Biomedical subjects

A Ciarmiello

Publications and source records attributed to A Ciarmiello.

25 records · Page 2Linked to original sources

PubMed1994

Evaluation of left ventricular asynchrony by radionuclide angiography: comparison of phase and sector analysis.

UNLABELLED: The aim of this study was to assess the optimal method to evaluate asynchrony in equilibrium radionuclide angiography (RNA). METHODS: We studied 20 patients (14 males and 6 females, age range 25-60 yr) with RNA during atrial and sequential atrioventricular (AV) pacing, which increased left ventricular (LV) asynchrony. Both studies were performed at the same heart rate. Asynchrony was assessed either on phase images, by computing the standard deviation of the phase distribution (SD-P) and by sector analysis. Systolic and diastolic asynchrony were evaluated as the coefficient of variation of time to end systole (CV-TES) and time to peak filling rate (CV-TPFR) in four sectors. In addition, phase values were computed on time-activity curves from the same sectors, and their standard deviation (SD-Psec) was computed. RESULTS: During atrial pacing SD-P was 32.3 degrees +/- 6.7 degrees and did not change during AV pacing (32.1 degrees +/- 5.6 degrees, p = n.s.). Both CV-TES and CV-TPFR had a significant increase during AV pacing (from 7.7% +/- 3.9% to 11.5% +/- 6.4%, p < 0.01, and from 8.4 degrees +/- 5.8 degrees to 12.9 degrees +/- 6.7 degrees, p < 0.001). AV pacing led to a significant increase in SD-Psec (from 6.3 degrees +/- 4.0 degrees to 12.6 degrees +/- 9.7 degrees, p < 0.05). Moreover, reproducibility was assessed in 15 additional age-matched patients. The results of the reproducibility study indicate a better repeatability for CV-TES and CV-TPFR. CONCLUSIONS: The findings of this study suggest that sector analysis with calculation of indices of LV systolic and diastolic asynchrony is better suited for quantitation of LV temporal nonuniformity.

Cardiac Catheterization↗

PubMed1993

Effects of induced asynchrony on left ventricular diastolic function in patients with coronary artery disease.

OBJECTIVES: This study was designed to increase asynchrony with sequential atrioventricular (AV) pacing and to study its effects on left ventricular isovolumetric relaxation, rapid filling and stiffness. BACKGROUND: Left ventricular nonuniformity is a major determinant of diastolic function. METHODS: Thirteen patients with coronary artery disease were studied by simultaneous equilibrium radionuclide angiography and cardiac catheterization during atrial and AV pacing. Ejection fraction and peak filling rate were measured by radionuclide angiography. Regional analysis was obtained by analyzing time-activity curves of four left ventricular sectors; systolic and diastolic asynchrony were evaluated as the coefficient of variation of time to end-systole and, respectively, time to peak filling rate in the four sectors. Cardiac index and left ventricular pressure were measured with high fidelity catheters at cardiac catheterization. The time constant of isovolumetric relaxation was derived from left ventricular pressure. Pressure-volume loops were assembled and constants of chamber stiffness were computed. RESULTS: Atrioventricular pacing led to a decrease in cardiac index (3.7 +/- 0.9 to 3.3 +/- 0.8 liters/min per m2, p = 0.01) and peak filling rate (352 +/- 125 to 287 +/- 141 ml/s, p = 0.03; 2.4 +/- 0.8 to 2.0 +/- 0.8 end-diastolic counts/s, p = 0.02; 4 +/- 1.3 to 3.2 +/- 1.0 stroke counts/s, p = 0.008). The time constant of isovolumetric relaxation increased (57 +/- 10 to 64 +/- 12 ms, p = 0.04) and the global diastolic pressure-volume relation shifted upward. CONCLUSIONS: Atrioventricular pacing induces left ventricular asynchrony, which is associated with a slower rate of isovolumetric relaxation. The isovolumetric relaxation lasts after the filling phase has begun, thereby reducing the rate of rapid filling.

Adult↗

PubMed1992

Left ventricular diastolic function in systemic sclerosis: assessment by radionuclide angiography.

The aim of this study was to assess left ventricular function in subjects with systemic sclerosis. Twenty-four women with systemic sclerosis (mean age 48 +/- 11 yr) and 14 age- and sex-matched normal subjects were studied by radionuclide angiography performed at rest with a temporal resolution of 20 msec/frame. Left ventricular volume curves were generated and indices of systolic and diastolic function were computed. Left ventricular diastolic asynchrony was evaluated by dividing the left ventricle into five regions and then computing the time-to-peak filling rate for each region. After excluding the valvular region, the coefficient of variation of this index was obtained. The isovolumic relaxation period was prolonged in systemic sclerosis patients in comparison to normal subjects (127 +/- 39 msec versus 87 +/- 44 msec, p less than 0.05). Moreover, 38% of the systemic sclerosis patients had a subnormal peak filling rate. Left ventricular diastolic asynchrony was increased in the systemic sclerosis group, as expressed by a higher coefficient of variation of the regional time to peak filling rate (27.9% +/- 11.5% versus 14.5% +/- 8.6%, p less than 0.05). Our results indicate an impaired relaxation and an increased diastolic asynchrony in patients with systemic sclerosis.

Female↗

PubMed1991

Assessment of left ventricular diastolic function: comparison of contrast ventriculography and equilibrium radionuclide angiography.

Twenty-two patients with coronary artery disease were studied first by radionuclide angiography (RNA) and then by contrast ventriculography. Cardiac medications were discontinued at least 72 hr before study. The patients were studied during atrial pacing at heart rates close to their spontaneous sinus rhythm. Contrast ventriculography was performed at 50 frames/sec in the 30 degrees right anterior oblique projection using 40 ml of a nonionic contrast medium (iopamidol) at a flow rate of 10-12 ml/sec. The contours of the left ventricular silhouette at contrast ventriculography were traced, frame by frame, on a graphic table with a digitizing penlight. Equilibrium 99mTc RNA was performed in the best septal 45 degrees left anterior oblique projection, acquiring 150,000 cts/frame, at 50 frames/sec and with a 5% gate tolerance. Time-activity curves from both end-diastolic and end-systolic ROIs were built and interpolated. Both RNA and contrast ventriculography volume curves were filtered with Fourier five harmonics. A close relationship was found between RNA and contrast ventriculography measurements of peak filling rate normalized to end-diastolic cps (r = 0.87, p less than 0.001) and stroke count (r = 0.87, p less than 0.001), ejection fraction (r = 0.94, p less than 0.001). Thus, in patients with coronary artery disease, LV filling can be accurately assessed using RNA.

Algorithms↗

PubMed1990

Effects of intravenous verapamil on left ventricular relaxation and filling in stable angina pectoris.

Left ventricular (LV) diastolic function is often impaired in coronary artery disease (CAD). To assess whether verapamil could improve LV diastolic properties, 12 patients with CAD undergoing right- and left-sided cardiac catheterization, as well as simultaneous radionuclide angiography, were studied before and during intravenous administration of verapamil (0.1 mg/kg as a bolus followed by 0.007 mg/kg/min). The heart rate was kept constant by atrial pacing in both studies. LV pressure-volume relations were obtained. Verapamil decreased LV systolic pressure (130 +/- 22 to 117 +/- 16 mm Hg, p less than 0.01) and the end-systolic pressure/volume ratio (2.4 +/- 1.3 to 1.6 +/- 0.5 mm Hg/ml, p less than 0.05), and increased LV end-diastolic (13 +/- 4 to 16 +/- 4 mm Hg, p less than 0.02) and pulmonary capillary pressures (10 +/- 5 to 12 +/- 5 mm Hg, p less than 0.005). Despite such negative inotropic effects, cardiac index increased (3.4 +/- 0.7 to 3.9 +/- 0.6 liters/min/m2, p less than 0.02). The time constant of isovolumic relaxation shortened (63 +/- 14 to 47 +/- 9 ms, p less than 0.02); peak filling rate increased (370 +/- 155 to 519 +/- 184 ml/s, p less than 0.001; 2.6 +/- 1.1 to 3.3 +/- 0.9 end-diastolic counts/s, p less than 0.02; and 4.1 +/- 1.6 to 5.5 +/- 1.5 stroke counts/s, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Multiparametric display of spin-echo data from MR studies of brain.

A magnetic resonance (MR) image processing technique that uses a single color image for simultaneous presentation of spin-echo information and its application to MR studies of the brain is described. Relaxation rate and proton-density maps were calculated from 160 brain MR studies performed at 1.5 and 1.0 T with standard spin-echo sequences. Maps were fused into single color images, with R1, R2, and proton density coded, respectively, by red, green, and blue. The possibility of standardizing the technique was evaluated. Comparative analysis of color and conventional MR images of white matter disease and brain tumors was performed to assess intra- and interobserver variability. Unequivocal and reproducible chromatic characterization of normal brain structures and a variety of lesions was obtained. Intra- and interobserver analysis showed that color images can be used as a diagnostic tool. The technique may provide a simplified and timesaving approach for interpretation and presentation of brain MR studies.

Adult↗

PubMedDate not supplied

Simultaneous display of multiple MR parameters with "quantitative magnetic color imaging".

A new technique for simultaneous display of multiple MR parameters with a single color-coded image is described. The method is based on the multiparametric nature of MR signals and benefits from the physiologic ability to discriminate color levels better than gray levels. The T1 and T2 relaxation rate maps are first obtained from multi-echo SE and partial saturation sequences. Each parameter is subsequently represented with one or with a combination of two fundamental colors (red, green, blue) into a composite quantitative magnetic color image. Each mixture of chromatic components in the magnetic color image represents a unique combination of the two relaxation parameters, easily interpretable by the human eye, without loss of anatomic information. The potential advantages of the technique are discussed and some practical applications are presented.

Brain↗