PubMed Health⌕ Search

Biomedical subjects

L Hatle

Publications and source records attributed to L Hatle.

At least 73 records · Page 4Linked to original sources
PubMed1986

Noninvasive estimation of systolic pressure in the right ventricle in patients with tricuspid regurgitation.

In 70 patients, tricuspid regurgitation was diagnosed with Doppler by recording reverse flow in systole originating at the tricuspid orifice, directed into the right atrium. The peak velocities were recorded, and the peak pressure drop from the right ventricle to the right atrium in systole was calculated from the simplified Bernoulli equation (pressure drop = 4 X 4 X Vmax2), and was found to correlate well with invasive measurements (r = 0.97, SEE +/- 6.1 mmHg). Central venous pressure was judged by neck vein congestion and added to the pressure drop to obtain a noninvasive estimation of systolic right ventricular pressure. Correlation with catheterization measurements was good (r = 0.96, SEE +/- 7.1 mmHg). In patients in whom the tricuspid regurgitation was judged as mild with Doppler, the correlation between noninvasive and invasive measurements of the transtricuspid pressure drop was still good (r = 0.95, SEE +/- 5.1 mmHg), indicating that the viscosity of the blood does not invalidate the use of the simplified Bernoulli equation when the regurgitant area of the valve is small.

Adolescent↗
PubMed1986

Diagnosis and assessment of valve stenosis and regurgitation and coarctation of the aorta with Doppler ultrasound.

With the use of Doppler ultrasound localized increases in blood flow velocities can be recorded and used to diagnose obstructions to blood flow. From the increase in maximal velocities the pressure drop across an obstruction can be calculated, both the peak instantaneous and the mean pressure drop. Regurgitations are diagnosed by recording reversal of blood flow across the valve. Semi-quantitative evaluation of the degree of regurgitation can be made by using both jet width, extension and intensity, as well as increase in forward flow velocity, reversal of flow in great vessels and influence on pressures. In coarctation of the aorta localized increase in velocity in the descending aorta can be shown and the pressure drop can be calculated. In some, more than one level of obstruction can be shown. In neonates the presence of a patent ductus arteriosus may mask the obstruction and a significant pressure drop may become apparent only when narrowing or closure of the duct occurs.

Aortic Coarctation↗
PubMed1986

Flow velocity patterns across atrial septal defects recorded with Doppler echocardiography.

During a two-year period pulsed Doppler combined with two-dimensional echocardiography was used in evaluating patients for atrial septal defects. Blood flow velocities were recorded with pulsed Doppler in the right atrium along the atrial septum, across the atrioventricular and semilunar valves and when a shunt was detected also on the left side of the atrial septum. The typical flow velocity pattern most often seen is described and is related to the differences in pressure between the two atria during the cardiac cycle. Deviations from this velocity pattern are described and their hemodynamic significances discussed. Diagnosis and assessment of pulmonary hypertension from tricuspid and pulmonary flow velocities are described.

Blood Flow Velocity↗
PubMed1985

Assessment of aortic blood flow velocities with continuous wave Doppler ultrasound in the neonate and young child.

Aortic flow velocities can be recorded with pulsed or continuous wave Doppler ultrasound. In the absence of obstruction or regurgitation, changes in flow can be assessed and stroke volume obtained. Continuous wave Doppler ultrasound has the advantage that there is no limit to the velocities that can be recorded. In left ventricular outflow obstruction and coarctation, the pressure drop across these can be calculated from increases in maximal velocity using a modification of the Bernoulli equation. Other systolic high velocity jets such as mitral regurgitation or ventricular septal defect may also be recorded with continuous wave Doppler ultrasound from the suprasternal notch, but they can be distinguished from aortic flow velocities by their timing and duration when the flow signals are recorded together with the electrocardiogram and phonocardiogram. In aortic regurgitation, reversal of flow across the aortic valve in diastole can be shown and with high velocity in the regurgitant jet.

Aorta↗
PubMed1985

Diagnosis of tricuspid regurgitation. Sensitivity of Doppler ultrasound compared with contrast echocardiography.

Fifty-one patients underwent Doppler studies of tricuspid flow and 2-D derived M-mode studies of the inferior vena cava (IVC) during upper extremity contrast injections. Tricuspid regurgitation (TR) was diagnosed with Doppler when reverse flow in systole was recorded at and behind the closure level of the tricuspid valve. TR was diagnosed with contrast echocardiography (CE) when contrast appeared in the IVC between the onset of the QRS complex and the end of the T-wave of the ECG. Of the 49 patients who had TR diagnosed with Doppler, contrast was recorded in the IVC in 46, but only 18 (37%) fulfilled the criterion for a positive CE study. When the severity of the TR was semiquantitated with Doppler, CE diagnosed 1 of 25 mild, 5 of 11 moderate, and 12 of 13 severe regurgitations. When systolic contrast appearance in the IVC after the peak of the R-wave was used as the criterion for a positive contrast study, CE missed 2 of 13 severe regurgitations. In the 24 catheterized patients the CE study was positive only when an abnormal V-wave in the right atrial pressure curve was present. Doppler is a more sensitive method than CE for diagnosing TR and is more readily applied.

Adult↗
PubMed1985

Aortic stenosis in adults. Non-invasive estimation of pressure differences by continuous wave Doppler echocardiography.

The peak and mean aortic transvalvar pressure differences measured invasively and non-invasively by continuous wave Doppler echocardiography were compared in 87 consecutive patients with aortic stenosis. The mean values were calculated from the maximal velocities of the aortic jet recorded with a spectral display of the Doppler frequency shifts and by applying a modified Bernoulli equation. Technically satisfactory velocity curves for estimating the mean pressure differences could not be obtained in three patients and invasive measurements were not obtained in two. In all patients the peak transvalvar pressure difference was calculated since the aortic jet was identified non-invasively. The peak and mean pressure differences measured invasively and non-invasively correlated well--with only minor underestimation of the pressure differences measured with the Doppler technique--regardless of age, sex, and the presence or absence of aortic valvar regurgitation, or other valvar lesions. With a systematic search for the highest velocities in the aortic jet and with on line spectral analysis of the Doppler frequencies the peak and the mean aortic pressure differences can be determined non-invasively with a high degree of precision in almost all patients.

Adult↗
PubMed1985

Noninvasive estimation of valve area in patients with aortic stenosis by Doppler ultrasound and two-dimensional echocardiography.

In 30 patients with aortic stenosis, 14 of whom also had significant aortic regurgitation, the velocities in the stenotic jet (V') and below the valve (V) were recorded by Doppler ultrasound. With two-dimensional echocardiography, two subvalvular areas (A) were calculated from leading-to-leading edge ("large") and trailing-to-leading edge ("inner") diameter measurements. The aortic valve area was calculated by the equation of continuity (A' = A X peak V/peak V') and by calculating stroke volume below the valve [A X integral of V (t) and dividing by the integral of V' (t) (= A"). Based on cardiac output estimations from single-plane angiographic images, Gorlin's formula was used to calculate invasive valve areas. In patients with no or mild aortic regurgitation a second invasive estimate was based on cardiac output measured by the Fick method. The best correlation was found when A' (with "large" diameter) was compared with invasive results based on cardiac output measured by the Fick method (r = .89, SEE +/- 0.12, n = 16); the worst was found when A" (with "large" diameter) was compared with invasive results based on cardiac output measurements by single-plane angiography (r = .80, SEE +/- 0.20, n = 30). The results indicate that valve area in patients with aortic stenosis can be reliably estimated noninvasively, even in those with significant aortic regurgitation.

Aortic Valve↗
PubMed1984

Noninvasive assessment of valve lesions with Doppler ultrasound.

Noninvasive assessment of valvular lesions with Doppler echocardiography is based on determination of velocities of blood flow in the region of cardiac valves, adjacent cardiac chambers and in the large vessels. Obstructions lead to an increase in the velocity of flow in the region of the stenosis which can be registered with the Doppler technique. Through application of the Bernoulli equation, from the maximal velocity, the pressure gradient across the stenotic valve can be calculated. Additionally, the severity of the stenosis is reflected in the temporal course of the velocity curve of the jet through the stenosed valve. For this purpose, in mitral stenosis, the pressure half-time is employed and, in aortic stenosis, the peak of the velocity curve during systole is used. The severity of tricuspid and pulmonic stenosis can also be classified with a method analogous to that used in obstruction of the left heart. The diagnosis of valvular incompetence is based on the detection of regurgitant flow. The extent of regurgitant flow into the proximal cardiac chamber enables semiquantitative classification of severity. The intensity of the jet through the incompetent valve is also indicative of the size of the regurgitant volume. Similar to that in obstructive lesions, the temporal course of the velocity curve is also related to the severity. In association with high-grade regurgitant lesions, there is a premature decrease in the velocity curve. Additionally, the severity of aortic regurgitation can be assessed on the basis of the extent of regurgitant flow in the descending aorta or the subclavian arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1981

Noninvasive diagnosis and assessment of ventricular septal defect by Doppler ultrasound.

The presence of ventricular septal defect can be diagnosed noninvasively by Doppler ultrasound. Care must be taken to distinguish between VSD and infundibular pulmonary stenosis. VSD was easily differentiated from other cardiac lesions. In 55% of the patients a pressure drop across the VDS, comparable to that present, could be calculated from maximal recorded. In the remaining patients velocity and pressure drop were underestimated, probably due to a too large angle between ultrasound beam and velocity. Pulmonary artery systolic pressure was correctly estimated from Pc-To interval and heart rate, and RPEP(RVET) indicated whether normal or raised diastolic pressure was present in most patients.

Adolescent↗
PubMed1981

Non-invasive estimation of pulmonary artery systolic pressure with Doppler ultrasound.

Systolic pressure in the pulmonary artery was estimated from the interval between pulmonary valve closure and tricuspid valve opening, and the heart rate using a nomogram previously described. The timing of valve movements was recorded by Doppler ultrasound. The estimated pressure correlated well with that obtained at catheterisation in 45 of 48 patients with pulmonary hypertension. Instantaneous variations in pressure and changes with treatment and during exercise could be measured. The method was easy to apply in all age groups, and was found useful both in detecting pulmonary hypertension and in the follow-up of patients. It may help to determine the optimal time for surgery or the effect of treatment.

Adolescent↗
PubMed1981

Noninvasive assessment and differentiation of left ventricular outflow obstruction with Doppler ultrasound.

Blood flow velocities in the left ventricle and the ascending aorta were recorded noninvasively with Doppler ultrasound. The ultrasound beam was aligned as much as possible to the direction of velocity, using the frequency shift in the audio signal as a guide to obtain velocities as close as possible to those present. From the maximal velocity recorded by continuous-wave Doppler, a peak pressure drop was calculated in 24 patients with aortic valve stenosis and nine with fixed subaortic stenosis. Fourteen patients with aortic stenosis and three with fixed subaortic stenosis were catheterized. In these patients, the correlation between calculated pressure drops and those obtained by pressure recording was good (r = 0.85). The pressure drop can be underestimated by underestimating velocity, but cannot be overestimated. With pulsed Doppler, the level of obstruction can be determined.

Adolescent↗
PubMed1980

Non-invasive assessment of aortic stenosis by Doppler ultrasound.

The peak pressure drop across the aortic valve in aortic stenosis has been measured by Doppler ultrasound. Maximum velocity in the Doppler signal from the aortic jet was recorded using a maximum frequency estimator. With an angle close to zero between ultrasound beam and maximal velocity in the jet, peak pressure drop can be calculated from the maximal velocity measured; a larger angle will underestimate maximal velocity and pressure drop. In 57 of 63 patients with aortic stenosis, the aortic jet could be reached by the ultrasound beam and, in 37 of these, peak pressure drop by ultrasound was compared with that obtained at catheterisation. In patients less than 50 years of age the aortic jet was easy to find, the measurement was reproducible, and underestimation of the pressure drop obtained at catheterisation was within 25 per cent in 17 of 18 patients. In patients over 50 years Doppler signals from the aortic jet were more difficult to obtain, and pressure drop was significantly underestimated in one-third, but time of maximum velocity in systole could indicate whether moderate or severe aortic stenosis was present.

Adolescent↗
PubMed1979

Noninvasive assessment of atrioventricular pressure half-time by Doppler ultrasound.

The mean pressure drop across the mitral valve and atrioventricular pressure half-time were measured noninvasively by Doppler ultrasound in 40 normal subjects, in 17 patients with mitral regurgitation, 32 patients with mitral stenosis and 12 with combined stenosis and regurgitation. In normal subjects pressure half-times were 20--60 msec, in patients with isolated mitral regurgitation 35--80 msec and in patients with mitral stenosis 90--383 msec. There was no significant change in pressure half-time with exercise or on repeat examinations, indicating relative independence of mitral flow. In 25 patients with mitral stenosis and seven with combined stenosis and regurgitation, pressure half-time was related to mitral valve area calculated from catheterization data. Increasing pressure half-times occurred with decreasing mitral valve area, and this relationship was not influenced by additional mitral regurgitation. Noninvasive measurement of pressure half-time together with mean pressure drop was useful for evaluating patients with mitral valve disease.

Adolescent↗
PubMed1978

Noninvasive assessment of pressure drop in mitral stenosis by Doppler ultrasound.

A noninvasive method is described for measuring the pressure drop across the mitral valve in mitral stensois by Doppler ultrasound. A maximum frequency estimator was used to record maximum velocity in the Doppler signal from the mitral jet. Provided the angle between the ultrasound beam and the maximum velocity is close to zero the pressure drop can be calculated directly. Good correlation was found between Doppler measurements and simultaneous pressure recordings during heart catheterisation in 10 patients. No false negative or false positive diagnoses of mitral stenosis were made among 55 patients (35 patients with mitral stenosis and 20 patients with other valve lesions). The measurements were easy to perform in most patients and the method seems well suited both to diagnose and to follow patients with mitral stenosis.

Aged↗
PubMed1977

Studies on digitalis. XIII. A prospective study of 649 patients on maintenance treatment with digitoxin.

In a prospective study of digitalis intoxication in 649 patients on maintenance treatment with digitoxin a low incidence of digitalis toxicity was found, namely, 5.8 per cent. This is mainly due to a more careful use to digitalis glycosides. It is especially important to reduce the dose of digitoxin in the liver and partly excreted metabolized in the liver and partly excreted through the kidneys as metabolities. Serum half-time of digitoxin is shortened in patients with impaired renal function. Patients with reduced renal function may be treated with digitoxin in the same doses as individuals with normal renal function. This is in contrast to patients treated with digoxin. Digitoxin should therefore be the cardiac glycoside of choice in treatment of patients with renal failure. Digitoxin is further rapidly eliminated in patients with reduced liver function in spite of its extensive hepatic metabolism. In this study extracardia symptoms were found equally often as cardiac signs of toxicity. Patients intoxicated usually had several symptoms and signs of toxicity at the same time. The specificity of commonly used symptoms and signs a digitalis intoxication is very low. In this study atrial tachycardia with block, which has been considered to be an important cardiotoxic arrhythmia, very seldom was found in digitalis intoxication. There is an overlap in digitalis serum concentration between toxic and nontoxic patients. The diagnosis of toxicity was made on clinical grounds. Most of the intoxicated patients had high serum concentrations, but some had concentrations in the normal or low range. Apart from being a guide to the diagnosis of digitalis intoxication, serum digitalis levels may further be a guide to underdigitalization of cardiac patients, especially patients in sinus rhythm.

Age Factors↗
PubMed1977

Diagnosis of valvular heart disease using transcutaneous Doppler ultrasound.

An ultrasonic Doppler instrument capable of measuring mean and maximum velocities inside a small sample volume is presented. The instrument has been used for determining velocities in normal and diseased heart valves. A method is described for identifying the different heart valves, based on their relation to one another as well as the form of the velocity curve. The pressure drop across the mitral valve can be determined from the maximum velocity and the mean velocity can be used to determine the degree of aortic insufficiency. Recordings of mean and maximum velocities can give an indication of the form of the whole spectrum, thus making complete frequency analysis unnecessary for most purposes.

Aorta, Thoracic↗
PubMed1977

Studies on digitalis. XIV. Is there any correlation between hypomagnesemia and digitalis intoxication?

In a prospective study on digitalis intoxication, low serum magnesium was found in 90 patients, while 388 patients had values above 1.5 mEq/l. Hypomagnesemia was more frequent in women than in men, in those with low body weight and in those with advanced heart failure. More patients with hypomagnesemia than those without had nausea, anorexia, fatigue, flickering of vision and atrial tachycardia with block. Patients with hypomagnesemia also had lower serum potassium than normomagnesemic patients. There was, however, no significant difference in the prevalence of digitalis intoxication or in serum digitoxin concentration. Nor was there any correlation between serum digitoxin and serum magnesium levels.

Body Weight↗