The echocardiographic assessment of pulmonary artery pressure and pulmonary vascular resistance

Echocardiographic changes of cardiac structures and LV function in newborns. A comparative study between normally delivered babies and babies born by caesarian section with regional anaesthesia

Cardiac chamber size and function indices were studied repeatedly over the first months of life in two groups of babies, born either spontaneously or by caesarian section under peridural anaesthesia. For cardiac chamber size, no significant differences were found between the two groups: cardiac structures increased in size as a linear function of age and weight in all babies. Right ventricular systolic time interval ratios, however, were higher at birth in babies born by caesarian section, and dropped more rapidly during the first 24h. The decrease of RV systolic time interval ratios followed a parabolic function for both groups, thus reflecting the physiological decrease of pulmonary vascular resistance after birth. The possible causes of more rapid decrease in pulmonary vascular resistance in babies born by caesarian section is discussed.

Contrast echocardiographic features of pulmonary hypertension and regurgitation

Linear contrast echo configuration on the pulmonary valve M-mode echogram was assessed in 28 patients with pulmonary hypertension, in 10 with pulmonary regurgitation, and in 10 normal subjects. Contrast echo parallel lines filling the total systolic phase of the pulmonary valve were recorded in normal subjects. Contrast echo lines stopping in early systole around the pulmonary valve mid-systolic notch were seen in all the patients with pulmonary hypertension in relation to changes with the pulmonary flow. Contrast echo lines reversing the early diastole and crossing the pulmonary valve echogram during diastole were detected in all the patients with pulmonary regurgitation, consistent with the reversed flow across the valve. The use of contrast echocardiography to diagnose both pulmonary hypertension and regurgitation may provide further useful information, particularly when the orientation and time of appearance of the contrast echo lines are related to the systolic and/or diastolic phases of the pulmonary valve M-mode echogram.

Endocardial fibroelastosis with predominant involvement of left atrium. Possibility of diagnosis by non-invasive methods

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Transient tachypnoea of the newborn: two distinct clinical entities?

Twenty-five infants with transient tachypnoea of the newborn (TTN) were examined by serial echocardiography during the first 4 days of life. The infants could be divided clinically into two groups: group 1 (n = 19) babies with mild classical TTN requiring less than 40% oxygen, and group 2 (n = 6) babies with severe TTN needing greater than 60% oxygen. Apart from amount of oxygen these two groups differed in that those with severe TTN had lower Apgar scores and arterial pH soon after birth. Echocardiography showed that the babies with classical TTN had increased left ventricular pre-ejection period to ejection times (LPEP/LVET) during the first day of life. Initial LPEP/LVET ratio correlated with duration of treatment with oxygen. The babies with severe TTN increased LPEP/LVET and right ventricular pre-ejection period to ejection times ratios (RPEP/ RVET) during the first 3 days of life. There was no correlation between systolic time intervals and duration of oxygen treatment. These findings suggest that there may be two distinct types of TTN: mild or classical type resulting from mild left ventricular failure, and a severe type associated with generalised myocardial failure, pulmonary hypertension, and right-to-left shunting.

Noninvasive radiographic assessment of cardiovascular function in acute and chronic respiratory failure

Noninvasive radiographic techniques have provided a means of studying the natural history and pathogenesis of cardiovascular performance in acute and chronic respiratory failure. Chest radiography, radionuclide angiocardiography and thallium-201 imaging, and M mode and cross-sectional echocardiography have been employed. Each of these techniques has specific uses, attributes and limitations. For example, measurement of descending pulmonary arterial diameters on the plain chest radiograph allows determination of the presence or absence of pulmonary arterial hypertension. Right and left ventricular performance can be evaluated at rest and during exercise using radionuclide angiocardiography. The biventricular response to exercise and to therapeutic interventions also can be assessed with this approach. Evaluation of the pulmonary valve echogram and echocardiographic right ventricular dimensions have been shown to reflect right ventricular hemodynamics and size. Each of these noninvasive techniques has been applied to the study of patients with respiratory failure and has provided important physiologic data.

Two dimensional echocardiographic evaluation of Mustard operation for d- transposition of the great arteries

Two dimensional sector scan echocardiography was used to evaluate the morphologic characteristics of the surgically revised atria in 17 patients with d-transposition of the great arteries who had undergone the Mustard operation. Echocardiographic imaging of the atria was obtained from various planar projections. Dimensional measurements of various segments of the systemic and pulmonary venous atria were obtained in each patient. Correlative hemodynamic, angiographic, postmortem and echocardiographic data showed that seven patients (Group I) had no structural abnormalities of the atria. These 7 patients served as controls for 10 other patients with structural abnormalities of the surgically created atria. One patient (Group II) showed stenosis of the junction of the superior vena cava and systemic venous atrium compared with findings in the control group. Three patients (Group III) had significantly reduced echocardiographic dimensions of the junction of the anterior and posterior segments of the pulmonary venous atrium. Six patients (Group IV) had increased echocardiographic dimensions of all components of the pulmonary venous atrium due to tricuspid regurgitation. These data show that qualitative and quantitative two dimensional sector echocardiography can reliably detect structural abnormalities of the surgically revised atria after the Mustard operation.

Echocardiographic method for the estimation of pulmonary artery pressure in chronic lung disease

The prognostic implications of pulmonary hypertension in chronic lung disease, and the difficulty in establishing its severity without cardiac catheterisation, indicate the need for a reliable non-invasive method of assessing the pulmonary artery pressure. It is likely that the time taken by the right ventricle to generate a sufficiently high pressure to open the pulmonary valve will increase progressively as the pulmonary arterial diastolic pressure rises. Therefore, the time interval between closure of the tricuspid valve and opening of the pulmonary valve has been obtained by high-speed echocardiographic recordings of the tricuspid and pulmonary valves in a group of 17 patients with chronic lung disease. Each patient underwent right heart catheterisation immediately after the echocardiographic examination so that the pulmonary arterial diastolic pressure could be obtained directly. A range for the group from 15 mmHg (2.0 kPa) to 45 mmHg (6.0 kPa) was observed. The linear correlation between the measured diastolic pressure and time interval from the tricuspid valve closure to pulmonary valve opening was highly significant (r = 0.94, p = less than 0.001) and the scatter was relatively small. It is therefore suggested that this time interval, obtained non-invasively by echocardiography, can be used as an index of the severity of pulmonary hypertension associated with chronic lung disease.

Echocardiography in cystic fibrosis: A proposed scoring system

An echocardiographic scoring system was developed on the basis of an observed sequence of echo abnormalities, beginning with RV hypertrophy, through RV dilation, to abnormal RV systolic time intervals, noted to be associated with the progressive pulmonary disease of cystic fibrosis. This score correlated significantly with both the Shwachman-Kulczycki (r = 0.87, P < 0.001) and Taussig-NIH (r = 0.86, P < 0.001) clinical scoring systems, the Brasfield chest roentgenogram score (r = 0.86, P < 0.001), and pulmonary function test results. The scoring of echos appears to be useful for the early detection and systematic quantitation of the cardiac effects of the progressive pulmonary disease. Preliminary sequential echo studies suggest that this system provides a method for assessing the progression of cardiac disease and evaluating prognosis in individual patients, and may prove to be useful in monitoring therapeutic interventions for cor pulmonale.

Noninvasive assessment of pulmonary hypertension from right ventricular isovolumic contraction time

In order to assess a noninvasive method of predicting pulmonary arterial pressure in adults, right ventricular systolic time intervals were determined with echocardiography simultaneously with pulmonary arterial end-diastolic pressure measurements. Right ventricular isovolumic contraction time was measured from echographic recordings of the tricuspid and pulmonary valves. Although this interval was found to increase as pulmonary arterial pressure increased, the method cannot be used to predict quantitatively the level of pulmonary arterial pressure in adults. However, an echocardiographically determined right ventricular contraction time of less than 25 ms suggests a normal pulmonary arterial pressure. In patients with pulmonary parenchymal diseases, echograms of the tricuspid and pulmonary valves are only rarely of such quality as to permit accurate delineation of the valvular events required for these measurements.

Echocardiography in hypoxemic neonatal pulmonary disease

Sixteen newborn infants with severe pulmonary parenchymal disease and profound hypoxemia were treated with mechanical ventilation, alkalinization, and intravenous tolazoline. Eight infants responded within two hours of initiation of tolazoline therapy with a rise in Pao2 by at least 100% of pretreatment values (mean = 188%, range = 103 to 427%). Eight infants showed little or no change in Pao2 with administration of tolazoline. Echocardiographic evaluation prior to therapy demonstrated marked elevation in both left (LPEP/LVET = 0.52 +/- 0.13) and right (RPEP/RVET = 0.56 +/- 0.08) ventricular systolic time intervals in the eight infants who subsequently responded to tolazoline. Systolic time intervals in nonresponders were within the normal range (LPEP/LVET = 0.37 +/- 0.03, RPEP/RVET = 0.33 +/- 0.04) and were not significantly different from those observed in a control group of 15 infants with pulmonary disease requiring mechanical ventilation but without hypoxemia. Following tolazoline therapy, systolic time intervals in all eight responders fell to normal values. Echocardiography can provide a safe, noninvasive method for identifying those infants with primary pulmonary disease and severe hypoxemia who could be expected to benefit from tolazoline therapy, thereby avoiding tolazoline side effects in infants for whom tolazoline therapy can be predicted to be of little benefit.

Growth patterns of cardiac structures and changes in systolic time intervals in the newborn and infant. A longitudinal echocardiographic study

A longitudinal study was undertaken in 21 newborns to determine cardiac growth pattern by echocardiography over the course of the first year of life. Most cardiac structures increased in size as a linear function of age and weight; however, the right ventricular end-diastolic diameter remained unchanged so that the RV/LV ratio decreased as a parabolic function of age. Left and right ventricular systolic time intervals (RVSTI, LVSTI) after birth were also studied. The ratio of left ventricular preejection period (LVPEP) to left ventricular ejection time (LVET) decreased markedly immediately after birth and subsequently remained at a constant mean value (0.30 +/- 0.04) for the rest of the study period. Right ventricular systolic time interval ratios (RVPEP/RVET) decreased rapidly and significantly during the first day of life (from a mean value of 0.39 +/- 0.08 in the first 24 hours to 0.28 +/- 0.05 on the 6th day of life). Constant values of 0.24 +/- 0.03 were found from the 3rd month of life onwards. The decrease in RVPEP/RVET in the first days of life followed a parabolic function reflecting the physiological decrease of pulmonary vascular resistance after birth.

Relation between isovolumic relaxation period of left ventricle and pulmonary artery pressure in d-transposition of the great arteries

The study aimed to identify the best echocardiographic time interval (systolic or diastolic) for assessing pulmonary artery pressure in children with d-transposition of the great arteries. Echocardiograms were performed in 21 children with d-transposition of the great arteries within 48 hours of cardiac catheterisation. None of the children had had a Mustard procedure. Twenty-four recordings were obtained, three patients having been catheterised twice. Highest correlations were found for the ratio of the isovolumic relaxation time over the ejection time of the left ventricle (IRT/LVET) to the systolic pressure in the pulmonary artery and also between IRT/LVET and the difference between mean pulmonary artery pressure and mean left atrial pressure. All patients with a negative IRT/LVET ratio had a pulmonary systolic pressure lower than 35 mmHg and a mean pulmonary pressure lower than 25 mmHg. In patients with d-transposition, a negative IRT/LVET ratio appears to be a reliable indication of normal pressure in the pulmonary circulation. Serial echocardiographic studies for the follow-up of patients with d-transposition should include measurement of the time of relaxation of the left ventricle.

Pulsed Doppler echocardiographic findings in total anomalous pulmonary venous drainage to the coronary sinus

The pulsed doppler echocardiographic (PDE) findings in a premature cyanotic infant with total anomalous pulmonary venous return to the coronary sinus are reported. Features that suggested the diagnosis of total anomalous pulmonary venous return were 1) an area of systolic-diastolic turbulent flow posterior to the apparent left atrial border, which was interpreted as representing the convergence of pulmonary venous return to a common pulmonary vein, and 2) systolic and diastolic turbulent flow within the right atrium suggesting pulmonary venous return through the coronary sinus. We suggest that PDE should be included as part of the evaluation of cyanotic infants in whom the diagnosis of total anomalous pulmonary venous return is considered.

Echocardiographic recognition of atrioventricular valve stenosis associated with endocardial cushion defect: pathologic and surgical correlates

The association of either mitral or tricuspid stenosis with endocardial cushion defects has been well recognized pathologically but is infrequenctly diagnosed clinically. M mode echocardiographic features such as markedly disproportionate ventricular size, abnormal mitral or tricuspid diastolic echoes or failure to define adequately an atrioventricular (A-V) valve are strongly suggestive of associated stenosis of that valve. In this study mitral stenosis in association with endocardial cushion defect was correctly diagnosed in four of five patients. In the fifth patient (the first seen) the condition was easily diagnosed retrospectively. Tricuspid stenosis was similarly diagnosed prospectively in three of four patients. Significant stenosis was not overlooked or misdiagnosed in any patient with an endocardial cushion defect. Significant stenosis of an A-V valve in association with endocardial cushion defect carries a high mortality. It is important to recognize the combined lesion clinically because infants with it are not suitable for total surgical correction. Palliative surgical procedures with aggressive medical therapy probably offer the infant the best chance of surviving until ventricular growth may render corrective surgery feasible.

Echocardiographic abnormalities in infants of diabetic mothers

In order to evaluate the presence of myocardial hypertrophy and/or abnormalities of postnatal cardiovascular adaptation, echocardiograms were performed on 34 infants of diabetic mothers. Based on cardiopulmonary assessment, the IDM were divided into three groups: Group I with congestive heart failure predominating: Group II with respiratory distress predominating: Group III asymptomatic. Hypertrophy of the interventricular septum and of the walls of left and right ventricles was frequently present in IDM: this change was most notable in association with clinical CHF. Six IDM, four of whom were found to have CHF, had additional echocardiographic signs of subaortic stenosis. All IDM had normal indices of left ventricular performance, despite the presence of CHE. In IDM with respiratory distress, the right ventricular pre-ejection period to ventricular ejection time ratio was elevated, suggesting an abnormality of the transitional pulmonary circulation. Poor maternal diabetes control and maternal systemic hypertension were closely correlated with evidence of myocardial hypertrophy in the infants.

Prospective diagnosis of d-transposition of the great arteries in neonates by subxiphoid, two-dimensional echocardiography

Subxiphoid, two-dimensional echocardiograms (S2DE) were performed and interpreted before diagnostic cardiac catheterization on 59 neonates who weighed 1.3--6.0 kg (median 3.3 kg) and were 1--35 days old (median 4.5 days). The echocardiographic studies were successfully performed on 58 of 59 infants. Using appropriate longitudinal and transverse projections, S2DE permitted simultaneous visualization of the branch pulmonary arteries, proximal thoracic aorta and ventriculoarterial attachments. D-transposition of the great arteries was correctly predicted in all 16 infants with levocardia, situs solitus and atrioventricular concordance. In these patients, the standard left ventricular longitudinal projection demonstrated the bifurcating main pulmonary artery attached to the posterior ventricle; the transverse projection displayed the relationship of the proximal thoracic aorta to the anterior ventricle. The broad acoustical window using the subxiphoid approach in conjunction with a high-frequency focused transducer and a large active-element diameter permitted detailed imaging of intra- and supracardiac structures.

Effects of acute hemodynamic alterations on pulmonic valve motion. Experimental and clinical echocardiographic studies

The purpose of this study was to assess the effects of acute alterations of the pulmonary circulation on the pulmonic valve echocardiogram. We measured the pulmonic valve opening velocity (PVOV) and right-sided systolic time intervals (right ventricular preejection period-to-right ventricular ejection time ratio [RPEP/RVET] in 22 open-chest dogs subjected to acute hemodynamic alterations produced by inferior vena cava constriction, atrial pacing, isoproterenol infusion and microsphere embolization of the pulmonary artery. We found only fair correlations between PVOV and peak pulmonary artery flow (r = 0.56), right ventricular dp/dt (r = 0.43), stroke volume (r = 0.42), pulmonary artery systolic pressure (r = 0.33) and peak pulmonary artery acceleration (r = 0.31). RVET was shortened by reduced venous return (caval constriction) and by increases in heart rate (atrial pacing and isoproterenol), which resulted in increases in RPEP/RVET that did not correspond well to simultaneous changes in pulmonary artery pressure. In seven patients breathing 10% O2 to raise pulmonary artery pressure acutely, we found no change or a fall in PVOV. Thus, the pulmonic valve echocardiogram is influenced by multiple factors relating to parameters of pulmonary flow and right ventricular contractility, and may be of limited clinical usefulness in predicting pulmonary artery pressures.

Echocardiographic assessment of the adequacy of pulmonary arterial banding

Thirty-one echocardiograms of 21 patients who had pumonary arterial banding were analyzed to assess the aequacy of surgery. In 5 patients the echocardiograms were obtained before and after banding and in 16 patients only after surgery. Right and left ventricular systolic time intervals were measured echographically. The ratios of the right ventricular preejection period to right ventricular ejection time (RPEP/RVET) were correlated with both diastolic (r = 0.94) and systolic (r = 0.86) pulmonary arterial pressures distal to the band. The analysis of right ventriclar systolic time intervals, especially the RPEP/RVET ratio, clearly differentiated patients with an adequate band (distal pulmonary arterial diastolic pressure less than 15 mm Hg) from patients with an inadequate band (distal pulmonary arterial diastolic pressure equal to or greater than 30 mm Hg). The results indicate that echocardiography is a useful noninvasive tool in evaluating the adequacy of the pulmonary arterial band and facilitates the follow-up of patients after banding.

Echocardiographic abnormalities in patients with cystic fibrosis

An echographic study was undertaken to evaluate left (LV) and right ventricular (RV) function in 30 patients with cystic fibrosis. Echographic recording of the pulmonary and aortic valve echogram permitted measurement of the phases of right and left ventricular systole. The ratio of the LV preejection period/LV ejection time (LPEP/LVET) and shortening of the LV internal dimension %SID was employed to reflect LV function, while RV preejection period/RV ejection time (RPEP/RVET) has excellent correlation with pulmonary artery diastolic pressure. RPEP/RVET and two other echographic measurements, right ventricular wall (RVW) and internal dimension (RVD) were compared with pulmonary function tests and clinical scores. RPEP/RVET correlated well with percent vital capacity(%VC), r = -0.73, percent residual volume (%RVol) r = +0.72, and clinical score, r = -0.77. Multilinear regression of RPEP/RVET, RVD, and RVW improved correlation for %VC (r = -0.80), %RVol, r = +0.82, and clinical score, r = -0.84. Patients in overt right heart failure exhibited elevated RPEP/RVET (mean = 0.48) when compared to patients not in right heart failure (mean = .33). Marked diminution of LV function was present in two patients. A variety of cardiovascular abnormalities were demonstrated echographically and were valuable in assessing the degree of cardiac involvement in patients with cystic fibrosis.

Ventricular septal defect in infancy: a combined vectorgraphic and echocardiographic study

Echocardiograms (echo) and vectorcardiograms (VCG) from 40 infants with ventricular septal defects (VSD) were compared with cardiac catheterization data to assess noninvasively the hemodynamics of VSD. The specific aim was to use VCG parameters of right ventricular hypertrophy and echo parameters which reflect pulmonary artery pressure to identify all patients with a nonrestrictive VSD. The configuration of the QRS vector in the horizontal plane was more reliable than individual voltages in assessing right ventricular systolic pressure. Among patients older than 2 months with a clockwise or anterior two-main-vector horizontal loop, 73% (eight of 11) had a nonrestrictive VSD. However, a counterclockwise or posterior two-main-vector loop was also frequently found (43%, six of 14) in infants with a nonrestrictive VSD. The most useful echo parameter was the ratio of right ventricular preejection period-to-right ventricular ejection time (RPEP/RVET), which closely (r = 0.74) reflected the pulmonary artery diastolic pressure. An elevated RPEP/RVET to greater than 0.30 was always associated with a nonrestrictive VSD, although many patients (36%, five of 14) with a nonrestrictive VSD had a normal ratio. By combining both echo and VCG parameters, a nonrestrictive VSD was correctly identified in all patients, while a restrictive VSD was correctly identified in 81% (21 of 26).

Echocardiographic diagnosis of pulmonary atresia with intact ventricular septum

The echocardiographic features of pulmonary valvar atresia with intact ventricular septum are described. The pulmonary valve fails to open during systole: there is a large pre-systolic 'a' wave dip, but the pulmonary valve membrane then returns to its closed diastolic position where it remains for the remainder of the cardiac cycle. The echocardiogram also provides valuable information about right ventricular size, the tricuspid valve, and aorta-mitral and aorta-septal relations.

Physiologic correlates of echocardiographic pulmonary valve motion in diastole

It has been shown that the echographic motion of the posterior aortic wall in diastole is closely related to the underlying left atrial events, possibly due to the anatomical proximity of the two structures. We observed that the pulmonary artery shares a similar close anatomical relationship with the left atrium. The present study in 55 consecutive patients with adequate echocardiographic recordings of the aortic root and the pulmonary valve demonstrates that the diastolic waveforms of the pulmonary valve and the posterior aortic wall are nearly identical in early diastole. The pulmonary valve e-f slope correlated with the posterior aortic wall O-R slope (r = 0.95) and the S2-f interval (second heart sound to f on the pulmonary valve) correlated closely with the S2-R interval (second heart sound to R on the posterior aortic root) (r = 0.94)). No significant correlation was found between the pulmonary valve e-f slope and the pulmonary artery pressures. The presence and amplitude of the maximum "a dip," on the other hand, correlated with the presence of pulmonary hypertension, with some notable exceptions. In addition, the "a dip" on the pulmonary valve and the depth of the A wave on the posterior aortic wall were significantly correlated (r = 0.85). It appears that the "a dip" on the pulmonary valve is influenced by dual mechanisms: pressure differences between the pulmonary artery and the right ventricle in late diastole and the left atrial events. Thus, the early diastolic waveform of the pulmonary valve, like the posterior aortic wall waveform, may primarily reflect underlying left atrial events and is not a measure of pulmonary artery pressure. The late diastolic waveform "a dip" has a dual mechanism, related in part to the underlying left atrial events, and also reflecting the instantaneous pressure differences across the pulmonary valve following atrial systole.

Estimation of pulmonary/systemic resistance ratios from echocardiographic systolic time intervals in young patients with congenital or acquired heard disease

Previous work has shown the positive correlation of echocardiographic right ventricular preejection period/right ventricular ejection time ratio (RPEP/RVET) with pulmonary vascular resistance and pulmonary arterial diastolic pressure obtained at cardiac catheterization. However, the correlation was insufficient to predict pulmonary arterial diastolic pressure or vascular resistance from a given RPEP/RVET ratio. In this study the RPEP/RVET ratio was compared with left ventricular preejection period/ejection time ratio (LVEP/LVET) in 25 patients undergoing cardiac catheterization, and a strong correlation was found between the ratio (RPEP/RVET)/(LPEP/LVET) = R/L and the ratio of pulmonary arteriolar resistance/systemic arteriolar resistance (PAR/RS), especially when R/L was correlated with log10 PAR/RS (r = 0.902). A very high correlation (r = 0.960) was found between R/L and log10 PAR/RS when the group was restricted to patients with a ventricular septal defect or a complete endocardial cushion defect. Regression equations for prediction of PAR/RS have been derived for the various groups.

Echocardiographic features of total anomalous pulmonary venous drainage into the coronary sinus

Echocardiograms were obtained from five infants with total anomalous pulmonary venous drainage to the coronary sinus or the portal system or the superior vena cava and from one child with a secundum atrial septal defect and a large coronary sinus due to persistence of the left superior vena cava. The results demonstrate that an enlarged coronary sinus is positioned consistently posterior to the left atrium in approximately the same horizontal plane as the aortic valve. Echocardiographically the coronary sinus can be located as an echo complex behind the left atrium by using the aortic root as a reference point. The echo complex can be differentiated from the other spurious echoes in the left atrium by its characteristic phasic motions. The additional demonstration of the enlarged common pulmonary venous chamber behind the right atrium confirms the diagnosis of anomalous pulmonary venous drainage to the coronary sinus. For other types of anomalous pulmonary venous return, anatomic diagnosis with single crystal M mode echocardiography is not always possible because of the positional variability of the common pulmonary venous chamber in relation to the left atrium.

Echocardiographic estimation of pulmonary artery pressure in transposition of the great arteries

To determine their usefulness in estimating pulmonary artery pressure, left ventricular systolic time intervals (STI) were determined by echocardiography in 65 patients with dextro-transposition of the great arteries (TGA). The STI were measured from recordings of pulmonary valve motion at 100 mm/sec paper speed. The pre-ejection period (PEP) and the ratio of PEP to left ventricular ejection time (PEP/LVET) were directly related to pulmonary artery pressure. The strongest correlations were that between PEP/LVET and pulmonary artery diastolic pressure (r = 0.70) and that between PEP/LVET and the ratio of mean pulmonary pressure to mean systemic pressure (r = 0.71). A value of PEP/LVET of less than 0.26 was consistently associated with pulmonary artery diastolic pressures of less than 20 mm Hg and, in 28 of 31 patients, pulmonary artery pressure less than one-third of mean systemic arterial pressure. Pulmonary hypertension was present in 18 of 22 patients with PEP/LVET of 0.30 or greater; elevated PEP/LVET was also present in four patients with abnormalities of cardiac rhythm or conduction, two of whom also had angiographic evidence of myocardial dysfunction.

Echocardiographic assessment of pulmonary arterial pressure in children with complete right bundle branch block

The time interval between tricuspid valve closure and pulmonary valve opening, termed the isovolumic contraction time of the right ventricle, was evaluated echographically in 38 normal children and within 24 hours of cardiac catheterization in 53 children with congenital heart disease and normal conduction as assessed with the electrocardiogram. In the 53 patients with congenital heart disease, isovolumic contraction time was strongly influenced by right ventricular afterload, as defined by pulmonary arterial end-diastolic pressure (r = 0.87). It was possible to utilize isovolumic contraction time to separate patients with normal or elevated values for pulmonary arterial end-diastolic pressure. Similar correlations were demonstrated between isovolumic contraction time and mean pulmonary arterial pressure and calculated pulmonary vascular resistance. Evaluation of 15 children with complete right bundle branch block revealed values for isovolumic contraction time that did not significantly differ from those of patients with similar pulmonary arterial end-diastolic pressure but no conduction abnormalities. These findings indicate that serial echographic evaluation of the interval from tricuspid valve closure to pulmonary valve opening can give an accurate reproducible assessment of right ventricular afterload in many children with congenital heart disease and complete right bundle branch block

Echocardiographic evaluation of valvar and shunt lesions in children

An evaluation of valvar and shunt lesions in children is directed toward appraising the need for, and timing of, surgical repair or palliation as well as demonstrating the cardiac anatomy which will, in turn, direct the type of surgery to be chosen. Static dimension measurements as well as dynamic measurements of wall velocity and time intervals are atraumatic and easily obtained values that increase our sensitivity to early cardiac decompensation. Contrast studies add both functional and anatomic information. Although one-dimensional time-motion scanning remains an invaluable source of anatomic detail, two-dimensional imaging has made positional information clearer and more reliable. The combined use of these three techniques offers the most complete evaluation of children with volume and pressure overload lesions.

Assessment of the pulmonary vascular bed by echocardiographic right ventricular systolic time intervals

Echocardiography was used to measure right ventricular systolic time intervals (RVSTI) in 85 normal children (group I) and in 229 patients undergoing cardiac catheterization (group II). Corrected right ventricular pre-ejection period (RPEPC) and right ventricular ejection time (RVETc) (based on regression analysis of group I) and RPEP/RVET were each correlated with pulmonary artery (PA) diastolic and mean pressures and pulmonary vascular resistance (PVR). The best correlation (0.83) was between a second degree polynomial of the RPEP/RVET and PA diastolic pressure. The RPEP/RVET allowed prediction of PA diastolic pressure within 10 mm Hg in 85% of the patients. The utility of RPEP/RVET was confirmed in sequential data of 22 patients, in whom alteration in RPEP/RVET accurately reflected the changing PA diastolic pressure. The RPEP/RVET could not be used to assess PA pressure in six patients with congestive cardiomyopathy nor in 18 patients with complete right bundle branch block (CRBBB).

Echocardiographic and hemodynamic correlation in transposition of the great arteries

Echocardiography was performed in 36 patients with transposition of the great arteries (TGA). Twenty patients were studied before a Mustard operation, 14 patients after operation and two patients both before and after operation. Right ventricular end-diastolic dimension (RVED) was larger than normal in each patient and tended to increase postoperatively. In contrast, the left ventricular end-diastolic dimension (LVED) was significantly reduced postoperatively in all patients. A linear relationship was demonstrated between the ratio of LVED/RVED and the ratio of peak systolic pressures in the left and right ventricles in studies both before and after Mustard operation. Systolic anterior motion of the mitral valve was observed in 18% of peroperative patients and increased to 44% postoperatively. The incidence of fluttering of the mitral valve increased from 50% to 94% after the operation. Abnormal septal motion was found in 39% of cases. Abnormal movement of the mitral valve and of the interventricular septum seems to be related to a reversed pressure relationship in the ventricles. Shifting of the ventricular septum toward the left ventricle and consequent distortion of the left ventricular cavity and mitral valve apparatus may be responsible for the abnormal echocardiographic findings. Serial echocardiographic studies may be useful as a noninvasive tool in the assessment of left ventricular pressure or the status of the pulmonary vascular bed in TGA.

The reliability and practicality of single crystal echocardiography in the evaluation of single ventricle. Angiographic and pathological correlates

A prospective clinical and echocardiographic diagnosis of single ventricle was made in 42 patients. Each was evaluated for the number of atrioventricular (A/V) valves, presence of an outflow chamber (OC), A/V valve-semilunar continuity, and orientation of the great arteries. Angiographic correlations were subsequently obtained in 40 and autopsies in 12. The overall diagnosis of single ventricle was substantiated in 39. Two other patients diagnosed as single ventricle by angiography were thought to have large ventricular septal defects on echocardiography. Tricuspid valve was interpreted as septum in one. The angiographic diagnosis of single ventricle was incorrect in another, correctly diagnosed by echocardiography and confirmed at pathology. The differential diagnosis also included A-V canal, L-transposition of the great arteries, double outlet right ventricle, and tricuspid atresia. This last condition has to be differentiated on clinical evidence. The echocardiograms were of particular value in determining the number of A/V valves. Two great arteries were demonstrated in 74% of patients and their relationship was correctly determined in 79% of these. Both imaging techniques agreed closely as to A/V valve-semilunar continuity and presence of an OC, but both showed some inaccuracies compared to pathological specimens. The echocardiogram helps both in planning catheterization and in evaluating the overall diagnosis.

Persistence of fetal circulation syndrome: an echocardiographic study

Serial echocardiograms were performed on 17 infants with persistence of fetal circulation syndrome to measure right ventricular systolic time intervals from pulmonic valve echograms and left ventricular systolic time intervals from aortic valve echograms. Right ventricular pre-ejection period/right ventricular ejection time ratio was prolonged in PFCS when compared to that in normal newborn infants, and diminished with clinical improvement. Left ventricular pre-ejection period/left ventricular ejection time ratio was prolonged in infants with PFCS. Echographic RPEP/RVET was consistent with the elevated pulmonary artery pressure and pulmonary vascular resistance of PFCS; elevated LPEP/LVET suggested left ventricular dysfunction.

Pitfalls and limitations of M-mode echocardiography

Newer diagnostic applications as well as the ability of obtaining physiologic information has resulted in a greater interest in echocardiography. As with any new technique, certain classical criteria have not been found to be as specific and diagnostic as was originally believed. This review has focused on the more important clinical applications in echocardiography. We have not attampted to discuss every single clinical entity. A critical evaluation as to the sensitivity and specificity of echocardiography in each clinical application is necessary. A thorough knowledge of the basic principles of ultrasound, a familiarity with recording devices, and a realization of the pitfalls and limitations of the technique in each cardiac disorder is essential. Hazards of echocardiographic interpretation may actually hamper its development as a diagnostic tool. Before embarking on complex and sophisticated two-dimensional echocardiography, problems with regard to technique and interpretation of M-mode echocardiography must be overcome.

Echocardiography in congenital heart disease

The utility of echocardiography in the evaluation of congenital cardiac disease is well established. The following discussion will be devoted to the application of single dimensional equipment in the assessment of selected congenital defects which will include secundum atrial defects, endocardial cushion defects, tetralogy of Fallot, Ebstein's anomaly of the tricuspid valve, and the use of systolic time intervals in assessing pulmonary artery diastolic pressures and pulmonary vasculature resistance. Since space is limited, only brief descriptions of these specific applications are possible and the readers are referred to more complete descriptions of the technic.

Pulmonary valve echo motion in clinical practice

Examination of the pattern of pulmonary valve echo motion provides useful diagnostic information in a variety of clinical situations. This report describes the normal patterns and variations in pulmonary valve echo motion. It further discusses the applications and limitations of M-mode and cross-sectional echocardiography in detecting obstruction to right ventricular outflow at both the valvular and infundibular level; the wide ranging effects of increases in pulmonary artery pressure on the pulmonary valve echogram; and alterations in right ventricular compliance and volume which may combine to produce diastolic opening of the pulmonary valve. It is emphasized that the thin pliable pulmonary leaflets move in response to local alterations in pressure and flow. The patterns of pulmonary valve echo motion, therefore, although not specific for any particular clinical disorder, may provide valuable, indirect information concerning local pressure and flow characteristics and, as such, may prove extremely helpful when applied to a specific clinical situation.

Late development of pulmonary venous obstruction following Mustard's operation using a dacron baffle

Three patients developed late pulmonary vein obstruction (PVO) following Mustard's operation for transposition of the great arteries. In all three the absence of PVO had been documented by an earlier postoperative cardiac catheterization. At reoperation shrinkage and kinking of the dacron baffle was evident. After Mustard's operation, patients should be observed closely for symptoms and signs of PVO since it can occur insidiously despite previously proven absence of this complication.

Echocardiographic evaluation of left-to-right shunt in ventricular septal defect and persistent ductus arteriosus

Forty-five patients with either a ventricular septal defect or a persistent ductus arteriosus were assessed by echocardiography and cardiac catheterisation. Left atrial dimension was expressed either as a function of the body surface area (LAD cm per m2 BSA), or as a multiple of the aortic root dimension (LAD/AR), and was compared with the shunt size as determined by oximetry. A highly significant (P less than 0-001) regression relation was found for the group as a whole. A significant relation also existed for each individual group: ventricular septal defect, ventricular septal defect with pulmonary hypertension, and persistent ductus arteriosus. Regression equations were derived for the whole group. The value of echocardiography is in separating large from small shunts and in adding a dimension to the follow-up of the individual patient.