Jean-Pierre Bourdarias

Influence of Positive End-Expiratory Pressure on Left Ventricular Performance

Although left ventricular dysfunction is common during ventilatory support with positive end-expiratory pressure (PEEP), the mechanism of this disorder remains unclear. In 10 patients with the adult respiratory-distress syndrome we studied the effects of a stepwise increase in PEEP from 0.to 30 cm H2O on left ventricular output, intracardiac transmural pressures, and two-dimensional echocardiographic measurements of left ventricular cross-sectional area at end-systole and at end-diastole. Increasing PEEP was associated with progressive declines in cardiac output, mean blood pressure, and left ventricular dimensions and with equalization of right and left ventricular filling pressures. The radius of septal curvature decreased at both end-diastole and end-systole, implying a leftward shift of the interventricular septum. At the highest PEEP, blood-volume expansion did not restore cardiac output, although left ventricular transmural filling pressures had returned to base-line values. We conclude that decreased cardiac output during PEEP is mediated by a leftward displacement of the interventricular septum, which restricts left ventricular filling.

Quantitative two-dimensional echocardiography in massive pulmonary embolism: emphasis on ventricular interdependence and leftward septal displacement.

In 14 patients requiring aggressive therapy for circulatory failure resulting from massive pulmonary embolism, hemodynamic and two-dimensional echocardiographic data were obtained at bedside (acute phase) and again after circulatory improvement (intermediate phase) and during recovery. The acute stage was characterized by a low cardiac output state despite inotropic support (cardiac index 1.9 +/- 0.6 liters/min per m2) associated with increased right atrial pressure (12.4 +/- 4.2 mm Hg), increased right ventricular end-systolic and end-diastolic area (12.4 +/- 3.4 and 15.4 +/- 4.1 cm2/m2, respectively) and reduced right ventricular fractional area contraction (20.1 +/- 8.6%). Two-dimensional echocardiography also revealed interventricular septal flattening at both end-systole and end-diastole and markedly decreased left ventricular end-diastolic dimensions. Left ventricular fractional area contraction remained normal. Hemodynamic improvement occurred during the intermediate phase as shown by restoration of cardiac index (3.3 +/- 0.6 liters/min per m2), decrease in right atrial pressure (8.3 +/- 4.8 mm Hg), reduction in right ventricular end-systolic area (9.0 +/- 3.6 cm2/m2 at the intermediate stage and 6.1 +/- 1.8 cm2/m2 at recovery) and end-diastolic area (10.5 +/- 3.6 cm2/m2 at the intermediate stage and 8.9 +/- 2.9 cm2/m2 at recovery) and improvement in right ventricular fractional area contraction (31.5 +/- 16.4%). The interventricular septum progressively returned to a more normal configuration at both end-systole and end-diastole, and left ventricular diastolic dimension steadily increased. It is concluded that circulatory failure secondary to massive pulmonary embolism was mediated through a profound decrease in left ventricular preload, resulting from both pulmonary outflow obstruction and reduced left ventricular diastolic compliance.(ABSTRACT TRUNCATED AT 250 WORDS)

Reevaluation of Hemodynamic Consequences of Positive Pressure Ventilation: Emphasis on Cyclic Right Ventricular Afterloading by Mechanical Lung Inflation

To examine the cyclic changes in right ventricular (RV) function induced by controlled ventilation, right heart catheterization and two-dimensional echocardiography were combined in a group of 20 patients requiring respiratory support for an episode of acute respiratory failure. Simultaneous measurements of RV pressure (using a modified pulmonary artery catheter), RV stroke output (thermodilution), and RV dimensions (two-dimensional echocardiography), permitted a beat to beat evaluation of RV function throughout the mechanical respiratory cycle. When compared with expiration, lung inflation produced an increase in RV systolic pressure and volume, an increase in RV diastolic volume with an unchanged RV diastolic pressure, and a marked decrease in RV ejection fraction. It is concluded that controlled ventilation altered RV function primarily by increasing RV afterload during the lung inflation period.

Two-dimensional echocardiographic evaluation of right ventricular size and contractility in acute respiratory failure.

Right ventricular size and contractility were evaluated using two-dimensional echocardiography during the first days of respiratory support in 23 patients requiring mechanical ventilation for acute respiratory failure. Nine patients had normal echocardiographic right ventricular function, and nine other patients had a slightly enlarged right ventricle with normal systolic function. The remaining five patients had a severely enlarged right ventricle with abnormal contractile pattern. In these five patients. two-dimensional echocardiography also showed a reduction in left ventricular size suggesting detrimental ventricular interdependence. All 23 patients had normal left ventricular systolic function by two-dimensional echocardiography.

Two-dimensional echocardiographic demonstration of acute myocardial depression in septic shock.

A 50-yr-old woman exhibiting streptococcal neck cellulitis developed severe septic shock with low cardiac output, which was reversed by infusion of dopamine plus dobutamine. Two-dimensional echocardiography performed at the bedside demonstrated severe myocardial failure. The patients condition remained dependent on inotropic drug support for 2 days and ultimately improved. Two-dimensional echocardiography repeated on the fourth day corroborated the disappearance of transient myocardial failure.

Effects of full-dose heparin anticoagulation on the development of left ventricular thrombosis in acute transmural myocardial infarction.

The incidence of left ventricular thrombosis after acute transmural myocardial infarction has been evaluated with two-dimensional echocardiography. To assess the preventive action of early anticoagulation with full-dose heparin, 90 patients, admitted within 5.2 +/- 4.6 hours after the onset of symptoms of their first episode of acute myocardial infarction (46 anterior and 44 inferior), were prospectively studied. Patients were randomly assigned either to therapeutic anticoagulation with heparin or to no anticoagulant therapy. Serial two-dimensional echocardiograms were recorded on the day of admission, the next day, days 4 to 7 and days 20 to 50 to detect left ventricular thrombus and to assess global left ventricular performance. On the first echocardiogram (10.3 +/- 8.0 hours after the onset of symptoms) no thrombus was visualized. In 44 patients with inferior myocardial infarction (23 receiving heparin and 21 not receiving heparin) no further left ventricular thrombus developed. In 46 patients with anterior myocardial infarction, 21 additional thrombi developed (45.6%) within 4.3 +/- 3.0 days after the acute event. Thrombus developed in 8 (38%) of 21 patients receiving heparin, compared with 13 (52%) of 25 patients not receiving heparin. This difference in ventricular thrombosis was not statistically significant (chi-square with the Yates correction = 0.76; NS). No difference was found between the subgroups in terms of clinical variables, infarct size, hemodynamic impairment, intensity of the inflammatory process and quantitative two-dimensional echocardiographic and cineangiographic left ventricular function. It is concluded that early anticoagulation with heparin reduced by 27% the incidence of left ventricular thrombus formation in anterior acute transmural myocardial infarction, and this relative risk reduction was not statistically significant when compared with findings in the untreated group.

Dynamic cardiomyoplasty: Effect of discontinuing latissimus dorsi muscle stimulation on left ventricular systolic and diastolic performance and exercise capacity

OBJECTIVES This study sought to assess the short-term effect of discontinuing latissimus dorsi muscle stimulation on left ventricular systolic and diastolic performance and exercise tolerance in patients with improved functional status by cardiomyoplasty, in whom latissimus dorsi muscle was fully conditioned. BACKGROUND Cardiomyoplasty has consistently improved the functional status of patients, but the short-term effect of latissimus dorsi muscle contraction has not been assessed in these patients. METHODS Right-heart catheterization, Doppler-echocardiography and maximal exercise testing with expired gas analysis were performed in 10 patients with congestive heart failure who had undergone cardiomyoplasty at least 6 months earlier. Data were obtained when the latissimus dorsi muscle was stimulated every other systole and after stimulation was discontinued for 1 h. The power of this study to detect a 10% difference was > 80%. RESULTS After cardiomyoplasty, left ventricular ejection fraction increased from 0.22 +/- 0.08 (mean +/- SD) to 0.27 +/- 0.07 after 6 months (p < 0.02 vs. before cardiomyoplasty) and to 0.24 +/- 0.09 after 1 year; functional class went from 3.0 +/- 0.0 to 2.0 +/- 0.5 after 6 months and to 2.0 +/- 0.7 after 1 year (both p < 0.001 vs. before cardiomyoplasty). After discontinuation of latissimus dorsi muscle stimulation, cardiac index did not change (2.28 +/- 0.45 vs. 2.30 +/- 0.46 liters/min per m2). Mean systemic arterial and pulmonary capillary wedge pressures were also similar (85.2 +/- 6.0 vs. 88.4 +/- 5.6 mm Hg and 14.9 +/- 7.1 vs. 13.6 +/- 6.8 mm Hg, respectively). Doppler E/A ratio decreased from 1.04 +/- 0.33 to 0.83 +/- 0.25 (p < 0.02), suggesting that left ventricular diastolic function may have been improved by latissimus dorsi muscle stimulation. Peak oxygen consumption was unaltered (1,633 +/- 530 vs. 1,596 +/- 396 ml/min). CONCLUSIONS Alterations in left ventricular diastolic rather than systolic function may be responsible for the long-term clinical benefits of cardiomyoplasty.

Aneurysms of sinus of Valsalva: Two-dimensional echocardiographic diagnosis and recognition of rupture into the right heart cavities

The aim of this study was to evaluate the role of echocardiography in the diagnosis of sinus of Valsalva aneurysms projecting toward the right heart cavities. Three patients who had a ruptured aneurysm of a sinus of Valsalva diagnosed by echocardiography and confirmed by catheterization underwent cardiac surgery. In two patients, the aneurysm originated from the right coronary sinus and had perforated into either the inflow or outflow tract of the right ventricle. In the third patient, the aneurysm, which originated from the noncoronary sinus, ruptured into the atrium. A fourth patient was also investigated and had an unruptured aneurysm of the right coronary sinus projecting into the right ventricular outflow tract. M-mode, two-dimensional and contrast echocardiographic studies were performed before cardiac catheterization in all patients and after surgery in three patients. M-mode echocardiography was useful only when the aneurysm had an anterior projection, whether or not the aneurysm was ruptured. Conversely, two-dimensional echocardiography was always able to identify the aneurysmal sac which appeared as an abnormal circular thin-walled structure protruding into the right heart cavities. By using multiple views, it was possible to investigate the whole abnormal structure and locate the sinus from which the aneurysm originated. The use of the echo contrast technique allowed more precise definition of the aneurysmal sac and diagnosis of a left to right shunt by demonstrating a negative contrast image in the right cavities. On the other hand, no negative contrast image was recorded in the patient with an unruptured aneurysm or in the two instances of a successful surgically reconstructed aorta.

Relation of Functional Improvement in Congestive Heart Failure After Quinapril Therapy to Peripheral Limitation

Angiotensin-converting enzyme inhibitors have been shown to increase maximal muscle blood flow in parallel to peak VO2 in patients with congestive heart failure (CHF). Whether this increase shifts factors limiting peak aerobic capacity from periphery (skeletal muscle or vessels) to central factors (cardiac or respiratory) is unknown. Comparison of peak oxygen consumption (VO2) obtained during leg cycling (VO2 leg) with peak VO2 obtained during combined leg cycling and arm cranking (VO2 arm + leg) allows determination of the relative role of central or peripheral factors. We compared VO2 leg with VO2 arm + leg before and after 3 months of therapy with quinapril 40 mg in 16 patients with CHF (age 53 +/- 13 years) due to left ventricular systolic dysfunction (ejection fraction 0.25 +/- 0.07). Before quinapril, VO2 arm + leg was significantly higher than VO2 leg (19.0 +/- 3.3 vs 16.9 +/- 3.8 ml/kg/min, p < 0.001), whereas after therapy these 2 values were similar (20.3 +/- 4.3 vs 21.0 +/- 4.3 ml/kg/min; p = NS), indicating that patients were no longer limited by peripheral factors. Besides, VO2 leg increase after therapy was higher in patients in whom difference between VO2 arm + leg and VO2 leg was the greatest (i.e., in patients who were initially more limited by peripheral factors). Simultaneously, calf peak reactive hyperemia and circumference significantly increased, indicating an improvement in vascular dilating capacity and an increase in skeletal muscle mass. No significant modification occurred in the forearm. Thus, patients who improved the most after 3 months of quinapril therapy were those who were initially limited by peripheral factors. The restricting role of these factors was reduced after quinapril therapy.

Posterior rupture of the interventricular septum after acute myocardial infarction: successful early surgical repair.

A patient with a large posterior ventricular septal defect complicating an acute inferior myocardial infarction is reported. Because of medically intractable biventricular failure, temporary circulatory assistance was initiated using intraaortic balloon pumping. Emergency coronary angiography, ventriculography, and subsequent operation were carried out. Operative repair involved closure of the septal defect with the use of a Dacron patch, infarctectomy, and aortocoronary bypass grafting and resulted in long-term survival of the patient.