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Biomedical subjects

G M Ziady

Publications and source records attributed to G M Ziady.

At least 19 recordsLinked to original sources
PubMed2001

Noninvasive/invasive correlates of exaggerated ventricular interdependence in cardiac tamponade.

Ventricular interdependence is that property of the normal heart such that distension of one ventricle alters the distensibility and filling pressure of the other. This phenomenon coupled with reciprocal changes in right and left heart venous return during normal quiet respiration results in minor decreases in left ventricular stroke volume, systolic blood pressure, pulse pressure, total electromechanical systole (Q-A2), left ventricular ejection time and mitral e-wave velocity during inspiration and minor increases in these parameters during expiration. Opposite changes in these parameters occur in the right heart with increases occurring during inspiration and decreases during expiration. Exaggerated ventricular interdependence occurs in cardiac tamponade when the pericardial constraint limits the total contents in the pericardial sac. This, together with the decreased effective left ventricular filling pressure which occurs during inspiration, is responsible for the exaggerated decrease in stroke volume, blood pressure, pulse pressure, left ventricular ejection time and mitral e-wave velocity in this condition. These observations, together with the echocardiographic findings of right atrial collapse, right ventricular collapse, and inferior vena cava plethora constitute the noninvasive diagnosis of pericardial tamponade. The utility of these noninvasive tests in detecting both the presence and degree of increased pericardial pressure was evaluated in 33 invasively studied patients with pericardial effusion. In Group 1 (n = 13) intrapericardial pressure was elevated but less than both right atrial pressure and pulmonary wedge pressure, in Group 2 (n = 10) intrapericardial pressure equaled right atrial pressure but was less than pulmonary wedge pressure, and in Group 3 (n = 10) intrapericardial pressure equaled right atrial pressure and pulmonary wedge pressure. From these data it is concluded that right atrial and right ventricular collapse are highly sensitive techniques for predicting increased intrapericardial pressure in all three groups, but fail to predict the level of intrapericardial pressure and the severity of hemodynamic compromise. However, the absence of inferior vena cava plethora helped separate Group 1 patients from Groups 2 and 3 patients, thereby aiding in distinguishing a group of patients with severe hemodynamic derangement requiring urgent intervention. Exaggerated reciprocal changes in mitral and tricuspid e-wave velocity is a very sensitive finding for increased intrapericardial pressure. However, its presence correlates poorly with the severity of tamponade. Acute pericardial tamponade is a clinical diagnosis determined by the integration of the history, physical exam and appropriate noninvasive physiologic and imaging techniques.

Adult↗
PubMed1995

Transesophageal echocardiography to evaluate patients with severe pulmonary hypertension for lung transplantation.

The surgical approach to lung transplantation for patients with severe pulmonary hypertension will be dependent on the primary disease and specific cardiac anatomy. To determine the safety and utility of transesophageal echocardiography in the management of patients with severe pulmonary hypertension who are being evaluated for lung transplantation, we studied 48 consecutive patients, aged 38 +/- 11 years, with pulmonary artery systolic pressure of 70 mm Hg or greater. All patients previously underwent left and right heart catheterization, transthoracic echocardiography, and radionuclide ventriculography. Transesophageal echocardiography was tolerated well by all patients. Additional data that significantly altered surgical therapy was found in 12 of 48 patients (25%): proximal pulmonary artery thrombi (3), patent foramen ovale with significant right to left shunting (2), atrial septal defect (2), double-outlet right ventricle (2), ventricular septal defect (2), and exclusion of atrial septal defect (1). These findings were confirmed surgically in all patients except 3, who died awaiting transplantation. Transesophageal echocardiography is useful in the evaluation of patients with severe pulmonary hypertension.

Adult↗
PubMed1993

Septal myectomy with a carbon dioxide laser for hypertrophic cardiomyopathy.

Septal myectomy with a noncontact carbon dioxide laser for hypertrophic cardiomyopathy is described. This technique results in improved visualization of the septum as the laser beam is held outside the heart and the resecting laser beam can always be clearly seen. We believe this approach provides an improved method of septal myectomy in hypertrophic cardiomyopathy.

Aged↗
PubMed1993

Recurrence of a left ventricular thrombus after surgical excision in a young patient with normal left ventricular systolic function--a case report.

The case report of a young patient with recurrence of intraventricular thrombus represents an unusual presentation with no apparent clinical explanation despite echocardiographic, surgical, and pathologic confirmation. The other unusual feature of this case is the absence of predisposing factors for intraventricular thrombus. The patient developed the second left ventricular thrombus after he stopped taking anticoagulants. The authors' recommendation for such a patient is that he continue to receive anticoagulants for life.

Adult↗
PubMed1992

Outcome and complications of prolonged intraaortic balloon counterpulsation in cardiac patients.

The risks and benefits of prolonged intraaortic balloon support for the management of refractory congestive heart failure and ischemia were studied in patients with end-stage heart disease who needed support for greater than or equal to 5 days. Fifty-two insertions were performed by the percutaneous femoral route in 49 patients. The duration of insertion ranged from 5 to 46 days (mean 11.3). Clinical outcome including hemodynamic parameters and complications were recorded. Mean systemic arterial pressure did not change with balloon insertion (74 +/- 19 vs 76 +/- 11 mm Hg; p = not significant). Both the mean pulmonary artery and pulmonary arterial wedge pressures decreased (33 +/- 8 to 26 +/- 9 mm Hg [p less than 0.01], and 25 +/- 8 to 17 +/- 6 mm Hg [p less than 0.01], respectively). Over time, both parameters tended to increase, but remained significantly less than those before insertion. Cardiac index increased from 1.6 +/- 0.4 to 2.2 +/- 0.5 liters/min/m2 on insertion and continued to increase to 2.7 +/- 0.5 liters/min/m2 (p less than 0.01) before removal. Definite balloon catheter infection developed in 7 patients, and hemorrhage occurred in an additional 7. Eleven patients had vascular compromise, with loss of pulse in 6, thrombosis of the femoral artery in 1, and pseudoaneurysm in 2. Lacerated femoral artery occurred in 1 patient, and mesenteric artery thrombosis in another. Twenty patients died from progressive heart failure and multiorgan system failure, and 19 survived to receive left ventricular assist device and heart transplantation. Only 10 patients were weaned off the balloon. In conclusion, prolonged intraaortic balloon pump support may be successfully used in end-stage heart disease.

Adolescent↗
PubMed1992

Efficacy of antihypertensive medication in orthotopic heart transplant recipients and its effect on renal function.

The authors looked at 77 patients following orthotopic heart transplant who received a triple immunosuppressive regimen including cyclosporine to see the effect of various antihypertensive medications on mean arterial blood pressure and renal function. There were 62 men and 15 women retrospectively classified into three groups according to the antihypertensive medications they received. Group 1 included 26 patients followed up for 10.7 +/- 2.7 months who received hydralazine therapy. Group 2 included 32 patients followed up for 9.0 +/- 3.4 months who received angiotensin-converting enzyme inhibition therapy. Group 3 included 19 patients followed up for 10.1 +/- 3.3 months who received beta-adrenergic blocking agents. Mean arterial pressure (MAP), serum blood urea nitrogen (BUN), and serum creatinine (CR) were determined for each group at the start and end of the follow-up period. The MAP at the start of the study was 107 +/- 14 in group 1, 110 +/- 13 in group 2, and 100 +/- 11 in group 3. It was not statistically significantly different in any of the groups. At the end of the follow-up period, MAP was 112 +/- 10, 111 +/- 10, and 106 +/- 12 for the three groups respectively, and it was not significantly different in any group. The serum BUN in group 3 was 25 +/- 8 mg/dL at the start of the study, and it was not significantly lower than that in group 1, 28 +/- 6, but it was significantly different from that in group 2, 34 +/- 9, P less than 0.05. At the end of the follow-up period, the difference was still maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1977

Primary restrictive cardiomyopathy. Non-tropical endomyocardial fibrosis and hypereosinophilic heart disease.

Eleven patients with a restrictive cardiomyopathy are described. Seven of these had biventricular disease and in them the haemodynamic abnormality resembled that in constrictive pericarditis but the condition was distinguishable because of unequal involvement of the two ventricles, murmurs of atrioventricular valve regurgitation, or characteristic ventricular deformity on angiography. Two of these patients had eosinophilia with the clinical features of Löffer's endocarditis. In 4 patients the disease was apparently confined to the left ventricle; they were investigated on account of atypical chest pain, third heart sound, or abnormal electrocardiogram. Simultaneous measurements of left ventricular pressure and volume throughout diastole were made in 3 patients and showed rapid but abruptly curtailed left ventricular filling. Transvenous endomyocardial biopsy in 2 patients showed fibrous tissue with collagen and irregular elastic fibrils. Surgical biopsy in 3 patients excluded pericardial constriction but was diagnostically unhelpful because of failure to obtain endocardium. Necropsy in one patient showed that the heart had features indistinguishable from tropical endomyocardial fibrosis. It is suggested that the spectrum of ventricular abnormalities in these patients results from endomyocardial fibrosis of varying severity and probably of differing cause. This study has shown that "tropical" endomyocardial fibrosis may occur outside the tropics and suggests that eosinophilia may play a leading role or associated part in the genesis of some cases.

Adult↗
PubMed1976

Effect of acute administration of propranolol on ventricular function in hypertrophic obstructive cardiomyopathy measured by non-invasive techniques.

Seventeen patients with hypertropic obstructive cardiomyopathy, were studied using non-invasive techniques before and after the intravenous injection of 5 mg propranolol. The folloeing were analysed: left ventricular ejection time index, derived from the carotid pulse and heart rate; the isovolumic relaxation time, derived from the apex cardiogram and phonocardiogram; the diastolic closure rate of the mirtal valve; and the left ventricular diameters, systolic and diastolic, both measured by echocardiography. Propranolol produced shortening of the isovolumic relaxation time, increase in both the diastolic closure rate of the mitral valve and left ventricular systolic and left ventricular diastolic diameters. These results show that propranolol increases the rate of filling and the volume of the left ventricle, indicating that an improvement in distensibility is produced by beta-adrenergic blockade.

Cardiomyopathy, Hypertrophic↗
PubMed1975

The functional defect in amyloid heart disease. The "stiff heart" syndrome.

Left ventricular performance was studied in three patients with heart failure due to amyloid deposits. The diagnosis of amyloidosis was proved by cardiac biopsy in two patients and by rectal biopsy in the third. One patient had myelomatosis, but the other two had no other identifiable disease. The investigative technique allowed simultaneous measurements of pressure and volume in the left ventricle. The functional defect with slow cardiac filling at high pressure and greatly reduced left ventricular contraction differed from that of constrictive pericarditis and other heart muscle disease. These features of a "stiff heart" are probably unique to amyloidosis and should make possible positive recognition of the condition on the basis of echocardiographic, angiographic and hemodynamic findings.

Adult↗
PubMed1975

The use of echocardiography to measure isometric contraction time.

The current methods for estimating isometric contraction time were discussed. Ultrasonically derived isometric contraction time, using external carotid pulse tracing, phonocardiogram, and the B-point of the mitral echogram was also measured. Recordings were performed in 10 normal subjects, and 15 patients. Hypertrophic cardiomyopathy (5), congestive cardiomyopathy (6), and ischemic heart disease (4). In 11 patients, the results were correlated with the internal isometric contraction time. The ultrasound isometric contraction time showed good correlation with the internal isometric contraction time (r equals 0.92, P less than 0.01). The external isometric contraction time showed less correlation with the internal isometric contraction time and was significantly shorter (P less than 0.01). The ultrasound isometric contraction time showed a superior discriminating value to the external isometric contraction time for differentiation the normal subjects from the patients' group.

Adolescent↗
PubMed1975

Measurement of stroke volume from pulmonary artery pressure record in man.

Stroke volume was determined from the pulmonary artery pressure record by application of the pulse contour method. Pulmonary artery pressure records were obtained in 17 patients using a high fidelity catheter-tip pressure transducer and simultaneous measurements of cardiac output were obtained from indicator dilution curves. The formula used was SV = KP sa (i plus T s/Td) where Psa is the planimetered area beneath the systolic portion of the pulmonary artery pressure curve. Ts and Td are the durations of systole and diastole, and K is a constant. Stroke volume was altered by isometric handgrip exercise and/or pharmacological agents in 15 patients. Serial measurementswere made in 2 patients in acute pulmonary oedema after myocardial infarction. Comparison of a wide range of values of stroke volume by the pulse contour method with those obtained from dye dilution curves showed a good correlation (r plus 0.97, P smaller than 0.001) regression line y = 1.01 times - 0.47. Measurement of stroke volume from the pulmonary artery pressure contour is a technique of potential value in serial haemodynamic monitoring.

Blood Pressure↗