AC) in 11 patients. Either apical sparing or a combination of ≥2 other echocardiographic red flags, excluding interatrial septum thickness, provided a diagnostic accuracy >70%. Conclusion: In a cohort of consecutive adults with echocardiographic findings suggestive of AC and preserved left ventricular ejection fraction, the prevalence of AC (either ATTR or AL) was 29%. Easily available echocardiographic red flags, when combined together, demonstrated good diagnostic accuracy.

An evaluation was made on the effects of using antimisting kerosene (AMK) on the performance of the components from the fuel system and the combustor of a current in-service JT8D aircraft engine. The objectives were to identify problems associated with using antimisting kerosene and to determine the extent of shearing or degradation required to allow the engine components to achieve satisfactory operation. The program consisted of a literature survey and a test program which evaluated the antimisting kerosene fuel in laboratory and bench component testing, and assessed the performance of the combustor in a high pressure facility and in an altitude relight/cold ignition facility. Performance of the fuel pump and control system was evaluated in an open loop simulation. Thus far, results of the program would not preclude the use of antimisting kerosene in a jet engine application. (Author)

This report covers progress made in the second year of the research program. The first part of the report is devoted to a generalized analytical prediction of the ground impulse that can be obtained from a blast wave, detonation wave, and an idealized fuel-air explosion. The latter consists of blast wave behavior for radius, r, less than a critical radius, r*, and Chapman- Jouguet detonation for r > r*. In all cases so far, the finite diameter of the cloud with the attendant shock wave propagation beyond the cloud has not been taken into account. The latter part of this report is devoted to the experimental aspects. Improvements in the facility for generating cylindrical shock waves and detonation waves are described controlled experiments on cylinderical blast waves with the associated data reduction techniques are discussed. The results are interpreted to yield a calibration on the effective energy release of the initiating charge of Detasheet. Two phase cylindrical detonation experiments were also conducted using a highly refined fraction of kerosene. The results indicate that at small radius blast wave behavior predominated whereas at larger radius a constant velocity detonation was realized when the initiation energy was sufficiently high. The experimentally determined transition radius between the two types of behavior agreed very well with theoretical values. Cylindrical detonations in gaseous MAPP-air mixtures were also studied. The variation in threshold energy required for initiation as well as rich and lean limits were established. The results agree very well with large scale field tests.