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Biomedical subjects

Z Vered

Publications and source records attributed to Z Vered.

At least 73 records · Page 4Linked to original sources
PubMed1993

Tricuspid valve surgery: recent experience at the Chaim Sheba Medical Center.

From 1 January 1989 to 30 June 1992, 35 patients underwent cardiac surgery that included a tricuspid valve (TV) procedure. All had severe TV dysfunction documented by echocardiography, and were in NYHA functional class III-IV. The etiology of TV dysfunction was rheumatic-functional in 19 patients, rheumatic-organic in 13, and infective in 3. Nineteen (54%) had had at least one previous cardiac operation, and in 29 an associated procedure (MVR, AVR, DVR, DVR + CABG) had been performed. The TV was repaired in 27 patients, was replaced by a bioprosthesis in 7, and was excised in 1. There were three (8.6%) operative and two late deaths. Except for two, all surviving patients are in NYHA functional class I-II. In two patients with organic lesions who underwent repair, residual moderate tricuspid regurgitation was observed. We conclude that in these critically ill patients TV surgery can be performed with acceptable results. Long-term fate of a bioprosthesis in the tricuspid position is yet to be determined.

Adult↗
PubMed1991

Noninvasive detection of the morphologic and hemodynamic changes during normal pregnancy.

To characterize the morphologic and hemodynamic changes during normal pregnancy, serial echocardiographic measurements (n = 210) of left ventricular (LV) dimensions and mass (M-mode), volumes and ejection fraction (two-dimensional), stroke volume, and cardiac output (Doppler: aortic, apical, and suprasternal) were performed in 15 patients (mean age 30 years) beginning as early as 12 weeks of gestation, at 2-week intervals through delivery, and up to 12 weeks postpartum. Left atrial size increased from 3.4 +/- 0.4 (SD) to 3.8 +/- 0.4 cm near term, decreasing to 3.4 +/- 0.5 cm postpartum (p = 0.006 overall). LV mass changes correlated with increases in body weight. No consistent significant changes in LV volumes and ejection fraction were observed. LV outflow tract cross-sectional area increased significantly from 3.0 +/- 0.2 cm2 at baseline to 3.5 +/- 0.3 cm2 near term, decreasing to 3.2 +/- 0.3 cm2 postpartum (p less than 0.002 for both). Heart rate increased from 70 +/- 7 to 77 +/- 10 beats/min near term decreasing to baseline postpartum (p less than 0.02 for both). Accordingly, cardiac output increased significantly, as detected from both the apical and suprasternal positions averaging from 4.7 +/- 0.6 to 6.5 +/- 1.5 l/min near term, returning to 4.3 +/- 0.6 l/min postpartum (p less than 0.0005 for both). Thus, in normal pregnancy, left atrial size increases significantly without significant changes in LV dimensions, volumes, and ejection fraction. Increased LV mass is related to increased body weight. Cardiac output changes result from increased heart rate and an increase in LV outflow area, which contributes to increased stroke volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Thiamine deficiency in patients with congestive heart failure receiving long-term furosemide therapy: a pilot study.

PURPOSE: To test the hypothesis that long-term furosemide therapy in patients with congestive heart failure (CHF) is associated with clinically significant thiamine deficiency via urinary loss. DESIGN: (1) Biochemical evaluation of thiamine status in hospitalized patients with CHF treated with long-term furosemide and in age-matched control patients. (2) Uncontrolled trial of the effect of intravenous thiamine on cardiac performance in a subset of six patients with CHF. SETTING: General medical ward of a teaching community hospital. PATIENTS: Twenty-three patients with chronic CHF receiving furosemide, and 16 age-matched control patients without heart failure and not taking diuretics. Daily furosemide doses were 80 to 240 mg, and duration of furosemide therapy was 3 to 14 months. Patients with identifiable causes of inadequate thiamine intake, absorption, or utilization or increased metabolic requirements were excluded. INTERVENTION: A 7-day course of intravenous thiamine, 100 mg twice daily, in six consenting patients with CHF. RESULTS: A high thiamine pyrophosphate effect (TPPE), indicating thiamine deficiency, was found in 21 of 23 furosemide-treated patients and in two of 16 controls (p less than 0.001). The mean (+/- SE) TPPE (normal: 0% to 15%) in furosemide-treated and control patients was 27.7 +/- 2.5% and 7.1 +/- 1.6%, respectively (p less than 0.001). Despite the high TPPE, the mean (+/- SE) urinary thiamine excretion in the furosemide-treated patients (n = 18) was inappropriately high (defined as greater than 130 micrograms/g creatinine), 410 +/- 95 micrograms/g creatinine, even in comparison with that in the controls (n = 14): 236 +/- 69 micrograms/g creatinine. In six patients treated with intravenous thiamine, the elevated TPPE decreased to normal, from a mean (+/- SE) of 27.0 +/- 3.8% to 4.5 +/- 1.3% (p less than 0.001), indicating normal thiamine utilization capacity. Left ventricular ejection fraction increased in four of five of these patients studied by echocardiography. CONCLUSIONS: These preliminary findings suggest that long-term furosemide therapy may be associated with clinically significant thiamine deficiency due to urinary loss and contribute to impaired cardiac performance in patients with CHF. This deficit may be prevented or corrected by appropriate thiamine supplements.

Adult↗
PubMed1991

Dissecting aortic aneurysm--failure of standard noninvasive and invasive diagnostic techniques.

The diagnosis of cardiac tamponade due to dissection of an ascending aortic aneurysm in a middle-aged woman was not confirmed by the usual noninvasive and invasive procedures. The decision for surgery was based on clinical grounds only, resulting in an unnecessary delay of surgical intervention. Although some of the current noninvasive techniques seem to be most useful in the investigation of these patients, the clinical findings remain the cornerstone of a correct diagnosis.

Aged↗
PubMed1990

Normal left ventricular performance in children with X-linked hypophosphatemic rickets: a Doppler echocardiography study.

To determine if chronic hypophosphatemia causes myocardial dysfunction, we explored one model for this metabolic derangement by prospectively investigating 11 patients (aged 5-18 years) with X-linked hypophosphatemic rickets (XLH) by M-mode, two-dimensional, and Doppler echocardiography. Inorganic phosphate and calcitriol (1,25-dihydroxyvitamin D3) treatment was withheld 72 h prior to study. None of the patients had cardiovascular symptoms. Fasting serum inorganic phosphate concentrations were subnormal in all: 2.6 +/- 0.5 mg/dl (SD). Serum total and ionized calcium, magnesium, sodium, potassium, and creatine kinase myocardial fraction (CK-MB) levels were unremarkable. Electrocardiograms revealed early repolarization abnormalities in 3 of the 11 patients: 1 had significant QT prolongation (corrected for heart rate), and 2 had T wave abnormalities. Exaggerated U waves occurred in 4 subjects. Resting echocardiograms were normal in 9 patients. In 1 subject there was mitral valve prolapse, and 1 patient possibly had an atrial septal defect (these findings were considered unrelated to hypophosphatemia). All M-mode measurements were normal. The two-dimensionally derived end-diastolic and end-systolic left ventricular volumes were 60.3 +/- 18.0 and 20.5 +/- 6.9 ml, respectively. Left ventricular ejection fraction was 66.1 +/- 4.7%, and the cardiac index by Doppler study was 4.1 +/- 0.8 liters/min per m2 (both values were within normal limits). Although the precise pathogenesis of XLH is unknown and our findings suggest that some electrocardiographic abnormalities may be common in this disorder, we found no evidence for left ventricular dysfunction in this human model of clinically significant long-standing hypophosphatemia.

Adolescent↗
PubMed1990

Myocardial ultrasonic backscatter for characterization of ischemia and reperfusion: relationship to wall motion.

We have previously shown that cardiac cycle-dependent variation of integrated backscatter occurs in normal myocardium. To determine whether myocardial ischemia and reperfusion can be distinguished by real-time integrated backscatter imaging we performed 10 min balloon occlusion of the Left Anterior Descending (LAD) coronary artery followed by reperfusion in 10 closed-chest anesthetized dogs. Images were obtained at baseline, during occlusion, and up to 120 min after reperfusion. We measured the magnitude and delay of cyclic variation of integrated backscatter in segments with and without asynergy. Radiolabeled microspheres were used to verify both ischemia and reperfusion. Ischemic segments exhibited decreased magnitude and increased normalized delay of cyclic variation of integrated backscatter (from 3.3 +/- 0.3 dB to 1.4 +/- 0.2 dB, mean +/- SE; and from 0.95 +/- 0.03 to 1.67 +/- 0.15, respectively, all p less than or equal to 0.001). Reperfusion promptly restored the magnitude of cyclic variation toward normal. However, the delay of the cyclic variation was restored only partially. Wall motion analysis of the ischemic sites revealed persistent abnormalities throughout the reperfusion interval despite return to normal of the magnitude and delay of cyclic variation. Thus, real-time integrated backscatter imaging permits detection and differentiation of changes in myocardial acoustic properties indicative of ischemia and of subsequent reperfusion.

Animals↗
PubMed1989

Normal left ventricular performance documented by Doppler echocardiography in patients with long-standing hypocalcemia.

INTRODUCTION: Several reports suggest significantly reduced left ventricular performance in subjects with chronic hypocalcemia. We prospectively investigated eight patients, aged 13 to 31 years, with long-standing hypocalcemia due to idiopathic hypoparathyroidism or pseudohypoparathyroidism by echocardiography. PATIENTS AND METHODS: Six subjects had symptomatic hypocalcemia manifested as recurrent tetany (four), seizures (four), mental retardation (three), behavior disorder (one), and skeletal abnormalities (four); three subjects were untreated when studied. None had cardiovascular symptoms. Each patient underwent clinical, biochemical, and cardiac studies, including Doppler, two-dimensional, and M-mode echocardiography, on the same day. RESULTS: In serum, both total and ionized calcium concentrations were reduced and averaged 7.2 mg/dl (range: 5.3 to 8.5 mg/dl; normal: 9.0 to 10.3 mg/dl) and 3.6 mg/dl (range: 3.0 to 3.9 mg/dl; normal: 4.5 to 5.3 mg/dl), respectively. Electrocardiograms revealed prolonged QTc intervals in six patients. Also noted were prominent U waves (five), T-wave abnormalities (four), and right-axis deviation (one). Resting echocardiography, however, demonstrated normal left ventricular function in all subjects. All M-mode measurements were normal. Two-dimensional-derived left ventricular end-diastolic and end-systolic volumes were 87.1 +/- 20.1 ml and 30.2 +/- 9.7 ml (mean +/- SD), respectively. Left ventricular ejection fraction was 65 percent (61.2 to 74.7 percent). Doppler-derived cardiac output and cardiac index averaged 5.1 liters/minute (2.9 to 6.7 liters/minute) and 3.0 liters/minute/m2 (1.7 to 4.3 liters/minute/m2), respectively. CONCLUSION: Our prospective study of eight subjects with functional hypoparathyroidism demonstrated that, despite electrocardiographic abnormalities, long-standing hypocalcemia was not associated with left ventricular dysfunction.

Adolescent↗
PubMed1989

Ultrasound integrated backscatter tissue characterization of remote myocardial infarction in human subjects.

To determine whether quantitative ultrasound tissue characterization differentiates normal myocardial regions from segments of remote infarction, 32 consecutive patients with a diagnosis of previous myocardial infarction were evaluated. Images were obtained in real time with a modified two-dimensional ultrasound system capable of providing continuous signals in proportion to the logarithm of integrated backscatter along each A line. In 15 patients, adequate parasternal long-axis images that delineated both normal and infarct segments were obtained with standard time-gain compensation. Image data were analyzed to yield both magnitude and delay (electrocardiographic R wave to nadir normalized for the QT interval) of the cyclic variation of backscatter. Cyclic variation was present in 55 of 56 normal myocardial sites, averaging (mean +/- SEM) 3.2 +/- 0.2 dB in magnitude and exhibiting a mean normalized delay of 0.87 +/- 0.03. The magnitude of cyclic variation in infarct segments was significantly reduced to 1.1 +/- 0.2 dB (42 sites), and the delay was markedly increased to 1.47 +/- 0.12 (21 sites) (p less than 0.0001 for both). In 20 of 42 infarct sites, no cyclic variation was detectable. Thus, ultrasound tissue characterization quantitatively differentiated infarct segments from normal myocardium in patients with remote myocardial infarction.

Adult↗
PubMed1989

Ultrasonic tissue characterization with integrated backscatter. Acute myocardial ischemia, reperfusion, and stunned myocardium in patients.

We have previously shown in studies of experimental animals that myocardium exhibits a cardiac cycle-dependent variation of integrated backscatter that reflects regional myocardial contractile performance and that is blunted promptly after arterial occlusion and recovers after reperfusion. To define the clinical utility of ultrasonic tissue characterization with integrated backscatter for detection of acute myocardial infarction and reperfusion, 21 patients (14 men and seven women) were studied in the cardiac care unit within the first 24 hours (mean time, 11.3 hours; range, 3.5-23.8 hours) after the onset of symptoms indicative of acute myocardial infarction with conventional two-dimensional and M-mode echocardiography and with analysis of integrated backscatter. The magnitude of cyclic variation of integrated backscatter was measured from several sites within acute infarct regions and normal regions remote from the infarct zone for each patient. The average magnitude of cyclic variation among all patients (n = 21) was 4.8 +/- 0.5 dB in normal regions compared with 0.8 +/- 0.3 dB in infarct regions (p less than 0.05) within the first 24 hours after the onset of symptoms. Among the patients who had two studies, 15 (mean, 7.1 days; range, 2-31 days for second study) underwent coronary arteriography to define vessel patency. In patients with vessels with documented patency (n = 10), the magnitude of cyclic variation in infarct regions increased over time from 1.3 +/- 0.6 to 2.5 +/- 0.5 dB from the initial to final study (p less than 0.05). Patients with occluded infarct-related arteries (n = 5) exhibited no significant recovery of cyclic variation (0.3 +/- 0.3-0.6 +/- 0.3 dB). A blinded analysis of standard two-dimensional echocardiographic images revealed no significant recovery of wall thickening in either group over the same time intervals. Ultrasonic tissue characterization promptly detects acute myocardial infarction and may delineate potential beneficial effects of coronary artery reperfusion manifest by restoration of cyclic variation of integrated backscatter in the presence of severe wall motion abnormalities.

Aged↗
PubMed1989

Automated determination of the magnitude and time delay ("phase") of the cardiac cycle dependent variation of myocardial ultrasonic integrated backscatter.

An algorithm for quantitative description of cardiac cycle dependent variation of integrated backscatter (cyclic variation) has been developed and is shown to be suitable for analysis of nonsinusoidal data typical of ultrasonic tissue characterization measurements from myocardium in vivo. The algorithm produces estimates of the magnitude of variation and of the time delay relative to the electrocardiographically recorded QRS-complex. To validate the algorithm, 246 integrated backscatter measurements were analyzed both manually and by the automated method. The magnitude and time delay estimates from the two methods correlated closely. With a separate set of data, the algorithm produced reasonable descriptions of the cyclic variation for 89 of 101 integrated backscatter measurements. Only modest computational power is required for effective implementation of this algorithm, facilitating inclusion of online automated analysis capabilities in quantitative ultrasonic tissue characterization systems.

Algorithms↗
PubMed1988

The transmitral pressure-flow velocity relation. Effect of abrupt preload reduction.

Although recent animal and clinical studies suggest that Doppler-derived indexes may be useful for the characterization of ventricular diastolic behavior, the hemodynamic basis for the preload dependency of these indexes has not previously been fully elucidated. Accordingly, effects of reduction of left atrial load on the pressure-flow velocity relation were characterized in 10 anesthetized, closed-chest dogs during transient inferior vena caval occlusion by means of simultaneously recorded left atrial and left ventricular micromanometric pressure measurement and transesophageal Doppler echocardiograms. Within four or five beats after inferior vena caval balloon occlusion, left atrial loading was reduced as evidenced by a decrease in the slope of the left atrial v wave from 21 +/- 4 to 13 +/- 4 mm Hg/sec (p less than 0.001) and by a decrease in the first crossover point of left atrial and left ventricular pressures from 5.6 +/- 1.1 to 2.9 +/- 1.5 mm Hg (p less than 0.001). This decrease in left atrial loading resulted in reductions during early diastole of minimum left ventricular pressure (from 1.0 +/- 0.8 to -0.4 +/- 1.2 mm Hg, p less than 0.001), the maximum early forward (i.e., left atrial pressure greater than left ventricular pressure) transmitral pressure gradient (from 2.8 +/- 0.8 to 2.4 +/- 0.5 mm Hg, p less than 0.01); the slope of the rapid filling pressure wave (from 44 +/- 11 to 38 +/- 10 mm Hg/sec, p less than 0.025); and the area of the reversed (i.e., left ventricular pressure greater than left atrial pressure) transmitral pressure gradient (from 79 +/- 42 to 53 +/- 33 mm Hg.msec, p less than 0.05). During late diastole, both the heights and slopes of the left atrial and left ventricular a waves fell, resulting in a decrease in the maximum late transmitral pressure gradient (from 1.2 +/- 0.7 to 0.9 +/- 0.5 mm Hg, p less than 0.05). Vena caval occlusion also altered Doppler transmitral velocity profiles during both the early and late phases of diastole. Peak velocity of the E wave decreased (from 50 +/- 11 to 41 +/- 7 cm/sec, p less than 0.01) as did acceleration (from 880 +/- 222 to 757 +/- 258 cm/sec2, p less than 0.025) and deceleration (from 597 +/- 260 to 429 +/- 197 cm/sec2, p less than 0.025). Peak velocity of the A wave also fell (from 29 +/- 9 to 22 +/- 5 cm/sec, p less than 0.005). Abrupt inferior vena caval occlusion did not significantly change heart rate or mean aortic pressure.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Review of echocardiographically diagnosed right heart entrapment of pulmonary emboli-in-transit with emphasis on management.

2DE permits detection of thromboemboli transiently entrapped in the right heart chambers while en route to the pulmonary arteries. Review of the 49 cases recorded to date reveals that the supple elongated clot produces a 2DE picture--a mass of changing configuration and striking mobility--that is highly characteristic. Since emboli that become entrapped are large, when managed by medical measures alone they have an attendant mortality rate of 50%, usually soon after 2DE diagnosis, upon completion of pulmonary embolization. Death occurred in 8 of 16 patients treated with anticoagulants, thrombolytic agents, or antiaggregants and in 6 of 13 who received supportive measures only. Of 20 patients referred for surgery (cardiotomy and, in 17, pulmonary embolectomy), only three died, two of them failures of preceding anticoagulant treatment. These data indicate that thromboemboli entrapped in the right heart chambers are best handled as a surgical emergency.

Echocardiography↗
PubMed1987

Quantitative ultrasonic tissue characterization with real-time integrated backscatter imaging in normal human subjects and in patients with dilated cardiomyopathy.

We have shown previously that the physical properties of myocardium in dogs can be characterized with quantitative ultrasonic integrated backscatter and that interrogation of the tissue with ultrasound can delineate cardiac cycle-dependent changes in ultrasonic backscatter in normal tissue that disappear with ischemia and reappear with reperfusion if functional integrity is restorable. To determine whether this approach can be applied to man, we implemented an automatic gain compensation and continuous data acquisition system to characterize myocardium with quantitative ultrasonic backscatter and to detect cardiac cycle-dependent changes in real time. We developed a two-dimensional echocardiographic system with quantitative integrated backscatter imaging capabilities for use in human subjects that can automatically differentiate ultrasonic signals from blood as opposed to those obtained from tissue and adjust the slope of the gain compensation appropriately. Real-time images were formed from a continuous signal proportional to the logarithm of the integrated backscatter along each A-line. In our initial investigation, 15 normal volunteers (ages 17 to 40 years, heart rates 44 to 88 beats/min) and five patients with dilated cardiomyopathy (ages 22 to 52, heart rates 82 to 120 beats/min) were studied with conventional parasternal long-axis echocardiographic views. Diastolic-to-systolic variation of integrated backscatter in the interventricular septum and left ventricular posterior wall was seen in each of the normal subjects averaging 4.6 +/- 1.4 dB (SD) and 5.3 +/- 1.5 dB (n = 127 sites), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Severe aortic regurgitation: a rare presentation of giant cell arteritis.

A 53-year-old patient with no past history of rheumatic fever or lues presented with severe aortic regurgitation, underwent hemodynamic evaluation, and subsequently, an uneventful aortic valve replacement. The initial pathological interpretation was nonspecific aortitis. Six months following surgery arthralgia, muscular pain, difficulty in mastication, and fatigue occurred. There was no fever, however, sedimentation rate was 100/130. Cardiac examination was normal. Review of the pathological specimens revealed granulomatous arteritis with giant cells, typical of giant cell arteritis. Though the association of aortic regurgitation and giant cell arteritis is well recognized, only two such cases of severe aortic regurgitation requiring valve replacements have yet been described, of them, one probably had Takayasu's arteritis. An accurate diagnosis is of importance since steroid treatment is effective, and if introduced early, the inflammatory process may be arrested.

Aorta↗
PubMed1986

Two-dimensional echocardiographic analysis of proximal left main coronary artery in humans.

The left main coronary artery (LMCA) was evaluated in 100 consecutive patients (88 men and 12 women; mean age 63 years) with anginal syndrome, all in New York Heart Association classes II and III. Each patient underwent two-dimensional echocardiography (2DE) from the parasternal short-axis and apical four-chamber views. Coronary angiography was subsequently performed within 24 hours. The LMCA was directly measured by 2DE and coronary angiography at its widest point. Each echocardiogram was blindly evaluated for LMCA aneurysm or obstruction. Eight patients (8%) were excluded because of inadequate visualization of the LMCA. The mean 2DE measurement was 4.4 +/- 0.9 mm vs 4.2 +/- 0.8 mm on coronary angiography (r = 0.86). Atherosclerotic aneurysms of the LMCA were correctly diagnosed in two patients by 2DE. LMCA stenosis (greater than 50%) was found in 11 patients on coronary angiography; three of them had ostial or proximal lesions, three had middle lesions, and five had distal lesions. 2DE correctly diagnosed all three ostial lesions, two of three middle lesions, but only two of five distal lesions. In four patients, dense echoes in the LMCA caused a false positive diagnosis. It was concluded that: the LMCA can be visualized and correctly measured by 2DE; atherosclerotic aneurysms can be detected; and 2DE is yet unable to screen patients for LMCA lesions; however, 2DE is a promising method for evaluating proximal and especially ostial LMCA stenosis.

Adult↗
PubMed1986

The cardiac pacemaker patient with a femoral neck fracture.

More than half the patients with permanent cardiac pacemakers (PCPMs) are over the age of 70 years. Patients in this age group are also more susceptible to fractures of the femoral neck requiring surgical intervention. The authors studied five patients with PCPMs who underwent surgery for femoral neck fracture. They discuss the special precautions necessary during surgery to prevent electromagnetic interference with the cardiac pacemaker as well as the special management of these patients.

Aged↗