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Although the Gorlin formula and the continuity equation are both used to calculate valvular areas in the clinical situation, there have been few comparisons of the 2 methods. Mathematically, it can be shown that both formulas are derived from similar hydrodynamic principles which basically give a measure of the physiologic or effective area occupied by flow. However, the Gorlin formula contains errors in formulation and incorporates a constant that purports to give a measure of the anatomic rather than of the effective area of the valve. If both formulas are applied to the same hemodynamic data from aortic and mitral bioprostheses studied in a pulse duplicator system, the Gorlin formula constantly yields results 1 to 2% higher than the continuity equation for aortic valves and 12 to 13% higher for mitral valves. For any given type and size of prosthesis, the areas calculated by either formula increase linearly in relation to increasing pressure and flow (up to 20% for aortic valves and up to 35% for mitral valves). It is concluded that the Gorlin formula and the continuity equation are both pressure- and flow-dependent and are primarily related to the effective area occupied by flow rather than to the anatomic area of the valve. The 2 methods yield consistently different results due to differences in mathematical formulation. Such factors are important to consider when interpreting valve area calculations clinically.

The quantitative relationships that exist between left ventricular (LV) wall shortening, wall thickening, and geometry during LV ejection are not well defined. We used a mathematical model to measure these parameters in 40 patients with various LV geometries studied by echocardiography. As opposed to wall shortening, the percent contribution of wall thickening to LV ejection (% delta Vh) was 25 +/- 2% in normal subjects; in all the patients, it varied from 18 to 45% and was inversely correlated (r = 0.94) to the midwall radius-to-wall thickness ratio (R/h) of the ventricle at end diastole. On the other hand, the ratio of the quantity of blood ejected per unit of LV wall volume magnitude of delta V/V omega magnitude of varied from 0.20 to 1.20 (normal subjects 0.83 +/- 0.11) and was directly correlated (r = 0.94) to R/h; using independent data in the literature, we also found a similar relationship (r = 0.80) between the ratio of quantity of blood ejected per unit of LV mass (magnitude of delta V/M omega magnitude of) and R/h. Patients with presumably abnormal myocardial function did not satisfy the relationship between magnitude of delta V/V omega magnitude of or magnitude of delta V/M omega magnitude of and R/h.(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler echocardiographic evaluation of aortic valve prostheses is based on the use of variables heretofore validated mostly for native valves. Accordingly, this study examined the validity and relative usefulness of the Doppler valve gradient and area measurements in 31 patients (mean age 69 +/- 10 years) 20 +/- 4 months after implantation of a given type of aortic bioprosthesis ranging in size from 19 to 29 mm. Valve area data obtained with both the standard and simplified continuity equations were compared with known in vitro prosthetic valve area measurements and an excellent correlation was obtained between the standard and simplified continuity equations (r = 0.98, SEE +/- 0.07 cm2, p less than 0.0005) and between in vivo and known in vitro prosthetic valve areas (r = 0.86, SEE +/- 0.16 cm2, p less than 0.0005). Peak gradient ranged from 10.8 to 75.0 mm Hg (mean 35 +/- 16) and mean gradient from 7.6 to 43.7 mm Hg (mean 20.5 +/- 9.5). The correlations between prosthetic valve gradient and in vivo area were r = -0.53, SEE +/- 14 mm Hg and r = -0.49, SEE +/- 8.63 mm Hg for peak and mean gradient, respectively. These relations were improved by indexing valve area by body surface area. The best correlations were obtained between indexed valve area and a quadratic function of the gradient (r = -0.72, SEE +/- 11.72 mm Hg and r = -0.70, SEE +/- 7.28 mm Hg for peak and mean gradient, respectively), reflecting a curvilinear relation.(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler echocardiography is used in the noninvasive evaluation of mitral valve prostheses using parameters heretofore validated primarily for native valves. Accordingly, this study was designed to examine the validity and relative usefulness of valve gradient and area measurements in a group of 26 patients (17 women, 9 men, mean age 62 +/- 8 years), 19 +/- 4 months after implantation of different sizes (25 to 31 mm) of a given type of bioprosthesis. Areas obtained with both the continuity equation, using stroke volume measured in the left ventricular outflow tract, and the pressure half-time method are compared to known prosthetic areas derived from an in vitro hydraulic model. Areas calculated by the continuity equation correlate well with in vitro areas (r = 0.82, standard error of the y estimate = 0.1 cm2, p less than 0.001), and are within the range of predicted in vitro values in 92% of cases. Areas derived by the pressure half-time method do not correlate with in vitro areas (r = 0.15, p greater than 0.3) or continuity equation areas (r = 0.23, p greater than 0.2), and are above the range of predicted values in 69% of cases. Correlations are also found between continuity equation areas and the peak and mean valvular gradients (r = 0.59, p less than 0.005 and r = -0.63, p less than 0.0005, respectively). Taking the effect of cardiac output on gradients into account results in projected relations between indexed prosthetic areas and the pressure gradients at rest and during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

The long-term effects of vasodilators in asymptomatic patients with aortic regurgitation have not been studied extensively. We retrospectively reviewed the echocardiograms of 19 asymptomatic patients with significant aortic regurgitation followed up annually for up to 4 years (average +/- SD, 3.1 +/- 0.7 years). Of these 19 patients, 12 were not receiving vasodilators and 7 were receiving hydralazine hydrochloride, 40 to 200 mg daily. In the patients not receiving vasodilators, left ventricular diastolic and systolic dimensions increased progressively in all patients by an average of 8% and 13%, respectively, after 3 years. In the patients receiving hydralazine, left ventricular dimensions increased by 9% and 5% in the year or more before hydralazine use and decreased by 7% and 7%, respectively, during the first year after using hydralazine. The reduction was observed in all patients during the first year, but an increase was detected in 3 patients followed up beyond that period. The results suggest that the progression of left ventricular dilatation in asymptomatic patients with aortic regurgitation can be delayed by long-term therapy with vasodilators. Pending further confirmation, such therapy may possibly influence the natural history of the disease and delay the timing of operation.

The acceleration term is included in the expression of the Bernoulli equation and an application of this formalism to the study of the Doppler measured mitral flow velocity is discussed. Based on calculation of the time-to-time variation of the parameters involved, a possible theoretical explanation of the pressure half-time method for the measurement of the cross-sectional area of the mitral valve is given.

Although many studies have shown that ventricular wall dynamics are a useful estimate of global and regional ventricular function, the precise relations that exist during contraction among myocardial fiber shortening, wall dynamics, and left ventricular cavity changes have not been previously established. To study the relation among some geometric variables used to describe left ventricular contraction, we used as a model of the left ventricle a thick-walled cylinder that contracts both radially and longitudinally. From this model, it can be shown that there is a direct relation during contraction between the relative thickening of the ventricular wall and the relative shortening occurring within the wall. On the other hand, the parameters derived from left ventricular cavity changes (relative ventricular internal radius shortening, ejection fraction, normalized blood flow velocity) are determined not only by the relative shortening occurring within the ventricular wall but also by the specific geometry of the ventricle, expressed in terms of its mid-wall radius-to-wall thickness ratio. In the clinical situation, the ejection fraction may vary up to 20%, uniquely as a result of a change of this ratio. These findings further validate the use of ventricular wall dynamics for the study of ventricular function. On the other hand, the specific geometry of the ventricle must be considered in interpreting the parameters derived from left ventricular cavity changes.

Regurgitations may be detected with great sensitivity and good specificity by Doppler ultrasound cardiography. Semi-quantitative methods to evaluate its gravity are based on "mapping" using the pulsed Doppler or the color Doppler. Too rigid or exclusive criteria may result however in errors of interpretation and, as far as we are concerned, we prefer a classification regrouping the most possible elements, including conventional ultrasound cardiography. Measurements of the regurgitating volume and the regurgitating fraction may also be carried out from output measurements in different sites; however, the recording must be of very good quality and methodologic problems remain, which might nevertheless be resolved in the future. Other semi-quantitative methods, which are more specific to either one of the valves, have been advocated.

There are still disagreements concerning the adaptation of cardiac structures in relation to different training stimuli. To eliminate some of the variance due to individual differences in body surface area, we utilized a new approach based on the calculation of the percentages of each individual's normal predicted values (%NPV). We studied 46 strength (S, bodybuilders) and 57 endurance (E, runners) athletes. Left ventricular (LV) mass was 143.8 +/- 21.9 %NPV (mean +/- SD) in E vs. 134.3 +/- 23.4 %NPV in S (P less than 0.05), and LV volume was 131.0 +/- 24.0 %NPV in E vs. 120.0 +/- 25.5 %NPV in S (P less than 0.05). Moreover, the LV wall thickness-to-radius ratio did not differ from normal values in either group. From these data we conclude that 1) cardiac modifications are greater in E than S, 2) the predominant stimulus is a volume overload type in both groups, and 3) concentric LV hypertrophy may not be as prevalent in S as previously suggested.

The Doppler ultrasound cardiography theoretically enables to measure the output at different sites of the cardiovascular system. Several studies now demonstrate a good correlation with haemodynamics. Doppler output measurements are however very sensitive to errors, even small ones; the examination must therefore by very thoroughly carried out in order to be valid. The velocity and acceleration of the blood flow may also be measured by Doppler, but the clinical applications for evaluation of the systolic function of the left ventricle still remain limited. The field which now appears to be the most promising is that of analysis of the diastolic function of the left ventricle, based on the mitral diastolic flow, especially in patients presenting a left heart failure with a normal systolic function as well as in certain conditions of volume overload. The non invasive evaluation of the intracardiac pressures with the Doppler, also proves interesting in some cases.

Although echocardiography has been useful in diagnosing significant left-to-right shunts at the atrial level, few studies using this technique to quantitate shunt size have been performed. Echocardiograms and hemodynamic data from 28 patients, ages 15 to 58 (mean : 30 years) were reviewed. Twenty patients had isolated atrial septal defects (ASD), 6 patients has associated partial pulmonary venous returns (PPVR) and 2 patients had isolated PPVR. Echocardiograms in the supine position were performed within 24 hours preceding cardiac catheterization. The presence or absence of paradoxical septal motion was noted and right ventricular diameter index (RVDE : right ventricular diameter/body surface area) was calculated. Hemodynamic parameters studied included pulmonary to systemic flow ratio (Qp/Qs) determined by oxymetry, right ventricular pressure (RVP) and pulmonary resistance (PR). One patient with a Qp/Qs of 1.3 had normal septal motion. Type A paradoxical septal motion was noted in 22 cases, type B in 5 cases. For these 27 patients, the average RVDI was 2.42 (range 1.45 to 3.7), Qp/Qs ranged from 1.5 to 5 (mean : 2.45), RVP from 23 to 71 mmHg (mean : 39) and PR from 0.6 to 4 units (mean : 1.79). A very strons correlation between RVDI and Qp/Qs was observed from equation Qp/Qs : 1.19 RVDI-0.43 with a standard error of 0.4. This relationship was not altered by either RVP or PR values, which also had no apparent correlation with RVDI. This study indicates that echocardiographic measurement of RVDI is a reliable and non-invasive method of evaluating the size of left to right shunts at the atrial level.

There is still controversy as to which characteristics of the pressure-volume relation should be used to define myocardial contractility. In the present study a mathematical model for the left ventricle as a two-dimensional cylinder contracting radially and symmetrically was used to establish a relation between a calculated intramyocardial pressure (Dh) and the P-V relation (PVR) at end-systole. Four new indices are introduced that allow a better assessment of change in inotropic state of the myocardium, namely the calculated intramyocardial pressure (Dh), the calculated resultant pressure across the inner surface of the myocardium (Dh-P) (P = cavity pressure), the work Wt related to the pressure (Dh) and the work Wd related to the pressure (Dh-P). A relation between Wt and Wd and different parts of the area under the PVR is established. Indices derived in this manner from the PVR to study changes in myocardial contractility appear to have a clear physical meaning.

We used a cylindrical model for the left ventricle contracting both radially and longitudinally to show how the ejection fraction is related to different variables that describe the ventricular geometry. The relations during ventricular contraction between wall thickening, midwall radius shortening and longitudinal shortening are used to derive precise formulas for the calculation of ventricular blood flow velocity and ejection fraction. Validation of the model is given by results from the literature and by a study of 40 patients. The formulas derived can be used to validate angiographic measurements or to assess more precisely blood flow velocity and ejection fraction from the M-mode echocardiogram. Ejection fraction is determined not only by the extent of myocardial shortening, but also by the relationship of ventricular wall thickness to ventricular cavity size.

An expression for the energy of motion of the wall of the left ventricle is developed. A cylinderical model is assumed for the left ventricle, and symmetry is used to produce the problem to a two-dimensional problem. Result obtained indicate that consideration of the energy of motion can be useful in problems of clinical diagnosis. Some correlation between previously published experimental results is also made with the equations derived in this paper.

This study reports on two more cases of left atrial myxoma. They were two women with embolic manifestation for several years and in whom the diagnosis was not clinically considered. It was made by echocardiography. Emergency surgery was applied in both cases one of whom without hemodynamic study. The presence of a recent brain embolism did not seem to us to be a contraindication to this surgery. In both cases the tumoral pedicle was implanted on the posterior wall of the left atrium, an unusual location.

A study was made of 9 cases of left atrial myxoma with emphasis on the echocardiographic, haemodynamic and anatomical aspects and on the main clinical features. An epidemiological enquiry was made regarding the possibility of recurrences or familial cases. It was negative, suggesting that such cases are rare. The echocardiographic signs of left atrial myxoma are inconstant. The mitral diastolic EF slope is variable, the delay in appearance of the tumour echo behind the mitral valve in diastole is not constant, and the atrial "a" wave may be preserved. The echocardiographic features are a function of the size and shape of the myxoma, as well as the length and site of implantation of its pedicle.

Regional wall dynamics of the left ventricle before and after sublingual administration of 0.6 mg of nitroglycerin were determined from left ventricular angiograms in 27 patients undergoing coronary arteriography. Regional wall dynamics were quantitatively measured from 60/sec determinations of wall thickness and derived peak rate of systolic wall thickening (peak dTw/dt) in selected sites of the left ventricle. A total of 70 regions were studied. Analysis of the same segment before and after administration of nitroglycerin revealed that the mean change in peak dTw/dt was +1.97 cm/sec in segments with an initial peak dTw/dt of less than 5 cm/sec, in contrast to a change of +0.66 cm/sec in segments with an initial control value of 5 cm/sec or greater. Akinetic or dyskinetic areas did not show improvements after nitroglycerin. In 11 left ventriculograms, an area that was initially hypokinetic manifested an increase in rate of wall thickening after nitroglycerin. The mean increase in peak dTw/dt in anterior segments with electrocardiographic evidence of myocardial infarction was 0.18 cm/sec (P less than 0.05) after nitroglycerin, compared with a mean change of 1.33 cm/sec in anterior segments without such evidence. This study presents evidence for a regional myocardial response to nitroglycerin with differing responses within the same ventricle apparently depending upon the functional state of the underlying myocardium.

The echocardiographic findings in a young man with a "paper-thin right ventricle" or Uhl's anomaly are reported. The usual signs of right ventricular diastolic overload with slight delay in tricuspid valve closure were observed. The discordance between the normal clinical examination and the pathological appearances on echocardiography led to cardiac catheterisation which established the diagnosis.

Echocardiographic studies were performed in 86 patients with right ventricular volume overload. In 45 of these 86 patients, 58 echocardiograms were performed at different intervals in the postoperative period. For control purposes, 60 normal subjects and 18 patients with right ventricular pressure overload were also examined. The right ventricular end-diastolic dimension (RVED) and the left ventricular end-diastolic dimension (LVED) were measured on the echocardiograms. The RVED/LVED ratio was significantly elevated in patients with right ventricular volume overload. In all groups, a RVED/LVED ratio above 0.65 was usually associated with an abnormal motion of the septum; and on this basis the subjects with abnormal septal motion could clearly be separated from those with normal motion. After surgery, significant reductions of the RVED/LVED ratio were observed in patients whose septal motion reverted to normal. The RVED/LVED ratio remained significantly higher, usually above 0.65, in patients with persistent abnormal septal motion. These findings suggest that the relative sizes of the right and left ventricular cavities are probably major determinants of ventricular septal motion. Abnormal motion may result from a change in the end-diastolic shape of the septum.

Heparin induced thrombocytopenia (HIT) is a relatively common complication of heparin therapy, occurring in approximately 5% of patients treated with this drug. HIT may be associated with diffuse arterial and venous thrombosis. The case of a patient without underlying heart disease who developed a right ventricular thrombus and recurrent pulmonary emboli in association with and possibly as a complication of HIT is reported. Ancrod was used as an alternative to heparin for the time required to obtain an effective oral anticoagulant effect. The patient recovered completely and has no residual right ventricular thrombus.

To determine the prognosis of patients with painless strongly positive exercise electrocardiogram, the 6-year cumulative survival rate was computed for 298 medically treated patients who terminated their exercise test with or without angina. All had horizontal or downsloping ST depression greater than or equal to 2 mm during a treadmill exercise test according to the standardized multistage Bruce protocol. Of the 298 patients, 119 terminated the exercise test because of dyspnea or fatigue and 179 stopped because of angina. Among the 119 patients without angina, there were 18 deaths, 16 from coronary artery disease (CAD), of which 8 occurred suddenly. Among the 179 patients with exercise-induced angina, 36 died, 33 from CAD, of which 13 were sudden deaths. The overall 6-year survival rate was 85 +/- 3% for patients without angina and 80 +/- 3% in those with angina (p less than 0.05). However, patients without angina achieved a significantly longer duration of exercise and had higher maximal heart rate and systolic blood pressure during exercise. In both groups, survival decreased with decreasing duration of exercise. In patients without angina, the 6-year survival rate was 97 +/- 3% in those achieving stage IV (greater than or equal to 541 s), 87 +/- 4% in stage III (361 to 540 s), 64 +/- 13% in stage II (181 to 360 s) and 60 +/- 15% in stage I (less than or equal to 180 s).(ABSTRACT TRUNCATED AT 250 WORDS)

To investigate the mechanism by which muscular coronary overbridging can cause myocardial ischaemia, we studied the effect of systolic compression (SC) of the proximal left circumflex coronary artery in ten anaesthetised dogs, with both intact autoregulation and maximally dilated coronary arteries. Systolic compression was produced by a mechanical device adjusted to interrupt circumflex coronary flow only during the aortic ejection period and we measured left ventricular, aortic and distal circumflex coronary pressures, phasic coronary blood flow, regional myocardial blood flow (RMBF), myocardial oxygen consumption (MVO2), and myocardial lactate extraction (MLE). During both autoregulation and maximal coronary vasodilatation, there was a diastolic time lag after SC to restart phasic circumflex coronary blood flow (34 +/- 3 vs 31 +/- 3 ms) and to increase distal circumflex coronary pressure (69 +/- 4 vs 79 +/- 6 ms). With autoregulation, SC reduced the diastolic circumflex coronary: systolic left ventricular pressure time ratio (DPTIc:SPTI) and there were no changes in the other measured variables. During maximal coronary vasodilatation and SC, the coronary vasodilator reserve, the DPTIc:SPTI ratio and the inner:outer myocardial blood flow distribution were decreased in the territory of the left circumflex coronary artery; a linear relationship was observed between the DPTIc:SPTI and the inner:outer myocardial blood flow ratio. Systolic compression during vasodilatation also produced a reduction in myocardial oxygen consumption of the whole heart and a production of lactate in the coronary sinus. These results suggest that myocardial ischaemia with a myocardial bridge is due to the combined effects of a diastolic time lag to repressurise the coronary vascular bed, of tachycardia and of coronary vasodilatation.

There is evidence that patients with signs of poor left ventricular function or marked ischemia at low work load during an exercise test have a poor prognosis for survival. To determine whether a pacing test can provide similar information, the 6-yr survival rate was computed in 118 medically-treated patients who had undergone a standardized atrial pacing test. Among the 118 patients, 80 had significant coronary artery disease (CAD). The variables measured for the atrial pacing test were: induced angina, myocardial lactate extraction (MLE), maximal heart rate (MHR) and left ventricular end-diastolic pressure (LVEDP) changes. There was no death in 38 patients without significant CAD. The 6-yr survival rate of the 80 patients with CAD was 84 +/- 4% (+/- SEM). Of all the variables, the combinations of MHR less than or equal to 150 beats min-1 during pacing associated with a LVEDP increase greater than or equal to 5 mmHg immediately after pacing or with MLE less than or equal to 0% during pacing constituted the best predictors. Patients with a MHR less than or equal to 150 beats min-1 and a LVEDP increase greater than or equal to 5 mmHg had a 6-yr survival of 56 +/- 12% in comparison to 92 +/- 3% for the remaining patients (P less than 0.001). Patients with a MHR less than or equal to 150 beats min-1 and MLE less than or equal to 0% during pacing had a 6-yr survival of 64 +/- 11% in comparison to 91 +/- 4% for the remaining patients (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Most echocardiographic laboratories now use continuous-wave Doppler to measure transvalvular pressure gradients in patients with valvular aortic stenosis (AS). In many cases, particularly in the elderly, this technique can be difficult and time-consuming, and there is no immediate means of verifying the accuracy of the results. In the present study, a new and simple method is proposed to calculate maximal aortic valve gradients from the pulsed-wave Doppler tracing recorded in the left ventricular outflow tract. The method consists of calculating maximal aortic flow velocity and thus the maximal gradient by extrapolating to their point of intersection the initial accelerating velocity and the terminal decelerating velocity recorded on the pulsed Doppler tracing. In 20 patients with varying degrees of AS, there was an excellent correlation (r = 0.96, p less than 0.001) between the results obtained by this method and those obtained by continuous-wave Doppler. In 10 patients who had cardiac catheterization, the results also correlated well with the maximal gradient (r = 0.93, p less than 0.001) measured at cardiac catheterization. Because the method is simple, it should become an integral part of the Doppler examination in patients with AS. Its main advantages will be to serve as an independent confirmation of the results obtained by continuous-wave Doppler and to reduce in many patients the duration of the examination.

The Medtronic Intact valve is a third-generation porcine bioprosthesis produced using a leaflet fixation process which imposes virtually zero hydrostatic pressure. This fixation method provides optimal preservation of the original leaflet structure and integrity and should result in an improvement in durability compared to conventional preservation techniques. The biomechanical basis for this hypothesis is presented along with early experience with 118 patients (125 valves). There have been no complications related to primary valve failure and the incidence of other valve related events is acceptable.