Biomedical subjects

L K Hatle

Publications and source records attributed to L K Hatle.

33 records · Page 2Linked to original sources

PubMed1989

Assessment of diastolic function of the heart: background and current applications of Doppler echocardiography. Part I. Physiologic and pathophysiologic features.

In the past, evaluation of the myocardium has been limited to examining systolic function of the heart. Recently, however, investigators have demonstrated that abnormalities of diastolic function of the heart provide important contributions to the signs and symptoms experienced by patients with heart disease. In addition, abnormalities of diastolic function may precede abnormalities of systolic function in the early stages of disease. Diastolic filling of the heart, however, is a complex sequence of interrelated events. In order to understand diastolic function, each of these factors contributing to filling of the heart must be examined. They include relaxation, passive compliance, atrial contraction, erectile effect of the coronary arteries, viscoelastic properties, ventricular interaction, and pericardial restraint--all of which are interrelated. In addition, diastolic factors are affected by changes in loading conditions and contractility, and they demonstrate nonuniformity in time and space. This report provides an overview of these various factors from the clinical perspective, based on studies involving the isolated papillary muscle and the isolated heart as well as basic clinical studies.

Animals↗

PubMed1989

Assessment of diastolic function of the heart: background and current applications of Doppler echocardiography. Part II. Clinical studies.

Evaluation of diastolic filling of the heart has been difficult because of its complexity and the numerous interrelated contributing factors. Previous determinations have depended on high-fidelity, invasive measurements of instantaneous pressure, volume, mass, and wall stress, which could not be done on a routine clinical basis. With the advent of Doppler echocardiography, intracardiac blood flow velocities can now be noninvasively assessed. For application of this technique to evaluation of diastolic function in patients with heart disease, it is necessary to understand what the Doppler-derived variables represent. It is also necessary to know how they are affected by changes in loading conditions and changes in myocardial relaxation. In this review, we provide an interpretation of the mitral valve, tricuspid valve, and systemic and pulmonary venous inflow velocities in the normal patient and in various disease states.

Blood Flow Velocity↗

PubMed1989

A hemodynamic and Doppler echocardiographic study of ventricular function in long-term cardiac allograft recipients. Etiology and prognosis of restrictive-constrictive physiology.

Conventional hemodynamic measurements and Doppler echocardiography were used to assess ventricular physiology of the human cardiac allograft and to examine the influence of pertinent clinical factors on chronic myocardial performance. Sixty-four patients (18-55 years old; mean, 39 years) undergoing routine annual hemodynamic assessment were studied. Blood-flow velocity properties across the mitral, tricuspid, and aortic valves were analyzed from Doppler ultrasound recordings. Ten of these patients had elevated diastolic pressures associated with a sharp early diastolic dip followed by an exaggerated and abrupt rise in pressure, consistent with restrictive-constrictive ventricular physiology. Left ventricular dP/dt and stroke volume were lower in these patients compared with the other 54 patients. Doppler echocardiographic indexes of left ventricular filling and ejection in these 10 patients differed significantly. Isovolumic relaxation time and pressure half-time were shorter, peak early mitral and tricuspid flow velocities were higher, and mean aortic flow velocity and acceleration were lower. A higher rejection incidence was the only demonstrable clinical factor associated with impaired ventricular function. Doppler echocardiography may, therefore, noninvasively identify patients with hemodynamic evidence of restrictive-constrictive physiology. This abnormality occurs in approximately 15% of allograft recipients, is associated with impaired systolic performance, and may be related to rejection incidence.

Adolescent↗

PubMed1989

Differentiation of constrictive pericarditis and restrictive cardiomyopathy by Doppler echocardiography.

Doppler ultrasound recordings of mitral, tricuspid, aortic, and pulmonary flow velocities, and their variation with respiration, were recorded in 12 patients with a restrictive cardiomyopathy and seven patients with constrictive pericarditis. Twenty healthy adults served as controls. The patients with constrictive pericarditis showed marked changes in left ventricular isovolumic relaxation time and in early mitral and tricuspid flow velocities at the onset of inspiration and expiration. These changes disappeared after pericardiectomy and were not seen in patients with restrictive cardiomyopathy or in normal subjects. The deceleration time of early mitral and tricuspid flow velocity was shorter than normal in both groups, indicating an early cessation of ventricular filling, but only patients with restrictive cardiomyopathy showed a further shortening of the tricuspid deceleration time with inspiration. Diastolic mitral and tricuspid regurgitation was also more common in the patients with restrictive cardiomyopathy. These results suggest that patients with constrictive pericarditis and restrictive cardiomyopathy can be differentiated by comparing respiratory changes in transvalvular flow velocities. In addition, although baseline hemodynamics in the two groups were similar, characteristic changes were seen with respiration that suggest differentiation of these disease states may also be possible from hemodynamic data.

Adult↗

PubMed1988

Diastolic mitral and tricuspid regurgitation by Doppler echocardiography in patients with atrioventricular block: new insight into the mechanism of atrioventricular valve closure.

The purpose of this study was to prospectively determine the incidence of diastolic mitral and tricuspid regurgitation in atrioventricular (AV) block using Doppler echocardiography. The temporal relation between mitral and tricuspid diastolic insufficiency and the diastolic murmur recorded in patients with complete heart block was also investigated. Twenty-two consecutive patients with AV block (referred to the Echo-Doppler laboratory for routine clinical studies), aged 18 to 87 years, were enrolled in the study. Eleven patients had third degree AV block and a ventricular-inhibited (VVI) pacemaker, two patients had second degree AV block, seven patients had first degree AV block, one patient had blocked premature atrial complexes and one patient had atrial flutter with 4:1 AV block. Diastolic mitral regurgitation was detected in 20 patients, and diastolic tricuspid regurgitation in 21. A mid-diastolic murmur was detected in all patients except in the three youngest. The murmur occurred before diastolic regurgitation and coincided with peak forward flow through the AV valve after atrial contraction. M-mode mitral valve echocardiograms obtained in nine patients demonstrated near closure of some portions of the mitral valve after atrial contraction. Effective closure of the valve, however, did not occur unless ventricular systole supervened. In conclusion, diastolic mitral and tricuspid regurgitation are almost universally present in patients with AV block and are associated with a diastolic murmur. The murmur coincides with forward AV valve flow. Diastolic regurgitation is silent. Effective AV valve closure is not established until ventricular systole occurs, as demonstrated by M-mode echocardiographic recording of the mitral valve.

Adult↗

PubMed1988

Doppler echocardiographic determination of the pressure gradient in hypertrophic cardiomyopathy.

The continuous wave Doppler ultrasound signal across the left ventricular outflow tract in hypertrophic cardiomyopathy has a characteristic pattern that is in keeping with the dynamic nature of the pressure gradient in this condition. To determine the accuracy and reliability of the peak Doppler flow velocity signal for measuring the peak pressure gradient in this condition, 340 beats were analyzed from five consecutive patients studied with simultaneous continuous wave Doppler ultrasound and dual catheter pressure recordings across the left ventricular outflow tract. Each patient was studied at steady state and during physiologic and pharmacologic manipulations of the pressure gradient. Peak velocity and calculated peak gradient were determined by two independent observers who did not know the catheter measurements. In addition, 18 beats with well defined flow velocity envelopes were digitized for analysis of the magnitude, timing and contour of the instantaneous Doppler ultrasound and catheter gradients throughout systole. Peak catheter gradient in the 340 beats ranged from 12 to 245 mm Hg. The correlations between the Doppler-derived and catheter peak gradients were close (r = 0.96, SEE = 4 mm Hg for Observer 1 and r = 0.97, SEE = 11 mm Hg for Observer 2). Interobserver variability for measurement of peak flow velocity was small (mean +/- SD 0.16 +/- 0.15 m/s). An interobserver difference greater than 0.3 m/s occurred in 25 of the 340 beats analyzed. By retrospective analysis, this was due to contamination of the outflow tract signal by mitral regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

Demonstration of restrictive ventricular physiology by Doppler echocardiography.

In patients with restriction of cardiac filling of various origins, cardiac catheterization has been traditionally used as part of the diagnostic evaluation to verify the presence of restrictive/constrictive hemodynamics. In an attempt to determine whether this "restrictive" physiology could be demonstrated noninvasively, 14 patients who had a history, physical examination, two-dimensional echocardiogram and catheterization data compatible with a restrictive myocardial process were studied with pulsed wave Doppler ultrasound. Forty normal subjects served as a control group. The Doppler ultrasound evaluation included measurement of peak mitral and tricuspid flow velocities and flow velocity integrals, mitral and tricuspid deceleration times and central venous flow patterns during apnea and inspiration. The flow velocity recordings across the mitral and tricuspid valves in patients manifesting restriction were markedly different from those in normal subjects, showing shortened deceleration times across both valves, which indicated both an abrupt premature cessation of ventricular filling and the presence of a diastolic dip-plateau contour in ventricular pressure recordings. In addition, abnormal central venous flow velocity reversals with inspiration and diastolic mitral and tricuspid regurgitation were frequently observed, also suggesting the reduced myocardial compliance characteristic of a restrictive myocardial process.

Adult↗

PubMed1988

Doppler echocardiographic observations during percutaneous aortic balloon valvuloplasty.

To evaluate the hemodynamic changes occurring with percutaneous aortic balloon valvuloplasty for aortic stenosis, Doppler echocardiography was performed during the procedure in 16 patients. During balloon inflation, peak velocity and ejection time of the aortic valve systolic signals increased (26 and 30%, respectively; p less than 0.001). Aortic regurgitation deceleration time decreased from 1,337 to 625 ms (p less than 0.001). In three patients, aortic regurgitation stopped before end-diastole; in four patients, end-diastole forward flow across the aortic valve was documented. The deceleration time of the mitral valve inflow signal decreased from 303 to 194 ms (p less than 0.001) during balloon inflation, concurrently with an increase in left ventricular diastolic pressure. Mitral regurgitation signals became more prominent during inflation in 10 patients. Changes that occur during balloon inflation in the aortic valve include progressive left ventricular outflow obstruction, equalization of diastolic aortic and left ventricular pressures and changes in diastolic compliance.

Aged↗

PubMed1988

Relation of transmitral flow velocity patterns to left ventricular diastolic function: new insights from a combined hemodynamic and Doppler echocardiographic study.

In an effort to determine what clinically useful information regarding left ventricular diastolic function can be inferred noninvasively with pulsed wave Doppler echocardiography, mitral flow velocity patterns and measured variables were correlated with hemodynamic findings in 70 patients: 30 with coronary artery disease, 20 with idiopathic congestive cardiomyopathy, 14 with a restrictive myocardial process and 6 without significant cardiac disease. The effect of sudden changes in hemodynamics on the mitral flow velocity pattern was also investigated in a subgroup of patients who had simultaneous recording of mitral flow velocity and left ventricular pressure before and after left ventriculography. Mitral flow velocity recordings from 30 healthy adults served as a reference group. This analysis suggests that 1) the majority of patients with these cardiac disorders demonstrate abnormal mitral flow velocity patterns or variables; 2) markedly different flow velocity patterns can be seen in patients with impaired left ventricular relaxation; 3) the different mitral patterns appear to relate more to myocardial function and hemodynamic status than to the type of disease process present; 4) certain mitral patterns suggest different filling pressures and rates of early diastolic left ventricular filling; 5) an increase in left atrial pressure can "normalize" an abnormal mitral flow velocity pattern and "mask" a left ventricular relaxation abnormality; and 6) the different patterns appear to represent a dynamic continuum with the potential to change from one to another as a result of disease progression, medical therapy or sudden changes in hemodynamics. It is concluded that, despite the indirect method of estimation and certain limitations, mitral flow velocity recordings have clinical potential in assessing left ventricular diastolic function that merits further investigation.

Adult↗

PubMed1988

Cardiac tamponade and pericardial effusion: respiratory variation in transvalvular flow velocities studied by Doppler echocardiography.

Cardiac tamponade has been associated with an abnormally increased respiratory variation in transvalvular blood flow velocities. To determine whether this finding is consistently present in cardiac tamponade, seven patients were studied prospectively with Doppler echocardiography before and after pericardiocentesis and the results were compared with those found in 20 normal adults and 14 asymptomatic patients with pericardial effusion who did not have definite clinical evidence of tamponade. Doppler ultrasound evaluation included measurement of mitral, tricuspid, aortic, pulmonary and central venous flow velocities, as well as left ventricular ejection and isovolumic relaxation times during inspiration, expiration and apnea. In the patients with severe cardiac tamponade, respiratory variation in transvalvular flow velocities and left ventricular ejection and isovolumic relaxation times were markedly increased compared with values in normal subjects and those obtained after pericardiocentesis. In the 14 asymptomatic patients with pericardial effusion but without overt tamponade, 7 showed respiratory variation in flow velocity similar to that of normal subjects. The other seven patients demonstrated increased respiratory change compared with normal, but less than that in the patients with tamponade. Clinical and hemodynamic data in this latter group suggest that these patients may represent an intermediate stage of pericardial effusion with an element of hemodynamic compromise.

Adult↗

PubMed1987

Influence of recipient atrial contraction on left ventricular filling dynamics of the transplanted heart assessed by Doppler echocardiography.

Recipient atrial remnants retain electrical and mechanical activity after orthotopic cardiac transplantation. This study investigated the influence of recipient atrial contraction timing on Doppler ultrasound mitral flow velocity curves, isovolumic relaxation time, peak early mitral flow velocity (M1), mitral valve pressure half-time and peak mitral flow velocity due to atrial systole (M2). Clearly identifiable recipient atrial electrical activity (P waves) was present in 7 of 10 patients studied early postoperatively 2 to 6 months (mean 2.5) (early group) and in 20 of 24 patients seen 1 to 11 years (mean 3) after transplantation (late group). Median age and gender distribution were similar in both groups. For analysis of its influence on isovolumic relaxation time, pressure half-time and M1, recipient atrial contraction was classified by its position in the cardiac cycle as early systole, late systole or diastole. For analysis of M2, it was classified as early diastole, late diastole or systole. Compared with its occurrence in diastole, recipient atrial contraction in late systole was associated with a shorter isovolumic relaxation time, shorter pressure half-time and higher M1. In early systole it was associated with a longer pressure half-time and lower M1 than in diastole; isovolumic relaxation time was unchanged. Recipient atrial contraction in early diastole resulted in a lower M2 than in systole, whereas simultaneous contraction of recipient and donor atria in late diastole resulted in an increase in M2. These results indicate that the timing of recipient atrial contraction and relaxation significantly influences left ventricular filling dynamics.

Adult↗

PubMed1987

Superior vena cava and hepatic vein Doppler echocardiography in healthy adults.

Pulsed wave Doppler ultrasound recordings of blood flow velocity in the superior vena cava were made in 40 healthy adults (aged 22 to 69 years) during both normal respiration and 10 second episodes of apnea. The forward flow velocity pattern was biphasic, with systolic flow velocity greater than diastolic flow velocity. During apnea, peak flow velocities ranged from 32 to 69 cm/s (mean 45.7 +/- 8.4) during systole and from 6 to 45 cm/s (mean 27.2 +/- 8.3) in early diastole. Systolic flow velocity integrals also exceeded diastolic values. With atrial systole (A wave), forward flow velocities were reduced or flow was reversed. Thirty-nine of 40 subjects had A wave flow reversal during apnea, and in these the ratio of reverse to total forward flow velocity integrals ranged from 1 to 16% (mean 6 +/- 4%). Compared with values during apnea, there were higher mean values with inspiration and lower values with expiration for velocities and flow velocity integrals. Hepatic vein tracings, when adequate (12 of 40 subjects), showed forward flow characteristics similar to those from the superior vena cava, but with more frequent and larger A wave and ventricular end-systole (atrial V wave) flow reversals. Superior vena cava flow velocity variables were calculated in subgroups to assess the effects of age, respiratory pattern and increased venous return. This study defines normal Doppler ultrasound superior vena cava and hepatic vein flow velocities and their variation with respiration in healthy adults. These results can be used for comparison with patterns found in disease states.

Adult↗

PubMed1987

Changes in Doppler echocardiographic indexes of left ventricular function as potential markers of acute cardiac rejection.

Changes in left ventricular filling and ejection as potential markers of cardiac allograft rejection were evaluated by serial Doppler echocardiography performed in 23 normal volunteers and within 24 hr of endomyocardial biopsy in 22 patients aged 14 to 53 years (mean 37). Peak aortic velocity, left ventricular ejection time index (ETI), isovolumic relaxation time (IVRT), mitral valve pressure half-time (PHT), peak early mitral flow velocity (M1), and velocity following donor atrial systole (M2) were measured without prior knowledge of endomyocardial biopsy findings. Biopsy specimens were graded histologically as: no rejection, mild rejection (cellular infiltrate), and moderate rejection (myocyte necrosis). A total of 120 biopsy-correlated Doppler echocardiographic studies were performed during 16 weeks after cardiac transplantation. Heart rate and mean arterial pressure were significantly higher in transplant recipients than in normal subjects. IVRT and PHT were significantly longer, while M1 and M2 were similar. Peak aortic velocity was higher in normal subjects than in transplant recipients, while ejection time was similar. Rejection of increasing severity was associated with a progressive shortening of IVRT and PHT and with an increase in M1 (p less than .0005 for all comparisons). Peak aortic velocity and ejection time index did not change significantly with rejection. These data indicate that acute cardiac rejection is accompanied by alteration in left ventricular filling dynamics detectable by Doppler echocardiography, without measureable changes in systolic function. These changes may provide noninvasive markers for surveillance of rejection.

Acute Disease↗

PubMedDate not supplied

Flow velocity acceleration in the left ventricle: a useful Doppler echocardiographic sign of hemodynamically significant mitral regurgitation.

Doppler echocardiography is a sensitive method to detect mitral regurgitation in patients with both native and prosthetic valves. However, estimates of the amount of mitral regurgitation remain semiquantitative, and even severe mitral regurgitation may be underestimated in the presence of markedly eccentric regurgitant jets or acoustic shadowing of the left atrium by mitral or aortic prostheses. This report describes the Doppler findings in 10 patients with severe native valve mitral regurgitation (angiographic grade III or IV) and in 15 patients with severe bioprosthetic mitral regurgitation that required valve replacement. An increase in peak mitral flow velocity above normal values was seen in eight of 10 patients with severe native valve mitral regurgitation (greater than or equal to 130 cm per second) and 11 of 15 patients with severe prosthetic valve mitral regurgitation (greater than or equal to 210 cm per second). One of 10 patients with a native valve and four of 15 patients with a bioprosthetic valve appeared to have only a localized left atrial systolic flow disturbance, incorrectly suggesting that the mitral regurgitation was mild. However, in all patients with severe mitral regurgitation, a low velocity (less than 100 cm per second) flow signal could be recorded in the left ventricle that was directed toward the mitral valve in systole. This flow signal showed a gradual increase in velocity as the sample volume was moved toward the mitral valve, with an abrupt further increase on entry into the left atrium. This signal was continuous with antegrade mitral flow and had the same orientation as mitral regurgitation recorded by continuous wave technique from the apex. A similar flow signal was not recorded in the left ventricle of any individual in a control group of 30 patients who had no mitral regurgitation or who had angiographic grade I or II mitral regurgitation. These findings suggest that acceleration of left ventricle flow toward the mitral valve in systole is only recorded when there is hemodynamically significant mitral regurgitation that is approximately equal to angiographic grade III or IV. Recognition of this Doppler finding may help in the estimation of mitral regurgitation severity, especially in difficult diagnostic situations.

Aged↗

PubMedDate not supplied

Variability of Doppler echocardiographic indexes of left ventricular filling in transplant recipients and in normal subjects.

This study examines the reproducibility and variability of pulsed wave Doppler versus continuous wave Doppler ultrasound indexes of left ventricular filling in cardiac allograft recipients and in normal subjects. The following indexes were studied: isovolumic relaxation time, pressure half-time, peak early mitral flow velocity, and peak mitral flow velocity after atrial systole. Intraobserver and interobserver variability were assessed by regression analysis. Individual components of variance (subject, reader, beat, day, and tracing) were estimated in a subset of five patients and five normal subjects, and estimated total variance defined for each group. Temporal (day-to-day) variability for 95% confidence was estimated for these patients and for normal subjects. Temporal variability in the group from which the subsets were drawn was measured from absolute and percent change in values on two occasions. Estimated and observed 95% confidence limits were compared. Intersubject variability was the largest component of variance in both transplant recipients and in normal subjects. For all indexes in transplant recipients (in the absence of rejection) and normal subjects, observed absolute mean differences (+/- 2 standard deviations) between values from recordings taken on two different days were larger than the 95% confidence limits estimated from the components of variance analysis. The observed 95% limits for transplant recipients versus normal subjects were as follows: isovolumic relaxation time, 20 msec versus 6 msec; pressure half-time, 16 msec versus 9 msec; peak early mitral flow velocity, 32 cm per second versus 17 cm per second; and peak mitral flow velocity after atrial systole, 28 cm per second versus 10 cm per second.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗