Biomedical subjects

M Ciavolella

Publications and source records attributed to M Ciavolella.

At least 37 records · Page 2Linked to original sources

PubMed1991

Exponential fit of QT interval-heart rate relation during exercise used to diagnose stress-induced myocardial ischemia.

The aim of this study was to analyze the dynamic changes of QT interval--heart rate relation during exercise, fitting their reciprocal variations to an exponential formula (QT = A - B.exp(-k.RR], in order to see whether diagnostic contributions might so be derived. The authors studied 139 patients who underwent a simultaneous assessment of regional myocardial perfusion and ventricular function by means of two injections of 99mTc-methoxy-isobutyl-isonitrile at rest and at peak of a submaximal exercise test, using first pass radionuclide angiography with multielement gamma-camera and single photon emission computerized tomography, in order to detect and localize the presence of stress-induced myocardial ischemia. According to radionuclide results, patients were divided into three groups: group A, 7 individuals with no sign of stress-induced myocardial ischemia; group B, 79 patients with evidence of ischemia in 1 (16.5%), 2 (65.5%), or 3 (17.7%) main coronary territories; and group C, 53 patients with previous infarction and evidence of ischemia in other territories. Conventional analysis of the exercise test (greater than or equal to 0.1 mV ST depression) showed a pathological response in no individual of group A, in 34 patients of group B (43%), and in 27 patients of group C (50.9%); overall sensitivity was 46.2%, specificity 100%, and diagnostic accuracy 48.9%. Exponential coefficients A, B, and k showed wide overlap of values among the three groups, although a significant difference was present in mean k values between groups A and B (p less than 0.001), and group C (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗

PubMed1991

ST/HR slope and improved exercise ECG detection of myocardial ischemia in patients with suspected coronary artery disease.

Predictive values of ST/HR slope and ST-segment displacement during symptom-limited exercise were determined in 85 patients who underwent coronary angiography for suspected coronary artery disease, using perfusional and functional radionuclide images with 99mTc-2-methoxy-isobutil-isonitrile as an index of stress-induced myocardial ischemia. ST/HR slope showed a better sensitivity than conventional stress-induced changes of ST-segment displacement (96% vs. 73%, respectively). In patients with clinical suspicion of coronary artery disease, the main result was the negative predictive value of ST/HR slope when compared with conventional ST-segment displacement (98% vs. 41%). ST/HR slope was unable to perfectly separate patients with different degrees of ischemia, however, subjects without scintigraphic signs of stress-induced ischemia and patients with ischemic impairment in three myocardial regions were correctly identified as distinct populations. In patients with a previous myocardial infarction, no difference was found between the two criteria and a wide overlap of ST/HR slope values was present. The authors conclude that ST/HR slope is useful to detect the rate of change in electric parameters during exercise and might therefore more adequately be used to separate normal from definitely abnormal responses to exercise.

Adult↗

PubMed1990

[Variations in QT interval and ventricular volume during exercise-induced myocardial ischemia].

Aim of this study was to evaluate the possible relationship among myocardial ischemia, left ventricular volume changes and QT interval changes during exercise in patients with coronary artery disease. QT interval, expressed as absolute value, corrected according to Bazett (QTc = aT/RR0.5) and Fridericia (QTf = QT/RR0.33) and calculated by adapting reciprocal changes in QT and heart rate during exercise to the exponential fit proposed by Sarma (QTs = A-B*exp (-K*RR], was compared to the scintigraphic finding of myocardial ischemia and to the changes in left ventricular volumes during exercise. We studied 151 patients (130 men and 21 women, mean age 56 +/- 11 years) with suspected or already ascertained coronary artery disease, who underwent a simultaneous evaluation of regional ventricular function and myocardial perfusion by means of first pass radionuclide angiography (multielement gamma-camera) and computerized tomography, with 2 injections of 99mTc-MIBI at rest and at peak of a computerized bicycle stress test. QT and RR intervals were measured on an averaged ECG complex through a magnifying lens, and the absolute values of left ventricular volumes were computed by radionuclide angiography. According to scintigraphic findings, patients were divided into normal subjects (n = 7) and ischemic patients with (n = 63) and without (n = 81) evidence of a previous myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1990

[Exponential analysis of the relationship between ST segment depression and heart rate during exercise in patients with ischemic cardiopathy].

ST segment displacement sensitivity and specificity during exercise in the detection of myocardial ischemia are controversial, even when using mathematical approaches such as a linear regression analysis of ST/heart rate slope. In an attempt to see whether an exponential fit (ST = A-B*exp (-K*RR] of ST/heart rate relation during exercise could increase the diagnostic accuracy of exercise test in the detection of myocardial ischemia, we studied 165 patients (141 men and 24 women, mean age: 56 +/- 10 years) undergoing a simultaneous radionuclide assessment of regional ventricular function and myocardial perfusion at rest and at peak exercise in 4 hours by means of 2 injections of 99mTc-MIBI. Normal radionuclide findings were found in 4 subjects, whereas exercise-induced myocardial ischemia was detected in 90 patients with no evidence of previous myocardial infarction, and in 71 patients with previous myocardial infarction. ST segment depression was present at peak exercise in no normal subject, and in 52.2% and 60.4% of ischemic and infarcted patients, respectively, achieving a sensitivity of 55.9%, a specificity of 100% and a diagnostic accuracy of 57%. A, B and K coefficients of exponential analysis showed a wide variability among patients; however, the algebraic sign of K coefficient was negative in 50% of normal subjects versus 9.9% of patients (chi 2-test: p less than 0.02), thus achieving a sensitivity of 90.1%, a specificity of 50% and a diagnostic accuracy of 89.1% in the detection of exercise-induced myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

[Improvement in the accuracy of diagnosis of ischemic heart disease with simultaneous radioisotope evaluation of regional myocardial function perfusion and an exercise test].

The recently developed myocardial agent methoxy-isobutyl-isonitrile (MIBI), labelled to 99mTc, allows one to evaluate global and regional ventricular function as well as myocardial perfusion by means of a single exercise stress test, significantly increasing diagnostic accuracy for coronary artery disease. Between September 1988 and March 1989, 407 patients with either suspected or already ascertained coronary artery disease underwent simultaneous assessment of regional ventricular function with first pass radionuclide angiography, and of myocardial perfusion with single photon emission computerized tomography, by means of 2 injections of 99mTc-MIBI at rest and at peak of the same exercise test. Out of these patients, 56 (52 men and 4 women, whose mean age was 57 +/- 7 years) underwent coronary angiography within 6 months of radionuclide examination and were included in the study. There were 13 1-vessel, 26 2-vessel and 17 3-vessel disease patients. Thirty-six of them had had a previous (greater than 6 months old) myocardial infarction, on the anterior wall in 16 patients, on the inferior wall in 20. In all patients a computerized bicycle stress test was performed; interruption criteria were ST segment depression greater than or equal to 1 mm in 27 patients (48%), the achievement of a heart rate greater than 85% of maximal age-predicted heart rate in 12 patients (22%) and fatigue in 17 patients (30%). Scintigraphic results were compared to angiographic findings: global sensitivity and specificity of the simultaneous evaluation were 82% and 81%, respectively, vs 95% and 56% of functional results and 85% and 71% of perfusion results, respectively. Regional analysis was also performed, by dividing scintigraphic images into the territories supplied by the 3 main coronary vessels, i.e., left anterior descending artery (LAD), left circumflex artery (LCx) and posterior descending artery (PD). On LAD territory the simultaneous evaluation achieved a sensitivity of 88% and a specificity of 63%, vs 98% and 38% of functional analysis and 88% and 50% of perfusional analysis, respectively. On LCx territory sensitivity and specificity were respectively 71% and 96%, vs 91% and 64% of function, and 77% and 96% of perfusion alone. On PD territory sensitivity was 85%, vs 94% and 91%, respectively; specificity was 73%, vs 55% and 55%, respectively. Combined functional and perfusional analysis achieved a 68% sensitivity in identifying less than or equal to 75% coronary narrowings, and a 90% sensitivity for greater than 90% narrowings.(ABSTRACT TRUNCATED AT 400 WORDS)

Coronary Disease↗

PubMed1990

[Changes in R wave voltage during exercise: are they a sign of changes in ventricular volume or of myocardial ischemia?].

In an attempt to assess the significance of R wave amplitude changes during exercise in patients with coronary artery disease, we retrospectively analysed radionuclide as well as exercise test results of 147 patients with either suspected or already ascertained coronary artery disease, 126 men and 21 women, whose mean age was 56.0 +/- 9.3 years, 56 of which with previous myocardial infarction (16 on the anterior, 33 on the inferior and 7 on the lateral wall), who underwent a simultaneous evaluation of regional ventricular function by means of first pass angiography with multielement gamma-camera and of myocardial perfusion by means of single photon emission computerized tomography. All patients received 2 iv injections of 99mTc-methoxy-isobutyl-isonitrile at rest and at peak of a computerized bicycle stress test, whose end-points were ST segment depression greater than or equal to 1 mm or the attainment of a heart rate greater than 85% of maximal age-predicted one. R wave amplitude was measured by means of a magnifying lens on an averaged ECG complex, selecting for each patient the precordial lead showing the largest R wave amplitude. Absolute values of left ventricular volumes were computed by means of a standardized method from first pass angiography data. Patients were divided in subgroups according to the presence and to the number of coronary territories with evidence of stress-induced myocardial ischemia at radionuclide study.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1988