Quality, Deming's principles, and physicians.
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Guidelines as Topic↗
Biomedical subjects
L E Teichholz
Publications and source records attributed to L E Teichholz.
Comparison of single plane videodensitometry-based right ventricular ejection fraction in right and left anterior oblique views to biplane geometry-based right ventricular ejection fraction.
To evaluate the reliability of the videodensitometric assessment of right ventricular ejection fraction, 38 patients were studied during diagnostic cardiac catheterization. Digital subtraction images of the right ventricle were obtained in both the right anterior oblique and the left anterior oblique views, using direct intraventricular injection of dilute contrast medium. From the end-diastolic and end-systolic images obtained in each view, analysis of the relative brightness values generated a videodensitometry-based right ventricular ejection fraction for both the right and the left anterior oblique views. These values were compared with those generated by applying the geometry-based Simpson's rule to the orthogonal images. Right ventricular ejection fraction ranged from 22 to 88%. Videodensitometric ejection fraction in the right anterior oblique view correlated well with that in the left anterior oblique view (r = 0.88) and each correlated well with geometry-based ejection fraction (r = 0.91 and 0.82, respectively). In a subset of 18 patients without significant cardiac disease, mean videodensitometric right ventricular ejection fraction was 68% (versus 61% in the abnormal subset), and it correlated closely with left ventricular ejection fraction (r = 0.82). Videodensitometric analysis of digital subtraction images provides a reliable method for calculating right ventricular ejection fraction that is independent of geometry and reliably separates normal from abnormal values. Application of videodensitometric techniques should simplify analysis of the response of the right ventricle to different interventions in patients with cardiac disease.
Adult↗
The paradox of pulsus paradoxus.
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Blood Pressure↗
The cardiointegram: detection of coronary artery disease in males with chest pain and a normal resting electrocardiogram.
The cardiointegram is a non-invasive technique for the analysis of the electrical signals of the heart obtained by a transformation of the voltage vs. time format by a series of integrations. This multicenter study compares the results of the cardiointegram with coronary arteriography in 140 male patients with chest pain and a normal resting electrocardiogram. The cardiointegram was determined on two resting complexes of Leads I, II, V4, V5 and V6 and called abnormal if greater than or equal to four of ten complexes were abnormal, i.e., fell outside of a previously determined template of normality. The sensitivity was 73% and specificity was 78% for the diagnosis of occlusive coronary artery disease. When greater than or equal to five of ten abnormal complexes were used as the cut-off for an abnormal test and "equivocal" results (four of ten abnormal, n = 18) were excluded from analysis there was a sensitivity of 69% and specificity of 88%. Thirty-seven of 38 patients (97%) with an abnormal cardiointegram and a positive exercise stress test had coronary artery disease. Thus, the cardiointegram appears to be a useful non-invasive test for the detection of coronary artery disease in males with chest pain and a normal resting electrocardiogram in whom the diagnosis of coronary artery disease is being considered.
Angiocardiography↗
Spontaneous echographic contrast in the inferior vena cava.
The inferior vena cava was examined for spontaneous contrast by two-dimensional echocardiography in 106 consecutive patients. Images of the inferior vena cava in six patients were inadequate and were excluded from further analysis. The study population included 100 patients, 41 men and 59 women. Twenty-three patients had an intravenous line or heparin lock in place at the time of the echocardiographic examination. Ten patients had definite contrast in the inferior vena cava, seven had equivocal contrast, and 83 had no contrast. The three groups did not differ significantly with respect to sex distribution, age, associated diagnoses, or inferior vena cava dimension. We concluded that spontaneous inferior vena cava contrast is commonly seen in adults, both normal subjects and patients with various types of heart disease. There was no specific category of heart disease that predominated in patients with spontaneous inferior vena cava contrast. Although it may be associated with impairment to filling of the right side of the heart and may resolve when normal right heart hemodynamics are restored, spontaneous inferior vena cava contrast is usually a finding with little clinical import. Several possible etiologic factors include microbubbles and aggregates of formed blood elements. Spontaneous inferior vena cava contrast is seen more frequently with a higher frequency imaging system.
Adolescent↗
Carotid sinus massage. Its diagnostic and therapeutic value in arrhythmias.
Carotid sinus massage is a simple bedside maneuver that helps to clarify the type and sometimes also the mechanism of different rhythm disturbances. The major indication for carotid sinus massage is the diagnosis of tachyarrhythmias in which the atrial activity is either absent or intermittently present. Carotid sinus massage is also useful in some patients with normal heart rates; increased vagal tone may normalize a bundle branch block or localize the site of type I second-degree atrioventricular block and can be used for evaluation of the sensing function of permanent pacemakers. Carotid sinus massage is also an important diagnostic procedure in patients with suspected hypersensitivity of the carotid sinus. Massage of the carotid sinus is contraindicated in patients with diseased carotid arteries because of the risk of cerebrovascular accident. In rare instances, carotid sinus massage may initiate ventricular tachycardia.
Aged↗
Effect of nitroglycerin on the pulmonary venous gradient in patients after mitral valve replacement.
Because the equality of the pulmonary artery wedge pressure and left atrial pressure has been questioned in patients with mitral valve disease and pulmonary hypertension, this study examined how vasomotor activity in the pulmonary capacitance vessels might contribute to a discrepancy between these pressures. The difference between the pulmonary wedge and left atrial pressures (designated as the pulmonary venous gradient) was measured after nitroglycerin administration in nine patients who had pulmonary hypertension (mean pulmonary artery pressure 40 mm Hg) after mitral valve replacement. Five minutes after sublingual nitroglycerin, 0.4 mg, the mean pulmonary wedge pressure decreased from 19 +/- 2 to 13 +/- 2 mm Hg (p less than 0.005), exceeding the decrease in left atrial pressure (15 +/- 2 to 11 +/- 2 mm Hg; p less than 0.005). Pulmonary blood flow increased from 4.6 +/- 0.4 to 4.9 +/- 0.4 liters/min (p less than 0.005). The decrease in mean pulmonary venous gradient from 4.0 +/- 0.8 to 1.7 +/- 0.6 mm Hg (p less than 0.025) was attributed to nitrate-mediated pulmonary venodilation. The ratio of venous gradient to blood flow, an index of pulmonary venous tone, decreased after nitroglycerin from 0.9 +/- 0.2 to 0.4 +/- 0.1 (p less than 0.01). These data indicate that reversible pulmonary vasoconstriction contributes to elevation of the pulmonary wedge pressure above the left atrial pressure in patients with chronic mitral valve disease and pulmonary hypertension and that nitroglycerin may produce pulmonary venodilation decreasing the pulmonary venous gradient.
Adult↗
Angiographic morphology and the pathogenesis of unstable angina pectoris.
In 110 patients with either stable or unstable angina, the morphology of coronary artery lesions was qualitatively assessed at angiography. Each obstruction reducing the luminal diameter of the vessel by 50% or greater was categorized into one of the following morphologic groups: concentric (symmetric narrowing); type I eccentric (asymmetric narrowing with smooth borders and a broad neck); type II eccentric (asymmetric with a narrow neck or irregular borders, or both); and multiple irregular coronary narrowings in series. For the entire group, type II eccentric lesions were significantly more frequent in the 63 patients with unstable angina (p less than 0.001), whereas concentric and type I eccentric lesions were seen more frequently in the 47 patients with stable angina (p less than 0.05). Type II eccentric lesions were also present in 29 of 41 arteries in patients with unstable angina compared with 4 of 25 arteries in those with stable angina (p less than 0.0001) in whom an "angina-producing" artery could be identified. Therefore, type II eccentric lesions are frequent in patients with unstable angina and probably represent ruptured atherosclerotic plaques or partially occlusive thrombi, or both. A temporary decrease in coronary perfusion secondary to these plaques with or without superimposed transient platelet thrombi or altered vasomotor tone may be responsible for chest pain in some of these patients with unstable angina.
Angina Pectoris↗
Generating precision microbubbles for use as an echocardiographic contrast agent.
To investigate whether precision microbubbles can be simply generated and used for quantitative contrast echocardiographic studies, precision microbubbles were fabricated in gelatin using a simple generator. The generator consisted of a fluid pump, a generating site containing a narrow bore tube and a bubble stream output port. Up to 5,000 microbubbles/s were generated with a controllable radius of 80 to 150 mu. No detectable interbubble size variation was observed under high power microscopy. To examine whether these bubbles could be used for quantitative contrast echocardiographic studies, they were then infused into a tube with a known flow of degassed water during ultrasonic imaging. The resulting ultrasonic contrast effect in the tube lumen at steady state was recorded and subsequently measured by videodensitometry. The precision microbubbles were visually and microscopically stable during the experimental run. Correlations between microbubble infusion rate and luminal videodensitometry on individual runs were r = 0.89, 0.83, 0.73 and 0.71. It is concluded that precision microbubbles can be generated in sufficient quantities on site to serve as an echocardiographic contrast agent for quantitative studies in vitro and at a very modest cost. These precision microbubbles are sufficiently stable to be collected and stored for short periods of time.
Air↗
Myopotential interference with DDD pacemakers: endocardial electrographic telemetry in the diagnosis of pacemaker-related arrhythmias.
Skeletal myopotentials may inhibit the output of unipolar demand ventricular pacemakers, resulting in protracted episodes of asystole in susceptible patients. The new DDD-mode pacemakers have, in addition to a unipolar ventricular lead, a unipolar atrial lead to enable atrioventricular sequential or atrial synchronous function. During clinical investigation of a new dual-unipolar cardiac pacing system programmed to operate in the DDD mode (Pacesetter AFP models 281 and 283), 6 patients were noted (5 men and 1 woman, aged 22 to 68 years) who manifested paroxysmal acceleration of ventricular pacing rate approaching the maximal tracking rate. Two patients also had abrupt slowing or cessation of ventricular output. With the use of atrial electrographic recordings (obtained with telemetry), the following mechanisms of rate change were found: myopotential tracking, myopotential inhibition, interference-mode asynchronous operation, sudden increases in sinus rate, and pacemaker-mediated reentrant tachycardia. In all patients, reprogramming of the implanted devices, based on telemetered atrial electrography, resulted in disappearance of the arrhythmias and loss of symptoms while maintaining the DDD pacing mode. Thus, several mechanisms of rhythm disturbances are peculiar to dual-chamber cardiac pacing systems that use unipolar electrodes. Endocardial telemetry combined with extensive programming capability offers the best opportunity for proper diagnosis and management of these problems.
Adult↗
Intraoperative contrast echocardiography to evaluate mitral valve operations.
Intraoperative two-dimensional contrast echocardiography was performed on 29 patients undergoing open heart surgery to determine the presence of mitral regurgitation before and immediately after the operative procedure: 14 patients had predominant mitral stenosis, 9 had severe mitral regurgitation and 6 had no mitral valve disease (control subjects). Two-dimensional echocardiography was performed by applying a 5 MHz transducer directly on the heart during injection of saline solution through an apical ventricular sump or transseptal needle, generating contrast microbubbles, with imaging in two planes. Baseline studies were performed after thoracotomy and pericardiotomy before cardiopulmonary bypass, and a second study was done after the operative procedure, with the patient off cardiopulmonary bypass with hemodynamic stabilization before chest closure. No control subject had contrast evidence of mitral regurgitation before or after cardiopulmonary bypass. Two of three patients with mitral valvuloplasty and two of five with commissurotomy required a second operative procedure before chest closure because of persistent mitral regurgitation detected by intraoperative two-dimensional contrast echocardiography. Thirteen of the 15 patients with valve replacement had no mitral regurgitation after cardiopulmonary bypass. Intraoperative two-dimensional echocardiographic findings correlated with data from postoperative clinical examinations and two-dimensional echocardiography-Doppler studies. It is concluded that two-dimensional echocardiography with contrast is an important intraoperative tool for assessing the presence and relative severity of mitral regurgitation after mitral commissurotomy, valvuloplasty or valve replacement. This technique may allow surgeons to be more aggressive in combining reparative operative procedures (that is, commissurotomy and valvuloplasty) in an attempt to retain native valves.
Adult↗
Spontaneous contrast in the inferior vena cava in a patient with constrictive pericarditis.
A 66 year old black man was examined because of fatigue and progressive right heart failure. A striking finding on his echocardiogram was intense and slow-moving contrast in the inferior vena cava. Cardiac catheterization revealed constrictive pericarditis, and pericardiectomy was performed. Postoperatively, spontaneous contrast was no longer present. This case helps explain the origin of spontaneous inferior vena cava contrast.
Aged↗
Acute coronary hemodynamic response to cigarette smoking in patients with coronary artery disease.
The acute changes in coronary blood flow and coronary resistance that occur in response to cigarette smoking have not been accurately determined. To define the factors that affect this response, coronary sinus blood flow was measured in 16 patients (group I) with coronary artery disease and in 6 patients (group II) without angiographically detectable coronary disease. Seven patients (group IA) had severe (greater than or equal to 75%) proximal left coronary lesions and nine patients (group IB) had significant distal lesions with 50% or less proximal stenoses. Group I had a smaller overall increase (increases 1.6 +/- 5.3%) in coronary sinus blood flow than did group II (increases 7.7 +/- 6.1%) (p less than 0.05). Coronary resistance increased overall (increases 2.7 +/- 5.3%) in group I but decreased (decreases 2.4 +/- 3.4%) in group II (p less than 0.05). Patients in group IA had a highly significant increase in coronary resistance as compared with group IB (increases 7.0 +/- 4.2% versus decreases 0.9 +/- 2.6%) (p less than 0.001). Coronary sinus flow tended to decrease (decreases 1.2 +/- 4.6%) in group IA but to increase (increases 3.8 +/- 5.1%) in group IB (p = 0.06). It is concluded that smoking increases coronary resistance in patients with coronary artery disease. A greater impact is observed in patients with a severe proximal stenosis than in those with a distal stenosis. It is proposed that smoking increases coronary artery tone at the site of the stenosis, limiting the coronary flow response proportionally to the size of the affected vascular bed.
Adult↗
Relation between exercise-induced changes in ejection fraction and systolic loading conditions at rest in aortic regurgitation.
To examine the role of systolic wall stress at rest in determining left ventricular performance during exercise in aortic regurgitation (AR), systolic wall stress (measured by M-mode echocardiography) was related to changes in left ventricular function during maximal exercise (evaluated by radionuclide ventriculography) in 30 patients with chronic aortic regurgitation. Of these 30 patients, 7 had a normal exercise response, defined as an absolute increase in ejection fraction of 5% or greater (Group I) and 23 had abnormal exercise response, defined as no change (less than 5% change) or a decline (less than or equal to 5%) in ejection fraction (Group II). Patients in Group I had a significantly lower radius/wall thickness ratio (2.5 +/- 0.2 versus 3.1 +/- 0.1, p less than 0.01) and lower peak systolic wall stress (123 +/- 11 versus 211 +/- 12 X 10(3) dynes/cm2, p less than 0.01) than patients in Group II. An increase in ejection fraction during exercise was seen in 6 of the 9 patients with normal systolic wall stress at rest (less than 150 X 10(3) dynes/cm2), but in only 1 of 21 patients with elevated systolic wall stress (p less than 0.001). Peak systolic wall stress at rest varied linearly, and inversely with changes in left ventricular ejection fraction during exercise (r = 0.60, p less than 0.001). Groups I and II did not differ in ejection fraction at rest, clinical symptoms or maximal work load achieved.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Microbubbles have intracardiac velocities similar to those of red blood cells.
The slope of an individual contrast trajectory on M-mode echocardiography represents the projection of the intracardiac velocity vector of a microbubble in the direction of the sound beam. Doppler echocardiography measures this projection of red blood cell velocity. To ascertain whether microbubbles have similar intracardiac velocities to those of red blood cells, 11 subjects were studied during intravenous injections of 5% dextrose solution. The flow across the tricuspid and pulmonary valves was examined. Microbubble velocity was measured by M-mode contrast slope analysis and simultaneously by Doppler technique. Results from both methods were correlated with red blood cell velocity measured by Doppler recording at the same time in the cardiac cycle, shortly before appearance of contrast medium (3 to 8 beats before the corresponding contrast velocity measurements). In all subjects, 10 sets of three velocities each (M-mode slope and Doppler data before and during contrast injection) were obtained for each valve. Visual inspection of the Doppler tracings showed similar velocity profiles before and during contrast appearance; the signal intensity was greater with contrast. Quantitatively, microbubble velocity assessed by M-mode trajectory slopes correlated well with the Doppler-derived velocity of red blood cells (r = 0.98, p less than 0.001, slope of the regression line = 0.99, standard error of the estimate = 7 cm/s). Doppler velocities measured with and without contrast medium showed a similar correlation (r = 0.99, p less than 0.001, slope of regression = 1.01, standard error of the estimate = 6 cm/s). In individual subjects, the correlation coefficient between microbubble and red blood cell velocities ranged form 0.978 to 0.998.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Early diastolic motion of the posterior aortic root as an index of left ventricular filling.
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Aorta↗
Effects of chronic tobacco smoking on the coronary circulation.
The effects of chronic smoking on the coronary circulation were studied by evaluating the coronary vascular reserve in 12 chronic smokers (group 1) and 10 nonsmokers (group 2). All patients were referred to cardiac catheterization for evaluation of chest pain and were found to have normal coronary and left ventricular angiograms. Coronary vascular reserve was measured by analyzing the hyperemic response to selective coronary injection of contrast agent. There was no statistically significant difference between groups 1 and 2 with regard to age, baseline electrocardiogram or response to treadmill or thallium-201 exercise tests. The mean coronary reserve (+/- standard deviation) was 74.1 +/- 20.1% in the smokers versus 117.1 +/- 45.1% in the nonsmokers (p less than 0.02). In patients who smoked 1 pack a day or less and in those who smoked more than 1 pack a day, the mean coronary reserve was 89.5 and 64.9%, respectively (p less than 0.05). Additionally, of 20 patients followed up for an average of 20 months, 7 of 10 smokers and 1 of 10 nonsmokers continued to have chest pain (p less than 0.03). The cause for the chest pain has not been established in these patients. These results suggest that coronary vascular reserve is significantly less in chronic smokers than in nonsmokers, and that this decrease is more pronounced in heavy smokers.
Adult↗
Quantification of cardiac conduction abnormalities using segmental vector Fourier analysis of radionuclide gated blood pool scans.
Timing abnormalities of myocardial contractility may occur as inter- or intraventricular asynchrony. Gated blood pool scintigraphy was performed on 21 patients with a normal ejection fraction and the following electrocardiograms: six normal, six with left bundle branch block, four with right bundle branch block and five with right ventricular pacemaker rhythm. A phase and amplitude of the first harmonic of the Fourier transform was obtained for each pixel, and left and right ventricles were trisected. A mean vector phase for each region was obtained by vector summation. Regional and global values were analyzed within each group and compared with normal values. The phase differences between the entire left and right ventricles (mean +/- standard deviation) were: 9 +/- 3 in the normal patients, 38 +/- 8 (p less than 0.01) in patients with left bundle branch block, -6 +/- 7 (p less than 0.05) in patients with right bundle branch block and 15 +/- 9 (difference not significant) in patients with pacemaker rhythm. The phase differences between left ventricular posterolateral and septal regions were -4 +/- 2 in the normal patients, 10 +/- 5 (p less than 0.01) in patients with left bundle branch block, -7 +/- 10 (p less than 0.05) in patients with right bundle branch block and 10 +/- 5 (p less than 0.01) in patients with pacemaker rhythm. Within the right ventricle, phase differences between the apical and septal segments were 14 +/- 9 in the normal patients, 14 +/- 10 (NS) in patients with left bundle branch block, -2 +/- 3 (p less than 0.01) in patients with right bundle branch block and -22 +/- 18 (p less than 0.01) in patients with pacemaker rhythm. Interventricular phase differences were greatest in patients with left bundle branch block and absent or reversed in right bundle branch block.(ABSTRACT TRUNCATED AT 250 WORDS)
Arrhythmias, Cardiac↗