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Biomedical subjects

R Natali

Publications and source records attributed to R Natali.

At least 19 recordsLinked to original sources
PubMed2001

Dipyridamole stress echocardiography vs dipyridamole sestamibi scintigraphy for diagnosing coronary artery disease in left bundle-branch block.

STUDY OBJECTIVES: To evaluate dipyridamole stress echocardiography (DSE) for predicting coronary artery diseases (CADs) in patients with complete left bundle-branch block (LBBB). DESIGN: Comparison of DSE and dipyridamole sestamibi myocardial perfusion scintigraphy (sestamibi). SETTING: Tertiary-care cardiac referral center. PATIENTS: Fifty-four consecutive patients (26 men; mean [+/- SD] age, 59 +/- 7 years) with complete LBBB (14 patients with left ventricular [LV] dilatation) and intermediate probability of CAD. METHODS: Simultaneous single photon emission CT scan (20 mCi technetium Tc 99m stress/rest sestamibi) and echocardiography (second harmonic imaging) during a two-step (0.56 to 0.84 mg/kg) dipyridamole infusion protocol. Two sestamibi readings were performed. The first reading considered only those studies with reversible defects (sestamibi-1) to be positive. The second reading considered those studies with any defect (sestamibi-2) to be positive. CAD was defined as a >or= 50% reduction in diameter in at least one major vessel seen on coronary angiography. RESULTS: CAD was present in 17 patients (31.5%). The global predictive accuracy for CAD was significantly higher for DSE (87.0%) and sestamibi-1 (79.6%) than for sestamibi-2 (57.4%) [p < 0.01 vs DSE; p < 0.05 vs sestamibi-1]. No significant differences in sensitivity were present, but specificity was significantly higher for DSE (94.6%) and sestamibi-1 (81.1%) than for sestamibi-2 (43.2%; p < 0.01 vs both the other two tests). Of 14 patients with LV dilatation, 26.8% were falsely positive for CAD (in some cases for posterior defects) as determined by sestamibi-1 and 64.3% were falsely positive for CAD by sestamibi-2 vs none by DSE. CONCLUSIONS: DSE is at least as accurate as dipyridamole sestamibi scintigraphy for predicting CAD in patients with complete LBBB and tends to be more specific in those patients with underlying LV dilatation.

Bundle-Branch Block↗
PubMed2000

Neuroadrenergic activation and response to dobutamine in congestive heart failure secondary to idiopathic dilated cardiomyopathy.

Detection of contractile reserve is important in heart failure patients. To determine if detection of contractile reserve is influenced by neuroadrenergic activation, we examined the relation between dobutamine stress echocardiography (DSE) findings and plasma norepinephrine levels (NE) at rest in 35 patients with nonischemic left ventricular (LV) dysfunction (New York Heart Association class >III in all; LV ejection fraction 0.27 +/- 0.5). Changes in global wall motion score (WMS), and separately in WMS of hypokinetic segments and akinetic segments, were analyzed. A patient was considered to be responsive to dobutamine if the change in global WMS was >/=4. Twenty-three patients were responsive and 12 were not responsive to dobutamine. Plasma NE and baseline heart rate were significantly higher in nonresponsive patients (p <0.001). Changes in global WMS and in hypokinetic segment WMS were inversely related to either plasma NE (r -0.68 and -0.67, respectively) or baseline heart rate (r -0.60 and -0.66, respectively). The change in akinetic segment WMS was related to plasma NE only (r -0.50). Changes in WMS were not related to age, diastolic and systolic LV volume, baseline global WMS, or number of akinetic segments at baseline. Plasma NE >602 pg/ml predicted a blunted or absent contractile reserve at DSE (sensitivity 92%; specificity 87%). Neuroadrenergic activation may influence contractile reserve found at DSE in patients with heart failure due to nonischemic LV dysfunction.

Adult↗
PubMed1998

Prognostic role of heart rate variability in patients with a recent acute myocardial infarction.

A low heart rate variability (HRV) has been shown to be a powerful predictor of cardiac events in patients surviving an acute myocardial infarction (MI), but it is not clear yet which among the HRV parameters has the best predictive value. Time domain and frequency domain HRV was assessed on 24-hour predischarge Holter recording of 239 patients with a recent MI. Patients were followed up for 6 to 54 months (median 28), during which 26 deaths (11%) occurred, 19 of which were cardiac in origin and 12 were sudden. Most HRVs did not show any difference between patients with or without mortality end points, but the average low-frequency and low-frequency/high-frequency ratio was lower in patients with events. However, when dichotomized according to cut points that maximized the risk of sudden death, several HRVs were significantly predictive of clinical end points. Overall, the mean of the standard deviations of all RR intervals for all 5-minute segments and the standard deviation of the mean RR intervals for all 5-minute segments were the time domain variables most significantly associated with mortality end points, whereas very low frequency was the most predictive frequency domain variable. Compared with the best time domain variables, very low frequency showed a better sensitivity (0.27 to 0.42 vs 0.19 to 0.33) for end points with only a small loss in specificity (0.92 vs 0.96). On multivariate Cox proportional analysis, a left ventricular ejection fraction <40% and a number of ventricular premature beats > or = 10/hour were the most powerful independent predictors for all end points, whereas no HRV was independently associated with the events. A low frequency/high frequency ratio < 1.05 only had a borderline association with sudden death (RR = 2.86, p = 0.076). Our data show a strong association between HRV and mortality in patients surviving a recent MI, with a slight better sensitivity of frequency domain analysis. In our study, however, HRV did not add independent prognostic information to more classic prognostic variables (e.g., left ventricular function and ventricular arrhythmias).

Aged↗
PubMed1989

A phase I study of human natural interferon-beta in cancer patients.

In this phase I study 15 patients with metastatic tumors were given interferon (IFN)-beta by i.v. bolus injections. Twelve individual doses of 1, 2, 3.3, 5, 7, 9, 12, 16, 21, 27, 35, and 46 x 10(6) IU were administered every other day. The single maximal tolerated dose ranged from 9 to 46 x 10(6) IU. Eight patients tolerated the dose of 46 x 10(6) IU without side effects. Disturbances of cardiac rhythm were observed, but were closely related temporally to severe chills and appeared to be the consequence of adrenergic stimulation associated with this side-effect. In addition, no significant variations in the left ventricular function as assessed by nuclear stethoscope were observed. Neurotoxicity was not a major side-effect. The toxicity of IFN-beta given as scheduled in this study was significant, but acceptable.

Adult↗
PubMedDate not supplied

Echocardiographic imaging in coronary artery disease: new techniques.

When analyzing left ventricular wall motion and thickening, two-dimensional echocardiography (2DE) represents a useful non-invasive tool for diagnosing and stratifying ischemic heart disease. New important technical advancements, such as harmonic imaging, allow to overcome limitations due to poor echocardiographic image quality in a large proportion of patients. Combination of exercise or pharmacological stress test with on-line echo images monitoring expands 2DE diagnostic and prognostic value in both ischemia or viability assessment. Study of contrast agents distribution is very promising for clarifying the complex interaction between myocardial perfusion and functional correlates, including myocardial stunning, hibernation and no-reflow phenomena. Direct visualization of epicardial coronary arteries and assessment of coronary artery blood flow has recently been demonstrated to be possible by either transthoracic (TTE) or transesophageal echocardiography (TEE). Acoustic quantification (AQ), automatic border detection (ABD), tissue Doppler imaging (TDI), and color kinesis are other technical modalities which may result to be useful for clinical evaluation of patients with either acute or chronic coronary syndromes.

Contrast Media↗