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Biomedical subjects

A D Waggoner

Publications and source records attributed to A D Waggoner.

At least 55 records · Page 3Linked to original sources
PubMed1982

Importance of preoperative hypertrophy, wall stress and end-systolic dimension as echocardiographic predictors of normalization of left ventricular dilatation after valve replacement in chronic aortic insufficiency.

To define and compare predictors of postoperative normalization of diastolic left ventricular dimension after aortic valve replacement, echocardiographic indexes of left ventricular size, function, degree of hypertrophy and systolic wall stress were examined in 43 patients with chronic and 14 with acute aortic insufficiency. In all of the latter 14 patients, left ventricular diastolic dimension returned to normal (mean 5.2 +/- 0.4 cm) in the postoperative follow-up period (mean 8.0 months). In contrast, of those with chronic insufficiency, 28 (group A) had postoperative normalization of diastolic dimension whereas the remaining 15 (group B) had persistent enlarged diastolic dimension. Preoperative end-systolic dimension, diastolic radius/thickness ratio, mean radius/thickness ratio, mean wall stress and end-systolic stress were 84 to 93 percent accurate in predicting normalization versus persistence of left ventricular dilatation postoperatively, and were superior to preoperative end-diastolic dimension and shortening fraction. Postoperatively, group A had complete normalization of end-systolic dimension and of mean and end-systolic wall stresses with persistence of a normal shortening fraction. Group B continued to have increases in end-systolic dimension, mean wall stress and end-systolic stress with a reduction in shortening fraction. Postoperatively there was a 43 and 29 percent incidence rate of heart failure and death by heart failure, respectively, in group B versus none in group A (p less than 0.01). These findings support the concept that inappropriate hypertrophy in chronic aortic insufficiency is associated with progressive increases in wall stress and end-systolic dimension and a reduction in shortening fraction that eventually result in irreversible cardiac dilatation and failure. Accurate and clinically relevant determination of reversible and irreversible alterations in left ventricular size and function may be obtained with these echocardiographic indexes.

Adolescent↗
PubMed1982

Pulsed doppler echocardiographic detection of mitral regurgitation in mitral valve prolapse: correlation with cardiac arrhythmias.

The incidence of mitral regurgitation in mitral valve prolapse was studied retrospectively in 88 consecutive hospital based patients with mitral valve prolapse using pulsed Doppler echocardiography. Pulsed Doppler findings of turbulence in the left atrium were predictive of angiographic findings of mitral regurgitation in 31 patients. On 24-hr Holter monitoring, patients with mitral valve prolapse and mitral insufficiency had a higher prevalence of ventricular arrhythmias than patients without mitral insufficiency (61 vs 22%; P less than 0.02). Detection of mitral insufficiency identified individuals with mitral valve prolapse who are at higher risk of ventricular arrhythmias.

Adolescent↗
PubMed1982

Effect of cardiac surgery on ventricular septal motion: assessment by intraoperative echocardiography and cross-sectional two-dimensional echocardiography.

Echocardiographic evidence of paradoxical septal motion frequently occurs after cardiac surgery. To assess possible etiologic factors 17 patients were studied preoperatively, intraoperatively, and 7 days after surgery. Preoperative septal motion was normal in 14 and paradoxical in three (two with previous cardiac surgery, one with atrial septal defect [ASD]). Intraoperative septal motion prior to surgical procedure was normal in 16 and paradoxical in one (ASD). Septal motion (excursion and thickening fraction) was normal in all patients prior to chest closure. Echocardiograms of adequate quality were obtained at 7 days post surgery in 15 patients; septal motion was paradoxical in nine (group A) and normal in six (group B). No significant differences were seen between the two groups in ischemic time or in the preoperative to postoperative change in left ventricular (LV) and right ventricular diastolic dimension, shortening fraction, or septal and posterior wall thickening fraction. A significant postoperative decrease in septal excursion was seen in group A but not in group B; significant postoperative increases in posterior wall excursion were seen in both groups. Cross-sectional two-dimensional echocardiograms performed in 20 patients (8 normal, 12 postoperative paradoxical septal motion) were analyzed. In normal controls no significant change was detected in the LV centroid position during systole. In contrast, the 12 postoperative patients showed significant anterior displacement of the LV centroid and right septum during systole. Thus, paradoxical septal motion after cardiac surgery appears to relate to excessive anterior cardiac mobility due to pericardiotomy rather than to myocardial ischemia resulting from cardiopulmonary bypass.

Adult↗
PubMed1981

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.

Adult↗
PubMed1980

Assessment of pulsed Doppler echocardiography in detection and quantification of aortic and mitral regurgitation.

Pulsed Doppler echocardiography was employed to detect disturbed or turbulent flow diagnostic of aortic or mitral regurgitation. Sensitivity, specificity, diagnostic accuracy, and predictive value were assessed by the independent interpretation and comparison of aortic root angiograms (91 patients) and left ventriculograms (94 patients) to the time interval histogram display of the pulsed Doppler. Sensitivity of Doppler in detecting mitral regurgitation was 94 per cent, with specificity 89 per cent, predictive value 81 per cent, and diagnostic accuracy 90 per cent (32 patients with, 62 without regurgitation). In aortic regurgitation, sensitivity was also 94 per cent, specificity 82 per cent, predictive value 94 per cent, and the diagnostic accuracy was 91 per cent (69 patients with, 22 without aortic regurgitation). Additionally, no Doppler evidence of mitral or aortic regurgitation was present in 20 normal subjects. The aetiology of left-sided valvular regurgitation varied widely, with prosthetic valvular insufficiency being the cause of mitral and aortic regurgitation in seven and 10 patients, respectively. Sixteen of 17 (94%) paraprosthetic leaks were correctly identified by pulsed Doppler. In patients with aortic regurgitation the flow-velocity curve recorded in the ascending aorta frequently showed a negative (or reversed) diastolic component, the magnitude of which (expressed as percentage negative area) correlated significantly with angiographic severity of regurgitation. Thus, pulsed Doppler echocardiography is a highly accurate and objective non-invasive technique for detecting mitral and aortic regurgitation. In aortic regurgitation, estimation of severity is possible from inspection of the Doppler ascending aortic flow velocity curve.

Aortic Valve Insufficiency↗
PubMed1980

Echo-phonocardiographic evaluation of obstruction of prosthetic mitral valve.

Echo-phonocardiograms of 64 patients with multiple types of prosthetic mitral valves (PMV) were evaluated. Six patients demonstrated findings suggesting valve obstruction: four had surgical confirmation of prosthetic obstruction, one reduced cardiac output and pulmonary hypertension but no prosthetic dysfunction at surgery, and one is asymptomatic. Three of four patients with confirmed obstruction had variable second sound to opening click intervals (A2-MO) with interrupted disc opening; two had interrupted disc closure with split closing clicks and three of four had reduced diastolic closure rate. In 58 clinically well patients with PMV, cycle-to-cycle A2-MO varied little: 0-10 msec in sinus rhythm and 10-25 msec in atrial fibrillation. Diastolic closure rates of five different types of PMV were similar: 21.6 mm/sec, (range 14-49). No patient had interrupted opening, closing or multiple closing clicks. Thus, delayed PMV opening or closure, altered A2-MO interval and double closing clicks are highly useful in detecting patients with obstruction of a variety of mitral prostheses.

Adolescent↗
PubMed1976

Aortic valve closure: echocardiographic, phonocardiographic, and hemodynamic assessment.

The temporal relationship between the closure of the aortic valve (AoV) and the onset of the aortic component of the second heart sound (A2) was defined by simultaneous recording of AoV echogram, phonocardiogram (PCG), and electrocardiogram in 25 subjects. Ten subjects had no heart disease (normal); 15 suffered from various cardiac conditions other than AoV disease (patients). The point of coaptation (C) of the AoV cusps to the onset of A2, the C-A2 interval, was measured to the nearest 5 msec. in 125 cycles. Fifty-eight cycles had a C-A2 of 10 msec., and 47 cycles had a C-A2 of 15 msec. The remainder were distributed at intervals below 10 or above 15 msec. The average C-A2 interval was 11.48 +/- 0.38 msec. (mean +/- 1 S.D.). A similar distribution pattern was observed when the total number of cycles was divided into "normal" and "patient" groups. In 3 subjects, simultaneous equisensitive (catheter-tip micromanometer) left ventricular and central aortic pressures, PCG, and AoV echograms were recorded. C-A2 ranged from 0 to 10 msec.; the interval between left ventricular and aortic pressure at the level of the incisura-hangout interval-ranged from 8 to 20 msec. Inhalation of amyl nitrite in one subject produced a significant fall in arterial pressure, accompanied by prolongation of the hangout interval from 10 to 20 msec. and of the C-A2 interval from 0 to 8 msec. Thus, the C-A2 interval is an integral part of the hangout time. Data suggest that A2 does not originate from the coaptation of the aortic valve cusps per se, but is related to events that occur at the time of or slightly after coaptation.

Adolescent↗
PubMed1976

Left atrial enlargement. Echocardiographic assessment of electrocardiographic criteria.

A comparison of electrocardiographic manifestations of left atrial enlargement (LAE) and left atrial size by echocardiography was made in 307 patients in sinus rhythm. Electrocardiographic criteria used were L:P wave duration in lead II equal to or greater than 0.12 sec; Va: the ratio of the duration of negative terminal P in V1 to the P-R segment equal to or greater than 1.0; Vb: a negative P terminal force in V1 less than -0.03 mm sec. The echocardiographic diagnosis of left atrial enlargement was based on 1) transverse dimension greater than 4.0 cm; or 2) a ratio of transverse atrial to transverse aortic root dimension greater than 1.17. In the presence of left atrial enlargement, a combination of criteria occurred more often than a single criterion. The overall predictive index of the electrocardiogram for left atrial enlargement was 63% (excluding criterion Vb raised probability to 80%); and that for absence of left atrial enlargement was 78%. The index of coarse versus fine fibrillary waves was unreliable in predicting left atrial enlargement. Changes in P wave morphology may be used as a reasonably specific but less sensitive indicator of left atrial enlargement.

Adolescent↗
PubMedDate not supplied

Echocardiographic automatic boundary detection to measure left atrial function after the maze procedure.

Automatic boundary detection (ABD) is a new echocardiographic modality providing continuous on-line measurements of cavitary area throughout the cardiac cycle. The maze procedure is a new surgical intervention designed to restore sinus rhythm and mechanical atrial contraction as a definitive treatment for patients with atrial fibrillations for whom medical therapy has failed. To evaluate whether ABD may define left atrial function in patients after the maze procedure, we obtained pulsed Doppler recordings of mitral inflow velocity and echocardiographic ABD in 25 patients, 6 +/- 2 months after the maze procedure. We measured the left atrial end-systolic cavitary area, mid-diastolic area before atrial contraction, and end-diastolic area (in square centimeters). Left atrial contraction by Doppler was compared with that derived by ABD in patients who underwent the maze procedure and control subjects (n = 13), both qualitatively and quantitatively (atrial filling fraction vs active atrial contraction [ABD] where atrial contraction (in percent) = (mid-diastolic area - end-diastolic area) x 100/(end-systolic area - end-diastolic area in percent]). Restoration of atrial contraction after the maze procedure was detected by Doppler in 19 patients (76%) and by ABD in 21 patients (84%). The atrial filling fraction was 19 +/- 4% in patients compared with values of 34% +/- 8% in control subjects (p < 0.001). By ABD atrial contraction was 20% +/- 6% in patients whereas control subjects exhibited values of 41% +/- 14% p < 0.001). The Doppler-derived atrial filling fraction and ABD-derived atrial contraction were closely correlated (r = 0.91; p < 0.001; y = 0.59x + 8.6). Thus Doppler techniques complemented by ABD provide direct quantitative indexes of left atrial function throughout the cardiac cycle. Although left atrial contraction and filling are reduced after the maze procedure, left atrial function is restored in most patients with a history of atrial fibrillation, and echocardiographic ABD is a sensitive technique for its detection.

Atrial Fibrillation↗
PubMedDate not supplied

Two-dimensional echocardiographic automatic boundary detection for evaluation of left ventricular function in unselected adult patients.

Recent modifications in two-dimensional echocardiographic imaging include automatic boundary detection (ABD) that permits instantaneous quantification of left ventricular (LV) function. To define its clinical application from different views in consecutive patients (n = 68), we performed both conventional two-dimensional imaging and ABD with lateral gain compensation and compared the ability of each method for visualization of myocardial segments. From each view (short-axis and apical four- and two-chamber), the LV was divided into six wall segments. The short-axis view was obtained successfully in 53 of 68 patients; of the possible 318 segments, 96% were visualized adequately by two-dimensional echocardiography and 89% by ABD. From the four-chamber view, obtained in 63 of 68 patients, visualization of 378 possible segments was 93% by two-dimensional imaging and 86% by ABD, respectively. From the two-chamber view obtained in 58 of 68 patients, the success rate was 88% and 80% (two-dimensional imaging and ABD, respectively). ABD detected LV endocardial/blood borders in all six segments of each view in 73%, 72%, and 72% of cases, concordant with adequate two-dimensional imaging. Discrepancies between two-dimensional imaging and ABD were usually in the short-axis inferior and lateral, four-chamber lateral, and two-chamber anterior segments. There were 46 patients with normal LV wall motion and 22 with wall-motion abnormalities. The average time required to perform ABD was 375 seconds (range 180 to 780 seconds).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Ultrasonic myocardial tissue characterization in the operating room: initial results using transesophageal echocardiography.

Ultrasonic tissue characterization provides quantitative assessment of myocardial function and viability. We have previously reported that normal myocardium is characterized by a diastolic-to-systolic cyclic variation of integrated backscatter (IB), whereas ischemic myocardium exhibits blunting of this pattern. To define the applicability of this measurement to characterize the left ventricular myocardium in the operating room, we studied 26 consecutive patients undergoing open heart surgery (12 coronary artery bypass graft, 13 valvular, 1 other) with 5 MHz transesophageal echocardiography. Images of the left ventricle were obtained in the short-axis plane (papillary muscle level) before cardiopulmonary bypass. M-mode acquisition of myocardial IB was attempted from the anterior and inferior segments in each patient. The cyclic variation of IB was measured in at least two consecutive cycles in addition to a qualitative assessment of wall motion. Quantitative measurement of IB was possible in 39/52 (75%) myocardial segments. Cyclic variation of IB averaged 5.7 +/- 1.4 dB (SD) in segments with normal wall motion (n = 25); no difference was noted in the cyclic variation of IB among anterior or inferior walls. Hypokinetic segments demonstrated significant reduction of the cyclic variation (3.8 +/- 1.8 dB; p less than 0.001). Difficulty with obtaining myocardial IB was related to near-field artifact or lateral displacement of the left ventricular wall during systole. Transesophageal echocardiography holds promise for the evaluation of myocardial function and its preservation during cardiac surgery.

Aged↗
PubMedDate not supplied

Ultrasonic integrated backscatter two-dimensional imaging: evaluation of M-mode guided acquisition and immediate analysis in 55 consecutive patients.

We have shown previously that cardiac cycle-dependent integrated backscatter characterizes the physical state of myocardium in patients with ischemic heart disease and cardiomyopathy. In the present study the clinical applicability of M-mode guided two-dimensional integrated backscatter imaging was defined in evaluation of 55 nonselected patients. The mean amplitude of cyclic variation of integrated backscatter in normal segments (long-axis view) was as follows: basal septum, 4.2 +/- 1.3 dB (mean +/- SD; n = 27), mid-septum, 4.5 +/- 1.0 dB (n = 26), basal posterior, 4.8 +/- 1.0 dB (n = 30), and mid-posterior, 4.8 +/- 1.2 decibels (n = 27). The respective mean delay values (R wave to nadir) were as follows: 0.89 +/- 0.09, 0.84 +/- 0.09, 0.86 +/- 0.09, and 0.85 +/- 0.12. At least one cardiac cycle could be analyzed fully in 62% of patients. Limitations included technically difficult two-dimensional echocardiography, inadequate M-line orientation, technically remediable errors, or poor quality integrated backscatter images. In abnormal segments (n = 13) cyclic variation was reduced and delay was prolonged (1.2 +/- 1.1 dB and 1.21 +/- 1.1, respectively). Intraobserver and interobserver variability for amplitude measurements were modest, with respective correlation coefficients of r = 0.93; r = 0.72. The findings demonstrate that M-mode--assisted integrated backscatter is a practical approach for characterization of regional myocardial properties promptly and at the bedside in a large portion of patients with cardiac disease.

Echocardiography↗
PubMedDate not supplied

Doppler assessment of left ventricular diastolic function: a review.

Two-dimensional echocardiography provides valuable information for the assessment of left ventricular function. Traditionally, evaluation has focused on determination of systolic performance. However, recent investigations indicate diastolic dysfunction may also contribute to symptoms of congestive heart failure in many patients despite normal systolic function. Pulsed Doppler echocardiography complements two-dimensional imaging for assessment of left ventricular filling properties that are often altered in the setting of diastolic dysfunction. The concept of diastolic function and recognition of abnormal filling patterns detected by pulsed Doppler echocardiography are reviewed.

Blood Flow Velocity↗
PubMedDate not supplied

The role of transthoracic echocardiography in the management of patients seen in an outpatient cardiology clinic.

Transthoracic two-dimensional (2D) Doppler echocardiography may provide new or additional information in patients, but it is often not known whether the results alter the treatment plan. We investigated whether results of clinically indicated 2D echocardiography were different from the physician's clinical examination or led to changes in management in 200 consecutive outpatients seen in a university-based clinic. A questionnaire was completed by the physician regarding physical findings and treatment plan before 2D echocardiography was performed. After results were known, the physician was asked to report any differences compared with clinical examination or changes in patient management. Most patients (83%) were studied to evaluate left ventricular (LV) or valvular function. 2D echocardiography confirmed clinical assessment in 182 patients (one inadequate 2D echocardiogram) and disclosed a new diagnosis in 17. 2D echocardiography provided additional information, not expected from clinical assessment or history, in 94 patients. Clinical assessment, compared with 2D echocardiography, was concordant in 154 (77%) of 199 patients with regard to LV systolic function but in only 22 (50%) of 44 with valve disease. Alterations in management based on results of 2D echocardiography were instituted in 73 patients (36%), most often manifested by changes in pharmacologic therapy (n = 45; 62%). Results of 2D echocardiography obviated the need for further cardiac evaluation, surgery, or procedures in 30 patients, avoiding additional patient charges of $125,754.00. In contrast, results of 2D echocardiography led to the need for further evaluation, surgery, or procedures in 32 patients, resulting in additional patient charges of $70,860.00. In conclusion, 2D echocardiography provides new or additional information that results in changes in management strategy in one third of patients, and 2D echocardiography offers relative cost savings by avoiding additional procedures.

Adolescent↗