Ernest Craige

Evaluation of Left Ventricular Function by Echocardiography

Echocardiographic assessment of left ventricular size and function correlates well with that made by cineangiography. The technic is particularly suited to the early detection and serial monitoring of left ventricular hypertrophy and dysfunction in valvular heart disease, hypertensive heart disease and the cardiomyopathies. It also has advantages over angiography in experimental situations in which frequently repeated or continuous assessment of left ventricular size and function may be required. The limited usefulness of a single ultrasound beam in segmental heart disease, such as ischemic heart disease, may be overcome in the future with improvements in two-dimensional echocardiographic technics.

Determination of Left Ventricular Volumes by Ultrasound

We compared dimensions of the left ventricular minor axis (S) measured at enddiastole (SD) and end-systole (SS) by echocardiography with dimensions and left ventricular volumes measured by biplane angiocardiography in 27 patients with diverse cardiac abnormalities. There were high correlations between echographic and angiographic ventricular minor-axis dimensions (r = 0.85 for SD and 0.87 for SS), between echographic dimensions and ventricular volumes (r = 0.84 for end-systolic volume [ESV] and SS, 0.83 for end-diastolic volume [EDV] and SD), and between the relative change in the echographic minor axis with systole (% &Dgr; S) and ejection fraction (r = 0.79). Regression formulae were derived from these relationships which allowed calculation of ventricular volumes from echo dimensions alone: ESV = 47 SD—120, EDV = 59 SD—153. These equations allowed relatively accurate prediction of volumes over a wide range of ventricular sizes. The use of a cube function of the echographic minor axis was an accurate predictor of volumes only in smaller ventricular chambers, but overestimated volumes in larger hearts.

Long-Term Prognosis of Mitral-Valve Prolapse

We examined the natural history of mitral-valve prolapse in 53 patients who had had a midsystolic click or late systolic murmur (or both) documented phonocardiographically a mean of 13.7 years earlier. Thirty-eight patients were alive without serious complications, and seven had died of unrelated causes. In two patients prolapse was implicated in the cause of death. Other complications were ventricular fibrillation in one patient and bacterial endocarditis in three. Progressive mitral regurgitation developed in five patients, requiring valve replacement in two. These complications occurred in a total of eight patients (15 per cent), and were significantly (P = 0.15) associated with a late systolic murmur rather than an isolated midsystolic click. Thus it appears that the diagnosis of mitral-valve prolapse should not be regarded as ominous; however, patients in whom this diagnosis is associated with a late systolic murmur should be followed carefully.

Determination of Systemic Vascular Resistance by a Noninvasive Technic

Measurement of systemic vascular resistance in man currently requires arterial and venous cannulation, so that cardiac output and mean arterial blood pressure may be simultaneously determined. This report describes a noninvasive technic for determining systemic vascular resistance (SVRn), utilizing an ultrasonic method for cardiac output measurement, and a combination of sphygmomanometry and external carotid pulse tracing analysis for determination of mean arterial blood pressure. SVRn was measured by this technic in 18 patients and compared with systemic vascular resistance determined by conventional methods at cardiac catheterization (SVRc). There was excellent correlation, with SVRc = 0.865 SVRn+216 and r = 0.85. The sensitivity of the method was verified in studies on 12 normal subjects in whom SVRn while supine (1235 ± 61 dyne-sec-cm–5, mean ± se) was less than SVRn while standing (1416 ± 81, P < 0.01) and greater than SVRn supine after amyl nitrite inhalation (652 ± 41,P < 0.0001). It is concluded t...

Assessing the Hemodynamic Severity of Acute Aortic Regurgitation Due to Infective Endocarditis

Nine patients who underwent aortic-valve replacement for acute aortic regurgitation due to infective endocarditis were studied for clinical features that may be useful in assessing the severity of this condition. The traditional physical signs of a wide pulse pressure were absent. As compared to a group of patients with chronic aortic regurgitation, the mean (plus or minus S.D.) pulse pressure (55 plus or minus 7 vs. 105 plus or minus 22 mm Hg), left ventricular end diastolic volume (146 plus or minus 28 vs. 264 plus or minus 64 ml per square meter) and stroke volume (89 plus or minus 22 vs. 163 plus or minus 57 ml per square meter) were significantly smaller in the acute group (P less than 0.01). Left ventricular pressure exceeded left atrial pressure in late diastole, causing premature closure of the mitral valve, and the degree of early closure reflected the increase in left ventricular end diastolic pressure. Premature closure of the mitral valve was demonstrated by echocardiography in all patients. Those with echocardiographic signs of very early mitral-valve closure have severely volume-overloaded ventricles and are candidates for early valve replacement.

Echocardiographic studies of left ventricular wall motion and dimensions after valvular heart surgery

Echocardiograms obtained from 50 patients after valvular heart surgery (in 33 cases within 2 months of the procedure) were examined to study patterns of interventricular septal motion and left ventricular dimensional changes. Preoperative echograms were available in 28 cases. Before and after mitral commissurotomy septal motion and left ventricular diameters as well as the percent systolic shortening of the echocardiographic transverse axis were within normal limits. Before operation, aortic and mitral regurgitation were associated with increases in end-diastolic and end-systolic diameters, septal motion and percent systolic shortening of the left ventricular diameter. Septal dyssynergy, defined as paradoxical motion or marked hypokinesia, was seen within 2 months of operation in 91 percent of patients after aortic valve replacement and in 42 percent after mitral valve replacement. Of subjects studied more than 2 months postoperatively, none with mitral valve replacement and only 33 percent with aortic valve replacement manifested septal dyssynergy. After valve replacement for aortic or mitral regurgitation there were significant decreases in end-diastolic diameter, septal excursion and total and percent left ventricular systolic shortening. Two subjects not having valve replacement also demonstrated paradoxical septal motion postoperatively. The cause of septal dyssynergy after valvular surgery was not apparent although the use of cardiopulmonary bypass was an esential condition. We conclude that echocardiography can be utilized to follow up changes in left ventricular wall motion and dimensions after surgery for valvular heart disease, and that it may be of value in assessing the early and late postoperative results.

On the Mechanism of the Austin Flint Murmur

We studied mitral valve motion in 15 patients with aortic regurgitation and an Austin Flint murmur by recording simultaneously the phonocardiogram, apexcardiogram, and mitral valve echocardiogram. In 14 patients the murmur was presystolic, and in 13 of these a middiastolic component was present as well. The middiastolic component occurred after the period of rapid ventricular filling as the mitral valve was closing. The presystolic component occurred either as the mitral valve was rapidly closing following normal atrial opening movement or during the entire period of atrial systole. In this latter situation the valve did not open completely with atrial systole. All of these patients demonstrated a prominent A wave on the apexcardiogram. In patients with a two-component Flint murmur, isometric handgrip exercise greatly accentuated the murmur, altered the pattern of valve motion so that atrial systole was no longer effective in opening the valve, and reduced the size of the apex A wave.One patient had only a middiastolic Flint murmur. The mitral valve was open for only a brief period in middiastole and did not reopen with atrial systole. Cardiac catheterization documented elevation of ventricular diastolic pressures above left atrial pressures during most of diastole. Amyl nitrite reduced diastolic ventricular pressure and permitted the mitral valve to open with atrial systole. The apex A wave, which was small at rest, increased in size after amyl nitrite.Our findings suggest that the Flint murmur is due to antegrade flow across the mitral valve. The rumble occurs during rapid closure of the valve as flow velocity is increasing although actual volume of flow may be decreasing.

Should auscultation be rehabilitated

IN this issue of the Journal, Lembo et al. provide a convincing report on the efficacy of auscultation in the bedside diagnosis of systolic murmurs.1 A high degree of accuracy was achieved in a gro...

Diagnosis of prosthetic mitral valve malfunction with combined echo-phonocardiography.

Fifty-three patients were studied with combined echo-phonocardiography or phonocardiography alone following prosthetic mitral valve replacement. In sixteen of these patients, clinical deterioration developed, and all subsequently underwent cardiac catheterization and/or surgery. Two patients came to autopsy. Included in this group of sixteen patients were five with obstructed prostheses, six with paravalvular regurgitation, and five with left ventricular dysfunction. Measurements were made of the time interval from the aortic valve closure sound to the peak opening of the mitral prosthesis determined echocardiographically or to the mitral prosthetic opening click (A,-MVO). Echocardiographic studies of left ventricular wall motion were also performed. The A2-MVO interval was significantly shortened (P ⩽ 0.01) with prosthetic valve obstruction (.05 ± .02 sec) and paravalvular regurgitation (.05 ± .01 sec) compared with normally functioning prostheses (Starr-Edwards ball valves .10 ± .02 sec, Lillehei-Kaster tilting disc prostheses .09 ± .01 sec). Shortening of this interval was not specific for these conditions because it was sometimes shortened with left ventricular dysfunction. Echocardiographic studies of left ventricular wall motion were helpful in distinguishing among prosthetic valve obstruction, paravalvular regurgitation and left ventricular dysfunction. The combined echophonocardiographic technique was especially helpful in detecting malfunction of tilting disc prostheses, because the technique enables measurement of the A,-MVO interval in the absence of an audible opening click.

Pulsus alternans determined by biventricular simultaneous systolic time intervals.

This investigation was performed to determine the presence of unilateral or bilateral pulsus alternans in the systemic and pulmonary circulations in heart failure and to estimate the prevalence of pulsus alternans in congestive cardiomyopathy. The subjects were 36 adult patients in heart failure due to a variety of cardiopulmonary diseases. We measured left- and right-sided systolic time intervals from simultaneous dual echocardiograms of both semilunar valves. The alternans was left-sided in seven patients, right-sided in one patient and bilateral in six patients. Pulsus alternans was induced by ventricular premature complexes (VPCs), except in one patient with bilateral and persistent alternans. For a VPC to precipitate alternans, the early beat itself must be associated with an abbreviated ejection time. Echophonocardiographic records of 100 patients with congestive cardiomyopathy were reviewed for evidence of pulsus alternans. We found persistent alternans in 10 patients and VPC-induced alternans in seven patients. We could not measure any difference in severity of disease in patients with pulsus alternans compared with those without.