Consumer behaviour survey for assessing exposure from consumer products: a feasibility study.

Evaluating chemical exposures from consumer products is an essential part of chemical safety assessments under REACH and may also be important to demonstrate compliance with consumer product legislation. Modelling of consumer exposure needs input information on the substance (e.g.

[Non-Q-wave-electrocardiograms. Signs of earlier myocardial infarction].

An increasing number of elderly people and diabetes patients with myocardial infarction go unrecognized because of painless ischemia and regression of major Q-waves over time. An increased awareness of diagnostic electrocardiogram (ECG) abnormalities other than Q-waves should allow physicians to optimize patient management. Particularly emphasized is the R-peak delay in V6, i.

Left ventricular function-conduction impairment as reflected by the ECG in chronic aortic regurgitation.

The study was conducted to ascertain that the ECG assists in the assessment of systolic dysfunction in chronic aortic regurgitation. Five variables were reviewed in 146 adults without bundle branch block who underwent angiocardiography: total 12-lead QRS amplitude, QRS duration, maximum R peak time in I, V5 or V6, maximum R peak time relative to S peak time of the maximum S in V1, V2 or V3, and maximum T wave amplitude and polarity in I, V6 or aVF. In order to define which of them could differentiate left ventricular ejection fraction (EF) ≥50% (n = 101) from EF <50% (n = 45) they were subjected to stepwise linear discriminant analysis.

[Cardiac memory of the ECG following ventricular pacing].

During abnormal pacemaker depolarization, abnormal repolarization occurs and persists in normal QRS beats often seen in alternation with paced beats. The T-wave direction of normal beats is typically similar to the direction of the QRS complex during pacing, hence the term cardiac memory. The normal nonpaced beats have shown a sensitivity of 92% and a specificity of 100% for cardiac memory in the presence of T-wave inversions (TWI) in the precordial and inferior (II, III and aVF) leads with a positive T wave in aVL, a positive or isoelectric T wave in lead I, and the maximal precordial TWI being greater than the TWI of lead III, discriminating it from ischemic precordial TWI.

R peak time prolongation and R peak delay in leads I, V5, or V6. Diagnostic values as signs of myocardial dysfunction in chronic mitral incompetence.

On the assumption that maximum R peak time prolongation in the left-sided leads I, V5, or V6 and its time relationship to the S peak time of the maximum S amplitude in leads V1, V2, or V3 (representing dorsally directed forces of ventricular depolarization) could indicate the extent of left ventricular volume overloading and possibly left ventricular systolic function, these variables and the preoperative findings of angiocardiography were compared between patients with chronic mitral incompetence who, late after corrective valve surgery, had either well-preserved radionuclide left ventricular ejection fraction (group 1, n = 36) or radionuclide left ventricular ejection fraction below 50% (group 2, n = 30). Before surgery, group 2 patients had a highly significant lower mean left ventricular ejection fraction, a highly significant greater mean end-systolic volume index, a significantly greater mean end-diastolic volume index, a significantly greater mean maximum R peak time in leads I, V5, or V6, and a significantly greater prolongation of the maximum R peak time above the S peak time in the right precordial leads, as compared with group 1. R peak times greater than 50 ms or the presence of R peak delay (maximum R peak time greater than the S peak time of the maximum right precordial S amplitude) yields less sensitive but highly reliable results in predicting radionuclide left ventricular ejection fraction below 50% with both specificity and positive predictive values of 100%.

Electrocardiographic characteristics indicating a risk of irreversibly impaired myocardial function in chronic aortic regurgitation.

In order to define which of selected ECG variables could indicate irreversibly impaired myocardial function in chronic aortic regurgitation 54 patients were stratified according to normal (> or = 50%; Group A, n = 41) or subnormal radionuclide left ventricular ejection fraction (LVEF < 50%; Group B, n = 13) late after aortic valve replacement. Preoperatively, Group B patients had a significantly greater QRS duration, greater R-peak time (RPT) prolongation in I, V5 or V6, greater RPT relative to the S-peak time of the maximum S in V1, V2 or V3 (R-peak delay) and a greater negative T-wave in I or V6, as compared with Group A. These ECG variables together with preoperative angiocardiographic LVEF and end-systolic volume index were subjected to stepwise linear discriminant analysis.

Role of the electrocardiogram in assessing irreversibly impaired left ventricular systolic function in chronic mitral regurgitation.

The study set out to determine whether the electrocardiogram (ECG) might be useful in assessing left ventricular (LV) volumes and systolic function in patients with pure, chronic mitral regurgitation. To do this preoperative haemodynamic and angiocardiographic data, QRS duration, total 12-lead QRS amplitude, R peak time in V6, R peak delay in V6 (RPDV6) (i.e.

R peak delay in V6. Diagnostic implications in coronary heart disease.

Epimyocardial excitation is delayed in areas overlying infarcted myocardium. On the assumption that a delayed R peak in V6 could indicate anterior myocardial infarction (AMI) in the absence of diagnostic Q waves, the findings of angiocardiography (n = 148) and thallium scanning (n = 46) of 194 patients with suspected coronary heart disease (CHD) were compared with regard to two criteria: A (R peak in V6 precedes S peak in V2, or both peaks occur simultaneously, n = 158) and B (R peak in V6 is later than S peak in V2 [R peak delay in V6], n = 36). Of 92 patients with unconfirmed CHD, 4 fit criterion B, and 3 of these had hypertensive heart disease.

Assessment of left ventricular function from the electrocardiogram in left bundle branch block.

The QRS duration, maximum right precordial S amplitude, sum of amplitudes of the maximum right precordial S and T wave and T wave polarity in lead I have been analyzed in order to identify electrocardiographic predictors of left ventricular end-diastolic volume index and ejection fraction in 165 patients with complete left bundle branch block and various forms of heart disease. Multivariate analysis selected the duration, maximal amplitude of the S wave and polarity of the T wave in decreasing order of discriminatory power, which correctly identify 76.6% of the patients with a normal end-diastolic volume index less than or equal to 90 ml/m2 and a normal ejection fraction greater than or equal to 60% (n = 64) and 73.

Electrocardiographic markers of impaired left ventricular ejection performance in aortic stenosis.

To determine whether the ECG would be useful in the prediction of impaired left ventricular ejection performance in aortic valve stenosis, the authors evaluated 121 patients according to (1) the time relationship of the R peak in V6 to the S peak in V2; and (2) the negative P wave terminal force in V1 (Morris index, n = 109). Left ventricular ejection fraction (LVEF) was significantly depressed in patients with the R peak in V6 later than the S peak in V2 (R peak delay in V6, n = 24), compared with those with the R peak in V6 preceding the S peak in V2 or with both peaks occurring simultaneously (n = 97) (LVEF 40.8 +/- 11.

Diagnostic implications of figure-of-eight and clockwise QRS loop rotation on the horizontal vectorcardiogram in chronic aortic valve disease.

In chronic aortic valve disease the left ventricular (LV) volumes, mass and ejection fraction (EF), as well as selected Frank ECG measurements of patients with a normal counterclockwise rotation (Type A) of the horizontal QRS vector loop are compared with those of patients showing an abnormal figure-of-eight or clockwise configuration (Type B) to investigate whether the different QRS patterns reflect ventriculographic alterations or depends on a conduction delay. In aortic stenosis (AS,n = 21) and combined AS and aortic insufficiency (AS + AI,n = 23) the Type B vectorcardiograms (VCGs) correlate with significantly increased LV end-diastolic volumes (p. .

Contribution of Frank ECG measurements to the quantitative estimation of old anterior myocardial infarction.

Twenty scalar and vector measurements of the Frank ECG were compared between men categorized as having suffered nontransmural (n = 47) and transmural anterior myocardial infarction (n = 124), on the basis of clinical and angiocardiographic findings. Variables which showed significant differences of group means between cases with anterior wall hypokinesis and anterior wall akinesis and/or dyskinesis were submitted to linear discriminant-function analysis. The stepwise selection procedure of Rao's method demonstrated the three most decisive variables for differentiation to be: (1) the angular sum of dorsal displacement of the 5 initial QRS vectors obtained at 0.

Contribution of Frank ECG measurements to the quantitative estimation of old posterodiaphragmatic myocardial infarction.

The extent of old posterodiaphragmatic myocardial infarction has been assessed by vector and scalar measurements of the Frank orthogonal ECG. 121 men angiographically proven to have coronary artery disease were selected on the basis of a Q/R amplitude ratio of greater than or equal to 0.25 and T wave inversion in lead aVF.