Posterior Wall Velocity Research Articles

Metabolic dysfunction in the myocardium three months after exertional heat stroke in mice

In humans, exposure to heat stroke has proven to be a risk factor for development of cardiovascular disease later in life. We hypothesized that exposure to exertional heat stroke (EHS) would result in the development of similar long-term cardiac disease in mice. In this study we followed mice for three months after EHS, using ultrasound imaging of the heart, metabolomics and histological analysis of ventricular tissue and biomarker analysis after 4 weeks of recovery. Methods: Mice were instrumented with temperature telemetry devices and were trained to run on forced running wheels using an incremental exercise protocol. EHS mice ran in an temperature elevated environmental chamber; females 37.5°C; males 34°C; whereas, matched exercise control mice (EXC) ran in 22-23°C. Running stopped when EHS mice reached symptom limitation (unconsciousness). The mice were followed for 12 wks post EHS, with two ultrasound measures at 2 and 10 wks of recovery. At the end of the study, mice were anesthetized, a blood sample drawn, and ventricular tissue collected for metabolomics. RESULTS: Male but not female EHS mice gained ~10% greater body mass compared to EXC over the course of recovery ( P<0.01). Hearts from male but not female EHS mice exhibited elevations in heart mass per tibia length ( P<0.01). At three months, metabolomics in male EHS hearts revealed significant elevations in glucose and glucose metabolites and significant decreases in acylcarnitines consistent with a metabolic shift toward glucose and away from lipid metabolism. In contrast, female hearts exhibited fewer abnormalities but with significant elevations in lipid and arachidonate metabolites. At two weeks post, there were no differences in male ultrasound measures between EHS and EXC mice but in females there was a reduced posterior wall velocity ( P=0.012) and a trend towards narrower posterior wall thickness ( P= 0.06) . Between 2 and 12 wks post EHS, there were significant elevations in fractional shortening in males ( P<0.05) and elevations in posterior wall velocity ( P<0.01). In contrast, females exhibited significant reductions posterior wall velocity. From blood samples, male EHS mice had increased HDL and females exhibited decreased HDL (p<0.01 in both). LDL increased only in males P<0.05. Vascular adhesion molecules sICAM ( P<0.01) and Pecam1 ( P<0.01) were significantly decreased in EHS males and females and e-Selectin was decreased in EHS males only ( P<0.001). Total serum protein was significantly reduced in both male and females ( P<0.01). Male EHS mice also exhibited significant elevations in white blood cell count and total lymphocytes ( P=0.01) suggesting ongoing activation of the immune system . CONCLUSIONS: In this controlled preclinical model of EHS, both male and female mice exhibited long-lasting cardiovascular and systemic disorders that could account for the lingering incidence of cardiovascular disease and poor overall health in heat stroke victims. Supported by US Army Med. Research and Devel. Command BA180078 and the BK and Betty Stevens Endowment. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

“Pure” diastolic dysfunction is associated with long‐axis systolic dysfunction. Implications for the diagnosis and classification of heart failure

To investigate regional systolic function of the left ventricle, to test the hypothesis that "pure" diastolic dysfunction (impaired global diastolic filling, with a preserved ejection fraction > or = 50%) is associated with longitudinal systolic dysfunction. One hundred thirty subjects (31 patients with asymptomatic diastolic dysfunction, 30 with diastolic heart failure, 30 with systolic heart failure; and 39 age-matched normal volunteers) were studied by conventional and tissue Doppler echocardiography. Global diastolic function was assessed using the flow propagation velocity, and by estimating left ventricular filling pressure from the ratio of transmitral E and mitral annular E(TDE) velocities (E/E(TDE)); and global systolic function by measurement of ejection fraction. Radial and longitudinal functions were assessed separately from posterior wall and mitral annular velocities. Global and radial systolic function were similar in patients with "pure" diastolic dysfunction and normal subjects, but patients with either asymptomatic diastolic dysfunction or diastolic heart failure had impaired longitudinal systolic function (mean velocities: 8.0+/-1.2 and 7.7+/-1.5 cm/s, respectively, versus 10.1+/-1.5 cm/s in controls; p<0.001). In subjects with normal ejection fraction, global diastolic function correlated with longitudinal systolic function (r=0.56 for flow propagation velocity, and r=-0.53 for E/E(TDE) ratio, both p<0.001), but not with global systolic function. Worsening global diastolic dysfunction of the left ventricle is associated with a progressive decline in longitudinal systolic function. Diastolic heart failure as conventionally diagnosed is associated with regional, subendocardial systolic dysfunction that can be revealed by tissue Doppler of long-axis shortening. Diagnostic algorithms and definitions of heart failure need to be revised.

Alteration of antioxidants during the progression of heart disease in streptozotocin-induced diabetic rats

Involvement of oxidative stress is implicated in the progression of complication of diabetes mellitus. With respect to heart diseases, we have studied role of oxidative stress/antioxidants using rats treated with streptozotocin to induce diabetes (DM). Hemodynamic and echocardiographic measurements showed thickening of the wall and an increase in the internal dimension of the left ventricle (LV) in DM rats at 8th week. Decrease in diastolic posterior wall velocity and rate of LV pressure change, and increase in LV end diastolic pressures also proved cardiac dysfunction. These changes were further developed in DM rats after 12 weeks. Utilizing rat hearts at 8th and 12th weeks, the following estimations were performed. There was a decrease in the activity of Mn-superoxide dismutase (SOD), suggesting abnormal mitochondrial metabolism of reactive oxygen species. The level of glutathione (GSH) decreased concomitant with a decrease in the expression of γ-glutamylcysteine synthetase (γ-GCS). The expression of transforming growth factor-β1 (TGF-β1), known as a growth factor and a suppressor of GSH synthesis, elevated in DM rat hearts. Immunohistochemical estimation showed an increase in type IV collagen in DM hearts. Collectively, it was suggested a linkage between mitochondrial damage to generate reactive oxygen species and inactivation of Mn-SOD and elevation of the expression of TGF-β1 to lead suppression of GSH synthesis and induction of fibrous change for the consequent cardiac dysfunction in DM.

Pre-ejectional left ventricular wall motions studied on conscious dogs using Doppler myocardial imaging: relationships with indices of left ventricular function

Duration of the pre-ejection period is a sensitive index of myocardial function. Our purpose was to document normal pre-ejectional left ventricular (LV) wall motions at rest and under dobutamine using Doppler myocardial imaging (DMI), and to correlate posterior wall velocities with indices of LV systolic function. M-mode recordings of both walls were imaged on eight conscious dogs chronically instrumented. Subendocardial pre-ejectional velocities were digitized and measured every 3.8 ms. DMI analysis consisted of sign recognition, velocity measurement, duration and timing from the Q wave of the electrocardiogram. Isovolumic contraction time (Ict) was represented by the time interval from onset to peak of the first derivative of LV pressure. Conventional Doppler labelling of velocity signs, positive toward and negative away from the transducer, was applied to the direction of encoded wall motions. For physiological understanding, wall motions of both walls were also labelled inward and outward with respect to the left ventricular cavity center. In each wall, PEP was shown as several colored strips, each strip representing the period of time that the wall was moving in one direction. Changes in velocity sign corresponding to changes in direction of motion were opposed in each wall (p < 0.001), featuring successive inward and outward wall motions. There was a markedly sustained inward motion during Ict. Its velocity amplitude increased with dobutamine. There was a positive correlation between velocities of the inward motion contemporaneous of Ict and ejection fraction (r = 0.72, p < 0.003). Values of Ict respectively drawn from DMI and from hemodynamics were also significantly correlated (r = 0.85, p < 0.007). Thus, the inward motion evidenced by DMI during Ict appears promising to assess myocardial function and effect of drugs.

Myocardial wall velocity assessment by pulsed Doppler tissue imaging: Characteristic findings in normal subjects

To validate the use of pulsed Doppler tissue imaging that measures myocardial wall velocities and to define the characteristics of these velocities in normal subjects, we obtained and compared the anteroseptal and posterior wall velocities in 24 volunteers with pulsed Doppler tissue imaging and digitized M-mode echocardiography. We also studied the relation between velocity components and hemodynamic events timed by standard Doppler flows. There was an excellent correlation between Doppler and M-mode-derived velocities ( r = 0.95, p < 0.001), with higher reproducibility for Doppler ( r = 0.99) than for M-mode ( r = 0.95, p < 0.001). Biphasic velocities that were uniformly present during isovolumic contraction and relaxation were attributed to geometric changes due to asynchronous contraction and ventricular interdependence. We conclude that wall velocities obtained by pulsed Doppler tissue imaging are accurate and reproducible. This method may prove useful for studying the contractile and elastic properties of the myocardium.

Color-coded measures of myocardial velocity throughout the cardiac cycle by tissue Doppler imaging to quantify regional left ventricular function

TDI is a new echocardiographic technique that calculates and displays color-coded myocardial velocity on-line. To determine the feasibility of endocardial velocity throughout the cardiac cycle as a means to quantify regional function, 20 normal subjects aged 30 ± 5 years and 12 patients with heart disease aged 62 ± 17 years were studied with a prototype TDI system. TDI M-mode images were acquired by using a multicolored velocity map (display range, −30 to 30 mm/sec; temporal resolution, 90 Hz). Color-coded velocity data were then converted to numeric values off-line at 50 msec intervals. Posterior wall velocities throughout the cardiac cycle by TDI were closely correlated with velocity calculations from the first derivative of routine digitized M-mode tracings (group mean r = 0.88 ± 0.03, SEE = 7.0 ± 1.1 mm/sec). Anteroseptal TDI color-coded systolic velocity occurred 164 ± 84 msec from the onset of the electrocardiographic QRS compared with 203 ± 33 msec in the posterior wall ( p < 0.05) in normal subjects, consistent with normal electrical activation. Significant differences in systolic and diastolic posterior wall TDI velocity data were observed in patients with hypokinetic or akinetic segments assessed by independent routine study when compared with normal controls. Calculated systolic and early diastolic posterior wall TDI indexes correlated significantly with percentage of wall thickening. Of abnormal anteroseptal segments, TDI systolic time velocity integrals were significantly different than normal and correlated with percentage of wall thickening. TDI has potential to quantitatively assess regional left ventricular function.

Evaluation of Left Ventricular Diastolic Function by Measurement of Posterior Myocardial Wall Velocity

Evaluation of Left Ventricular Diastolic Function by Measurement of Posterior Myocardial Wall Velocity

774-5 Effect of Cardiac Translation on Measurement of Left Ventricular Wall Velocities: Implications for Doppler Imaging of Myocardium

Doppler imaging of the myocardium is a new application which has the potential to record myocardial velocities. These recorded velocities, however, include cardiac motion independent of ventricular contraction. A measured myocardial velocity, therefore, represents the net vector of contraction, translation, and rotation. To determine the effects of cardiac translation on myocardial velocities, 2-dimensional (2D) and M-mode echocardiographic recordings were obtained in 10 normal subjects. The average anteroseptal (AS) and posterior wall (PW) velocities were measured by 2D echo directed M-mode in the centerline of the parasternal short-axis view. Translation was measured from 2D echo cine-loop display as the displacement of the epicardial junction of the right ventricular free wall and interventricular septum during systole. The average translational velocity is reported as the component of the displacement vector parallel to the M-mode beam (+ = toward transducer). The AS and PW velocities (cm/sec) displayed in the table represent net measured velocities, which include the translational vector. AS PW Translation Mean ± SD 3.2 ± 0.5 4.5 ± 1.1 +1.3 ± 0.6 Range 2.4 to 4.0 3.4 to 6.9 -l.4 to + 2.4 In 8/10 subjects the velocity vector was positive. The mean percent error in the M-mode derived velocities due to translation was 41% for the AS wall and 31% for the PW. 1) As measured by 2D echocardiography, the magnitude of the translational vector is significant when compared to the M-mode derived myocardial velocities. 2) The relative error demonstrated in the measured velocities may be further modified when applied in two dimensions, due to the angle of incidence of the Doppler beam. 3) New techniques for measuring myocardial velocities, such as Doppler imaging of the myocardium, should incorporate algorithms which correct for the translational vector.

Abnormal signal‐averaged electrocardiogram in patients with duchenne muscular dystrophy: Comparison of time and frequency domain analyses from the signal‐averaged electrocardiogram

The clinical significance of an abnormal signal-averaged electrocardiogram (SA-ECG) in time- and frequency-domain analyses was assessed in patients with Duchenne muscular dystrophy (DMD). Twenty-four DMD patients and 20 age-matched healthy volunteers were studied. The SA-ECG was recorded by time-domain signal processing using the vector-magnitude method and frequency-domain signal processing using the fast-Fourier transform. Abnormal SA-ECGs were based on comparison with controls and eight abnormal SA-ECGs were detected among 24 DMD patients, seven by frequency-domain analysis and four by time-domain analysis. The end-diastolic left ventricular volume was larger in the patients with abnormal SA-ECG than in those with normal SA-ECG (136 +/- 32 ml vs. 77 +/- 43 ml, p < 0.01). Compared with patients with normal SA-ECGs, the DMD patients with abnormal SA-ECGs had a lower left ventricular (LV) ejection fraction (54 +/- 6 vs. 61 +/- 8%, p < 0.05), as an index of LV contractility, and less LV posterior wall velocity (46 +/- 9 mm/min vs. 62 +/- 16 mm/min, p < 0.01), as an index of LV relaxation. The sensitivity and specificity of frequency-domain analysis for predicting malignant ventricular arrhythmias was 60 and 85%, respectively, compared with 30 and 92%, respectively, for time-domain analysis. The combination of time- and frequency-domain analyses can facilitate identification of DMD patients with ventricular tachyarrhythmias associated with depression of cardiac performance.

Depressed systolic and diastolic cardiac function after prolonged aerobic exercise in healthy subjects.

We studied 11 healthy untrained volunteers (aged 28.9 +/- 4.6 years) during 60 minutes of aerobic ergometric exercise with constant heart rates of 130 to 140 beats/minute. We found a continuous and significant decrease in systolic and diastolic pressure from 175 +/- 18/77 +/- 7 mmHg in the 5th minute to 144 +/- 14/68 +/- 6 mmHg in the 60th minute of exercise. Cardiac function and structure were assessed by M-mode echocardiography before exercise, after 5 minutes and after 60 minutes of exercise at comparable heart rates. The results demonstrated significant decreases in cardiac output, ejection fraction, and diastolic posterior wall velocity and an increase in total peripheral resistance after 60 minutes of exercise. We conclude that the decrease in blood pressure during long-term aerobic exercise in healthy untrained subjects might be at least influenced by a decrease in left ventricular filling and contractility, possibly indicating cardiac fatigue.

Left Ventricular Excursions and Velocities During Coronary Arterial Ligation. Effects of Nitroglycerin Infusion in an Experimental Model

To determine the effects of intravenous nitroglycerin on the velocities and excursions of the acutely ischemic myocardium, 20 open-chest dogs were studied by use of ultrasound. In 10 dogs with acute septal ischemia, the posterior wall excursion during contraction (B-C excursion), the mean systolic posterior wall velocity, and the posterior wall excursion remained unaltered. Nitroglycerin, however, increased all these parameters (P less than 0.01). In 10 dogs with acute posterior wall ischemia the B-C excursion (aneurysmal bulging) increased (P less than 0.01), but the mean systolic posterior wall velocity and posterior wall excursion decreased (P less than 0.01). Nitroglycerin increased even more the aneurysmal bulging (P less than 0.01) and the other parameters (P less than 0.01). Increased regional blood flow, reduced afterload, and mechanical pulling of the ischemic myocardium seem to be a possible mechanism. The measurements were obtained using the recently described method of the specific points.

Effects of Nitroglycerin on Myocardial Excursions and Velocities in the Early Hours of Acute Myocardial Infarction

The effects of sublingual nitroglycerin on septal and left ventricular wall motion were determined by echocardiography in the early hours of acute myocardial infarction (MI) in 20 patients admitted via a mobile coronary care unit. Left ventricular and septal echoes were obtained in 11 patients with acute anterior MI and in 9 with acute inferior MI before and after administration of 500 micrograms sublingual nitroglycerin. In the group with acute anterior MI, nitroglycerin did not significantly affect the B-C excursion, posterior wall excursion, and mean posterior wall velocity. Nitroglycerin significantly increased (P less than 0.01), however, the systolic septal excursion, systolic septal velocity, diastolic septal excursion, and diastolic septal velocity. In the group with acute inferior MI, nitroglycerin significantly increased the B-C excursion (P less than 0.01); posterior wall excursion (P less than 0.01); mean posterior wall velocity (P less than 0.01); systolic septal excursion (P less than 0.01); diastolic septal excursion (P less than 0.05), and diastolic septal velocity (P = 0.01) but did not affect the systolic septal velocity. All measurements were obtained by use of a method of labeling and describing specific points of the wall motion that has been described recently.

Systolic and diastolic septal and posterior wall echocardiographic measurements in normal subjects.

M-mode echocardiographic measurement of septal and left ventricular excursions and velocities was attempted in 109 subjects. Seventy subjects had adequate echocardiograms enabling detailed measurement. Two groups of subjects were studied: a group of normal adults aged nineteen to seventy-eight years and a group of normal juveniles aged nine to eighteen years. The posterior wall excursion (PWE), systolic septal excursion (SSE), diastolic septal excursion (DSE), and diastolic septal velocity (DSV) did not differ in these groups. There were significant differences in the posterior wall excursion during isovolumetric contraction (B-Ce, p less than 0.002), mean posterior wall velocity (PWV mean, p less than 0.002), and systolic septal velocity (SSV, p = 0.05) between the two groups. The measurements were obtained by using the recently published method of the specific points for labeling and description of the wall motion.

Effects of chronic atenolol therapy on cardiovascular response to isometric exercise in essential hypertension.

Cardiovascular response to 2 min of isometric handgrip exercise at 50% of maximum voluntary contraction was studied echocardiographically in 10 essential hypertensives, before and during treatment with atenolol for a mean of 2 months. The patients responded with increases in heart rate, systolic and diastolic blood pressures, cardiac output and calculated triple product, no changes in stroke volume and total peripheral resistance, and decreases in ejection fraction, mean velocity of circumferential shortening and mean diastolic posterior wall velocity of the left ventricle before treatment. Chronic atenolol therapy attenuated the increases in heart rate, blood pressure and triple product, and the decreases in ejection fraction, mean velocity of circumferential shortening and mean diastolic posterior wall velocity of the left ventricle but resulted in a marked increase in total peripheral resistance. The pressure response and triple product rise in response to isometric handgrip exercise were also decreased. This suggests an obvious advantage to hypertensive patients who may, therefore, be protected from the risk of cardiovascular complications following isometric exercise.

An echocardiographic study of cardiac function in chronic hemodialysis patients

Echocardiography was studied in 83 uremic patients on maintenance hemodialysis and 18 normal subjects. Cardiac systolic and diastolic functions were evaluated according to Yamaguchi's method. Systolic functions such as ejection fraction and fractional shortening decreased in the patients receiving hemodialysis for less than 3 months. However, they remained within normal range in the patients under hemodialysis for more than 3 months. There were no significant correlations between systolic functions and mean blood pressure or various serum biochemical parameters such as urea nitrogen, creatinine, Na, K, Ca, P, hematocrit and PTH-C. Diastolic functions such as rapid filling rate/endosystolic volume, mean velocity of circumferential fiber lengthening during rapid filling, diastolic descent rate and diastolic posterior wall velocity also decreased in the patients receiving hemodialysis for less than 3 months. However, they increased slightly in the patients under hemodialysis for more than 3 months, although they were still lower than those in normal subjects. They were not related to mean blood pressure or various serum biochemical parameters. Hemodialysis patients had left ventricular hypertrophy regardless of duration of hemodialysis. Diastolic dysfunction in hemodialysis patients seemed to be due to systolic dysfunction, left ventricular hypertrophy and diminished ventricular compliance with myocardial degeneration. It was also suggested that increasing slow filling and atrial contraction in diastole might be related to diastolic dysfunction. These cardiac changes may be compensatory reactions of cardiac muscle to various uremic environments such as anemia, hypertension, fluid retention, electrolytes disturbance or uremic toxins.

Clinical features and cardiopulmonary function of patients with atrophic heart in duchenne muscular dystrophy.

The clinical features and cardiopulmonary function of 5 patients with atrophic heart in Duchenne muscular dystrophy (DMD) were studied by echocardiography and spirometry. Atrophic heart was defined as a state where the left ventricular end-diastolic volume decreased markedly during long-term follow-up (over 5 years). The patients with atrophic heart were more emaciated and showed more severe motor disability than the controls (18 DMD patients with a normal left ventricular cavity size). The pre-ejection period/ejection time ratio was significantly higher in patients with atrophic heart than in controls, and the maximal diastolic posterior wall velocity was reduced. The forced vital capacity was lower in patients with atrophic heart than in controls, but the one-second forced expiratory volume rate was similar in the 2 groups. Three patients with atrophic heart died. Examination at autopsy showed that their hearts were small and of low weight, and showed not only fibrosis, but also brown atrophy and waxy degeneration. These findings indicate that cardiopulmonary function is significantly reduced in DMD patients with atrophic heart.

136 COMPARISON BETWEEN N MODE AND DIGITIZED ECHOCARDIOGRAPHY IN THE DETECTION OF ANTHRACYCLINE CARDIOTOXICITY

This study compared standard m-mode echo (ME) and digitized echocardiography (DE) to detect anthracycline cardiotoxicity. 25 paediatric patients with leukaemias or solid tumors (13 male), mean age - 10.4 yr. (1.9-15.6) had ME before (PRE), at 200-300 mg/m2 (MID), after maximum dosage (POST) of adriamycin or duanorubicin (mean 2.3 months, 0.3-6.5 m) and compared to 33 age matched normals (NORM). 14 had previous chemotherapy some with cyclophosphamide and/or radiation. Mean follow-up duration was 21.5 months (7.8-33.8 m), mean maximum dose was 409.6 mg/m2 (300-582 mg/m2). None had cardiac failure. Left ventricular (LV) systolic time intervals (STI), shortening fraction (SF), mean velocity of shortening (VCF) were done on ME. Peak LV velocity in systole (PLVS) and diastole (PLVD), normalized L.V. velocity in systole (NLVS) and diastole (NLVD), peak posterior wall velocity in systole (NPWVS) and diastole (NPWVD) and similarly peak and normalized septal velocities (PSVS, PSVD, NSVS and NSVD) were obtained by tracing and digitizing the echo (DE). Bonferroni tests of significance were determined. ME showed a) declining VCF from PRE(1.43) to MID(1.23) and POST(1.2) (p=.0005 & .001) b) declining SF from PRE(36.9) to MID(32.7) to POST (32.0) (p=.0002 & .0014) c)STI's were not useful. DE showed a) greater PLVS for PRE(9.47) than NORM(8.21) (p=.0017) but no sig. fall. b)PRE NLVS(2.83) was greater than NORM(2.54) and fell at POST(2.28) (p=.0000 & .0013) c)PLVD & NLVD were normal. Posterior wall and septal motion in systole and diastole was normal except PRE PPWVD(6.85) was greater than NORM(5.17) and fell to normal at MID. Thus 1)ME is as useful for screening for LV dysfunction as DE, 2)DE showed hyperfunction in some parameters PRE. This did not correlate with age, haemoglobin, fever, heart rate, previous therapy or dose. The aetiology of this apparent hyperfunction is not known.

Contractile reserve of valvular heart diseases echocardiographically evaluated by epinephrine loading before and after cardiac surgery.

In order to evaluate cardiac contractile reserve, echocardiographic studies were performed on 59 patients with acquired valvular heart disease and 13 patients with atrial septal defect. After epinephrine loading, the 59 patients were classified into three groups. In group I, echocardiographically-obtained left ventricular posterior wall excursion (PWE) remained below 10 mm after the administration of 2 microgram/min epinephrine. This group included patients with PWE below 10 mm after 1 microgram/min epinephrine loading but who could not endure the 2 microgram/min infusion because of significant adverse effects. In group II, PWE was less than 10 mm before the loading, but exceeded 10 mm after the administration of 1 or 2 microgram/min epinephrine loading. In group III, PWE exceeded 10 mm without stress. The conclusions derived from our data are as follows: The PWE and mean left ventricular posterior wall velocity (mPWV) obtained by echocardiography reflect the stroke volume derived from the thermodilution technique. It is possible to estimate the cardiac contractile force in patients who have a paradoxical motion of the interventricular septum, in the preoperative and even in the early postoperative periods. Patients whose PWE and mPWV are less than 10 mm and 35 mm/sec, respectively, after 2 microgram/min loading of epinephrine (group I), are likely to have severe cardiac failure after surgery. Inotropic stimulation is considered to be a very useful indicator for prediction of cardiac contractile reserve. Patients having decreased PWE, mPWV, mVcf and EF before surgery may have arrested recovery in both short- or long-term follow-up. However, surgical treatment is recommended for these patients with low cardiac function, because some improvement can be expected after surgery.

Echocardiographic determination of septal and left ventricular wall motion in the early hours of acute myocardial infarction.

Interventricular septal and left ventricular posterior wall excursions and velocities were determined by M-mode echocardiography in the early hours of acute myocardial infarction in 43 patients. In the group with anterior infarction, including 24 patients, the systolic septal excursion (SSE), systolic septal velocity (SSV), diastolic septal excursion (DSE), and diastolic septal velocity(DSV) were decreased (P less than 0.001). The posterior wall excursion during isovolumetric contraction (B-C) and the mean systolic posterior wall velocity (PWVmean) were also decreased (P less than 0.02). The posterior wall excursion during ejection (PWE) was not affected significantly. In the group with inferior infarction, including 19 patients, the B-C excursion was not significantly affected, but the PWE and PWVmean were diminished (P less than 0.001). The opposing healthy interventricular septum showed an increased movement-compensatory hyperactivity. These findings indicate that the acute myocardial ischemia which grossly affects the mobility of the myocardium can be detected and determined in the early hours by M-mode echocardiography.

SERIAL EVALUATION OF CARDIAC FUNCTION IN CHILDREN UNDERGOING DIALYSIS

Serial echocardiographic (echo) evaluation of cardiac performance in children undergoing chronic dialysis is currently not feasible due to significant dialysis induced changes of heart rate (HR), preload and afterload which alter selected echo indices in the absence of true dysfunction. To eliminate this problem the effect of the independent variables heart rate (HR), preload index (PI) (represented by left ventricular end diastolic dimension (LVED)/a matched control LVED) and afterload (represented by a simultaneously recorded aortic diastolic pressure (DP)) upon pre-ejection period (PEP), ejection time (ET), PEP/ET, shortening fraction (SF), mean circumferential fiber shortening (Vcf), isovolumic contraction time (ICT), maximum posterior wall velocity (PWV) and cardiac output (CO) was evaluated on 92 echograms obtained from four children undergoing chronic dialysis. Multiple linear regression analysis of the data was performed for each patient and for the entire group in order to express each echo index as a function of HR, DP, and PI. Few significant regressions were obtained for the group as a whole but were obtained (r>0.77,P<0.05) in all individuals for ET, CO, and SVR; in three for Vcf and PEP/ET; in one for ICT and SF but in none for PEP. For each echo index except CO, the independent variables differed among children. We conclude that these regressions should significantly improve the ability to interpret selected echo indices in some patients with frequent alterations of HR, preload, and afterload.