Exercise hemodynamics during long-term implantation of a left ventricular assist device in patients awaiting heart transplantation

OBJECTIVES

The goal of this study was to assess patients with end-stage heart disease after implantation of a left ventricular assist device at rest and during exercise compatible with activities of daily life.

BACKGROUND

Mechanical circulatory assistance with a left ventricular assist device is an accepted therapy for bridging patients with end-stage heart disease to heart transplantation and has been proposed for long-term implantation.

METHODS

Three patients (aged 37, 42 and 57 years) with end-stage heart failure required implantation of a pneumatically driven, asynchronous Thermedics left ventricular assist device while awaiting heart transplantation. All were assessed 1 month later during graded supine bicycle exercise (maximal work load 100 to 150 W). Detailed central hemodynamics, including continuous pulmonary artery oxygen saturation and oxygen consumption measurements, were obtained. Two of the patients also underwent upright treadmill exercise with oxygen consumption measurements.

RESULTS

During supine bicycle exercise, the heart rate increased from 93 +/- 37 beats/min (95% confidence interval: mean +/- t0.025 x SE) at rest to 119 +/- 54 beats/min and left ventricular assist device rate increased from 82 +/- 47 to 109 +/- 55 beats/min. Oxygen consumption increased from 3.0 +/- 0.9 to 8.7 +/- 2.9 ml oxygen/min per kg body weight. Cardiac output increased from 6.0 +/- 4.4 to 9.6 +/- 7.1 liters/min, yielding an average exercise factor of 8.5 +/- 7.7 and an exercise index of 0.83 +/- 0.61. The patients assessed during treadmill exercise achieved a maximal oxygen consumption of 14.3 and 16.7 ml of oxygen/min per kg. No thromboembolic or other complications attributable to left ventricular assist device implantation occurred during the duration of support. All patients survived orthotopic heart transplantation and are doing well.

CONCLUSIONS

Significant work loads compatible with activities of daily life and adequate exercise hemodynamics were demonstrated by these patients while awaiting heart transplantation. Definitive conclusions regarding the use of this device must be viewed as preliminary because only three patients were involved in this study and the failure rate may be as high as 71% (95% confidence interval of left ventricular assist device success as a bridge to transplantation 29.3% to 100%). Final conclusions regarding the safety and efficacy of the left ventricular assist device as a possible long-term circulatory support device must await results of larger multicenter trials in progress.

Bipolar hooked-wire electromyographic technique in the evaluation of pediatric vocal cord paralysis

Laryngeal electromyography is a valuable test to assess vocal cord paralysis in adults. This technique can be applied and adapted to the pediatric patient. In the operating room under general anesthesia and endoscopic guidance, bipolar hooked-wire electrodes are passed percutaneously through the anterior neck skin into both thyroarytenoid muscles. Electromyographic signals are evaluated during light anesthesia and on awakening. A critical appraisal of this technique is presented, including an analysis of sources of electrical interference in the operating room.

Increased afterload intensifies asynchronous wall motion and impairs ventricular relaxation

To clarify whether impaired left ventricular relaxation elicited by increased afterload is attributable to regional dyssynchrony, we analyzed in dogs simultaneous left ventricular contrast ventriculography and pressure before and during angiotensin II infusion. Regional shortening was measured by a centerline method and a video-intensity method that served to define asynchronous motion. During angiotensin II, peak left ventricular pressure increased 35 +/- 6 mmHg, and the isovolumic pressure time constant (tau) was prolonged from 32.7 +/- 4.1 to 39.2 +/- 7.6 ms (P < 0.01). During increased afterload, early diastolic asynchrony, confined to the apical (5 of 7) and inferior regions (2 of 7), was detected in all dogs. Early systolic asynchrony was detected in the apical (5 of 7) and inferior (1 of 7) regions in six dogs. At control, systolic excursion was lower in the anteroapical than in the anterobasal region (P < 0.05). During angiotensin II, excursion of all regions was reduced, with the apical region lower than other regions (P < 0.01). In the normal dog heart, impaired relaxation with augmented afterload is coincident with asynchronous wall motion, especially in the apical-inferior region. Temporal dispersion of regional contraction may explain delayed left ventricular relaxation associated with increased afterload.

Inhibitors of Ca2+ channels, calmodulin and protein kinases prevent A23187 and other inductions of metallothionein mRNA in EC3 rat hepatoma cells

The role of calcium in the induction of MT mRNA has been studied in EC3 rat hepatoma cells, using various inducers (A23187, TPA, norepinephrine, and 2-chloroadenosine) and inhibitors (H7:PK-A and PK-C; W7:calmodulin; verapamil:calcium channel blocker; and TMB-8; cytosolic calcium chelator). The inhibitions of inductions observed in this study were consistent with calcium playing an important role in MT mRNA induction by itself and via crosstalk among the PK-A, PK-C, and calmodulin-dependent protein kinase pathways. Calcium has an important role in the complicated second messenger pathways which result in the positive interaction of transcription factors with the promoters of MT genes.

Evaluation of inotropic effect of endothelin-1 in vivo

The vasoconstrictive peptide endothelin-1 (ET-1) has been reported to exert a very important positive inotropic effect in vitro. To assess the effect of ET-1 on myocardial contractility in vivo, we compared the effect of intracoronary infusion of 10(-8) M ET-1 (constant coronary blood flow) to that of 10(-8) M dobutamine in 8 swine. ET infusion did not produce changes in segmental shortening (control vs. drug, mean +/- SD): 33.8 +/- 14.3 vs. 30.8 +/- 12.1%, shortening velocity: 10.3 +/- 4.3 vs. 10.7 +/- 4.5 mm/s, or maximum +dP/dt: 1,691 +/- 701 vs. 1,772 +/- 773 mm Hg/s, whereas dobutamine infusion induced an important increase in these measurements; segmental shortening: 36.9 +/- 14 vs. 48.4 +/- 18.8%, shortening velocity: 10.1 +/- 2.6 vs. 14.7 +/- 4.5 mm/s, and maximum +dP/dt: 2,041 +/- 567 vs. 2,389 +/- 765 mm Hg/s (all p less than 0.05). Mean myocardial blood flow assessed by microspheres was unchanged by ET-1 despite a marked increase in coronary artery pressure (88.6 +/- 12.9 vs. 157 +/- 8.8 mm Hg, p less than 0.001). Regional infusion of ET-1 at a dose provoking extensive coronary vasoconstriction does not induce any change in regional or global myocardial function in swine.

Chronic major-vessel thromboembolic pulmonary artery obstruction: appearance at angiography

The pulmonary angiograms of 250 patients evaluated for chronic thromboembolic pulmonary hypertension were reviewed. Pulmonary thromboendarterectomy was performed in each of these individuals, and the surgical findings were correlated with abnormal angiographic patterns. The pulmonary angiographic findings suggestive of chronic thromboembolic disease included "pouching" defects, webs or bands, intimal irregularities, abrupt vascular narrowing, and complete vascular obstruction. Pouching is reported by the authors to be a previously undescribed angiographic feature of this disease. Carefully obtained and properly interpreted pulmonary angiograms are necessary to confirm the diagnosis of operable chronic thromboembolic disease. Differential diagnostic possibilities should be considered prior to a decision to perform surgical correction.

Right and left ventricular function after cardiac transplantation. Changes during and after rejection

BACKGROUND

Attempts to identify noninvasive markers of ventricular dysfunction accompanying acute rejection have been hampered by a lack of detailed simultaneous hemodynamic data. Therefore, we prospectively performed serial monitoring of detailed left and right heart hemodynamic parameters in cardiac transplant recipients at the time of routine endomyocardial biopsy to better define the physiology of the allograft heart during and after acute rejection.

METHODS AND RESULTS

To better assess the pathophysiology of the rejection process, 18 cardiac transplant patients were prospectively studied by serial right heart micromanometer catheterization and digital image processing at the time of routine endomyocardial biopsy. Eleven patients had 18 episodes of rejection. Studies of baseline (negative biopsy preceding rejection), rejection (acute moderate rejection), and resolved (first negative biopsy after rejection) states were compared. Seven patients who did not experience an episode of rejection served as the control group. Right ventricular minimum and end-diastolic pressures increased from baseline values of 0.9 +/- 3.2 and 6.9 +/- 3.7 mm Hg, respectively, to 3.2 +/- 5.5 and 9.9 +/- 6.6 mm Hg, respectively, with rejection (both variables, p less than 0.05) and remained elevated despite histological resolution of rejection (4.3 +/- 5.5 and 10.0 +/- 7.1 mm Hg, respectively; p less than 0.05 for both variables compared with baseline values). Concurrently, right ventricular end-diastolic volumes (133 +/- 29, 119 +/- 27, and 114 +/- 30 ml; baseline, rejection, and resolved, respectively) and left ventricular end-diastolic volumes (133 +/- 24, 117 +/- 20, and 113 +/- 30 ml; baseline, rejection, and resolved, respectively) significantly decreased during rejection and remained decreased after resolution of rejection (rejection and resolved compared with baseline values, p less than 0.05). Right ventricular chamber stiffness (0.055 +/- 0.035, 0.085 +/- 0.057, and 0.092 +/- 0.076 mm Hg/ml; baseline, rejection, and resolution, respectively; rejection and resolved compared with baseline values, p less than 0.05) increased with rejection and remained elevated after resolution of rejection. Right ventricular peak filling rate also increased from a baseline value of 2.48 +/- 0.45 to 2.76 +/- 0.63 ml end-diastolic volumes per second with rejection (p less than 0.05). Elevation of right ventricular filling pressures, peak filling rate, and chamber stiffness with a concomitant decrease in end-diastolic volume is consistent with a restrictive/constrictive physiology. Mean arterial blood pressure and systemic vascular resistance were elevated after the resolution of rejection (compared with either rejection or baseline values, p less than 0.05) associated with a higher mean daily dose of prednisone (resolved compared with either baseline or rejection values, p less than 0.05). The control group experienced a time-dependent increase in mean and diastolic systemic arterial pressures (both comparisons, p less than 0.05) without detectable diastolic dysfunction.

CONCLUSIONS

Persistence of biventricular diastolic dysfunction may be due to an irreversible effect of rejection, although multifactorial changes in left ventricular afterload occur that may complicate serial assessment of ventricular function.

Catheter-based intravascular ultrasound imaging of chronic thromboembolic pulmonary disease

Pulmonary thromboendarterectomy is now the treatment of choice for pulmonary hypertension due to chronic pulmonary thromboemboli. A precise assessment of location and extension of these thrombi is important because only proximal chronic pulmonary thromboemboli are accessible to surgery. Because intravascular ultrasound imaging can assess not only arterial luminal size, but also wall thickness, its value as a complement to angiography was assessed in 11 patients aged 35 to 64 years with severe pulmonary hypertension (systolic pulmonary artery pressure, mean +/- standard deviation 70 +/- 19 mm Hg; pulmonary artery resistance, 609 +/- 297 dynes.s.cm-5). Intravascular ultrasound was obtained in 10 of 11 patients and no complication occurred. Intravascular ultrasound identified 10 segments with suspected chronic pulmonary thromboemboli in 7 patients, all confirmed at operation. Nine segments were considered normal, all of which (except 1) were free of chronic pulmonary thromboemboli at operation. Image quality was highly dependent on pulmonary artery size and position of the catheter. Therefore, intravascular ultrasound of pulmonary arteries is feasible and safe in patients with pulmonary hypertension. It may help to assess the location and extension of the pathologic process involving pulmonary arteries.

Intracoronary urokinase for intracoronary thrombus accumulation complicating percutaneous transluminal coronary angioplasty in acute ischemic syndromes

Intracoronary urokinase was used to treat flow-limiting intracoronary thrombus accumulation that complicated successful percutaneous transluminal coronary angioplasty (PTCA) during acute ischemic syndromes in 48 patients who were followed up through the acute phase of their illness. The study group comprised 10 patients with unstable angina pectoris, 18 patients with an evolving acute myocardial infarction, and 20 patients with postinfarction angina. The initial mean percent coronary diameter stenosis for the entire population was 95 +/- 7% and decreased with initial PTCA to 41 +/- 20% (p less than 0.001), with improved corresponding coronary flow by Thrombolysis in Myocardial Infarction trial (TIMI) grade. However, thrombus accumulation then resulted in a significant increase in percent diameter stenosis to 83 +/- 17% (p less than 0.001); a corresponding significant reduction in coronary flow also occurred by TIMI grade. After administration of intracoronary urokinase (mean dose, 141,000 units; range, 100,000-250,000 units during an average period of 34 minutes), with additional PTCA, mean percent diameter stenosis significantly decreased to 34 +/- 17% (p less than 0.001); a correspondingly significant improvement in mean coronary flow by TIMI grade occurred to 2.9 +/- 0.2. Overall, the angiographic success rate was 90%. There were no ischemic events requiring repeat PTCA and no procedure-related myocardial infarctions or deaths before hospital discharge. One patient was referred for urgent coronary artery bypass graft surgery after a successful PTCA. Plasma fibrinogen levels were obtained in 15 patients, and in no patient was the level below normal for our laboratory.(ABSTRACT TRUNCATED AT 250 WORDS)

A 62-dose, 6-month therapy for pulmonary and extrapulmonary tuberculosis. A twice-weekly, directly observed, and cost-effective regimen

STUDY OBJECTIVE

To evaluate the efficacy and toxicity of a 62-dose, four-drug, 6-month, and directly observed regimen for treatment of pulmonary and extrapulmonary tuberculosis.

DESIGN

An open, nonblinded clinical trial, with intended follow-up of patients for 36 months after the completion of therapy.

SETTING

A metropolitan tuberculosis clinic in a public health department.

PATIENTS

From March 1981 through April 1989, we enrolled 160 patients with suspected or known tuberculosis; 35 of these patients were excluded from the analysis.

INTERVENTIONS

Isoniazid, rifampin, pyrazinamide, and streptomycin were administered daily for 2 weeks; these drugs were then given in higher doses twice weekly for 6 weeks, followed by isoniazid and rifampin twice weekly for 6 weeks, followed by isoniazid and rifampin twice weekly for 18 weeks. A total of 62 doses were administered, and all therapy was directly observed by a nurse or an outreach worker.

MEASUREMENTS AND MAIN RESULTS

Of the 125 evaluable patients, 101 (81%) had pulmonary tuberculosis, 7 (6%) had both pulmonary and extrapulmonary involvement, and 17 (13%) had extrapulmonary disease only. Seventy-one (57%) patients had a history of recent alcoholism. There were two relapses (1.6% +/- 2.2%), occurring 6 and 56 months after the completion of therapy. The time at which sputum samples became culture negative in pulmonary patients ranged from 1 to 19 weeks (median, 4.6 weeks); 40% +/- 9.6% of patients were culture-negative after 4 weeks of therapy, 75% +/- 8.5% after 8 weeks, 94% +/- 4.7% after 12 weeks, 97% +/- 3.3% after 16 weeks, and 100% after 20 weeks. Adverse drug reactions included hyperuricemia (greater than 178 mumol/L [3 mg/dL] above normal) secondary to pyrazinamide in 80 patients (64%), twofold or greater elevations of aspartate aminotransferase in 21 patients (17%), 1.5-fold or greater elevations of alkaline phosphatase in 33 patients (27%), cutaneous abnormalities in 8 patients (6%), nausea in five patients (4%), and dizziness in 1 patient (1%).

CONCLUSIONS

This 62-dose, largely twice-weekly tuberculosis treatment regimen is efficacious and relatively nontoxic and is especially useful for patients in whom directly observed therapy is indicated.

Familial aortic dissecting aneurysm

A family is described in which nine members over two generations had an aortic dissecting aneurysm or aortic or arterial dilation at a young age. The family has been followed up since 1977 after the death of a second teenager from a kindred of 11. None of the patients had the Marfan syndrome or a history of systemic hypertension. Three members died of ruptured aortic dissecting aneurysm and acute hemopericardium at 14, 18 and 24 years of age, respectively; a fourth member died suddenly at age 48 years, a few years after aortic repair for aneurysmal dilation. One member underwent surgical repair of an ascending aortic dissecting aneurysm at age 18 years and is still alive. Four members are currently under close medical observation for aortic or arterial dilation. Histologic examination of the aortic wall at autopsy or surgery in three patients revealed a loss of elastic fibers, deposition of mucopolysaccharide-like material in the media and cystic medial changes. Types I and III collagen from cultured fibroblasts appeared normal on gel electrophoresis. Results of indirect immunofluorescent studies of the elastin-associated microfibrillar fiber array in skin and fibroblast culture from multiple family members were also normal. This dramatic familial cluster of aortic dissecting aneurysm and aortic or arterial dilation suggests a genetically determined disease of autosomal dominant inheritance although the basic defect remains unknown.

Early diastolic filling dynamics during experimental mitral regurgitation in the conscious dog

Diastolic flow into the left ventricle during mitral regurgitation must increase as total stroke volume increases in response to the volume overload. The mechanisms that allow augmented diastolic filling are not fully defined. Accordingly, the left ventricle of five dogs was instrumented with a micromanometer and sonomicrometers and studied during the conscious state before (control) and after the creation of significant mitral regurgitation. Serial measurements were made at control and up to 4 weeks after the creation of the volume overload. Heart rate, peak systolic wall stress, and peak positive dP/dt showed no significant changes between control and subsequent observations. End-diastolic volume and total stroke volume progressively and significantly increased during the 4-week course. When compared with the control state (51 +/- 4, mean +/- SD), the filling fraction during the first 40% of diastolic time was increased at 4 days (67 +/- 10%, p less than 0.001), 2 weeks (72 +/- 6%, p less than 0.001), and 4 weeks (76 +/- 10%, p less than 0.001). During the period of adaptation to the volume overload, filling fraction correlated with end-diastolic volume (r = 0.52, p less than 0.02) and total stroke volume (r = 0.80, p less than 0.001). Compared with the control state (0.81 +/- 0.04), eccentricity of the left ventricle at end systole decreased at 4 weeks (0.79 +/- 0.06, p less than 0.05); the absolute change in this ratio during the first 40% of diastolic time was significantly augmented at 2 weeks (0.09 +/- 0.02, p less than 0.05) and 4 weeks (0.11 +/- 0.04, p less than 0.005) compared with control (0.05 +/- 0.02). Ventricular elastance (pressure/volume) at end systole (minimum volume) was 1.70 +/- 0.50 mm Hg/ml at control, 1.09 +/- 0.46 at 4 days (p less than 0.05), 0.96 +/- 0.42 at 2 weeks (p less than 0.01), and 0.99 +/- 0.22 at 4 weeks (p less than 0.01). Moreover, the elastance change during the rapid-filling phase was significantly diminished after creation of mitral regurgitation. Thus, during the volume overload of mitral regurgitation, the left ventricle accommodates a higher percentage of its total stroke volume during early diastole; this adaptation can be correlated with augmented systolic shortening, and thereby with increased restorative forces or elastic recoil, and with reduced chamber elastance and eccentricity during the early part of diastole. Other potential mechanisms include altered systolic and relaxation loading, augmented elastic recoil of the left atrium, left atrium and left ventricular pressure gradient, accelerated myocardial inactivation, and increased adrenergic stimulation.

Temporal Fourier transform of digital angiograms for left ventricular regional wall motion analysis

To determine whether or not the first harmonic of a temporal Fourier transform, applied pixel-by-pixel on time-intensity curves, can detect the subtle wall motion abnormalities due to ischemia, 6 dogs were instrumented with a micromanometer in the left ventricles, a hydraulic cuff occluder around the circumflex coronary artery, and sonomicrometers on the inferior (ischemic) and anterior (non-ischemic) walls. Left ventricular images, obtained after contrast injection via the pulmonary artery, were compared with dimension signals in control and 3 progressive levels of coronary stenosis (Stenosis I, II and III). Normalized, digital functional images (512 x 512 matrix, 256 shades of gray/pixel) were divided into anterior, apical, and inferior areas to acquire regional mean phase (degrees) and amplitude (intensity units) values. After inducing stenosis, phase in ischemic region significantly increased at all 3 levels of stenosis, whereas amplitude significantly decreased at Stenosis II and III. However, amplitude images showed clearly the topographic site of ischemia. There was a progressive increase in phase and decrease in amplitude in ischemic areas as the percent wall thickening (%WTh) fell (phase vs. %WTh: r = -0.55, p less than 0.005; amplitude vs. %WTh: r = 0.71, p less than 0.001). Heart rate and peak systolic pressure showed no significant changes during stenosis. We conclude that quantitative functional images, generated from a temporal Fourier transform, are sensitive to the detection of left ventricular regional wall motion abnormalities during mild, moderate, and severe degrees of ischemia.

Early changes of right heart geometry after pulmonary thromboendarterectomy

To determine the changes in right heart hemodynamics and geometry early after surgery for chronic pulmonary hypertension due to large vessel thromboembolic occlusion, 30 patients were evaluated 8 +/- 8 days (mean +/- SD) before and 6 +/- 4 days after pulmonary thromboendarterectomy by two-dimensional echocardiography and right heart catheterization. Surgery resulted in an early significant improvement in hemodynamic variables including mean pulmonary artery pressure (48 +/- 12 to 28 +/- 8 mm Hg, p less than 0.001), right ventricular systolic pressure (76 +/- 20 to 47 +/- 15 mm Hg, p less than 0.001), pulmonary vascular resistance (935 +/- 620 to 278 +/- 252 dynes.s.cm-5, p less than 0.001) and cardiac index (2.0 +/- 0.5 to 2.9 +/- 0.6 liters/min per m2, p less than 0.001). Similarly, echocardiographic variables of right heart structures, which were well outside the normal range preoperatively, improved significantly early after thromboendarterectomy. These included diameters of the pulmonary artery (2.8 +/- 0.3 to 2.4 +/- 0.4 cm, p less than 0.001), inferior vena cava (2.9 +/- 0.6 to 2.2 +/- 0.4 cm, p less than 0.001) and right atrium (6.8 +/- 1.5 to 5.9 +/- 1.5 cm, p less than 0.001) as well as right ventricular short axis (4.5 +/- 0.8 to 3.7 +/- 0.8 cm, p less than 0.001) and long axis (8.7 +/- 0.9 to 8.1 +/- 0.9 cm, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative assessment of regional left ventricular function by densitometric analysis of digital-subtraction ventriculograms: correlation with myocardial systolic shortening in dogs

Conventional wall motion analysis of contrast ventriculograms assesses only that part of the wall that is tangential to the x-ray beam. To assess regional left ventricular function in three dimensions, a new computerized method based on densitometric analysis of digital subtraction left ventriculograms was developed and validated in nine open-chest dogs instrumented with a circumflex coronary artery occluder and sonomicrometers in the anterior and posterior walls. Each dog underwent digital subtraction ventriculography at baseline and at five levels (I to V) of dysfunction of the inferior wall induced by progressive stenoses of the circumflex coronary artery. The ventriculogram was divided into six segments around the end-diastolic center of gravity. Time-volume curves were obtained by densitometry in the normal anterior and ischemic inferior segments containing the sonomicrometers. From these curves, regional ejection fraction (R-EF), regional peak ejection rate (R-PER), and regional phase (R-PH) and amplitude (R-AMP) of the first Fourier harmonic were derived. From baseline to level V of dysfunction, myocardial systolic shortening determined by sonomicrometry decreased by 124 +/- 34% of control (mean +/- SD; p less than .001) in the ischemic wall, while it increased by 12 +/- 19% (NS) in the normal wall. At the same time, R-EF, R-PER, and R-AMP decreased in the ischemic segment by 65 +/- 12%, 46 +/- 30%, and 45 +/- 15% of control, respectively (all p less than .01), while they remained unchanged or increased in the normal segment. R-PH was delayed by 14 +/- 5% (p less than .01) in the ischemic segment, but remained unchanged in the normal segment, reflecting the asynchrony of regional left ventricular contraction during ischemia. Densitometric indexes of regional function correlated well with sonomicrometric systolic shortening both in normal and ischemic segments, with r values of .84 for R-EF, .80 for R-AMP, .64 for R-PER, and .55 for R-PH (all p less than .0001). Thus, densitometric analysis of digital subtraction left ventriculograms allows three-dimensional assessment of the extent, velocity, and synchrony of regional left ventricular contraction. Densitometric indexes of regional contraction correlate well with direct measurements of myocardial systolic shortening and are useful in quantitating regional left ventricular dysfunction.

Densitometric regional ejection fraction: a new three-dimensional index of regional left ventricular function--comparison with geometric methods

Densitometric regional ejection fraction obtained by computer analysis of digital subtraction ventriculography was evaluated as a new, quantitative, three-dimensional index of regional left ventricular performance. Eighteen patients with coronary artery disease and seven control subjects had right anterior oblique ventriculography at rest and immediately after rapid atrial pacing using central venous injection of contrast material. Regional left ventricular ejection fraction was determined by densitometry in six segments drawn around the end-diastolic center of gravity, and compared with two conventional indexes of segmental wall motion: area and radial regional ejection fraction. Densitometric, area or radial regional ejection fraction was classified as abnormal if it fell at least 2 standard deviations below the corresponding mean value in the normal group. The densitometric method did not require outlining of the end-systolic left ventricular silhouette and was the easiest and fastest to perform of all three techniques. In addition, intra- and interobserver reproducibilities were higher with the densitometric method (r = 0.97 and 0.95) than with either the area (r = 0.84 and 0.82) or the radial method (r = 0.82 and 0.76). Regional left ventricular dysfunction as assessed by the densitometric, area and radial techniques allowed the detection of coronary artery disease in 50, 50 and 44% of the patients at rest and in 83, 67 and 61% of the patients in the post-pacing period, respectively. Post-pacing regional left ventricular dysfunction accurately predicted the presence or absence of greater than 70% diameter stenosis in the supplying coronary artery in 75, 67 and 56% of the cases, respectively. Thus, densitometric analysis of digital subtraction ventriculography allows a fast and reproducible three-dimensional determination of regional left ventricular ejection fraction. Using this technique, pacing-induced regional dysfunction can be detected in most patients with coronary artery disease and corresponds well with the location of significant coronary artery lesions.

The development of the entire end-systolic pressure-volume and ejection fraction-afterload relations: a new concept of systolic myocardial stiffness

In this study we introduce a new concept of systolic myocardial stiffness that extends the Suga-Sagawa maximum ventricular elastance concept to the myocardium. End-systole is defined as the time of maximum systolic myocardial stiffness (max Eav), which we examined for its load independence and sensitivity to changes in the inotropic state and to heart rate. Seven adult mongrel dogs were instrumented with ultrasonic crystals for measurements of long and short axes and left ventricular wall thickness, and a high-fidelity micromanometer was inserted for measurement of left ventricular pressures. Preload and afterload were altered by inferior vena cava occlusion, nitroprusside, angiotensin II, atropine, propranolol, and various combinations with propranolol. End-systolic stress-strain relations (slope: max Eav) were linear in all seven dogs, implying that end-systolic myocardial stiffness is independent of end-systolic stress. Changes in max Eav (for constant preload and afterload) reflected changes in the ejection fraction; max Eav was also insensitive to propranolol and to changes in heart rate over the range from 120 to 180 beats/min. End-systolic pressure-volume relations (ESPVRs), derived analytically from these stress-strain relations, were nonlinear, and estimates of volume at zero stress (Vom) were always positive. On the other hand, ESPVRs obtained on the basis of the Suga-Sagawa maximum ventricular elastance concept, were linear, and volume at zero pressure (Vop) estimated by linear extrapolation was negative in one case. Based on the concept of systolic myocardial stiffness, the slope of the ESPVR varies with end-systolic volume and attains its maximum value (Emax) at zero end-systolic pressure. Normalization of Emax with Vom demonstrated a close relationship to max Eav. Thus both max Eav and Vom and Emax are ideal variables for assessing changes in myocardial contractility when preload and afterload are constant. Furthermore, Vom and max Eav permit development of the entire ejection fraction-afterload relationship for a given preload, thus providing a method for comparing myocardial contractile states between ventricles.

Modifications of techniques and early results of pulmonary thromboendarterectomy for chronic pulmonary embolism

In 1980 we described bilateral pulmonary thromboendarterectomy with median sternotomy, cardiopulmonary bypass, deep hypothermia, and circulatory arrest for the relief of pulmonary hypertension caused by chronic pulmonary embolism. In our subsequent experience, which totals 41 patients, we have identified three groups of patients characterized by differences of intraoperative management. In Group A (N = 16) myocardial protection consisted of single-dose crystalloid cardioplegia followed by pericardial irrigation with cold saline. Extrapericardial dissection of the pulmonary arteries was performed. Group B (N = 7) was treated the same as Group A except for the substitution of saline slush contained in a laparotomy pad for iced saline. In Group C (N = 18) myocardial protection was single-dose blood cardioplegia followed by the application of a specially designed cooling jacket to the right and left ventricles. Another modification was that of intrapericardial dissection of the pulmonary arteries with extension of the dissection into the hilar tissues without entrance into the pleural spaces. The hospital mortalities of Groups A, B, and C were 18.7%, 14.3%, and 5.5%, respectively (not statistically significant differences). However, other statistically significant differences (p less than 0.05) among the groups were observed: Phrenic nerve paresis occurred in five of seven (71%) Group B patients but in no Group A or C patients; Group B patients required ventilatory support for 32.2 days compared with 8.4 days for Group A and 6.2 days for Group C; time in the intensive care unit was 36 days for Group B patients versus 13 for Group A and 10.3 for Group C; pulmonary vascular resistance decreased 59% (649 versus 259) intraoperatively in 13 patients in Group C. We believe simultaneous bilateral pulmonary thromboendarterectomy with median sternotomy, cardiopulmonary bypass, deep hypothermia with circulatory arrest, and the modified methods of myocardial preservation and dissection represent current optimal surgical management of this problem.

Ischemic myocardial dysfunction assessed by temporal Fourier transform of regional myocardial wall thickening

A Fourier analysis including the first 20 harmonics was performed on sonomicrometric measurements of regional myocardial wall thickness in eight conscious dogs under control conditions and at four levels of ischemia produced by a hydraulic occluder on the left circumflex coronary artery. Systolic wall thickening was reduced from 26.47 +/- 6.20% (S.D.) (control) to 22.05 +/- 5.73% (mild stenosis), 17.00 +/- 5.86% (moderate stenosis), 11.46 +/- 3.56% (severe stenosis), and 3.69 +/- 2.57% (30-second occlusion), values significantly different from each other (p less than 0.01). The amplitude of the first harmonic decreased stepwise from 1.35 +/- 0.31 to 1.08 +/- 0.29 mm, 0.90 +/- 0.27 mm, 0.69 +/- 0.24 mm, and 0.43 +/- 0.12 mm, all significantly different from each other (p less than 0.05). These amplitude values correlated to percent systolic wall thickening (r = 0.894, p = 0.001). A phase shift of the first harmonic from 137 +/- 11 to 139 +/- 14 degrees, 150 +/- 15 degrees (p less than 0.05 vs control), 161 +/- 21 degrees (p less than 0.01 vs control), and 191 +/- 21 degrees (p less than 0.01 vs control and severe stenosis) correlated with the increase in time from end diastole to the point of maximum wall excursion (r = 0.662, p less than 0.001). These data indicate that the extent of ischemic regional myocardial hypokinesis can be adequately described by the amplitude of the first harmonic, and that the asynchrony of ventricular contraction and relaxation can be detected from the phase of the first harmonic.

Timing of surgical intervention in chronic mitral regurgitation

Determination of the optimal time for surgical intervention in chronic mitral regurgitation has remained controversial. There are similarly important factors in favor of temporizing with medical treatment alone as there are in support of relatively early surgery (Table 1). Since rheumatic valvulitis may play a subordinate role, in contrast to etiologies such as myxomatous degeneration of the mitral valve, rupture of chordae tendineae, papillary muscle dysfunction due to coronary artery disease and other causes, left ventricular function is generally determined by the adaptations of the myocardium to the volume overload, or to ischemia or infarction from coronary artery disease rather than to a concomitant myocarditis. Based on actuarial survival curves in symptomatic patients with combined mitral regurgitation and stenosis or mitral regurgitation alone, it can be assumed that surgery can result in improved survival, in particular if a reconstructive mitral valve procedure rather than prosthetic valve replacement is performed. Medical treatment is carried out with digitalis to enhance myocardial contractility, diuretics and vasodilators to reduce pre- and afterload with resultant diminished effective mitral orifice area and regurgitant volume, lowering of pulmonary artery and pulmonary venous pressures and an increase in systemic cardiac output. Presently, however, there is no convincing evidence that symptom-status is improved or the natural history favorably affected over a number of years. For assessment of left ventricular myocardial function the end-systolic pressure/volume or the end-systolic stress/volume index appear preferable. Values of the latter less than or equal to 2.2 are associated with increased postoperative mortality and improbable improvement in functional status. Additionally, patients with an ejection fraction less than 40% or end-diastolic volume greater than 140 ml/m2 as well as those with end-diastolic dimension greater than 8 cm or end-systolic dimension greater than 5.5 cm have less favorable postoperative survival or further deterioration in ventricular function. Impaired right ventricular function secondary to the increased afterload imposed by pulmonary hypertension generally can be normalized postoperatively. Depression of right ventricular myocardial contractility is not, however, a common pathophysiologic feature in chronic mitral regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary vascular occlusion and fibrosing mediastinitis

Patients with fibrosing mediastinitis causing obstruction of pulmonary veins and arteries may present with many of the historic, physical, and laboratory findings of patients with pulmonary hypertension due to chronic thrombotic obstruction of major pulmonary arteries. Because the latter is subject to surgical correction, and the former is not, it is important to differentiate between the two and to be aware of the similarities in presentation. Three patients with pulmonary hypertension due to compression of pulmonary veins and the right pulmonary artery by fibrosing mediastinitis are presented who illustrate these points. A review of the literature documents other instances in which vascular involvement due to fibrosing mediastinitis has mimicked other types of pulmonary hypertension.

Wedge and subselective pulmonary angiography in pulmonary hypertension secondary to venous obstruction

Pulmonary wedge or subselective angiography provided key diagnostic information in two cases of pulmonary hypertension secondary to pulmonary venous obstruction. Whereas conventional pulmonary angiograms and ventilation-perfusion lung scans were interpreted as showing embolism, plain radiographs demonstrated Kerley B lines, suggesting venous obstruction. Subselective or wedge angiography of nonopacified arteries verified their anatomical patency and also revealed venous stenoses, collaterals, and atrophy indicative of obstruction.

Effects of atrial pacing on global and regional left ventricular function in coronary heart disease assessed by digital intravenous ventriculography

Digital i.v. ventriculography in conjunction with rapid atrial pacing was used to assess the effects of ischemic stress on global and regional function in 22 patients referred for cardiac catheterization (5 had normal coronary arteries and 17 had greater than 70% diameter reduction of at least 1 major coronary artery). End-diastolic, end-systolic and stroke volume indexes and the ejection fraction were determined by an area-length technique from the mask mode images before and after pacing. In addition, segmental responses were quantitated using a radial shortening method. Subjects with normal coronary arteries showed no overall change in the postpacing volume or ejection fraction indexes. Coronary patients showed no overall change in postpacing end-diastolic volume (86 +/- 25 ml/m2 at control vs 90 +/- 31 ml/m2 after pacing, difference not significant), but there was a significant increase in end-systolic volume (25 +/- 15 ml/m2 at control vs 32 +/- 18 ml/m2 after pacing, p less than 0.005) and a decrease in ejection fraction (72 +/- 11% at rest vs 64 +/- 18% after pacing, p less than 0.025). Furthermore, quantitative deterioration in wall motion was seen in 14 of 17 coronary patients (82%) and in none of the normal patients. Analysis of segmental wall motion was the most sensitive diagnostic variable. A combination of atrial pacing stress testing and digital i.v. ventriculography is useful in detecting functionally significant coronary disease through quantitation of global and regional dysfunction which does not require arterial cannulation.

Quantitative assessment of segmental wall motion abnormalities at rest and after atrial pacing using digital intravenous ventriculography

Digital intravenous ventriculography lends itself readily to quantitative assessment of ventricular wall motion with computer algorithms. Forty-five patients referred for cardiac catheterization were studied by digital intravenous ventriculography (mask mode) and direct ventriculography in the 30 degrees right anterior oblique position. Quantitative wall motion was analyzed by a radial shortening method applied to both studies. Lower limits of normal radial shortening were determined for each technique and used to determine the presence or absence of wall motion disorders. The inter- and intraobserver variability of radial shortening measurements was +/- 5.3 and +/- 8.8%, respectively, with maximal discrepancies of -6 and +7% fractional shortening units. The overall agreement between the two techniques in wall motion assessment was 87% (274 of 315 radii). A subset of patients also underwent atrial pacing, and a second digital intravenous ventriculogram was obtained (5 normal subjects and 15 patients with coronary artery disease). Although analysis of wall motion at rest showed a poor sensitivity for detection of significant coronary stenoses, nine of nine patients with coronary artery disease and normal wall motion at rest showed a quantitative decrease in radial wall motion after atrial pacing. Thus, digital intravenous ventriculograms can be used to provide quantitative wall motion analyses that show a high degree of agreement with those of standard, direct left ventriculography. Atrial pacing can be used to increase the sensitivity of wall motion analysis for the detection of significant coronary disease.

Comparison of digital intravenous ventriculography with direct left ventriculography for quantitation of left ventricular volumes and ejection fractions

Digital images of the left ventricle obtained at 30 frames/second from continuous fluoroscopy after intravenous injection of contrast medium (digital intravenous ventriculography) were used to estimate left ventricular (LV) volumes and ejection fraction with use of several techniques for identifying the ventriculographic silhouette. The digital technique was compared with direct contrast left ventriculography in 26 patients undergoing diagnostic cardiac catheterization. End-diastolic and end-systolic volumes calculated from digital intravenous and direct left ventriculograms were obtained with use of a standard area-length formula. Both end-diastolic volume (EDV) (r = 0.88, y = 1.06x - 17.1 ml) and end-systolic volume (ESV) (r = 0.89, y = 0.96x + 0.43 ml) determined from digital intravenous ventriculography (mask mode images) correlated closely with those obtained by direct left ventriculography. Combining the EDV and ESV to define the relation between the 2 techniques yielded an even closer correlation (r = 0.96). There was also good correlation between the 2 techniques for measurement of ejection fraction (r = 0.81, standard error of the estimate 6.7%). Measurements from direct left ventriculography were frequently invalidated by ventricular arrhythmias during the time of opacification of the left ventricle; this was rarely the case for digital intravenous ventriculography. It is concluded that area-length estimates of LV volumes and ejection fraction can be accurately obtained from digital processing of fluoroscopic LV images after intravenous injection of contrast medium.

Utilization of appropriate projective techniques in assessing preschool children's personal space and body orientation

65 preschool children were assessed for use of personal space and body orientation with a model-room projective technique and video tapes of behavior in the actual setting. Correlations were computed to express the relationship between the projected and observed physical distance and body-orientation scores. In the case of distance and body-orientation variables, zero correlations were obtained between the projective measures and the means of observed measures obtained by time sampling the video recordings.

Reliability of echocardiographic and electrocardiographic parameters in assessing serial changes in left ventricular mass

A reliable noninvasive index of left ventricular mass would be useful in following patients with valvular heart disease and left ventricular hypertrophy. We reviewed concurrent electrocardiograms and echocardiograms from 54 subjects, 39 patients with aortic or mitral valve disease and 15 normal subjects. Pre- and early postoperative echocardiographic estimates of left ventricular mass in 17 patients who had valve replacements correlated well (r = 0.96, p less than 0.001) and demonstrated little change in mean values despite altered left ventricular dimensions. Echocardiographic estimates of left ventricular mass were, therefore, used as a standard for evaluating other noninvasive indices. Precordial electrocardiographic voltage showed a weak correlation with left ventricular mass in the study group as a whole (r = 0.59, p less than 0.001), but no correlation in patients with volume overload (r = 0.36, p = NS). In 18 patients who had preoperative and three separate postoperative studies at least eight weeks apart, changes in left ventricular cross-sectional area (an index of left ventricular mass which corrects for changes in left ventricular volume) closely followed alterations in left ventricular mass. However, changes in posterior wall and interventricular septal thickness often resulted from altered ventricular volume and did not accurately reflect directional changes in left ventricular mass. Serial changes in electrocardiographic voltage were similarly unreliable. We conclude that left ventricular mass and cross-sectional area by echocardiography allow accurate noninvasive assessment of left ventricular mass, whereas wall thickness and electrocardiographic changes do not.

[Overall and regional sensitivity of myocardial thallium-201 scintigraphy compared with the number and location of coronary lesions and the presence of previous myocardial infarction]

An evaluation is presented of (1) the overall sensitivity and specificity of 201Tl myocardial scintigraphy in 230 patients with suspected coronary artery disease and (2) the effects of the number and location of the diseased vessels, and the presence of previous infarction, on regional sensitivity in 151 patients. Overall sensitivity was 91% (80%, 95%, 97%) in patients with 1, 2 or 3 vessels respectively. Overall specificity was 81% or 89% if 7 patients with infarction and normal coronaries were excluded. In 80% of patients with one diseased vessel, in 41% of patients with 2 diseased vessels, and in only 24% with 3 diseased vessels were all lesions detected. 201Tl scintigraphy detected 52% of circumflex lesions as compared to 75% of right coronary and 74% of left anterior descending lesions. Of the 151 patients with proven coronary disease, 75 had a previous infarction. Overall and regional 201Tl sensitivity were greater (but not significantly) in this subgroup as compared to patients without myocardial infarction.

Diastolic left ventricular pressure-volume and stress-strain relations in patients with valvular aortic stenosis and left ventricular hypertrophy

Left ventricular (LV) chamber and myocardial stiffness were determined in 17 patients, four subjects with normal LV function and 13 subjects with valvular aortic stenosis and concentric myocardial hypertrophy, using simultaneous catheter micromanometry and LV cineangiography. Pressure (P), volume (V), and wall thickness (h) were measured. Variability in both chamber and myocardial stiffness parameters was found with five of the aortic stenosis patients (Group 1, left ventricular end-diastolic pressure = 15 +/- 2 (SEM) mm Hg) exhibiting normal values for end-diastolic dP/dV and dP/dV/V, for chamber stiffness constants (a,a') derived from P-V and normalized P-V relations, respectively, for end-diastolic myocardial elastic stiffness (ES or EE, where S = spherical model and E = ellipsoidal model) at the midwall of the minor axis circumference, and for the myocardial stiffness constants (KS or KE) of the circumferential stress-strain relation. Eight other patients with aortic stenosis (Group II, left ventricular end-diastolic pressure = 20 +/- 3 (SEM) mm Hg) exhibited significant increases in end-diastolic dP/dV,dP/dV/V,ES and EE and a tendency for increase in the chamber stiffness constants (a,a') and myocardial stiffness constants (KS, KE). These observations suggest that concentric increase in muscle mass (increase in wall thickness/minor axis radius ratio and wall volume/chamber volume ratio) is an important determinant of elevated mid- and late diastolic pressures in patients with valvular aortic stenosis, while concurrently mitigating increases in both systolic and diastolic wall stress. In some patients with aortic stenosis, however, diastolic filling pressures are elevated more severely, not only as a result of concentric hypertrophy, but also in response to augmented muscle stiffness. Reversibility of increased ventricular diastolic stiffness and elevated filling pressures was documented as concentric hypertrophy regressed post-aortic valve replacement in one patient, suggesting that fibrosis is not invariably the cause of enhanced myocardial stiffness in this secondary and compensatory form of hypertrophy.

False aneurysms of the left ventricle. Identification of distinctive clinical, radiographic, and angiographic features

False aneurysms of the left ventricle were observed in 14 patients. They were caused by obstructive coronary arterial disease with resultant myocardial infarction in 11, bacterial endocarditis in 1, a knife wound in 1, and disruption of a ventriculotomy in 1. Most of them extended posteriorly on the lateral radiograph, as opposed to the usual anterior position of true aneurysms. Enlargement was frequently observed on sequential studies. Angiography usually demonstrated involvement of the diaphragmatic or posterolateral segment due to occlusion of the right coronary artery; in contrast, true aneurysms are apical or anterolateral and are due to occlusion of the left anterior descending artery. The frequency of rupture of false aneurysms points up the importance of dinstinguishing them from true aneurysms.

Mitral valve replacement versus reconstruction. An analysis of indications and results of mitral valve procedures in a consecutive series of 80 patients

Case histories of 80 patients undergoing mitral valve procedures over a 2 year period were analyzed to determine the preoperative and intraoperative factors favoring reconstruction. Of 34 patients undergoing valve reconstruction, 31 (90 per cent) were women, and the average age of patients undergoing reconstruction was 41 versus 51 for patients who underwent replacement. Absence of calcification on fluoroscopic study and at operation favored reconstruction, as did the finding of good leaflet mobility by preoperative echocardiograms and operative assessment. Pure lesions, i.e., stenosis or insufficiency, favored reconstruction. In this regard, the use of new annuloplasty techniques has facilitated the surgeon's ability to reconstruct regurgitant mitral valves. No operative deaths and excellent functional and clinical results obtained in 80 per cent of patients undergoing mitral reconstruction justify the aggressive application of this technique in properly selected patients.

Myocardial adaptations in aortic valve disease

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