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In the last decade, many efforts have been made to study myocardial perfusion by contrast echocardiography. The possibility of differentiating normal from nonperfused myocardium and measuring the extent of the area at risk and myocardial infarction size has already been demonstrated. The aim of this paper is to review the approaches to quantitation of coronary blood flow by contrast echocardiography. In a series of studies, echocardiographic contrast agents have been treated like "deposit tracers." After an upstream contrast injection, myocardial contrast intensity (according to the partition principle) hypothetically reflects the fraction of contrast, and consequently of flow, distributed to the myocardium. A good correlation was found between changes in peak myocardial contrast intensity and corresponding changes in coronary blood flow (r = 0.83). However, this approach is limited by electronic signal distortion and attenuation artifacts. In other studies contrast agents have been treated as intravascular "free-passing" tracers, and (according to the dilution principle) their myocardial transit times hypothetically reflect coronary blood flow. A prolonged myocardial washout halftime with coronary underperfusion has been documented in animal experiments and patients with severe coronary stenosis. However, the majority of contrast agents have intermediate characteristics and do not belong to either category of tracers; furthermore, signal distortion and attenuation phenomena affect the washout phase. The time of myocardial contrast appearance, which is independent of tracer characteristics, permitted the differentiation of baseline conditions from coronary underperfusion but seemed inaccurate in the quantitation of coronary blood flow (r = 0.60).(ABSTRACT TRUNCATED AT 250 WORDS)

The quantitative approaches to the assessment of regional left ventricular (LV) function described in the preceding paper were applied in a well-defined population of patients with coronary artery disease. Two groups were chosen by electrocardiographic and angiographic criteria: group 1 had infarction and regional wall motion abnormalities and group 2 had no infarction and normal wall motion. Sensitivity to detect wall motion defects, specificity to correctly categorize normal segments, and overall predictive accuracy were evaluated for each two-dimensional echocardiographic approach. In addition, the ability of each method to localize regional contraction defects properly was evaluated. Area methods yielded better predictive accuracy than linear methods (87-95% vs 76-84%). No significant differences in accuracy were noted between quadrant and octant approaches. The fixed external-axis system was superior to a floating one for localizing contraction defects. We conclude that an area-based method, using a fixed-axis system and either octant or quadrant image subdivision, provides the best combination of predictive accuracy in categorizing LV segments as normal or abnormal and the greatest ability to localize LV regional abnormalities.

This paper provides guidelines for the optimal, rather than minimal, performance of ultrasonic examination of the heart for current clinical applications using conventional echocardiographic equipment. Since the original report of this Inter-Society Commission on Heart Disease Resources Committee in 1975, M-mode echocardiography has continued to be a valuable clinical tool, and two-dimensional echocardiography has been developed. Guidelines are presented for optimal physician and cardiac sonographer training, case loads, space and support systems, equipment design features and performance testing, and administrative considerations. The developing area of Doppler ultrasound and the competitive technologies are noted.

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.

The spontaneous closure of ventricular septal defects is frequently associated with septal aneurysm formation. In this paper we discuss the M-mode and two-dimensional echocardiographic findings in nine children with aneurysms of the ventricular septum in association with ventricular septal defects. In all patients the diagnosis was confirmed by angiography. The ventricular septal aneurysms were detected by both M-mode and two-dimensional echocardiography. With M-mode echocardiography, septal aneurysms could be recognized by a pattern of multiple systolic echoes within the right ventricle. With two-dimensional echocardiography, the protrusion of the septal aneurysm into the right ventricle could be seen from several views and the location and the relative size of the aneurysm assessed. Echocardiographic techniques useful in the detection of ventricular septal aneurysms are discussed and examples presented.

The clinical and echocardiographic findings of four patients with right ventricular tumors (three myxomas and one metastatic melanoma) are presented. All four patients previously had been evaluated by competent cardiologists, and the diagnosis of a right ventricular tumor was missed. The initial echocardiograms were interpreted as not showing any right ventricular tumor; but on review we found that the correct diagnosis could have been made. The presence of the right ventricular myxomas was confirmed at angiography and surgery. However, the attachment of the stalk of the mycoma could not be determined confidently by angiography alone, and in two of the three cases two-dimensional echocardiography was required to identify correctly the location of the base of the stalk. This paper emphasizes the usefulness and technical difficulties of M-mode and two-dimensional echocardiography in the diagnosis of a right ventricular tumor.

The normal posterior aortic wall echocardiogram shows anterior motion during left ventricular systole and predominantly posterior motion in three phases during left ventricular diastole. In six patients undergoing simultaneous left atrial angiograms and posterior aortic wall echocardiograms, there was excellent correlation between the posterior aortic wall motion and the change in the left atrial angiographic area showing the value of the posterior aortic wall echocardiogram in describing the left atrial volume curve. Left atrial and left ventricular pressures were measured with manometer tip catheters and correlated with simultaneous posterior aortic wall and mitral valve echocardiograms in four patients with atrial septal defects. These echocardiographic, angiographic, and hemodynamic correlations, as well as other evidence reported in this paper suggest that a major portion of posterior aortic wall motion is related to left atrial events and describes the left atrial volume curve.

Echographic aortic valve closure was compared to the dicrotic notch of the aortic pressure and intracardiac A2 to define the exact temporal relationship of the echographic, pressure, and sound parameters of aortic valve closure. Sixteen children, ages 3--20 years, were evaluated by simultaneous aortic valve echograms, micromanometric aortic root pressure tracings, and intracardiac phonocardiograms recorded at paper speeds of 200 mm/sec. Our observations demonstrated that echographic coaptation of the aortic valve leaflets coincides with the trough of the aortic pressure incisura and the onset of A2. The data suggest that A2 is a result of valve closure.

Introduction: Left ventricular hypertrophy (LVH) is a very important prognostic indicator. Multiple ECG criteria were developed in the 1960s using dye cast and autopsy studies and the relative sensitivity, specificity, and accuracy in relation to standardized echo criteria is unclear. Aim: Identify the ECG criteria that have best sensitivity, specificity and accuracy in LVH detection, using echo as a reference. Hypothesis: We hypothesize that conventional ECG criteria have different and overall poor sensitivity for detection of LVH. Methods: We used the echocardiographic database at Vancouver General hospital to identify consecutive patients September 2009-September 2017 with an echocardiographic diagnosis of LVH by ASE criteria. ECGs completed within 30 days of echo study were analyzed. •LVM(g) = 0.8 x 1.04 x [(IVSd+ LVd+ PWd)3 - LVd3] + 0.6g•All LV mass indexed to BSA.•RWT=2x PWd) / LVd. Relativewall thickness (RWT) allows further classification of LV mass increase as either concentric hypertrophy (RWT >0.42) or eccentric hypertrophy (RWT ≤0.42). A comparative analysis was done to identify the most sensitive and specific ECG criteria to detect LVH. Results: Data comprised of 27,564 subjects (46% Female). Our analysis showed all ECG criteria have comparable accuracy which ranges between 62% - 85%. Overall accuracy is being driven primarily by the negative predictive value indicating those not meeting ECG criteria are very unlikely to have LVH. False positive rates for all methods (1-PPV) are very high. Some of the previously validated precordial criteria are examples of simple criteria with among the highest overall accuracy, very high NPV and highest sensitivity. None of the criteria appear to have differential sensitivity to concentric vs eccentric hypertrophy. Limitations: We used echo as reference standard for LVH assessment. We acknowledge that which is associated with inter-observer and intra-observer variabilities in measurement of wall thickness. We will be using machine learning platform to uniformly classify wall thickness to enhance accuracy in the final paper. Conclusions: The results of our analysis confirm our hypothesis that ECG criteria for LVH have similar but overall poor sensitivities in detecting LVH. A large proportion of patients with hypertrophy on echo were not detected by any of the ECG criteria. Future Directions: Echo LVH can be more accurately characterized using machine learning platform that we will apply to >20, 000 patients, further assessing the validity of our preliminary findings. [ABSTRACT FROM AUTHOR]