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Biomedical subjects

E Goldhammer

Publications and source records attributed to E Goldhammer.

At least 19 recordsLinked to original sources

Diagnostic accuracy of serum B-type natriuretic peptide for myocardial ischemia detection during exercise testing with spect perfusion imaging.

OBJECTIVE: To determine whether serum B-type natriuretic peptide measured at rest and peak exercise and DeltaBNP contribute to the predictive value and diagnostic accuracy of exercise test in the diagnosis of myocardial ischemia. BACKGROUND: Ventricular myocytes release BNP in response to increased wall stress that occurs in acute ischemia. During exercise testing, transient myocardial ischemia could also cause acute myocardial stress and changes in circulating BNP. METHODS: BNP was measured before and immediately after exercise testing with radionuclide imaging in 203 consecutive subjects referred for chest pain evaluation. Tested subjects were classified as ischemic and non-ischemic based on exercise results, and no ischemia, mild-moderate, and severe ischemia according to perfusion scan results. A logistic regression model, constructed of an ROC and an AUC (area under the curve), was used. RESULTS: Ischemic ECG changes (> or =1 mm, horizontal S-T shift) were detected in the treadmill exercise test in 127 subjects (62.6%), and 76 (37.4%) had neither ST segment shift nor chest pain. Baseline BNP was higher in the ischemic group compared to the non-ischemic group (p=0.044); peak BNP was also higher in the ischemic group (p=0.025), as was DeltaBNP (p=0.0126). Of these 127 subjects, 106 (52% of all) had abnormal perfusion scan results. In the ischemic group, the median baseline, peak exercise BNP, and DeltaBNP values from baseline to peak were higher than in the non-ischemic group. In the severe ischemic group these variables were approximately three-fold higher than in the mild-moderate ischemic group (p<0.0001 for baseline; p<0.0001 for peak; and p<0.0001 for DeltaBNP). Rest, peak exercise, and DeltaBNP values were significantly higher in patients with previous myocardial infarction (p<0.001) and in patients treated with beta blockers; peak exercise BNP was higher in hypertensives and diabetics (p<0.05). The ROC convergence model showed that the AUC for peak-exercise BNP was best able to discriminate and predict severe ischemia and no ischemia, while DeltaBNP from rest to peak exercise discriminated best between mild-moderate and severe ischemia. CONCLUSIONS: Peak exercise BNP and DeltaBNP improved the sensitivity, specificity, positive likelihood ratio, predictive value, and diagnostic accuracy of severe ischemia detection during an exercise test. The contribution of BNP determination during exercise was, however, less impressive than previously reported by others.

Aged↗

Left ventricular contractility and function at peak aerobic and anaerobic exercises.

PURPOSE: The present study compared and evaluated left ventricular function and contractility at peak incremental aerobic type exercise and all-out explosive anaerobic effort in young healthy trained subjects. METHODS: Twenty-two young healthy trained subjects (19 +/- 1 yr) were studied by two-dimensional direct M-mode echocardiography at peak aerobic and at peak all-out anaerobic exercises, performed on cycle ergometer. RESULTS: All subjects completed the study without any electrocardiographic abnormalities. Significant (P < 0.05) differences between the aerobic and the anaerobic efforts were noted for peak cardiac output (24 +/- 2.0 and 15.0 +/- 1.1 L x min (-1), respectively), left ventricular pressure-volume ratio (5.8 +/- 0.6 and 4.7 +/- 0.5 respectively), end systolic volume (33 +/- 4 and 42 +/- 5 mL, respectively), ejection fraction (79 +/- 7 and 66 +/- 5%, respectively), and total peripheral resistance (TPR) (367 +/- 90 and 704 +/- 90 dynes x s(-1) x cm(- 5), respectively). CONCLUSIONS: These data suggest that left ventricular at peak all out anaerobic effort differed markedly from those observed at peak aerobic exercise. These differences are presumably due to the different after-load responses between the two exercise modes. Therefore, it is suggested that anaerobic-type effort should be performed with great caution in normal young healthy subjects.

Adolescent↗

[Circadian fluctuations in the success and efficacy of streptokinase thrombolytic therapy in acute myocardial infarction].

This study was designed to assess possible diurnal fluctuations in the efficacy of thrombolysis with streptokinase. 156 consecutive patients treated with streptokinase during the period 1.1.95-1.7.96 were studied retrospectively. Success or failure of thrombolysis was determined according to the accepted clinical and angiographic criteria starting at midnight, 12 times at 2-hour intervals, then 8 times at 3-hour intervals, and then 6 times at 4-hour intervals. A definite peak for successful thrombolysis was found in the late afternoon and early evening hours. Between 16:00-20:00 PM, in 30.23% successful thrombolysis were observed, compared to 6.98% between 20:00-24:00 PM (p < 0.05) and in 10.53% between 00.00-04:00 AM (p < 0.05). Multiple regression analysis showed that the independent factor with the greatest impact on successful reperfusion was the actual time until thrombolysis (p = 0.037); then came the interval from pain onset to streptokinase administration (p = 0.020), while age and gender had much lesser impacts (p = 0.328 and 0.215, respectively), and individual risk factors even less. These findings may have several clinical implications: dose adjustment for the time of day may be required, with larger doses needed during morning hours, or preference for primary coronary angioplasty to avoid increase in bleeding complications due to higher doses of thrombolytic agents.

Adult↗

Effects of low altitude on exercise performance in patients with congestive heart failure after healing of acute myocardial infarction.

Patients with chronic congestive heart failure (CHF) have impaired oxygen delivery to working muscles. The Dead Sea, the lowest site on earth, is distinguished by natural oxygen enrichment, low humidity, high barometric pressure, and temperature with increased bromide and magnesium concentrations in the inspired air. The aim of this study is to examine the effects of descent to the Dead Sea on patients with CHF. Twelve patients with CHF and 4 age-matched healthy controls underwent complete echocardiographic studies at rest as well as treadmill and metabolic stress tests, both in Haifa, 130 m above sea level and 3 days after descent to the Dead Sea, 402 m below sea level. Significant changes in parameters at the Dead Sea compared with Haifa included time on treadmill, which increased from 612+/-198 to 672+/-1 86 seconds (p <0.05); the Borg scale decreased by 1 to 2 grades (p <0.05); and oxygen saturation increased by 3% throughout exercise (p <0.05). Systolic blood pressure decreased by 9 mm Hg at rest (p <0.05) and increased by 14 mm Hg at peak exercise at the Dead Sea in patients with CHF (p <0.05). Cardiac output at rest increased by 300 ml/min (p <0.05). Maximum oxygen consumption (VO2max) increased by 126 ml/ min (p <0.05), and even more so in patients with more severe exercise-induced oxygen desaturations, which was associated with lower peak minute ventilation to CO2 production ratio (p <0.05). Thus, descent to the Dead Sea acutely improved exercise performance due to better oxygenation and loading conditions in patients with CHF.

Altitude↗

Dilated inferior vena cava: a common echocardiographic finding in highly trained elite athletes.

Typical structural features of the athlete's heart as defined by echocardiography have been extensively described; however, information concerning extracardiac structures such as the inferior vena cava (IVC) is scarce. Fifty-eight top-level athletes and 30 healthy members of a matched control group underwent a complete Doppler echocardiographic study. IVC diameter was determined in the subxiphoid approach 10 to 20 mm away from its junction to the right atrium. Measures reflect the median values between maximal inspiratory and expiratory values. IVC respiratory collapsibility index was determined as well. IVC in athletes was 2.31 +/- 0.46 cm compared with 1.14 +/- 0.13 cm in the control group (P <.001). Swimmers had an IVC diameter of 2.66 +/- 0.48 cm compared with 2.17 +/- 0.41 cm in other athletes (P <.05). The IVC was normal ( /=2.6 cm) in 24.1% of athletes. The collapsibility index was 58% +/- 6.4% in athletes compared with 70.2% +/- 4.9% in the control group (P <. 001). Correlation was found between IVC size and VO(2) max (r = 0.81, P <.001) and the right ventricle (r = 0.81, P <.001) and with collapsibility index (r = -0.57, P <.05). Multiple regression analysis showed the impact of VO(2) max, cardiac index, and right ventricular and left ventricular end-diastolic dimensions on IVC diameter. IVC dilatation probably represents adaptation of an extracardiac structure to chronic strenuous exercise in top-level, elite athletes.

Adolescent↗

Direct vs. indirect blood pressure measurement at peak anaerobic exercise.

The present study compared the direct intra-arterial method with the indirect conventional sphygmomanometer during all-out anaerobic exercise, in young healthy subjects. Systolic and diastolic blood pressures were measured by intraarterial means and by auscultation. Fourteen young healthy males (23+/-2 yrs) were measured at rest and during all-out anaerobic exercise. Comparisons were made with simultaneously determined intra-arterial catheter and auscultation measurements. The data suggest that indirect systolic pressure is highly correlated with the direct method at rest (r = 0.684), with mean of 107+/-7 and 101+/-6 mmHg, respectively, and during all-out anaerobic exercise (r = 0.87), with mean of 197+/-11 and 191+/-9 mmHg, respectively. Indirect diastolic blood pressure correlates well with intra-arterial at rest (r = 0.62), with mean of 84+/-11 and 77+/-9 mmHg, respectively. However, during all-out anaerobic exercise, the correlation coefficient between the direct and the indirect methods was low (r = 0.36), with mean of 101+/-12 and 103+/-9 mmHg, respectively. These results suggest that when utilizing an all-out anaerobic exercise, the indirect method is not valid for assessment of diastolic pressure. In addition, although the anaerobic test is a dynamic type of exercise, its blood pressure responses for both direct and indirect methods were similar to those seen during isometric exercise.

Adult↗

Circadian fluctuations in the efficacy of thrombolysis with streptokinase.

This study was designed to investigate possible diurnal fluctuations in the efficacy of thrombolysis with streptokinase and whether they follow the circadian periodicity which has already been well documented for the time of onset of acute myocardial infarction, transient myocardial ischaemia, sudden cardiac death, thrombotic stroke, and for the efficacy of thrombolysis with tissue-type plasminogen and urokinase. A total of 156 consecutive patients treated with streptokinase were studied retrospectively; success or failure of thrombolysis was determined according to accepted clinical and angiographic criteria. A definite time peak for successful thrombolysis could be detected at the late afternoon and early evening hours; between 16.00 and 20.00 h, 30.2% of all successful thrombolysis cases were observed compared with 7.0% between 20.00 and 24.00 (p < 0.05) or 10.5% between 00.00 and 04.00 (p < 0.05). Between 16.00 and 20.00 h, 75.8% of treated patients had successful thrombolysis compared to 15.2% of failed treatments and 9% equivocal results (p < 0.001). Multiple regression analysis showed that the independent factor with the major impact on successful reperfusion was the actual time of thrombolysis (p = 0.037), followed by the time delay from pain onset to streptokinase administration (p = 0.020), while age and gender had much lesser impact (p = 0.328 and 0.215, respectively) and the individual risk factors even less. These findings may have several clinical implications; dose adjustment for the time of day may be required, with higher doses during morning hours, or preference for primary coronary angioplasty in order to avoid the increase in bleeding complications related to higher doses of thrombolytic agents.

Adult↗

[Circadian fluctuations of the signal-averaged electrocardiography].

Circadian periodicity for the time of onset of acute myocardial infarction has been shown; the early morning peak of infarction coincides with the onset of other related phenomena, including sudden cardiac death, ventricular arrhythmias, thrombotic stroke, etc. Late potentials detected by the signal-averaged ECG are considered to be independent markers of vulnerability to ventricular arrhythmias. The signal-averaged ECG enables the amplifying and recording of small bioelectric signals of cardiac origin, while eliminating extraneous electrical "noise." To determine whether late potentials are themselves subject to circadian influence, 31 patients (age range 41-79) who had had an old or recent myocardial infarction underwent late potential assessment by the signal-averaged ECG. 4 indices were studied: duration of late LPD potentials (LPD), total QRS duration (TQRS), and root mean square voltage of the last 40 msec, and of the last 50 msec (RMS 40 and RMS 50). These indices were assessed 3 times, during the early morning hours, at noon and during the evening. Morning LPD differed significantly from noon and evening LPD and the morning RMS 40 similarly differed from noon and evening values. TQRS and RMS 50, even though remaining in the normal range, also showed a tendency to abnormal values during morning hours. These findings could possibly be related to the early morning incidence peaks of severe ventricular arrhythmia and sudden cardiac death, since abnormal late potentials constitute the physiopathological basis for certain ventricular arrhythmias.

Adult↗

The outcome of patients with acute myocardial infarction ineligible for thrombolytic therapy. Israeli Thrombolytic Survey Group.

PURPOSE: The aim of this study was to determine the proportion of patients with acute myocardial infarction (AMI) excluded from thrombolytic therapy on a national basis and to evaluate the prognosis of these patients by reasons of ineligibility and according to the alternative therapies that they received during hospitalization. PATIENTS AND METHODS: During a national survey, 1,014 consecutive patients with AMI were hospitalized in all the 25 coronary care units operating in Israel. RESULTS: Three hundred and eighty-three patients (38%) were treated with a thrombolytic agent and included in the GUSTO study. Ineligible patients for GUSTO were treated: (1) without any reperfusion therapy (n = 449), (2) by mechanical revascularization (n = 97), or (3) given 1.5 million units of streptokinase (n = 85) outside of the GUSTO protocol. The inhospital and 1-year post-discharge mortality rates were 6% and 2% in patients included in the GUSTO study; 6% and 5% in those mechanically reperfused; 15% and 10% in those treated with thromoblysis despite ineligibility for the GUSTO trial, and 15% and 13% among patients not treated with any reperfusion therapy. CONCLUSIONS: Ineligibility for thrombolysis among patients with AMI remains high. Patients ineligible for thrombolysis according to the GUSTO criteria, but nevertheless treated with a thrombolytic agent were exposed to an increased risk.

Actuarial Analysis↗

The effects of isometric stress on left ventricular filling in athletes with isometric or isotonic training compared to hypertensive and normal controls.

Hypertrophy of the left ventricle may be associated with altered left ventricular filling dynamics. To test whether isometric and isotonic training affect left ventricular filling differently at rest and during isometric stress, 38 males, 13 long distance runners, eight weight-lifters, eight hypertensive patients and nine age-matched healthy male controls with a mean age of 30 +/- 7 years, were studied before and after 90 s of 50% maximal handgrip force. Left ventricular Doppler filling parameters were compared in the four groups while they were resting and during isometric stress testing, and the results assessed in relation to left ventricular mass index and wall stress. All subjects had normal resting filling patterns except for hypertensive patients, and peak meridional wall stress was low in both athletic groups at rest. Weight-lifters had a hypertensive response during isometric stress testing, associated with a reduction in peak E velocity and a marked increase in peak A velocity, resembling the filling pattern in hypertensive subjects. In runners the filling pattern remained normal. Thus, while the resting left ventricular pattern was normal in all athletes, isometric stress testing was associated with a hypertensive filling pattern only in weight-lifters compared to normal filling in runners.

Adult↗

On-site catheterization laboratory and prognosis after acute myocardial infarction. Israeli Thrombolytic Survey Group.

BACKGROUND: Since the introduction of thrombolytic therapy for patients with acute myocardial infarction, the use of coronary angiography has substantially increased. We sought to determine whether the presence of on-site coronary angiographic facilities influenced the utilization of coronary procedures in patients with acute myocardial infarction hospitalized in Israel's coronary care units. METHODS: A prospective survey was conducted in January and February 1992 in the 25 coronary care units operating in Israel, 15 of which had on-site catheterization facilities. Data on demographics, clinical features, thrombolytic therapy, and the type of coronary diagnostic or therapeutic procedures performed during the current in-hospital stay were recorded. Mortality, both in-hospital and 1 year after discharge, was assessed for all patients in the survey. RESULTS: One thousand fourteen consecutive patients with acute myocardial infarction were hospitalized during the survey, 307 (30%) of whom were admitted to 10 coronary care units without and 707 of whom were treated in hospitals with on-site coronary angiography facilities. Demographic and baseline characteristics were similar in both groups. Thrombolytic therapy was provided equally (46%) to patients admitted to hospital with and without catheterization laboratories. Patients admitted to hospitals with these laboratories underwent coronary angiography (26%) and percutaneous transluminal angioplasty and/or coronary artery bypass grafting (12%) in greater numbers than counterparts admitted to hospitals without such laboratories (10% and 5%, respectively). Hospital and cumulative 1-year mortality rates were 11% and 18%, respectively, in patients admitted to hospitals with on-site catheterization facilities vs 10% and 17%, respectively, in the patient group admitted to the other hospitals. Patients receiving thrombolytic therapy had similar hospital mortality rates unrelated to the availability of coronary catheterization laboratories. CONCLUSION: This national survey showed that the availability of invasive coronary facilities led to increased use of diagnostic and therapeutic coronary procedures among patients with acute myocardial infarction. There was no difference in hospital or 1-year mortality rates in patients admitted to hospitals with or without on-site coronary angiographic facilities.

Aged↗

[Do on-site coronary angiographic facilities influence management and prognosis of acute myocardial infarction?].

Whether the presence of on-site coronary angiographic facilities (CAF) influences the use of invasive coronary procedures and the outcome of acute myocardial infarction in coronary care units was studied. A prospective survey was conducted early in 1992 when 1014 consecutive patients with acute infarction were admitted. Of them 707 (70%) were admitted to coronary care units of hospitals with, and 307 (30%) without CAF. Thrombolytic therapy was given to 46% in both groups. Those admitted to hospitals with CAF underwent more coronary angiographies (26%) and percutaneous transluminal angiography and/or coronary artery bypass grafting (12%) than those without CAF (10 and 5%, respectively--p < 0.005). In-hospital and 1-year mortality were 11 and 18% respectively in those with CAF, vs 10 and 11%, respectively, in those without CAF. All patients treated with a thrombolytic agent had similar mortality, unrelated to the availability of CAF. The survey showed that the availability of on-site coronary angiography facilities led to greater use of invasive coronary procedures in cases of acute myocardial infarction, but there was no significant difference in mortality.

Angioplasty, Balloon, Coronary↗

P3 event-related potentials and performance of young and old subjects for music perception tasks.

Event-related potentials and performance data were recorded from young and old subjects performing six tasks involving auditory discrimination of musical stimuli. Tasks included pure tone, timbre, rhythm, and interval discrimination, detection of a meter shift, and discrimination of open and closed harmonic endings for chord progressions. P3 latencies were generally longer for the old subjects. P3 amplitude and performance differences between subject groups were not significant. Our results provide a quantitative probe of the neural and behavioral significance of the influence of aging and stimulus complexity on the processing of some of the elementary constituents of music. In particular, pure tone and timbre discrimination appear to correspond to behaviorally and neurally simpler processing than does discrimination of the other musical constituents tested in our study.

Adolescent↗

24 h electrocardiographic monitoring in morbidly obese patients during short-term zero calorie diet.

The medical literature of the previous decades has reported sudden unexpected death among cases of very low calorie dieters. Cardiac arrhythmias, possibly produced by a prolonged QT interval, were suspected to be the main cause of death in a considerable number of these cases. The aim of this study was to investigate the occurrence of significant cardiac arrhythmias and prolongation of the QT interval, during short-term zero calorie diet, in morbidly obese patients. A group of 11 such patients (BMI > 35 kg/m2) were treated with a short-term zero calorie diet, as in-patients for ten days, followed by an out-patient regime on an 800 kcal diet. Their ages ranged from 19-58 years (mean 43.6). None had diabetes mellitus, cardiac, liver or renal disease, or thyroid or pituitary abnormalities, and none took any medication except Allupurinol 300 mg/day. We used a 24h holter monitoring system to detect cardiac arrhythmias or prolonged QT interval. Recordings were performed on the day before starting the fast, while the patients were on their regular diet, and compared with similar recordings of the same patients taken on the 10th day of the fast. No significant cardiac arrhythmias or prolongation of the QT interval were recorded during the fasting period. Short-term zero calorie dieting provided the patients with physical and psychological encouragement and is a safe method for reducing weight if it is carried out under strict medical supervision.

Adult↗

Comparison between end-systolic pressure-volume and end-systolic wall stress in determining left ventricular contractility with increased afterload.

This study compared end-systolic pressure-volume relationship (P/V) versus wall stress index (WS) as a tool for the evaluation of ventricular contractile state during upright isometric exercise. Both indices of contractility exhibit significant (p < 0.001) increase during exercise compared to resting values. The correlation coefficients for the two indices of contractility were r = -0.45 for exercise and r = -0.70 for rest. Both were significant at the p < 0.01 level. The correlation of the difference scores between rest and exercise as computed by both indices was low (-0.20) and insignificant. These data suggest that changes in contractility from rest to exercise as measured by one index do not reflect the pattern of individual differences that are measured by means of the other index. However, from a reliability point of view, it seems appropriate to prefer the use of P/V index over the WS index in order to determine contractile state.

Adult↗