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Biomedical subjects

E Craige

Publications and source records attributed to E Craige.

At least 37 records · Page 2Linked to original sources
PubMed1983

Origin of the third heart sound. I. Studies in dogs.

We studied 13 anesthetized dogs in which a third heart sound (S3) was repeatedly induced by hypoxemia plus fluid overload. A miniature accelerometer with a mass of about 1.1 g was applied at three levels--intact chest wall over cardiac apex, in the pericardium and on the epicardium--to record motion of the structures under observation as well as sound. Intraventricular pressure and sound were monitored using a Millar catheter. Application of two accelerometers simultaneously over the epicardium permitted observation of the chronologic sequence of ventricular wall dynamics in early diastole. The S3 at each level occurred simultaneously with the sudden onset of reduced acceleration, or negative jerk. These dynamic phenomena were maximal at or near the cardiac apex. We conclude that the event that triggers the S3 is a sudden intrinsic limitation of longitudinal expansion of the left ventricular wall.

Animals↗
PubMed1983

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.

Cineangiography↗
PubMed1983

Chest wall velocity and the second heart sound. An improved sensor of S2 splitting.

We report a new method of detection of the timing of the aortic and pulmonary valve closure that depends not on the registration of audible vibrations, but rather, on subtle but distinct movements of the chest wall, which are external manifestations of these events. We studied these phenomena in six open-chest dogs and in 69 human subjects. The dog studies show that the two distinct inward movements detected by a motion sensor applied to the epicardium in the vicinity of the right ventricular outflow tract correlate with the timing of the incisural notches of the pressure signals from the great vessels. In humans, these movements are transmitted to the skin surface and can be detected noninvasively. In 48 of the 69 human subjects (70%), these spikes provided a significantly better indication of the timing of semilunar valve closure than did the conventional phonocardiogram.

Animals↗
PubMed1982

Continuous noninvasive monitoring of left ventricular function during exercise by thoracic impedance cardiography-automated derivation of systolic time intervals.

Systolic time intervals (STI) obtained during exercise are useful as a method of estimating global left ventricular function. The conventional method, however, which requires a carotid pulse tracing as well as a phonocardiogram of high quality, is technically difficult under conditions of exercise. We have validated a new method of obtaining STI which employs the first derivative of thoracic electrical impedance (DZ/DT). The DZ/DT was recorded using surface electrodes and a microcomputer for automated signal processing. The new method was studied in 20 male normal subjects (aged 18 to 53 years) at rest and during increasing levels of upright exercise. Heart rate ranged from 61 to 173 beats/min. Results obtained simultaneously by both techniques showed no significant difference. Thus impedance cardiography allows continuous monitoring of STI during exercise and may prove to be a valuable addition to multistage stress testing.

Adolescent↗
PubMed1982

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.

Adult↗
PubMed1980

Right ventricular myxoma. Case report and review of phonocardiographic and auscultatory manifestations.

Tumors in the right ventricle are extremely rare. This report concerns the pathogenesis of physical signs resulting from a right ventricular myxoma. In systole a loud midsystolic murmur representing outflow obstruction was present. In diastole a prominent vibration was heard and recorded. By echophonocardiography this noise could be ascribed to sudden halting of the retrograde excursion of the mass into the right ventricle--a mechanism analogus to the tumor "plop" associated with the halting of antegrade movement of a left atrial myxoma in the left ventricle in early diastole.

Adolescent↗
PubMed1980

Noninvasive assessment of pulmonary hypertension from right ventricular isovolumic contraction time.

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

Adolescent↗
PubMed1980

Early aortic valve closure in combined idiopathic hypertrophic subaortic stenosis and discrete subaortic stenosis.

A patient with idiopathic hypertrophic subaortic stenosis (90 mm Hg resting intraventricular gradient) and discrete subaortic stenosis was found to have two separate systolic closing movements of the aortic valve on M mode echocardiography, each movement being associated with a separate systolic ejection murmur. The first closing movement occurred early in systole and was attributed to alterations in flow across the discrete stenosis. The second closing movement coincided with a later systolic murmur and systolic anterior motion of the mitral valve. The case supports the concept that timing of early closing movements of the aortic valve is useful in the diagnosis of subvalvular obstruction.

Adolescent↗
PubMed1980

Non-invasive diagnosis of subpulmonary outflow tract obstruction.

We have studied the echocardiographic and phonocardiographic findings in 18 patients with obstruction to ventricular outflow at subpulmonary valve level. The aetiology was congenital in 13 patients, a result of hypertrophic cardiomyopathy in three, and infiltration of the right ventricular outflow tract by glycogen or lymphoma in the remaining two. Abnormal systolic motion of the pulmonary valve, fluttering, and early or midsystolic closure were seen in 16 of 17 patients in whom the cusps were visualised. Normal pulmonary valve motion was found in one patient with coexisting pulmonary valve stenosis. In congenital infundibular stenosis the delay of the pulmonary component of the second heart sound (P2) was related to the severity of the obstruction. A pulmonary ejection sound, defined as a high-frequency sound occurring at the moment of full pulmonary valve opening, was absent except in the patient with coexisting pulmonary valve stenosis. In hypertrophic cardiomyopathy with obstruction to the right ventricular outflow, the ejection systolic murmur was softer with inspiration, a finding that contrasts with the respiratory variation seen with fixed obstruction. Recognition of these abnormalities should allow an accurate non-invasive diagnosis to be made and permit assessment of severity when P2 can be recorded.

Adolescent↗
PubMed1980

Dicrotic pulse after open heart surgery.

Pre- and postoperative echophonocardiograms (EPCGs) and preoperative hemodynamic data of 108 patients who underwent valve replacement were reviewed to establish the frequency and significance of a dicrotic pulse (DP) postoperatively. DP occurred almost exclusively in patients who underwent valve replacement for regurgitant lesions (20 of 28 with aortic regurgitation, nine of 25 with mitral regurgitation, and four of six with both aortic and mitral regurgitation). These patients were divided into dicrotic and nondicrotic groups. Preoperatively, the dicrotic group had significantly larger end-diastolic volumes (p < 0.01) and end-systolic volumes (p < 0.01) and significantly lower ejection fractions (p < 0.01). Echocardiographically, the dicrotic group had larger left ventricular dimensions, both systolic (p < 0.01) and diastolic (p < 0.05), reduced percentage fractional shortening of the left ventricular cavity (p < 0.01) and poor thickening properties of the left ventricular posterior wall (% delta Th-LVPW) (p < 0.01). Postoperatively the dicrotic group had a slightly larger end-diastolic dimension (p = NS) and markedly depressed % delta Th-LVPW (p < 0.001) compared with the nondicrotic group. On follow-up EPCG the persistence of a DP correlated with continued left ventricular dysfunction by echocardiographic and hemodynamic studies and an extremely poor clinical course. DP after valve replacement is therefore an important prognostic sign.

Adolescent↗
PubMed1980

Enhancement of tactile perception in palpation.

We studied tactile perception in palpation of the precordium to determine the frequency response of the hand and to improve, if possible, the sensitivity of the hand as a transducer for precordial movement. The threshold of tactile sensation was determined for 10 subjects by manipulating the amplitude of movement of an impulse generator at each of a series of frequency settings in the subaudible range (1-40 Hz.) Relatively gross movements were necessary to achieve threshold in the lowest frequencies. A more than four-fold increase in sensitivity was obtained by restraining the fingers with the application of a light but unyielding disc to their dorsal surface. Clinical application of this device permitted the easy perception of a systolic thrust as well as a rapid filling wave in normal adult subjects over the right ventricle at the left sternal edge, an area generally considered to be motionless by conventional palpation.

Hand↗
PubMed1980

Assessment of the severity of aortic stenosis from the carotid pulse tracing.

The morphology of the externally recorded carotid pulse tracing was studied in 33 patients with valvular aortic stenosis for indices of severity. Comparisons were made with 10 normal controls. In aortic stenosis, initial upstroke time (IUT) of the carotid pulse, and left ventricular ejection time index were significantly higher and the rate of rise of the carotid pulse was slower than in the control group. Severity of stenosis (calculated valve area and mean pressure gradient) could not be predicted, however, from any of these indices. The IUT of the carotid pulse did correlate well with mean velocity of circumferential fiber shortening (mVcf) (r=-0.72). The rate of rise of the carotid pulse had also a correlation with mVcf(r=0.66). However, other commonly used hemodynamic indices (cardiac index, systemic vascular resistance, stroke volume, and ejection fraction) did not have a good correlation with IUT and rate of rise of the carotid pulse. These results suggest that we are able to separate by carotid pulse tracings aortic stenosis from normal subjects, but we cannot say what is the degree of severity of aortic stenosis from analysis of the external carotid pulse recording.

Adolescent↗
PubMed1978

Dual echocardiographic determination of atrial contraction sequence in atrial flutter and other related atrial arrhythmias.

We have applied the new technique of dual echocardiography to determine the sequence of atrial contraction as reflected in the simultaneously recorded movements of the tricuspid and mitral valves. The study group included 29 normal subjects and 23 patients with either atrial flutter, coarse atrial fibrillation or atrial tachycardia with block. In normal individuals, right atrial contraction preceded left atrial contraction, with an average interatrial contraction time of 17 +/- 8 msec. In contrast, the atrial contraction sequence was reversed in atrial flutter, with left preceding right atrial contraction and a prolonged interatrial contraction time of 82 +/- 20 msec. In two patients with atrial tachycardia with block, atrial contraction was either simultaneous or left preceded right atrial contraction by a brief interval. The sequence of atrial excitation, as determined by electrode catheter recordings from the right and left atria in one patient with atrial flutter and one patient with normal sinus rhythm, was the same as the contraction sequence. Left atrial pacing reversed both excitation and contraction sequences. After cardioversion of three patients from atrial flutter to normal sinus rhythm, interatrial contraction time was shortened but remained longer than in normal subjects, suggesting an interatrial conduction disturbance in patients with atrial flutter. In coarse atrial fibrillation, the contraction sequence varied. Significant motion of both mitral and tricuspid valves coincident with fibrillary waves occurred frequently, especially when the fibrillary waves were coarse and regular. Dual echocardiography permits the noninvasive determination of the sequence of atrial contraction and excitation, and may be useful in studying the characteristics of atrial arrhythmias.

Atrial Fibrillation↗
PubMed1977

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.

Adolescent↗