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Biomedical subjects

W L Henry

Publications and source records attributed to W L Henry.

At least 73 records · Page 4Linked to original sources
PubMed1986

Effect of imaging view and sample volume location on evaluation of mitral flow velocity by pulsed Doppler echocardiography.

Pulsed Doppler mitral flow velocity measurements have been used to evaluate left ventricular diastolic filling. In normal persons these measurements are affected by age and respiration, but not by gender, body surface area or normal blood pressure. Additional factors that may influence these measurements include the imaging view and sample volume location. In this study, the effects of imaging view and sample volume location were evaluated in 52 normal subjects, aged 21 to 78 years. Pulsed Doppler recordings were obtained from the apical 4-chamber and apical 2-chamber views with the sample volume located both in the left atrium and at the level of the mitral valve leaflet tips. Doppler measurements were slightly, but not significantly, higher (4% on average) for recordings obtained from the apical 4-chamber than from the 2-chamber view for peak flow velocity in both early and late diastole. However, apical 4-chamber recordings from a sample volume in the left atrium resulted in measurements significantly lower (p less than 0.05) for both early and late diastolic mitral peak flow velocity than those obtained near the mitral leaflet tips (peak flow velocity in early diastole = 43 +/- 12 vs 57 +/- 12 cm/s and peak flow velocity in late diastole = 36 +/- 7 vs 46 +/- 11 cm/s, respectively). The higher mitral peak flow velocity values recorded in early and late diastole near the mitral leaflet tips may be related to the smaller flow area at the mitral valve orifice compared with the left atrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

A simple Doppler echocardiographic method for estimating severity of aortic regurgitation.

Doppler echocardiography is useful for detecting aortic regurgitation (AR). To determine if the presence of retrograde holodiastolic flow in the abdominal aorta can be used to assess the severity of AR, abdominal aortic flow velocity was examined by pulsed Doppler echocardiography in 33 patients with AR and 10 patients without AR confirmed by aortography, and in 15 normal subjects. Among the 33 patients with AR, 15 had mitral regurgitation, 11 had mitral stenosis, 8 had aortic stenosis, 5 had prosthetic mitral valves, 4 had prosthetic aortic valves and 2 had aorticopulmonary shunts. No retrograde holodiastolic flow was found in the abdominal aorta of 15 normal subjects or 10 patients without AR. Of the 22 patients with 1+ or 2+ AR independently determined by injection of iodinated contrast into the aortic root, 21 did not have retrograde holodiastolic abdominal aortic flow, whereas all 11 patients with 3+ or 4+ AR had retrograde holodiastolic flow in the abdominal aorta. One patient with 1+ AR and a left-to-right aorticopulmonary shunt had retrograde holodiastolic flow in the abdominal aorta. The finding of holodiastolic retrograde flow in the abdominal aorta is useful for distinguishing patients with severe AR from those with mild or absent AR. Moreover, the method is easy to perform and results appear to be independent of the presence of other cardiac diseases except significant aorticopulmonary shunt.

Adolescent↗
PubMed1986

Studies of Doppler aortic flow velocity during supine bicycle exercise.

Although Doppler echocardiography is useful in the assessment of left ventricular function at rest, little information is available on the application of this technique during exercise. Consequently, Doppler aortic flow studies were performed in 17 young normal subjects during and after supine bicycle exercise. The purposes of the study were to determine the feasibility of recording Doppler aortic flow velocity with a suprasternal notch transducer during exercise and to assess the changes in normal aortic flow velocity parameters during exercise and early recovery. Each subject exercised until fatigue; mean duration of exercise was 10 minutes. Heart rate increased from a mean of 69 beats/min at control to 159 beats/min at peak exercise. On average, aortic peak flow velocity increased by 45% from control, reaching its maximum at 2 minutes after exercise. Ejection time decreased by 34% during exercise, being shortest at peak exercise. Heart rate, peak flow velocity and ejection time had not returned to normal by 10 minutes after exercise. Aortic flow velocity integral (a relative measure of stroke volume) decreased by 10% at peak exercise (p less than 0.05) compared with control, but had returned to control at 2 minutes after exercise. Despite mild aliasing, increased spectral dispersion, faster heart rates and increased respiratory rate during maximal exercise, aortic flow velocity measurements could be recorded using the suprasternal technique. These baseline Doppler exercise data should be useful in further studies of exercise hemodynamic changes in patients with heart disease.

Adolescent↗
PubMed1986

Enhanced survival in patients with heart failure and life-threatening ventricular tachyarrhythmias.

Previous reports have suggested that patients with heart failure and coexistent ventricular tachyarrhythmias have a 1-year mortality of 40% to 60%. To assess whether an antiarrhythmic management program could reduce mortality, we studied 20 consecutive patients with ventricular fibrillation (12) or ventricular tachycardia (eight) and heart failure. Coronary disease was the most common underlying cardiac disorder (85%). Heart failure was managed with digoxin (16), diuretics (16), and vasodilators (seven). All patients received antiarrhythmic drug therapy guided by both noninvasive and invasive studies. This included single (10) or combination drug therapy (10). Beta blockers were used alone or in combination for arrhythmia control in 11 patients. One-year survival was 89%. We conclude that an effective program can be developed for patients with life-threatening ventricular tachyarrhythmias and heart failure. Combination antiarrhythmic drug therapy is often required. Despite impaired left ventricular function, beta-blocking drugs can be used, and may be important.

Anti-Arrhythmia Agents↗
PubMed1986

Left ventricular filling in hypertrophic cardiomyopathy: a pulsed Doppler echocardiographic study.

Abnormal left ventricular diastolic properties have been described in patients with hypertrophic cardiomyopathy. To evaluate the diastolic filling characteristics of the left ventricle in patients with this disease, pulsed Doppler echocardiography was used to study mitral flow velocity in 17 patients with hypertrophic cardiomyopathy (11 with and 6 without systolic anterior motion of the mitral valve) and 16 age-matched normal subjects. There were no statistically significant differences between patients with hypertrophic cardiomyopathy with and without systolic anterior motion with regard to ventricular septal thickness, left ventricular posterior wall thickness, left ventricular internal dimensions or the extent of hypertrophy evaluated by two-dimensional echocardiography. Mitral regurgitation was detected by Doppler echocardiography in all 11 patients with and in 2 (33%) of the 6 patients without systolic anterior motion of the mitral valve. Early and late diastolic peak flow velocity, the ratio of late to early diastolic peak flow velocity and deceleration of early diastolic flow were measured from Doppler mitral flow velocity recordings. There were no statistically significant differences in these four indexes between the patients with systolic anterior motion and normal subjects. In contrast, the patients with hypertrophic cardiomyopathy without systolic anterior motion showed lower early diastolic peak flow velocity, higher ratio of late to early diastolic peak flow velocity and lower deceleration of early diastolic flow compared with the patients with systolic anterior motion and normal subjects, suggesting impaired left ventricular diastolic filling.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Solitary beta-blocker therapy for idiopathic life-threatening ventricular tachyarrhythmias.

To determine the clinical characteristics of patients with life-threatening ventricular tachyarrhythmias with no identifiable heart disease, we analyzed six patients who presented with either cardiac arrest or syncope associated with documented ventricular tachycardia or fibrillation. Electrocardiographic and echocardiographic examination and cardiac catheterization results were normal in all patients. Electrocardiographic monitoring revealed ventricular tachycardia in all patients. Exercise testing did not provoke sustained ventricular tachycardia in any patient. Programmed extrastimulation did not induce ventricular tachycardia in any patient. Isoproterenol infusion facilitated provocation of sustained ventricular tachycardia in only one patient. All six patients were treated with solitary beta-blocker therapy. Following treatment, there was a significant reduction in the incidence of ventricular tachycardia, couplets and total ventricular ectopic beats. During a follow-up period ranging from 16 to 36 (mean 22) months, all patients remain alive without clinically significant recurrence. Therefore, patients with life-threatening ventricular tachyarrhythmias without identifiable heart disease may respond to solitary beta-blocker therapy.

Adrenergic beta-Antagonists↗
PubMed1985

Echocardiographic and Doppler flow observations in obstructed and nonobstructed hypertrophic cardiomyopathy.

Some investigators have suggested that left ventricular (LV) ejection is completed much earlier than normal in patients with hypertrophic cardiomyopathy (HC), whether or not a LV outflow gradient is present, and they have therefore concluded that LV ejection is not impeded in HC, but merely ends early because of early completion of LV emptying. This possibility was examined using pulsed Doppler echocardiography to record ascending aortic flow velocity patterns in 20 patients with HC, 12 with evidence of LV outflow gradient at rest (obstructed HC) and 8 without evidence of a significant resting gradient (nonobstructed HC). Peak aortic flow velocity was similar in patients with nonobstructed HC (92 +/- 26 cm/s) and those with obstructed HC (94 +/- 26 cm/s) and in 20 normal subjects (92 +/- 11 cm/s). However, mean ejection time measured from the aortic flow velocity tracing or aortic echogram was longer in those with obstructed HC (345 +/- 30 ms) than in those with nonobstructed HC (296 +/- 24 ms, p less than 0.02) and in normal subjects (294 +/- 19 ms, p less than 0.01). Furthermore, a rapid decrease in aortic flow velocity in midsystole was seen in 11 of 12 patients with obstructed HC, but in none of the patients with nonobstructed HC or normal subjects. Doppler left atrial flow velocity recordings, obtained in 11 patients, demonstrated mitral regurgitation in 4 of 5 patients with obstructed HC but in none of 6 patients with nonobstructed HC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Determination of the optimal timing for performing digital ventriculography during atrial pacing stress tests in coronary heart disease.

To determine the optimal time for recording left ventricular angiograms during atrial pacing stress tests, digital subtraction left ventriculograms were obtained using 12 ml of contrast material in 40 patients at rest and at peak pacing. Nineteen of the 40 patients had a third digital left ventriculogram performed between 5 and 10 seconds and 21 patients had a third digital left ventriculogram performed 30 seconds after pacing was stopped. Coronary angiography showed significant coronary artery disease (CAD) in 29 patients and no evidence of significant CAD in 11 patients. Ejection fraction (EF) increased or did not change at peak pacing in 10 of 11 patients without CAD. In the 29 patients with CAD, mean EF decreased an average of 10 percentage points (p less than 0.001) and fell 2 or more percentage points in 25 patients (86%) at peak pacing. These changes in EF were accompanied by the development of wall motion abnormalities, which occurred in segments of myocardium that were supplied by coronary arteries with angiographic CAD (more than 50% diameter narrowing). In contrast, the mean EF during the postpacing studies decreased only 2.2 percentage points (difference not significant) over rest values. Moreover, 15 of 29 patients (52%) with CAD had a decrease in EF of 2 or more percentage points. Therefore, the sensitivity of the atrial pacing stress test was diminished when the analysis was performed at 10 or 30 seconds after pacing. It is concluded that EF changes and wall motion abnormalities induced by atrial pacing are of short duration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Propafenone therapy for ventricular tachycardia in the setting of congestive heart failure.

The combined occurrence of impaired left ventricular function and ventricular tachyarrhythmias portend a high annual mortality. Although antiarrhythmic drugs can reduce ventricular arrhythmias, the prognosis may be unchanged. We administered propafenone to 12 patients with ventricular tachyarrhythmias and left ventricular ejection fractions less than 40%. Propafenone significantly reduced isolated ventricular premature depolarizations, couplets, and ventricular tachycardia on ambulatory monitoring. Propafenone eliminated all exercise provocable ventricular tachycardia. Propafenone additionally abolished ventricular tachycardia inducible by programmed stimulation in five of six patients. In eight patients studied before and during therapy, there was no significant change in left ventricular ejection fraction determined by nuclear ventriculography. Propafenone was discontinued in three patients due to side effects. All patients remain alive and without recurrence of clinically significant arrhythmia over a mean follow-up period of 14 months. Propafenone is an effective drug for the management of ventricular tachyarrhythmias, and may be used in patients with impaired left ventricular function.

Administration, Oral↗
PubMed1985

Superiority of two-dimensional measurement of aortic vessel diameter in Doppler echocardiographic estimates of left ventricular stroke volume.

Attempts to measure left ventricular stroke volume utilizing the Doppler aortic flow method have found varying correlations between invasive thermodilution and non-invasive Doppler methods. Because stroke volume is the product of the Doppler flow velocity integral (that is, the area under the flow velocity curve) and the cross-sectional area of the vessel through which blood flows, both variables are potential sources of error. Previous studies have shown that the Doppler flow velocity integral can be measured with acceptable reproducibility in the ascending aorta. Consequently, in this study an attempt was made to determine empirically the optimal method for measuring aortic diameter and area. The diameter of the ascending aorta was measured utilizing four M-mode and seven two-dimensional echocardiographic conventions. Doppler aortic flow velocity patterns were recorded with a 2.25 MHz M-mode echocardiographic transducer from the suprasternal notch by mapping the ascending aorta until aortic peak flow velocity was recorded. In 19 adult patients undergoing cardiac catheterization for clinical indications, Doppler stroke volume estimates utilizing the various echocardiographic conventions for measuring aortic root diameter and area were compared with simultaneous measurements of stroke volume by the thermodilution technique. The best correlation (r = 0.87) with thermodilution stroke volume was obtained by estimating aortic area from the two-dimensional parasternal long-axis images with the aortic dimension measured distal to the aortic sinuses from the inner to inner wall. The data were related by the equation: Thermodilution stroke volume = (0.73) X (two-dimensional Doppler stroke volume) + 17 cc.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1984

Reproducibility of Doppler aortic blood flow measurements: studies on intraobserver, interobserver and day-to-day variability in normal subjects.

Doppler aortic flow velocity measurements have been used to assess quantitatively left ventricular performance at rest and after pharmacologic and other hemodynamic interventions. To permit more meaningful interpretation of Doppler data, 10 normal subjects were studied to establish the intraobserver, interobserver and day-to-day variability in Doppler aortic flow velocity measurements. In each subject, pulsed Doppler recordings of ascending aortic flow velocity were obtained from the suprasternal notch on 2 different days (mean interval 6 days), with the same technician performing and same physician reading both Doppler studies to evaluate day-to-day variability of measurements. Interobserver variability was assessed by having 2 observers read each Doppler study. Both observers read the Doppler records from both days again at a second session to determine intraobserver variability. Intraobserver variability ranged from 1.9 +/- 1.8 to 3.2 +/- 2.9% for ejection time, peak flow velocity and flow velocity integral, but was higher for acceleration time (7.9 +/- 6.6%). Interobserver variability ranged from 3.5 +/- 2.2 to 5.4 + 3.4% for peak flow velocity, ejection time and flow velocity integral, but was notably higher for acceleration time (17 +/- 9%). Day-to-day variability was higher for acceleration time (7.0 +/- 5.2%) than for ejection time, peak flow velocity and flow velocity integral (range from 3.6 +/- 3.1 to 5.2 +/- 4.0%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Detection and quantitation of coronary artery stenoses from digital subtraction angiograms compared with 35-millimeter film cineangiograms.

To assess the ability to detect coronary artery narrowings from computer-acquired angiograms, a panel of 4 observers independently identified and measured focal coronary narrowings from digital subtraction angiograms and compared the results to those obtained from standard 35-mm cine film angiograms. Both cine and digital angiograms were obtained sequentially using selective intracoronary artery injection of standard amounts of iodinated contrast media. Digital images were obtained at 8 frames/s with a 512 X 512 X 8-bit pixel matrix. Modifications in the imaging chain for computer acquisition included a slower pulsed radiographic mode, a progressive scan camera, and initial storage of the images on an 80-megabyte digital hard disk. Postprocessing computer algorithms were used to enhance the unsubtracted digital images; these included single-frame, mask-mode subtraction, vessel boundary edge enhancement, and 4-fold pixel magnification. In 19 patient studies, 32 arteries were reduced more than 25% in diameter according to at least 1 of 4 observers on either the digital or cine film angiograms. There was no significant difference in the mean percent diameter narrowing for all the narrowings between the digital angiograms (53 +/- 31%) and the cineangiograms (52 +/- 31%). In addition, a 2-way analysis of variance yielded no significant difference between the amount of variability in the measurements between the cine film and the digital technique. This similar variability persisted when subsets of patients based on the degrees of stenosis were considered (e.g., only narrowings from 50 to 90% diameter reduction).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Evaluation of blood flow velocity in the ascending aorta and main pulmonary artery of normal subjects by Doppler echocardiography.

Blood flow velocity measurements were made in the ascending aorta and proximal main pulmonary artery of 20 adult normal subjects (12 men and eight women, age range 21 to 46 years) with the use of a commercial prototype ultrasound instrument combining a spectrum analyzer-based, pulsed Doppler velocimeter with a two-dimensional sector scanner. The sector scanner was used to produce two-dimensional images of the main pulmonary artery so that the Doppler sample volume could be placed parallel to the flow stream. A 2.25 MHz right-angle M-mode ultrasound transducer was positioned in the suprasternal notch and was used to measure blood flow velocity in the ascending aorta. There were significant differences (p less than 0.001) between the ascending aorta and main pulmonary artery (PA) in the following blood flow parameters: peak flow velocity (aorta = 92 cm/sec, PA = 63 cm/sec), average acceleration (aorta = 940 cm/sec2, PA = 396 cm/sec2), acceleration time (aorta = 98 msec, PA = 159 msec), deceleration time (aorta = 197 msec, PA = 172 msec), average deceleration (aorta = 473 cm/sec2, PA = 356 cm/sec2), and ejection time (aorta = 294 msec, PA = 331 msec). These data indicate that despite a four to five times higher arterial resistance in the systemic circuit compared to the pulmonary circuit, blood is accelerated two to three times more rapidly in the ascending aorta than in the main pulmonary artery. Also, the peak flow velocity is higher in the aorta and is achieved earlier in systole than in the pulmonary artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Non-invasive measurement of cardiac output by a single breath constant expiratory technique.

A new single breath test has been developed that measures pulmonary blood flow (Qc) and pulmonary tissue volume by using the fact that Qc is proportional to the relationship between the absorption rate of acetylene (C2H2) from the alveolar gas and the rate of change of lung volume during constant expiratory flow. To make these measurements a bag in bottle system with a rolling seal spirometer, a mass spectrometer, and a minicomputer with analogue to digital conversion have been used. Qc was compared with cardiac output measured by the thermodilution technique in 20 patients with cardiac disease; some also had mild chronic obstructive pulmonary disease. The mean (SD) resting Qc for the group was 5.27 (1.22) l/min and the cardiac output measured by thermodilution was 5.30 (1.31) l/min. The mean difference between the two estimations of cardiac output was 0.03 l and the standard deviation of this difference was 0.76 l. The Qc technique was not successful in patients with an FEV1/FVC less than 60%, but seemed to be accurate in those with higher FEV1/FVC values. Correction of Qc for the effect of venous admixture in 14 patients resulted in an average 19% overestimation of cardiac output (6.01 (2.52) l/min v 5.05 (1.64) l/min). It is concluded that cardiac output can be accurately measured in patients with cardiac or mild pulmonary disease. No correction for venous admixture due to ventilation-perfusion mismatch was necessary in these patients, presumably because the large breath used by the technique overcomes most mild ventilation-perfusion maldistribution. These findings, in addition to the non-invasive nature of the technique, suggest potential value for the measurement of cardiac output in various clinical conditions.

Adult↗
PubMed1983

Measurement of left ventricular ejection fraction by videodensitometric analysis of digital subtraction angiograms.

Left ventricular ejection fraction (LVEF) was calculated from 25 first-pass digital subtraction angiograms using a densitometric analysis. Digital subtraction angiograms are obtained in a computerized format; therefore, they can be readily analyzed with computer software to measure the density of the iodine signal within the image. The video signals from the image intensifier were logarithmically amplified so that there was a linear correlation between the video signal intensity and the depth of the iodine contrast material represented by that video signal. LVEF was also calculated by the area-length method from the same digital subtraction angiograms. There was close correlation between these two techniques (r = 0.94, standard error of the estimate = 5.04%). The videodensitometric EF technique is simple to perform, it correlates well with the standard area-length method, and is not dependent on geometric assumptions of LV geometry.

Absorptiometry, Photon↗
PubMed1983

Digital angiography in assessment of ventricular function and wall motion during pacing in patients with coronary artery disease.

Using digital subtraction angiography, left ventriculograms were obtained with 10 ml of iodinated contrast material in 21 patients both at rest and during atrial pacing. In 15 patients with significant coronary artery lesions (CAD) (greater than 50% diameter narrowing in at least 1 major artery), ejection fraction decreased during atrial pacing from a mean of 62 +/- 14% to 51 +/- 15% (p less than 0.001). In 14 (93%) of 15 patients, ejection fraction decreased or was unchanged during pacing. In 6 patients with chest pain but normal coronary arteries, ejection fraction increased from a mean of 66 +/- 9% at rest to 72 +/- 6% during atrial pacing (p less than 0.01). Ejection fraction increased by greater than or equal to 5% during pacing in 5 of 6 patients with normal coronary arteries. Patients with CAD also had an abnormal response in end-systolic volume during atrial pacing (50 +/- 31 ml at rest versus 47 +/- 24 ml during pacing) compared with patients with normal coronary arteries (46 +/- 16 ml at rest versus 26 +/- 9 ml during pacing; p less than 0.01). The digital ventriculograms demonstrated new or increased wall motion abnormalities during atrial pacing in 4 of 5 patients with CAD who had wall motion abnormalities at rest and in 8 of 10 patients with CAD who had normal wall motion at rest. Moreover, these wall motion abnormalities occurred in myocardial wall segments that were supplied by coronary arteries with significant lesions. Thus, because digital subtraction angiography allows multiple left ventriculograms to be obtained during routine cardiac catheterization, intervention studies such as atrial pacing can be used to obtain a functional assessment of the severity of coronary arterial lesions.

Adult↗
PubMed1983

Correlation of 10-milliliter digital subtraction ventriculograms compared with standard cineangiograms.

Left ventriculograms were obtained with the use of 10 ml of contrast media by passing fluoroscopic video images through a video image processor. The low concentration of dye in the left ventricle was enhanced by the technique of mask mode subtraction, and the images were postprocessed to increase visibility by manipulation of the gray scale and contrast levels. These digital subtraction angiograms were compared to standard cineangiograms by means of 40 ml of contrast media. Of 30 patients studied, six (20%) had runs of ventricular tachycardia during the cineangiogram and had to be excluded. In the remaining 24 patients, there was a good correlation between the two techniques for left ventricular end-diastolic volume (r = 0.77, end-systolic volume (r = 0.95), and ejection fraction (r = 0.97). Spatial resolution in the digital studies was adequate to appreciate wall motion abnormalities that were visualized on the cineangiograms. Left ventricular end-diastolic pressure (LVEDP) did not change after the 10 ml injection, but the mean LVEDP rose 6.0 mm Hg after the 40 ml cineangiograms (p less than 0.01). Digital subtraction angiography can be used to obtain left ventriculograms with one-fourth the amount of contrast media and one-fourth the x-ray exposure compared to standard cineangiograms. This technology will permit multiple left ventriculograms to be obtained which, in turn, will allow intervention studies to be performed in the catheterization laboratory.

Adult↗