Adele Chiddo

Functional and structural abnormalities in patients with dilated cardiomyopathy

Passive diastolic properties of the left ventricle were determined in 10 control subjects and 12 patients with dilated cardiomyopathy. Simultaneous left ventricular angiography and high fidelity pressure measurements were performed in all patients. Left ventricular chamber stiffness was calculated from left ventricular pressure-volume and myocardial stiffness from left ventricular stress-strain relations with use of a viscoelastic model. Patients with dilated cardiomyopathy were classified into two groups according to the diastolic constant of myocardial stiffness (beta). Group 1 consisted of seven patients with a normal constant of myocardial stiffness less than or equal to 9.6 (normal range 2.2 to 9.6) and group 2 of 5 patients with a beta greater than 9.6. Structural abnormalities (percent interstitial fibrosis, fibrous content) in patients with dilated cardiomyopathy were assessed by morphometry from right ventricular endomyocardial biopsies. Heart rate was similar in the three groups. Left ventricular end-diastolic pressure was significantly greater in patients with cardiomyopathy (18 mm Hg in group 1 and 22 mm Hg in group 2) than in the control patients (10 mm Hg). Left ventricular ejection fraction was significantly lower in groups 1 (37%) and 2 (36%) than in the control patients (66%). Left ventricular muscle mass index was significantly increased in both groups with cardiomyopathy. The constant of chamber stiffness (beta*) was slightly although not significantly greater in groups 1 and 2 (0.58 and 0.58, respectively) than in the control group (0.35). The constant of myocardial stiffness beta was normal in group 1 (7.0; control group 6.9, p = NS) but was significantly increased in group 2 (23.5). Interstitial fibrosis was 19% in group 1 and 43% (p less than 0.001) in group 2 (normal less than or equal to 10%). There was an exponential relation between both diastolic constant of myocardial stiffness (beta) and interstitial fibrosis (IF) (r = 0.95; p less than 0.001) and beta and fibrous content divided by end-diastolic volume index (r = 0.93; p less than 0.001). It is concluded that myocardial stiffness can be normal in patients with dilated cardiomyopathy despite severely depressed systolic function. Structural alterations of the myocardium with increased amounts of fibrous tissues are probably responsible for the observed changes in passive elastic properties of the myocardium in patients with dilated cardiomyopathy. The constant of myocardial stiffness (beta) helps to identify patients with severe structural alterations (group 2), representing possibly a more advanced stage of the disease.

Electrophysiological properties of intravenous metoprolol in man.

Electrophysiological changes produced by intravenous (0.1 mg/kg) metoprolol, a new selective beta 1-blocking agent devoid of intrinsic activity, were studied in 16 subjects with estimated normal impulse formation and conduction. The most important effects were sinus bradycardia, mild increase of sinoatrial conduction time, depression of intranodal conduction, and prolongation of AV node refractory periods. Sinus node recovery time and atrial refractory periods were unmodified. Infranodal conduction and the refractory periods of the His-Purkinje system, as well as of the bundle-branches, were unchanged. These effects are compared with those observed after intravenous propranolol, pindolol, and oxprenolol.

Hemodynamic study of intravenous propionyl-L-carnitine in patients with ischemic heart disease and normal left ventricular function

SummaryPropionyl-L-carnitine was given intravenously to ten patients with chronic ischemic heart disease who had normal left ventricular function and had not had a previous myocardial infarction. Subsequently, pulmonary and systemic circulation, left ventricular function, and the relationship between the ventricle and afterload were evaluated. This drug, at a dose of 15 mg/kg, improves ventricular function by easing the load and by enhancing cardiac efficiency. The ejection impedance is reduced with a consequent increase in stroke volume as a result of a) a decrease in systemic and pulmonary resistance and b) an increase in arterial compliance. Arterial pressure is maintained due to an increase in total external heart power. Since the tension time index shows a proportionally smaller increase in the energy requirement, it follows that cardiac efficiency has been improved and ventricle-after load matching is optimal. These results suggest but do not prove that propionyl-L-carnitine exhibits a positive inotropic property.

Two-dimensional echocardiographic recognition of an atrial septal aneurysm

Abstract We report the detection by cross-sectional echocardiography of an atrial septal aneurysm in a 29-year-old woman with mitral and tricuspid valve prolapse.

Electrophysiologic properties of intravenous oxprenolol in man

Electrophysiologic modifications produced by intravenous administration of 0.1 mg/Kg Oxprenolol were studied in 16 subjects with estimated normal impulse formation and conduction. Significant effects were sinus bradycardia, mild increase of sino-atrial conduction time, depression of intranodal conduction and prolongation of A-V node refractory periods. Sinus node recovery time and atrial refractory periods were unchanged. Infranodal conduction and the refractory periods of the His-Purkinje system, as well as of the bundle branches, were unchanged. These effects are compared with those observed after intravenous Propranolol and Prindolol.

Doppler continuous-wave analysis of grafted mammary artery as a non-invasive technique for static and dynamic assessment of coronary flow in man

SummaryIn this paper, Doppler continuous-wave analysis of blood velocity in the internal mammary artery, anastomosed to the left coronary vascular bed in humans who have undergone myocardial revascularization, is proposed as a non-invasive technique to study coronary blood flow during physiological procedures which cause it to change. Blood velocity curves obtained in normal and anastomosed internal mammary arteries were compared during hyperventilation and the Valsalva manoeuvre. During hyperventilation, blood velocity increased in the normal mammary but not in the anastomosed artery. During the expiratory effort of the Valsalva manoeuvre, the mean blood velocity decreased in the normal mammary artery but it did not change significantly in the anastomosed artery. Variations in the mean velocity were largely prevented by simultaneous and well-balanced increases and decreases in the diastolic and systolic velocities, respectively.

Behandlung der chronisch stabilen Angina pectoris mit Gallopamil

In den vergangenen Jahren hat die Zahl der fur die Therapie zur Verfugung stehenden Kalziumantagonisten rasch zugenommen, nachdem ihre Wirksamkeit bei der Behandlung der stabilen und instabilen Angina pectoris nachgewiesen werden konnte. Mit Gallopamil steht ein neuer Kalziumantagonist zur Verfugung, der nach tierexperimentellen Untersuchungen drei- bis viermal wirksamer als Verapamil zu sein scheint (3, 4). Die Resorptionsrate von Gallopamil liegt um 900/0, die Bioverfugbarkeit der Substanz bei ungefahr 25% (21). Patientenstudien ergeben eine mittlere Halbwertzeit von 2,8 bis 4,8 Stunden (21) mit maximalen Konzentrationen der unveranderten Substanz 1 bis 2 Stunden post applicationem (20). Nach intravenoser Gabe dieses Medikaments kommt es zu einer Erweiterung der Arterien und Venen (5, 14), einer Reduktion des peripheren arteriellen Widerstands und damit einer Verringerung der Herzarbeit (−13%) und des myokardialen Sauerstoffverbrauchs (−10%) (12). Des weiteren werden die epikardialen Koronargefase dilatiert und Vasospasmen verhutet (10, 11). Gallopamil verringert die Erregbarkeit des Sinusknotens und verzogert die Erregungsleitung im AV-Knoten (4, 6).

Invasive Assessment of Left Ventricular Function in Ischemic Heart Disease

Left ventricular function considerably affects prognosis and choice of treatment in patients with coronary artery disease (CAD). Nevertheless, a correct assessment of left ventricular (LV) performance, irrespective of the influence of pre- and after-load, is a hard and still unresolved problem, although solving it has been the aim of a number of clinical and experimental studies.