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Biomedical subjects

G Ziady

Publications and source records attributed to G Ziady.

At least 19 recordsLinked to original sources
PubMed1993

Diastolic dysfunction in cardiac transplant recipients: an important role in the response to increased afterload.

We evaluated the hemodynamic and functional response to acute elevations in left ventricular (LV) afterload in 22 recent recipients of cardiac transplants to determine whether abnormalities in LV diastolic function influence the response to this intervention. In seven patients (group 1) LV ejection fraction decreased significantly from baseline values (> or = 5%) during methoxamine infusion, whereas in 15 patients (group 2) LV ejection fraction was maintained. Peak filling rate was lower in group 1 versus group 2 (3.36 +/- 0.46 vs 4.23 +/- 0.68 end-diastolic volumes/sec, p < 0.01). In addition, patients in group 1 did not have LV dilatation during methoxamine (percentage change in end-diastolic counts, -3.4 +/- 6.9%) and had a large increase in pulmonary artery wedge pressure. In contrast, patients in group 2 had LV dilatation (percentage change in end-diastolic counts, +10.7 +/- 14.7%) and a smaller increase in pulmonary artery wedge pressure. There was a relationship between the baseline peak filling rate and the change in LV ejection fraction during methoxamine (r = 0.65, p = 0.001). Therefore in a subset of cardiac transplant patients, abnormalities in LV filling can have an impact on the response to increased afterload.

Adult↗
PubMed1993

Effect on verapamil on ventricular function: studies in denervated human heart.

Verapamil has complex influences on ventricular function owing to its direct myocardial effects, vasodilation, and reflex activation of the sympathetic nervous system. To investigate the direct myocardial effects of verapamil in humans independent of reflex sympathetic stimulation, we administered the drug to 13 recent heart transplant recipients with denervated ventricles. Hemodynamics and radionuclide angiograms were recorded at baseline, with altered loading conditions, and after intravenous (i.v.) verapamil (median dose 4 mg). Left ventricular (LV) systolic and diastolic function was analyzed by systolic pressure-volume relations (SPVR) and peak filling rate (PFR), respectively. Verapamil caused a decrease in blood pressure (BP) and heart rate (HR) with increases in right atrial pressure (RAP 6 +/- 3-8 +/- 3, p < 0.01) and pulmonary artery wedge pressure (PAWP, 9 +/- 3-11 +/- 3 mm Hg, p < 0.01) pressures. LV ejection fraction (EF) decreased (69 +/- 7-66 +/- 8%, p < 0.02) in association with an increase in LV end-systolic counts (3.45 +/- 1.27 to 4.72 +/- 1.78 kcts, p < 0.001). In 11 of 13 patients, the SPV point after verapamil administration was decreased from the line established during altered loading conditions. PFR (4.05 +/- 0.81 to 4.11 +/- 0.76 EDV/s) was unchanged. In the denervated ventricle, verapamil has negative chronotropic and inotropic effects with minimal effects on PFR.

Adult↗
PubMed1993

Right ventricular thallium-201 kinetics in pulmonary hypertension: relation to right ventricular size and function.

Right ventricular ischemia occurs in experimental models of pulmonary hypertension. We analyzed right ventricular size and function and 201Tl uptake to determine if there was a relationship between 201Tl uptake and systolic function in 19 patients with pulmonary artery hypertension who were being evaluated for heart-lung transplantation. All patients had dipyridamole stress 201Tl scintigraphy, radionuclide angiography and echocardiography. In nine patients (Group 1), right ventricular ejection fraction was < 30% (mean 22% +/- 8%). In 10 patients (Group 2) it was > 30% (mean 45% +/- 11%). In Group 1, right ventricular 201Tl uptake in the lateral wall after dipyridamole was increased compared to Group 2 (40% +/- 7% versus 28% +/- 15% counts/pixel, p < 0.05) while left ventricular free wall uptake was similar. The ratio of right to left ventricular 201Tl uptake was increased in Group 1 versus Group 2 (0.81% +/- 0.30% versus 0.49% +/- 0.18%, p < 0.05). At 4 hr, right ventricular free wall 201Tl clearance was comparable, 51% +/- 13% versus 51% +/- 18% in Groups 1 and 2, respectively. No patient had perfusion abnormalities. Right ventricular ejection fraction was inversely related to dipyridamole stress right ventricular 201Tl uptake, r = -0.49, p < 0.03, s.e.e. = 13.6. Right ventricular 201Tl uptake was directly related to right ventricular wall thickness (r = 0.56, p = 0.18, s.e.e. = 10.4). Therefore, patients with more severe right ventricular systolic dysfunction have greater 201Tl uptake after dipyridamole stress, suggesting increased myocardial mass and possibly blood flow in response to hypertrophy. Patients with the most marked hypertrophy have impairment of right ventricular systolic function, independent of ischemia.

Adult↗
PubMed1991

Effects of acute alterations in left ventricular loading conditions on peak filling rate in the denervated (transplanted) ventricle.

Peak filling rate is an indicator of left ventricular (LV) diastolic function. It is influenced by heart rate, loading conditions, sympathetic nervous system activity, ejection fraction and other factors. To determine the effect of altered loading conditions on peak filling rate, independent of heart rate and sympathetic nervous system activity, 12 patients were studied 3 weeks after orthotopic heart transplantation. Plasma catecholamine level, heart rate and ejection fraction were not changed by any maneuver. Nitroglycerin caused a decrease in pulmonary artery wedge pressure (9 +/- 2 to 6 +/- 1 mm Hg, p less than 0.001) and in absolute peak filling rate (46.0 +/- 3.0 to 42.8 +/- 2.5 kcts/s, p less than 0.01), but no change in normalized peak filling rate. Volume infusion increased pulmonary artery wedge pressure (9 +/- 2 to 12 +/- 2 mm Hg, p less than 0.001) and absolute peak filling rate (46.0 +/- 3.0 to 51.5 +/- 5.3 kcts/s, p less than 0.01), but peak filling rate normalized to stroke volume was unchanged. During nitroglycerin and volume infusions, there was a high correlation between changes in pulmonary artery wedge pressure and absolute peak filling rate (r = 0.82, p less than 0.001). With normalization of peak filling rate, these variables correlated less well. With methoxamine, 4 patients demonstrating systolic dysfunction had a decrease in absolute and normalized peak filling rate despite a large increase in pulmonary artery wedge pressure. The other 8 patients without systolic dysfunction had an increase in pulmonary artery wedge pressure with increased absolute but unchanged normalized peak filling rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1990

Cardiac rhythm disturbances early after orthotopic heart transplantation: prevalence and clinical importance of the observed abnormalities.

To precisely define the incidence, type and consequences of cardiac arrhythmias early after heart transplantation, 25 cardiac transplant recipients were monitored continuously for 728 days from the day of surgery to discharge or death. A subset of 15 patients had sinus node function studies with overdrive suppression performed weekly at the time of endomyocardial biopsy. Results revealed sinus bradycardia in 10 patients (40%) and junctional bradycardia in 6 (24%). Supraventricular tachycardia in the form of atrial tachycardia, atrial fibrillation and atrial flutter occurred in 11 patients (44%). Ventricular tachycardia occurred in 15 patients (60%) and was nonsustained in all. Cardiac pacing for 1,403 h was used in nine patients with a pulse rate less than 50 beats/min; seven recovered and permanent pacing was instituted in two. In the subgroup that had sinus node function studies, seven patients were identified with clinical bradyarrhythmia; each had abnormal sinus node recovery time (greater than 1,400 ms) and abnormal corrected sinus node recovery time (greater than 525 ms) in at least one study. These seven patients also had a significantly prolonged ischemic time (236 +/- 26 versus 159 +/- 68 min, p less than 0.01). In conclusion, cardiac arrhythmias, particularly ventricular tachycardia and bradyarrhythmia, occur more commonly early after orthotopic heart transplantation than has previously been reported. Sinus node dysfunction due to prolonged organ ischemic time, antiarrhythmic drug use or surgical trauma, alone or in combination, may contribute to these arrhythmias.

Arrhythmia, Sinus↗
PubMed1989

Coronary artery disease, HDL cholesterol, and insulin-gene flanking sequences.

The relationship between coronary artery disease, HDL cholesterol, and the hypervariable region flanking the human insulin gene was studied in Saudi Arabian non-diabetic subjects (n = 68) and in patients with Type 2 diabetes (n = 35). A locus of insulin-gene-linked DNA polymorphism with three average size classes of alleles was found: a small class 1, a rare medium size class 2, and a large class 3 allele. In the total group of subjects (n = 103), those with the class 3 allele had a lower plasma HDL cholesterol concentration than those without the class 3 allele (0.93 +/- 0.26 vs 1.12 +/- 0.30 mmol l-1, 2p less than 0.003). No difference in genotype and allelic frequency was found between patients with and without coronary artery disease in the combined group of subjects, with and without diabetes. Similarly the genotype distribution was not different between non-diabetic subjects and patients with Type 2 diabetes in the combined group of subjects, both with and without coronary artery disease. In conclusion, the study did not confirm a previous study showing an association between the class 3 allele and atherosclerosis in a Caucasian population. However, the class 3 allele was associated with a low plasma HDL cholesterol concentration.

Alleles↗
PubMed1988

Mitral valve prolapse and social phobia.

Of 30 Saudi patients with social phobia, eight had echocardiogram evidence of mitral valve prolapse. Only two out of 30 controls had echocardiogram evidence of mitral valve prolapse. The clinical and research implications of this finding are discussed.

Adolescent↗
PubMed1987

Hemodynamic evaluation of porcine bioprostheses in the mitral position by Doppler echocardiography.

Twenty-four patients with porcine bioprostheses in the mitral position were studied by Doppler echocardiography followed by cardiac catheterization within 24 hours. Doppler mean diastolic mitral valve gradient was calculated by a 3-point method and mitral valve area was determined by the pressure half-time method. Data from Doppler echocardiography and cardiac catheterization were compared. There was a strong correlation between Doppler echocardiography and catheterization-determined mean diastolic gradient: r = 0.9, standard error of estimate (SEE) = 1.4 mm/Hg (regression equation y = 0.63x + 1.41), p less than 0.001. There was also a strong correlation between Doppler echocardiography and catheterization-determined mitral valve area: r = 0.86, SEE = 0.18 cm2 (regression equation y = 0.64x + 0.52), p less than 0.001. Fourteen patients whose valvular function was considered normal by clinical evaluation had Doppler-calculated mean diastolic gradients of 4.5 to 9.5 mm Hg (mean 6.5 +/- 1.4); the Doppler-determined valve area was 1.15 to 2.0 cm2 (mean 1.54 +/- 0.3). Ten patients had a malfunctioning bioprosthesis, 7 had severe mitral regurgitation and 3 had stenosis. Valvular malfunction in all 10 patients was detected by Doppler echocardiography and confirmed by catheterization and angiocardiography. Nine patients underwent reoperation. Doppler hemodynamic evaluation of porcine bioprostheses in the mitral position provided noninvasive information comparable to that obtained by cardiac catheterization.

Adult↗
PubMed1987

Brucella endocarditis.

Brucella endocarditis is an underdiagnosed, fatal complication of human brucellosis. Four successfully treated cases of Brucella endocarditis are reported. The development of a new valvar lesion and bulky vegetations seen on echocardiography helped to identify Brucella endocarditis occurring during systemic brucellosis. The aortic valve was affected in all four patients, and in one the mitral valve was also affected. Medical treatment did not cure the patients and all needed valve replacement--for haemodynamic deterioration in three and because a further embolism was feared in one. Antibiotics were continued for six to nine months after operation. There was no early or late mortality and no recurrence after a follow up of 15 months.

Adult↗
PubMed1985

Endomyocardial fibrosis: report of eight cases.

Endomyocardial fibrosis is a disease of unknown origin which has not previously been described in detail from the Middle East. The clinical, echocardiographic, hemodynamic and angiocardiographic findings in eight patients (five men and three women, mean age 38 years) are presented. Two patients had right-sided involvement, two had left-sided involvement and four had biventricular involvement. The presence of a small ventricle with obliteration of the apex and a large atrium is a two-dimensional echocardiographic finding highly suggestive of endomyocardial fibrosis. Hemodynamic characteristics of dip and plateau on ventricular pressure curves were present in six patients. Ventricular angiography was diagnostic in all cases. Endomyocardial biopsy yielded positive findings in three of six patients and is not essential for diagnosis.

Adult↗