Estimation of left ventricular volume by one-plane cineangiography

Relations of preoperative hemodynamics and coronary blood flow to improved left ventricular function after valve replacement for aortic regurgitation

In this study of the limits of reversibility of left ventricular function after aortic valve replacement for aortic regurgitation, measurements were made of pre- and postoperative coronary blood flow and left ventricular volumes. Eighteen patients who had undergone aortic valve replacement for pure aortic regurgitation using the Björk-Shiley valve or the Bicerval valve were restudied an average of 8 +/- 3 months after surgery. Postoperative left ventricular end-systolic and end-diastolic volumes returned to near normal values. The slight left ventricular wall thickening apparent before surgery remained unchanged after surgery and, consequently, left ventricular mass, though somewhat reduced, remained abnormally high. Ejection fraction, which was low preoperatively, returned to normal postoperatively. Total coronary sinus blood flow decreased after surgery, but coronary sinus blood flow per 100 g of left ventricular mass increased. This recovery of coronary flow per unit mass was believed to cause the improvement in left ventricular function. A significant correlation was found between postoperative systolic function and preoperative left ventricular end-systolic and end-diastolic volumes, wall thickness and, especially, left ventricular mass, the latter indicating that, if preoperative left ventricular mass is less than 350 g/m2, postoperative improvement of systolic function is attainable. Another significant correlation was indicated by measurements of coronary sinus blood flow per 100 g of left ventricular mass. If this is greater than 35 ml/min before surgery, a postoperative improvement in systolic function to within the normal range may be expected.

Coronary hemodynamics in hypertensive heart disease. Basic concepts, clinical consequences, and experimental analysis of regression of hypertensive microangiopathy

Myocardial hypertrophy may influence coronary hemodynamics variably. Therefore, coronary sinus blood flow (gas chromatic argon technique) was determined in patients with left ventricular hypertrophy, with or without dilatation, associated with entirely normal coronary arteriographic results: 12 patients with hypertrophic obstructive cardiomyopathy (left ventricular mass-to-volume ratio, 3.66 +/- 0.52 g/ml), 22 patients with hypertensive heart disease due to essential hypertension (left ventricular mass-to-volume ratio, 2.12 +/- 0.26 g/ml), 18 patients with hypertensive dilatation (left ventricular mass-to-volume ratio, 1.6 +/- 0.48 g/ml), six patients with aortic stenosis (left ventricular mass-to-volume ratio, 1.99 +/- 0.41 g/ml), 12 patients with aortic incompetence, and 20 patients with normal heart function. Coronary sinus blood flow was determined as a control value and as the value following intravenous injection of dipyridamole (0.5 mg/kg of body weight). Coronary reserve was calculated as the ratio of coronary resistance before and after dipyridamole. Normal coronary reserve averaged 4.89 +/- 0.11. Similar values, despite marked left ventricular hypertrophy, were present for both hypertrophic obstructive cardiomyopathy (4.4 +/- 0.19) and aortic stenosis (4.66 +/- 0.12), whereas coronary reserve was considerably reduced in the concentrically hypertrophied hypertensive hearts (3.22 +/- 0.19) (p less than 0.001). Moderate decrease in coronary reserve was found in aortic incompetence and in dilated essential hypertension. These results indicate that patients with nonhypertensive hypertrophy, despite left ventricular mass augmentation, may have normal coronary reserve, whereas at a comparable degree of left ventricular hypertrophy, patients with hypertensive hypertrophy have a specific reduction in coronary reserve. Independent from vascular effects, ventricular dilatation may result in deterioration of coronary reserve because of an abnormal component of coronary vascular resistance. These results were also verified in experimental hypertension. Moreover, prevention and/or regression of the impaired coronary circulation in experimental hypertensive heart disease, most probably due to the reduction of smooth muscle layers of the media of coronary resistance vessels, could be achieved by long-term vasodilator therapy.

Quantitation of cardiac dimensions from ECG-synchronized MRI studies

The ability to measure the heart is useful for evaluation of a wide variety of conditions. Magnetic resonance imaging (MRI) has a number of characteristics that make it potentially one of the best methods for obtaining cardiac measurements, in particular its ability to produce uniformly high-quality images in any desired plane. It is important that techniques for measurement be standardized so that methods are reproducible from patient to patient, allowing normal standards to be established, and from examination to examination in the same patient, so that serial measurements accurately reflect change in cardiac status.

Comparison of medical and surgical treatment for unstable angina pectoris. Results of a Veterans Administration Cooperative Study

We conducted a multicenter, randomized, prospective study comparing medical therapy alone with coronary-artery bypass surgery plus medical therapy in 468 men with unstable angina pectoris. Patients were entered in the study from June 1, 1976, to June 30, 1982. Among those assigned to surgery who received bypass grafts, operative mortality was 4.1 percent. Arteriography performed after one year of follow-up revealed that 74.8 percent of the grafts studied were patent. The cumulative rate of crossover from medical to surgical therapy after two years was 34 percent; the operative mortality among patients crossed over was 10.3 percent. Nonfatal myocardial infarction occurred in 11.7 percent of the patients treated surgically and 12.2 percent of those treated medically (no significant difference). Most of the nonfatal myocardial infarctions in the surgical group occurred in the perioperative period. Overall, the two-year survival rate computed by life-table analysis did not differ between the two groups. However, the curves reflecting mortality as a function of left ventricular ejection fraction were significantly different (P = 0.03); surgery was associated with a significantly reduced mortality among patients with lower ejection fractions. We conclude that patients with unstable angina pectoris have a similar outcome after two years whether they receive medical therapy alone or coronary bypass surgery plus medical therapy. However, patients with reduced left ventricular ejection fractions may have a better two-year survival rate after coronary bypass surgery.

Assessment of a procedure for left ventricle volumetry

A three-step radiographic procedure is described for the determination of left ventricle volumes, based on one lateral and two angled single plane images. The first angled image is taken to yield a minimally foreshortened LV image and the second image, at the same angle, is taken of a calibration sphere. Five sources of operator-related, or 'input', error are analysed, two of which are normally removable. The remaining three input errors are assessed using a commercial digital subtraction angiography system and comparisons with the analysis are given. A summary result is that relative errors in end-systolic and end-diastolic LV volumes, as well as cardiac output, should normally be less than 13% under reasonable operator care. The input errors should not contribute to errors in calculated ejection fractions.

Could inspiratory apnea disturb left ventricular volume assessment by contrast angiography?

To assess the influence of postinspiratory apnea on the measurement of the left ventricular volumes, contrast ventriculography was performed on 19 patients during spontaneous breathing and then in postinspiratory apnea. Data obtained were similar for end diastolic volumes (81 +/- 29 ml/m2 vs. 83 +/- 25; NS), end systolic volumes (35 +/- 20 ml/m2 vs. 34 +/- 19; NS), systolic index (46 +/- 13 ml/m2 vs. 49 +/- 12; NS), and ejection fraction (0.57 +/- 0.11 vs. 0.59 +/- 0.12; NS). Postinspiratory apnea suppressed the overlapping of the left ventricle with abdominal viscera in 15 of 17 patients. Diaphragmatic immobility permitted the assessment of regional left ventricular function in all 19 patients. However, pressures recorded in inspiratory apnea can no longer be compared to a transmural pressure, and, to assess ventricular compliance, intrapleural pressure must be measured simultaneously. We conclude that left ventricular volume assessment by contrast ventriculography is not disturbed by inspiratory apnea. This maneuver improves the quality of the images and allows a better evaluation of left ventricular segmental function. Spontaneous breathing can be recommended to simplify left ventricular compliance study.

T-wave changes in patients with hemodynamic evidence of systolic or diastolic overload of the left ventricle: a retrospective study on 168 patients with isolated chronic aortic valve disease

The effect of systolic and diastolic overload of the left ventricle on the T wave was studied in 86 patients with pure aortic stenosis and in 82 patients with pure aortic insufficiency documented by hemodynamic investigation. All patients had hemodynamically significant, chronic isolated aortic valve disease with electrocardiographic evidence of left ventricular hypertrophy (Sokolow index greater than or equal to 45 mm). All had undergone selective coronary angiography. Flattened or negative T waves were present in 44 patients with aortic stenosis (51%) and in 66 (80%) with aortic incompetence. Inversion of the T wave in left ventricular leads was unrelated to the presence of ventricular conduction disturbances or to coronary artery disease or to low cardiac index. It was significantly related to older age (P = 0.0001) and, in patients with aortic incompetence, to the end-diastolic volume (P = 0.04). Digitalis intake was a nonsignificant (P = 0.10) independent variable. These findings suggest that patients with aortic stenosis cannot be distinguished from patients with aortic incompetence by the electrocardiogram and that the theory of Cabrera and Monroy is not valid in this set of patients.

Ventricular development and function in complete transposition: angiocardiographic evaluation

We studied 50 left ventricular cineangiograms and 41 right ventricular cineangiograms of 40 patients with usual atrial arrangement (situs solitus) together with concordant atrioventricular and discordant ventriculo-arterial connexions (complete transposition), catheterized between 1 day and 12 months of age. Our purpose was to evaluate ventricular development and function. The patients were subdivided on the basis of associated lesions into groups with intact ventricular septum; with ventricular septal defect; with ventricular septal defect together with pulmonary stenosis and with pulmonary stenosis in isolation. Each group was further separated according to age into those patients below and above 60 days. Ventricular volumes, ejection fraction and the ratio between systolic pressure and end-systolic volume were evaluated for both ventricles. The left ventricular mass, stress, and the ratio of stress to end-systolic volume were also calculated. A volume overload leads to increased left ventricular volume even at birth. With an intact ventricular septum, the left ventricle in patients with complete transposition is normal at birth and also during the first weeks of life. Myocardial mass, however, does not increase proportionately with increase in volume as the patient grows and it remains inadequate by the age of one year. The left ventricular mass is also inadequate in patients with associated anomalies when the left ventricular pressure is less than 60 mm Hg. Moreover, the left ventricle in presence of an intact ventricular septum presents a decrease in contractility during the first year of life despite the finding of a satisfactory arterial oxygen saturation. The right ventricle has a normal volume at birth which increases during the first year due to a greater diastolic filling following atrial septostomy. We noted a progressive decrease in ejection fraction, however, which is related to various factors including a reduction in contractility.

Evaluation of methods of measurement and estimation of left ventricular function after acute myocardial infarction

Using multiple gated cardiac blood pool imaging and single-plane ventriculography from cardiac catheterization, 2 independent measures of left ventricular (LV) ejection fraction (EF) were determined in each of 21 patients. Patients were seen 2 to 6 weeks after their first acute myocardial infarction and were free of electrocardiographic evidence of conduction abnormalities and left or right ventricular hypertrophy. Differences between the 2 measures of LVEF were examined and then compared with the extent of myocardial necrosis estimated from the standard 12-lead electrocardiogram using the complete 54-criteria/32-point Selvester QRS scoring system. Regression analysis yielded an r value of 0.81 (SEE = 8.05) for the overall relation between the 2 measures of LVEF. Correlation coefficients of -0.70, -0.66 and -0.72 were obtained for the relations of radionuclide LVEF, catheterization LVEF and the mean of these 2 determinations, respectively, compared with QRS score. A QRS score 4 or less achieved 100% specificity and that of 8 or less 100% sensitivity for predicting an LVEF greater than 40%. Thus, the Selvester QRS scoring system may be of value in identifying patients with or without markedly impaired LVEF. This risk stratification may be important in reaching optimal postinfarction therapeutic decisions.

The effects of Valsalva maneuver on global and segmental left ventricular function in presence and absence of coronary artery disease

To determine the effects of the Valsalva maneuver on global and regional left ventricular function, single-plane left ventriculograms were performed in the 30-degree right anterior oblique projection in 50 patients during normal breath holding and during the late strain phase of the Valsalva maneuver. Thirty-one patients had significant coronary artery disease (greater than 70% luminal narrowing in a major coronary artery). Ventriculograms were analyzed for determination of ejection fraction, end-diastolic, and end-systolic volumes. Regional wall motion was analyzed by a chord method of calculating segmental fractional shortening. Ejection fraction increased significantly in the entire group of patients (62 +/- 16% to 70 +/- 19%, p less than 0.0001), while both end-diastolic (105 +/- 33 cc to 88 +/- 34 cc, p less than 0.0001) and end-systolic volumes (43 +/- 29 cc to 30 +/- 29 cc, p less than 0.0001) showed striking reductions with Valsalva maneuver. Patients without significant coronary disease usually exhibited global augmentation in left ventricular function, while those with coronary disease often exhibited only segmental improvement. This augmentation appeared to be dependent on the patency of the supplying coronary vessel.

A method for volume estimation by two-dimensional echocardiography: examination with excised animal left ventricles

Applicability of a newly developed volume estimation method was examined with excised left ventricles of pigs and dogs. Serial oblique-sectional images of a left ventricle were recorded with a two-dimensional echocardiograph. The probe of the echocardiograph was fixed at one point and was tilted stepwise. Contours of the left ventricle in the images were traced to put into a computer and volume was calculated. Calculated volume of 19 left ventricles agreed well with true volume in wide range (r = 0.982 for left ventricular myocardium and r = 0.989 for left ventricular cavity).

Chronotropic incompetence in clinical exercise testing

Chronotropic incompetence has been found to be an important predictor of obstructive coronary artery disease (CAD). However, few data define the normal heart rate response to progressive exercise and allow a clear definition of chronotropic incompetence. In this study, 312 patients who underwent an exercise stress test and coronary angiography were evaluated. The exercise heart rates of 140 normal subjects were used to define the normal mean heart rate at progressive work loads. Two standard deviations of the mean were chosen to represent a normal response at various levels of exercise. Analysis of the exercise heart rates in 172 patients who had CAD revealed 16 patients who had a peak exercise heart rate below 2 standard deviations of the mean. Of the 16 patients, 5 had 1-vessel, 5 had 2-vessel and 6 had 3-vessel CAD. Of 65 patients who had no significant ST-segment shift and who did not reach 85% of age-predicted heart rate, 13 (20%) had an inappropriately low heart rate for the work load performed. Each of the 13 patients had CAD. Of the 172 patients with CAD, those with chronotropic incompetence exercised further than the patients who did not have chronotropic incompetence (9.4 +/- 2.1 vs 7.0 +/- 3.4 METs, p less than 0.01). In conclusion, chronotropic incompetence is a relatively infrequent occurrence in an exercise test population; however, this finding, when present, is relatively specific for CAD, and may be useful in detecting patients with CAD who have an indeterminate exercise test.

Accurate internal correction for the magnification of cineangiocardiography in infants with congenital heart disease

Correction for x-ray magnification at cineangiocardiography (cine) requires accurate localization of the level of the left ventricle (LV). This study compared LV volumes calculated using a standard external reference object (area grid) with volumes calculated using an intracardiac radiopaque catheter balloon in cine studies of casts (n = 26), normal lambs (n = 15), and infants with congenital heart disease (n = 11). Comparisons of LV volumes calculated using both correction methods with true cast displacement volumes were excellent (r = 0.99). Correlations of both methods were highly significant (p less than 0.001) in casts (r = 0.99), normal lambs (r = 0.97), and in infants (r = 0.83). The absolute percent difference (17.6 +/- 2.4 SE%) between LV volumes calculated by both methods was greatest in infants. Thus external localization of the LV may be more difficult in infants. The radiopaque balloon provides convenient accurate correction for cine x-ray magnification and calculation of LV volumes, particularly since flow-directed catheters are widely used for diagnostic cine ventriculography in infants.

Myocardial material mechanics: characteristic variation of the circumferential and longitudinal systolic moduli in left ventricular dysfunction

Active systolic moduli for the circumferential (E theta) and longitudinal (E phi) axes of the left ventricle were determined along with circumferential and longitudinal contractile filament stress (sigma theta and sigma phi) and circumferential and longitudinal fiber strain (epsilon theta and epsilon phi). These material property parameters were determined at four points during cardiac systole. Thirty-nine patients comprising five clinical groups were evaluated using pressure and volume data acquired from single-plane cineangiography. The results indicate that the active moduli exponentially decrease during cardiac systole. Characteristic variations from normal differentiated the various pathological groups. With compensated volume overload, E theta was significantly reduced during the latter half of systole (p less than 0.25). With decompensated volume overload, both E theta and E phi were not significantly different from the normal group throughout cardiac systole. With compensated pressure overload, both E theta and E phi were significantly lower than the normal group at end-systole (p less than 0.005; p less than 0.005). With congestive cardiomyopathy, both E theta and E phi were significantly greater during the latter half of systole compared to the normal group (p less than 0.05 and p less than or equal to 0.025).

Single versus biplane right and left ventricular volumetry: a cast and clinical study

True volume (y) and measured volume (x) determined from 23 right and 22 left normal human casts in four biplane angiographic positions and in their eight single-plane components were used to find the correction factor (b) by regression through the origin (y = bx). The correction factors were applied to human studies to assess the validity of the various biplane and single-plane modalities in vivo. The casts studies yield excellent correlations in both right and left biplane methods (right volumetry: 0.555 less than or equal to b less than or equal to 0.708, 0.917 less than or equal to r less than or equal to 0.954, 4.10 less than or equal to SEE less than or equal to 6.01 left volumetry: 0.748 less than or equal to b less than or equal to 0.825, 0.974 less than or equal to r less than or equal to 0.982, 4.81 less than or equal to SEE 5.79). Good results were obtained with single-plane volumetries as well (right volumetry: 0.316 less than or equal to b less than or equal to 0.887, 0.750 less than or equal to r less than or equal to 0.917, 10.75 less than or equal to SEE less than or equal to 18.96; left volumetry: 0.728 less than or equal to b less than or equal to 0.881, 0.897 less than or equal to r less than or equal to 0.976 5.73 less than or equal to SEE less than or equal to 11.97). The correction factors for the single-plane studies depend much more strongly on the spatial position relative to the radiographic system, particularly in the case of the right ventricular volumes. Thus, the application of the appropriate correction factors is mandatory. The human studies (141 left and 60 right volumetric studies in various single-plane and biplane projections) showed a larger scatter of single-plane values, more pronounced for the right ventricle. In certain disease conditions, single plane volumetric studies using cast-derived correction factors cannot be used to obtain meaningful results. Correction factors for the following single or biplane mode volumetry are presented for the first time: biplane hepatoclavicular view (right and left ventricle), biplane long axial oblique view (right ventricle), and their single-plane components; lateral and 60 degree Left Anterior Oblique (LAO) single plane for the left-sided measurements, Postero-Anterior (PA), lateral, and 60 degree LAO for the single-plane right-sided calculations.

Measurement of right and left ventricular ejection fraction in dogs

Three techniques for measurement of right (RVEF) and two techniques for left (LVEF) ventricular ejection fraction were evaluated in five dogs. RVEF was measured with a first-pass radionuclide technique using erythrocytes labelled in vitro with Technetium-99m methylene disphosphonate (MDP) and compared with RVEF measured with a thermodilution technique. Thermodilution-determined RVEF was compared with RVEF values measured with cine angiocardiography. LVEF was measured with a radionuclide ECG-gated equilibrium technique and compared with cine angiocardiography. Measurements were performed before and during a continuous infusion of dopamine. There was an excellent correlation between RVEF measured with the first-pass and the thermodilution technique, rs being 0.86, n = 9, P less than 0.01. When RVEF measured with the thermodilution technique was compared with cine angiocardiography rs was 0.75, n = 10, P less than 0.01. LVEF measured with the ECG-gated equilibrium technique correlated well with cine angiocardiography (rs = 0.91, n = 10, P less than 0.01).

Estimation of absolute left ventricular volume from gated radionuclide ventriculograms. A method using phase image assisted automated edge detection and two-dimensional echocardiography

Twenty-four patients underwent gated cardiac blood pool (GBP) imaging, two-dimensional echocardiography (2-D echo), and single-plane contrast ventriculography (within 24 hours). Variable left ventricular (LV) regions of interest on GBP images were identified by an automated threshold radial search. To avoid excluding LV counts we indexed the search threshold to the threshold identified by a phase image generated by Fourier analysis. LV depth calculated by 2-D echo was used for attenuation correction of LV counts. LV end-diastolic volume (EDV) and end-systolic volume (ESV) were calculated by dividing attenuation, background and deadtime corrected LV count rates by the background corrected count rate/ml of venous blood drawn during the study. Correlations between radionuclide and contrast volumes were good (EDV + ESV r = 0.97, EDV r = 0.94, ESV r = 0.95). Regression lines were close to the lines of identity. This method, in which GBP imaging and automated LV edge finding are complemented by 2-D echo for count attenuation correction, demonstrated reliable and reproducible noninvasive estimates of absolute LV volume.

End-systolic pressure-volume and end-systolic stress-volume relationships in patients with aortic stenosis and with normal valvular function

In order to study the effect of left ventricular hypertrophy on the endsystolic pressure-volume relationship, three left ventricular angiograms were performed in ten patients with normal valvular function but with varying left ventricular function (group 1) after 0.15 mg/kg propranolol and 1 mg atropine: at rest, after isosorbide-dinitrate at a decreased afterload and after methoxamine at an enhanced afterload. In eight patients with aortic stenosis (group 2) two left ventricular angiograms were performed: at rest and after isosorbide-dinitrate. Heart rate was kept constant by atrial pacing. Left ventricular mass in group 1 was 89 g/m2 and in group 2 180 g/m2. In group 1 the slope k of the end-systolic pressure-volume relation was related to the ejection fraction (EF) at rest: k = 0.024 . e0.072 EF; r = 0.93. In group 2 this relation was shifted to the left (P less than 0.001): k = 0.135 . e0.057 EF; r = 0.81. The relations, however, between the slope k of the end-systolic stress-volume relation and the ejection fraction were close together in group 1 and in group 2 and crossed at an ejection fraction of 67%. It is concluded: 1. In patients with aortic stenosis the end-systolic pressure-volume relation is steeper than in patients without valvular dysfunction at a given ejection fraction, so the relation between the slope k and the ejection fraction is shifted to the left. 2. The end-systolic stress-volume relationship is not altered in patients with aortic stenosis and seems to be advantageous for the evaluation of left ventricles with substantial hypertrophy due to pressure load.

Role of cardiovascular nuclear medicine in evaluating trauma and the postoperative patient

In the patient with cardiac trauma, radionuclide imaging may provide important information about cardiac mechanical function, vascular anatomy and integrity, myocardial perfusion, and myocardial metabolism. Studies require only minimal patient cooperation, can be performed relatively rapidly and often at the bedside, and may be repeated at frequent intervals for serial evaluations. These studies provide valuable adjunctive knowledge when selected and interpreted with knowledge of the mechanism of injury, timing of the examination relative to the time of injury, and most likely differential diagnoses.

Absolute left ventricular volume from gated blood pool imaging with use of esophageal transmission measurement

A new method for determining absolute left ventricular (LV) volume from equilibrium gated blood pool images was validated in 36 patients by comparing gated blood pool (GBP) imaging with contrast ventriculography (CV) using both Simpson's rule (SR) and area-length (AL) calculations. The technique is geometry-independent and is the first to correct for tissue attenuation with use of an in vivo point source. An orally administered capsule containing 1 to 2 mCi of technetium-99m (Tc-99m) sulfur colloid is used for this purpose. Left ventricular volumes are determined by dividing attenuation and background-corrected count rates obtained from semiautomated LV regions of interest by the count rate per milliliter from a blood sample. The correlation between GBP and CV (SR) was 0.96 (CV [SR] = 0.99 GBP + 1.32 ml; standard error of the estimate [SEE] = 21.2 ml) for diastole and 0.97 (CV [SR] = 0.93 GBP - 0.03 ml; SEE = 11.9 ml) for systole. The correlation between GBP and CV (AL) was 0.92 (CV [AL] = 0.90 GBP + 16.72 ml; SEE = 27.8 ml) for diastole and 0.95 (CV [AL] = 0.87 GBP + 4.56 ml; SEE = 14.4 ml) for systole. The method is noninvasive and can be performed easily as part of routine gated blood pool imaging and analysis.

Origin of the third heart sound. II. Studies in human subjects

We report noninvasive and invasive studies designed to clarify the mechanism of the third heart sound (S3) in humans. The noninvasive observations were made using a miniature accelerometer attached to the skin surface at the cardiac apex. In subjects with no S3, the tracings were either flat or showed very low undulations throughout diastole. Those with an S3, however, demonstrated a distinct reduction of acceleration, or negative jerk, of the rapid filling movement at the apex at the time of the sound. The invasive studies in the cardiac catheterization laboratory consisted of frame-by-frame measurements of left ventricular dimensions in the transverse and long axes during early diastole in patients with diastolic overload abnormalities to investigate the temporal sequence of filling in these two principal axes. The maximal long-axis filling rate occurred after the short axis, a finding that helps to resolve a discrepancy noted in the time of maximal short-axis filling and S3 production. These studies support the concept that the S3 is due to a sudden intrinsic limitation of longitudinal expansion of the left ventricular wall during early diastolic filling, resulting in a negative jerk that is transmitted to the skin surface.

New method: calculation of magnification factor from an intracardiac marker

In order to calculate a magnification factor (MF), an intracardiac marker (pigtail catheter with markers) was evaluated using a new formula and correlated with the conventional grid method. By applying the Pythagorean theorem and trigonometry, a new formula was developed, which is (formula; see text) In an experimental study, MF by the intracardiac markers was 0.71 +/- 0.15 (M +/- SD) and one by the grid method was 0.72 +/- 0.15, with a correlation coefficient of 0.96. In patients study, MF by the intracardiac markers was 0.77 +/- 0.06 and one by the grid method was 0.77 +/- 0.05. We conclude that this new method is simple and the results were comparable to the conventional grid method at mid-chest level.

Haemodynamic effects of intravenous amrinone in patients with impaired left ventricular function

The effects of intravenous amrinone on resting haemodynamic function were investigated in 15 patients with impaired left ventricular function. All patients received 1 X 5 mg/kg and 10 received a further 2 mg/kg. We observed dose related increases in heart rate and cardiac index, and reductions in mean arterial pressure, left ventricular end-diastolic pressure, and systemic vascular resistance. A small reduction in left ventricular end-diastolic volume and a 36% increase in ejection fraction occurred. No significant change in max dp/dt, min dp/dt, (Max dp/dt/P), max (dp/dt/P), KVmax or the ratio of left ventricular end-systolic pressure to left ventricular end-systolic volume was detected. It is concluded that the beneficial effects of intravenous amrinone on the resting haemodynamics in our patients were attributable to vasodilatation, with the drug having no demonstrable positive inotropic effect.

An accurate and simplified method to calculate angiographic left ventricular ejection fraction

An accurate and simplified method to calculate left ventricular (LV) ejection fraction (EF0 derived from the ellipsoidal formula for LV volume calculation is described. The LV Minor axis (D) is obtained from the average of three equidistant LV diameters at end-diastole (Ded) and end-systole (Des), and the shortening fraction of D2 (% delta D2) calculated as (D2ed - D2es)/D2ed. EF is calculated as EF = [delta D2 + ([1 - delta D2] X delta L)] X 100, where delta L = the shortening fraction of the long axis. The coefficient of correlation between the EF by this method and the EF derived from measurements of LV volumes with the area-length method was 0.98, SEE = 3.57% (n = 50). No significant over- or underestimation was observed according to the regression equation Y = 0.922X + 0.82. Thus, this simplified method allows accurate LVEF calculation without the need for planimetry of LV area.

Imaging of the left ventricle in patients with ischemic heart disease: role of the contrast angiogram

The contrast left ventriculogram is the gold standard against which all other cardiac imaging techniques are measured. In the past decade, noninvasive methods such as radionuclide angiography, echocardiography, computed tomography (CT), and digital substraction imaging have become available. This review examines the role of these techniques, and whether they will supersede the selective contrast ventriculogram. Each of these modalities seems to have specific capabilities and superiority in a certain area. Contrast ventriculography is best suited for the functional assessment of the left ventricular wall. Isotopes and CT have great potential for evaluating the myocardium properly. Echocardiography produces good visualization of atrioventricular valves and intracavitary structures. The role of contrast angiography is considered in the workup of the cardiac patient. The contrast angiogram is closely related to the coronary angiogram in the assessment of the patient with arteriosclerotic heart disease and it is still a necessity for the preoperative evaluation of the patient with congenital heart disease.

Anatomic and prognostic implications of an early positive treadmill exercise test

Eighty men (group A) with clinical coronary artery disease underwent coronary angiography regardless of symptoms and previous therapy because they had a positive treadmill exercise test in stage I or II of the Bruce protocol. Thirty-four other men (group B) who also had an early positive treadmill test underwent coronary angiography because they had disabling angina pectoris despite medical therapy. We found left main coronary artery stenosis of 50% or greater of the vessel diameter in 28% of group A and 35% of group B (p greater than 0.3). In contrast, only 10% of 93 other catheterized patients who had treadmill tests that were not early positive had left main coronary disease (p less than 0.001). Fifty-four patients from group A who did not have left main stenosis of 50% or greater were treated medically. In this subgroup, 85% had 2 or 3 major coronary vessels with 75% or greater stenosis. These patients had a 36 month survival rate of 89.2%. We conclude that an early positive treadmill test identifies patients who have an increased likelihood of having left main coronary stenosis, even if they are minimally symptomatic. To identify left main coronary stenosis, catheterization may be justified in patients whose angina pectoris has been mild or not intensively treated when they have an early positive treadmill response. After left main coronary stenosis has been excluded, these patients may be treated medically with a low mortality.

Intracoronary streptokinase in clinical practice

The candidacy for streptokinase (SK) infusion was studied in 95 patients displaying ECG evidence of acute or impending infarction who were catheterized within 5 hours of the onset of chest pain. Intracoronary SK was administered to 84 patients in whom occlusions of the infarct-related vessel were identified, with early recanalization having been achieved in 74 (88%). Because of completeness of studies, a data base of 72 patients was employed for further analysis. Recanalization was sustained at follow-up in 45 of 55 patients (82%). Spontaneous thrombolysis was demonstrated at follow-up in five patients (8%) initially resistant to SK, and rethrombosis occurred in 10 patients (18%). Preservation of R waves relative to Q wave depth was limited to patients with less than 90% residual stenosis. Eight of nine patients with continuing thrombolysis and patients with recanalized occlusions of the left anterior descending coronary artery displayed more impressive increases in mean (+/- SEM) ejection fraction (47% +/- 4% to 53% +/- 5% [p less than 0.05], and 47% +/- 3% to 52% +/- 5, respectively). The ejection fraction also increased significantly in 15 patients with pre-SK values of less than 50% (41% +/- 2% to 48% +/- 3%; p less than 0.05). Ventricular function deteriorated in SK failures. Reperfusion arrhythmias occurred in 28 of 62 recanalized patients (45%). Minor bleeding tendencies were displayed in 18 of 72 patients (25%). Major hemorrhages, one of which may have been fatal, occurred in four patients (5.6%). Of 84 patients, four (4.7%) died, two of whom were in cardiogenic shock when first seen. In contrast, there were 11 deaths (11.8%) in a consecutive simultaneously enrolled series of 93 control patients with similar entry criteria (p less than 0.05). Two additional SK-treated patients died, 16 and 30 days after treatment, both more than a week after surgical revascularization. It is concluded that SK recanalization is a promising new therapy that may decrease mortality and preserve myocardial function in certain circumstances. Its efficacy in a setting closer to the mainstream of cardiologic practice extends the favorable experience issuing from earlier clinical investigations.

Radionuclide measurement of left ventricular volume: comparison of geometric and counts-based methods

Radionuclide measurements of left ventricular volume were determined in 20 patients by geometric and nongeometric, counts-based techniques using data from first-pass and equilibrium blood pool scintigraphy. Two geometric analytic approaches were used: directly measured long and short axes and the area-length method. Each approach was applied to the single-plane right anterior oblique images obtained by the first-pass technique and to biplane data, using the right anterior oblique first-pass and left anterior oblique blood pool data together. For the nongeometric determinations, background-corrected left ventricular counts were related to blood counts. This ratio was converted to volume by means of a linear regression relationship with angiographic volumes. All methods yielded high correlation coefficients (r greater than or equal to 0.93), but the standard errors of the estimates for the geometric techniques were high, and therefore the 95% confidence limits were wide. The use of biplane data improved the correlations, but area-length analysis of digitized data was no better than direct measurement of short axes from the analog images. The counts-based, nongeometric method provided the highest correlation and lowest standard error. These findings indicate that nongeometric left ventricular volume measurements using equilibrium blood pool scintigrams are the most accurate radionuclide technique. This approach also permits multiple determinations with a single dose of radiotracer.

Changes in left ventricular wall motion after coronary artery bypass surgery: signal or noise?

We evaluated changes in ventricular wall motion after surgery by comparing smoothed, filtered measurements of regional percent shortening (RPS) from right anterior oblique ventriculograms in 37 patients before and after surgery. After surgery there was a significant (p less than 0.05) decrease in the number of regions with hypokinetic wall motion. The distribution of RPS values was also different (p less than 0.005). However, the mean value of RPS for the surgery group as a whole was not significantly altered. These data were contrasted with RPS data from 11 control patients, who were each studied twice but did not have surgical intervention. Similar analysis of the control group did not show any significant change between studies in the number of hypokinetic regions, and the distributions of RPS for the first and second angiograms were not different. We found a 10.3% absolute mean change in repeated measurements of RPS in the control group. We conclude that significant changes occurred after surgery that were not evident in the control group, and the amount of variability in repeated measurements of RPS suggests that analysis should be applied to group rather than individual data.

Diastolic amplitude time index: a new apexcardiographic index of left ventricular diastolic function in human beings

Left ventricular apexcardiography was performed in 260 normal subjects and 37 patients undergoing diagnostic cardiac catheterization: 13 without left heart disease (group 1), 18 with congestive cardiomyopathy (group 2) and 6 with idiopathic hypertrophic subaortic stenosis (group 3). In the patients undergoing catheterization the apexcardiogram was recorded simultaneously with left ventricular pressure (tipmanometer) and its first derivative (dP/dt). The following variables were measured in the apex tracing: (1) the time from the onset of the aortic component of the second heart sound (A2) in the phonocardiogram to the nadir of the apexcardiogram, termed total apexcardiographic relaxation time (TART), (2) the time from A2 to the onset of the systolic upstroke (C point) of the apexcardiogram (A2-C), and (3) the ratio of the A wave (A) to the total diastolic amplitude (D) of the apexcardiogram (A/D). The diastolic amplitude time index (DATI) was calculated according to the following formula DATI = (square root A2-C/TART)/(A/D). In the normal subjects the diastolic amplitude time index was 0.82 +/- 0.26 (mean +/- standard deviation). In group 1 this index was within normal limits; in groups 2 and 3 it was decreased (0.23 +/- 0.07 and 0.18 +/- 0.05, respectively). This index showed excellent correlation with specific compliance of the left ventricle (r = +0.90) and close correlations with the maximal rate of decrease of left ventricular pressure (minimal dP/dt) (r = +0.79) as well as the velocity of lengthening of the contractile elements at minimal dP/dt (r = +0.77); less close correlation was obtained with the end-diastolic volume compliance (r = +0.67). These results demonstrate that the diastolic amplitude time index reflects interpatient differences in both relaxation ability and diastolic distensibility of the human left ventricle. Thus, this measurement provides an important new method for noninvasive evaluation of the overall function of the left ventricle during diastole.

A new, simplified and accurate method for determining ejection fraction with two-dimensional echocardiography

A new method to determine left ventricular (LV) ejection fraction (EF) with wide-angle, two-dimensional echocardiography (2-D echo) has been developed using the parasternal long-axis, apical four-chamber and apical long-axis views. End-diastolic and end-systolic measurements of LV short axes at the base and mid-LV cavity in the parasternal long-axis view and at the upper, middle and lower thirds of the cavity in the apical views are made, from which an averaged minor axis at end-diastolic and at end-systole is calculated. Fractional shortening of the LV long axis (delta L) is estimated from apical contraction. Satisfactory 2-D echoes were obtained in 55 of 58 nonselected patients (all three views in 32 patients, two views in 22 and one view in one); 42 of 55 patients had coronary artery disease. EF by 2-D echo was compared with EF by gated cardiac blood pool imaging in all patients (r = 0.927, SEE = 6.7%) and to EF by single-plane cineangiography (angio) in 35 of 55 patients (r = 0.913, SEE = 7.4%). LV dyssynergy was frequently present and involved the apex in 29 of 55 patients. Using angio as the standard for evaluating wall motion at the apex, 2-D echo was 100% sensitive and specific in detecting abnormal apical wall motion. We conclude that EF can be determined accurately with 2-D echo in a large group of patients with and without dyssynergy by a simple method that eliminates the need for planimetry or computer assistance.

Effect of left ventricular size on mitral E point to ventricular septal separation in assessment of cardiac performance

Increased mitral valve E point to ventricular septal separation (EPSS) is widely used as an echocardiographic index of depressed left ventricular (LV) ejection fraction (EF), yet LV size has not been examined as an independent variable potentially affecting EPSS. Accordingly, we studied end-diastolic dimensions (EDD). Twenty normal controls had EPSS 3.2 +/- 2.2 mm (mean +/- SD), EDD 47 +/- 5 mm, EPSS/EDD ("normalized" EPSS) 0.07 +/- 0.04, and fractional shortening (FS%) 38 +/- 6%. Nine patients with pure chronic mitral regurgitation had dilated LV (EDD = 65 +/- 7 mm) with normal LV function (FS% 41 +/- 5%; angiographic EF 62 +/- 9%); eight patients had dilated cardiomyopathy (EDD 69 +/- 8 mm) with decreased LV function (FS% 16 +/- 7%; angiographic EF 32 +/- 8%); and eight patients with amyloid cardiomyopathy had nondilated LV (EDD 42 +/- 5 mm) with decreased LV function (FS% 19 +/- 6; angiographic EF 35 +/- 7%). Mitral E point to ventricular septal separation and EPSS/EDD accurately separated individuals with normal and abnormal LV function irrespective of LV size (chi 2 = 36.7; p less than 0.00001). Increased internal dimensions per se did not affect EPSS unless depressed LV function coexisted. EPSS is therefore a valid predictor of depressed ejection phase indices independent of LV size.

The linearity of the end-systolic pressure-volume relationship in man and its sensitivity for assessment of left ventricular function

The linearity and sensitivity of the end-systolic pressure-volume (P-Ves) relation to the inotropic state of the left ventricle were investigated in 11 patients with coronary heart disease and one patient with congestive cardiomyopathy. To minimize autonomic reflex responses, propranolol, 0.15 mg/kg, and atropine, 1 mg, were administered i.v. at the beginning of the study. Three ventriculograms were performed: at rest, after oral isosorbide dinitrate, 10 mg (systolic pressure decrease greater than or equal to 15 mm Hg), and during infusion of methoxamine, 2 mg/min (systolic pressure increase greater than or equal to 10 mm Hg). The three points of the Pv-Ves relation showed linearity (r greater than or equal to 0.96). The relation between the slope k of the P-Ves relation and the left ventricular ejection fraction at rest was best described by an exponential function (r = 0.94). The use of peak systolic pressure instead of end-systolic pressure showed equally good results. The intercept of the P-Ves line on the abscissa, which represents the theoretical end-systolic volume at zero pressure, was not related to the ejection fraction under control conditions. The P-Ves relation in postextrasystolic beats was displaced toward the left (smaller end-systolic volumes) and became steeper.

Critical analysis of endomyocardial biopsies from patients suspected of having cardiomyopathy. II: Comparison of histology and clinical/haemodynamic information

Endomyocardial biopsies showing histological evidence of "ordinary" hypertrophy or changes compatible with congestive cardiomyopathy (COCM) were obtained from 125 patients. Statistical analysis compared histological/morphometric data with clinical/haemodynamic findings such as ejection fraction, left ventricular end-diastolic pressure, and length of history. Patients were grouped either according to the histological description or the clinical diagnosis. Comparison of the morphological description with the final clinical diagnosis was also undertaken. Follow-up of the patients was between two and 66 months. The results of the statistical analyses showed no correlation between quantitative, morphological assessment and either clinical information, that is length of history and subsequent course, or the haemodynamic variables. In 86 per cent of cases a rough agreement between the morphological description and the clinical diagnosis was obtained, but no specific pattern permitting a morphological diagnosis of COCM was established. The findings suggest that pronounced topographic variation in biopsy material exists and that, therefore, the severity of COCM or its prognosis cannot be assessed from histological changes.

Direct measurement of cardiac output by gated equilibrium blood pool scintigraphy: validation of scintigraphic volume measurements by a nongeometric technique

A nongeometric technique for the determination of left ventricular volumes from the count data derived from gated equilibrium blood pool scans was previously described and validated by the demonstration of an excellent correlation between the derived data and angiographically determined left ventricular volumes. To provide a further prospective evaluation of this method and to validate its ability to determine stroke volume and cardiac output by a technique that is itself independent of geometric assumptions, simultaneous measurements of cardiac output by the thermodilution technique and gated scintigraphy were performed in 21 patients without valve regurgitation or intracardiac shunts. To substantiate the reliability of scintigraphic measurements at high levels of cardiac output, seven patients had multiple measurements of cardiac output at rest and during an infusion of isoproterenol. There was an excellent correlation between thermodilution and scintigraphic values for cardiac output (scan cardiac output = 0.99 thermodilution cardiac output - 0.005 liters/min; n = 31, standard error of the estimate [SEE] = 0.175 liters/min, r = 0.97) as well as between thermodilution and scintigraphic stroke volumes (scan stroke volume = 1.03 thermodilution stroke volume - 2.8 ml; n = 31, SEE = 2.5 ml, r = 0.95). In addition, the relation between scintigraphic and angiographic measurements of left ventricular volumes continued to be excellent: In 15 patients with technically adequate angiograms, scintigraphic left ventricular volume = 0.90 angiographic left ventricular volume + 7 ml (n = 30, SEE = 10 ml, r = 0.91). Thus, this study further validates the nongeometric method of measuring left ventricular volumes with gated scintigraphy and demonstrates its ability to measure left ventricular stroke volume and cardiac output reliably.

Reduced coronary dilatory capacity and ultrastructural changes of the myocardium in patients with angina pectoris but normal coronary arteriograms

Hemodynamic and metabolic studies were performed in 15 patients without heart disease (controls, group A), in 21 patients with typical stress-induced anginal pain but normal coronary and left ventricular angiograms (angina pectoris with normal arteriogram, group B), and in 10 patients with angiographically proved coronary artery disease (CAD, group C). Coronary dilatory capacity, determined by measuring total myocardial blood flow at rest and during maximal coronary vasodilatation (dipyridamole, 0.5 mg/kg i.v.), was markedly reduced in group B and C patients. In group B patients, left ventricular catheter biopsy specimens revealed no evidence of small-vessel disease, but did show histologic alterations of mitochondria. During atrial pacing, the control subjects showed no changes in myocardial lactate uptake, whereas in group B patients, myocardial lactate production occurred. In contrast to controls, patients in group B showed a significant decline in ejection fraction and circumferential fiber shortening during isometric exercise. These findings suggest that myocardial ischemia is the cause of angina pectoris in patients who have angina but normal coronary arteriograms.

Long-term survival after coronary bypass surgery. Comparison of various subsets of patients with general population

Life-table analysis consecutive cases of isolated coronary bypass surgery at the Buffalo Hospital between 1973 and 1977 showed an estimated survival of 94 per cent at five years, equal to that of an age- and sex-matched group of the US population. Subsets of these patients divided according to sex, age, number of vessels narrowed, number of segments grafted, history of myocardial infarction, ejection fraction, and presence of unstable angina have estimated survivals not statistically less in any of these subsets than that of matched cohorts of the general population.