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Biomedical subjects

P A de Milliano

Publications and source records attributed to P A de Milliano.

7 recordsLinked to original sources

Relationship between cardiac metaiodobenzylguanidine uptake and hemodynamic, functional and neurohormonal parameters in patients with heart failure.

BACKGROUND: Sympathetic activation plays a pivotal role in heart failure attributing to the disease process and symptoms of the patient. Myocardial sympathetic activity can be visualized using radioiodinated metaiodobenzylguanidine 123I-MIBG, a structural analogue of norepinephrine (NE). AIM OF THE STUDY: We investigated whether a relation exists between myocardial MIBG uptake and different functional, hemodynamic and neurohormonal parameters in patients with chronic heart failure. METHODS AND RESULTS: The study comprised 52 patients with stable congestive heart failure functional class II or III and left ventricular ejection fractions of <35%. The heart/mediastinum ratio (H/M ratio) was calculated to quantify myocardial MIBG uptake. A significant correlation was found between peak oxygen consumption and maximal exercise duration as exercise parameters and H/M ratio of MIBG (R, respectively, 0.36 and 0.4, P<0.05). From all other measured parameters, only plasma NE showed a significant correlation with the H/M ratio of MIBG. CONCLUSION: Cardiac sympathetic activity, as measured by myocardial MIBG uptake, is correlated with peak exercise parameters.

3-Iodobenzylguanidine↗

Comparison between iodine 123 metaiodobenzylguanidine scintigraphy and heart rate variability for the assessment of cardiac sympathetic activity in mild to moderate heart failure.

This study demonstrates that in patients with mild to moderate heart failure, cardiac metaiodobenzylguanidine (MIBG) washout positively correlates with normalized low-frequency power in the heart rate variability spectrum. Alterations of the cardiac sympathetic nervous system could be detected with MIBG scintigraphy in patients with normal plasma norepinephrine levels. Therefore cardiac MIBG washout may be a valuable noninvasive technique to assess early alterations in cardiac sympathetic activity that may have potential clinical implications in patients with mild to moderate heart failure.

3-Iodobenzylguanidine↗

Increased myocardial [123I]-metaiodobenzylguanidine uptake after enalapril treatment in patients with chronic heart failure.

OBJECTIVE: To assess non-invasively the effect of enalapril on cardiac sympathetic neuronal uptake function in patients with congestive heart failure, by using [123I]-metaiodobenzylguanidine (MIBG), which is a noradrenaline analogue. Cardiac MIBG uptake was visualised by single photon emission tomography (SPET). In addition, plasma noradrenaline concentration, indicating systemic sympathetic activity, was measured to see whether it was related to cardiac MIBG uptake. DESIGN: Consecutive patients were treated with enalapril and served as their own controls. SETTING: Cardiac unit of a tertiary care centre. PATIENTS: 23 Patients with chronic, mild to moderate, stable congestive heart failure, and a left ventricular ejection fraction less than 40%. Heart failure was caused by ischaemic heart disease or was idiopathic. INTERVENTIONS: Cardiac MIBG SPET was performed and plasma noradrenaline concentration was measured before and after 6 weeks treatment with enalapril. MAIN OUTCOME MEASURES: Cardiac uptake of MIBG was measured by using the left ventricular cavity and a venous blood sample as a reference. RESULTS: Cardiac uptake of MIBG increased significantly after enalapril treatment, indicating improved cardiac neuronal uptake function. Plasma noradrenaline concentration did not decrease significantly. Cardiac MIBG uptake was not related to plasma noradrenaline concentration. CONCLUSIONS: Cardiac MIBG SPET can be used to assess changes in cardiac sympathetic neuronal uptake function caused by pharmacological intervention. Enalapril seemed to improve cardiac sympathetic neuronal uptake function but did not significantly affect plasma noradrenaline concentrations in a group of patients with predominantly moderate heart failure. These results accord with the hypothesis that restoration of cardiac neuronal uptake of noradrenaline is one of the beneficial effects of enalapril in such patients.

3-Iodobenzylguanidine↗

Quantitation of myocardial iodine-123 MIBG uptake in SPET studies: a new approach using the left ventricular cavity and a blood sample as a reference.

In patients with chronic heart failure increased sympathetic activity is related to unfavourable prognosis. Since myocardial iodine-123 metaiodobenzylguanidine ([123I]MIBG) uptake is related to myocardial noradrenaline content, i.e. cardiac sympathetic activity, measurement of myocardial [123I]MIBG uptake may be of clinical use in determining prognosis or the effect of pharmacological intervention in these patients. The aim of the present study was to evaluate a new method to quantitate myocardial [123I]MIBG uptake with respect to reproducibility and accuracy. Eighteen [123I]MIBG planar and single-photon emission tomographic (SPET) studies of patients with chronic heart failure were evaluated. Myocardial uptake was calculated from the myocardial (MYO) to left ventricular cavity (C) count density ratio and the 123I activity in a blood sample. This was performed employing planar LAO images, a single-slice SPET method using the midventricular myocardial short-axis slice, and finally a multi-slice SPET method analysing semi-automatically drawn volumes of interest (VOIs). The accuracy of the multi-slice SPET method was verified using a cardiac phantom. The planar method was found to be reproducible [intra- and interobserver coefficients of variation (IACV and IRCV) were 0.025 and 0.012 respectively] but the mean MYO/C count density ratio was only 1.31 +/- 0.16 as a consequence of overprojection. For the single-slice SPET method IACV was 0.2 and IRCV was 0.13, representing poor reproducibility. For the multi-slice SPET method IACV was 0.051, IRCV was 0.047 and the mean MYO/C count density ratio was 5.4 +/- 2.42. Accuracy was 81% at a true MYO/C count density ratio of 6 in the phantom. It is concluded that the multi-slice SPET method using the left ventricular cavity VOI and a blood sample as a reference is a reproducible and accurate method for assessing myocardial [123I]MIBG uptake.

3-Iodobenzylguanidine↗

Long-term efficacy of continuous and intermittent use of transdermal nitroglycerin in stable angina pectoris.

To assess efficacy of transdermal nitrate use, a randomized, placebo-controlled trial of continuous and intermittent use of nitroglycerin patches (10 mg/24 hours) was conducted in 127 patients with stable angina pectoris who discontinued exercise testing within 9 minutes because of angina. After a placebo run-in week, baseline (day 0) symptom-limited exercise testing was performed and repeated on day 1 and 14 before and after the administration of 0.5 mg of sublingual nitroglycerin. On day 0, total exercise duration was the same (within narrow limits) in all 3 groups and remained unchanged in the placebo group. On day 1, total exercise duration increased from 406 +/- 115 to 469 +/- 158 seconds (p less than 0.001) in the continuously treated group and from 396 +/- 105 to 475 +/- 171 seconds (p less than 0.001) in the intermittently treated group. In the intermittent group, exercise duration increased slightly to 483 +/- 140 seconds on day 14, and in the continuous group exercise duration decreased to 447 +/- 144 seconds. However, this decrease was not statistically significant. Similar treatment effects were seen for time to 1-mm ST depression. Sublingual nitroglycerin remained effective in all 3 groups and on all days. Eleven actively treated patients and 1 patient taking placebo discontinued the study because of headache. It is concluded that continuous use of transdermal nitroglycerin remains partially effective and intermittent therapy remains fully effective in improving long-term exercise capacity with acceptable adverse effects in patients with stable angina pectoris.

Administration, Cutaneous↗