Simple electrocardiographic markers for the prediction of paroxysmal idiopathic atrial fibrillation

Background The prolongation of intraatrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses are well known electrophysiologic characteristics in patients with paroxysmal atrial fibrillation (PAF). Methods To search for possible electrocardiographic markers that could serve as predictors of idiopathic PAF, we measured the maximum P-wave duration (P maximum) and the difference between the maximum and the minimum P-wave duration (P dispersion) from the 12-lead surface electrocardiogram of 60 patients with a history of idiopathic PAF and 40 age-matched healthy control subjects. Results P maximum and P dispersion were found to be significantly higher in patients with idiopathic PAF than in control subjects. A P maximum value of 110 msec and a P dispersion value of 40 msec separated patients from control subjects, with a sensitivity of 88% and 83% and a specificity of 75% and 85%, respectively. Conclusions P maximum and P dispersion are simple electrocardiographic markers that could be used for the prediction of idiopathic PAF

Ischemia-induced reflex sympathoexcitation during the recovery period after maximal treadmill exercise testing

Background: Heart rate variability (HRV) analysis is problematic during maximal treadmill exercise testing (ET) due to rapidly changing heart rate. Hypothesis: The aim of this study was to assess HRV spectral components during treadmill ET in patients with coronary artery disease (CAD) and in healthy controls, and to search for possible differences between the two groups, Methods: Thirty patients with CAD and 30 age-matched healthy controls underwent symptom-limited ET and continuous electrocardiographic monitoring. For adequate assessment of HRV during maximal ET, we calculated the HRV measures [normalized units (NU)]-low-frequency (0.040-0.150 Hz) power (LF), high-frequency (0.150-0.400 Hz) power (HF), and the LF/HF ratio-from all the sequential stages of the ET with Limited changes (20 beats/min) in heart rate (stress 80-100, 100-120, 120-140, 140-160, 160-180/recovery 180-160, 160-140, 140-120, 120-100, 100-80). Results: Both LF and HF were found to decrease gradually during ET and to increase during the recovery period in both patients and controls (p<0.001). LF values were higher during the recovery period than during the respective stages of exercise time in both patients and controls, and LF/HF ratio was higher during recovery in patients only. Conclusions: During maximal ET (1) vagal tone withdraws during the exercise time and increases during the recovery period; (2) the sympathetic activity predominates during the recovery period, especially in patients with CAD and exercise-induced myocardial ischemia, This finding raises the possibility of ischemia-induced cardiocardiac sympathetic excitatory reflexes

Effects of cardiac versus circulatory angiotensin-converting enzyme inhibition on left ventricular diastolic function and coronary blood flow in hypertrophic obstructive cardiomyopathy

Background-Left ventricular (LV) diastolic function and coronary flow are impaired in hypertrophic obstructive cardiomyopathy (HOCM). This study was designed to evaluate the impact of cardiac and circulatory ACE inhibition on such derangements. Methods and Results-Twenty patients with HOCM underwent cardiac ACE inhibition with intracoronary (IC) enalaprilat (0.05 mg/min infused into the left anterior descending coronary artery for 15 minutes) followed by circulatory ACE inhibition with 25 mg sublingual (SL) captopril. Contrast ventriculography, pressure, and coronary flow measurements were performed at baseline, after IC enalaprilat infusion, and 45 minutes after SL captopril. Heart rate was not affected by the respective interventions (75+/-11 versus 76+/-13 versus 75+/-10 bpm; P=NS), whereas mean aortic pressure dropped slightly after IC enalaprilat and significantly after SL captopril (90+/-8 versus 85+/-10 versus 74+/-9 mm Hg; P<.05). Compared with baseline, IC enalaprilat resulted in a decrease in LV end-diastolic pressure (17.6+/-5.9 versus 14.4+/-4.9 mm Hg; P<.05), time constant of isovolumic LV pressure relaxation (tau(G)) (69+/-9 versus 52+/-10 ms; P<.05), and outflow gradient (45.2+/-6.9 versus 24.4+/-3.7 mm Hg; P<.05) and in an increase in coronary blood flow (107+/-10 versus 127+/-12 mL/min; P<.05) and coronary flow reserve (2.2+/-0.4 versus 2.6+/-0.3; P<.05). After SL captopril, tau(G), was prolonged (60+/-13 ms; P<.05 versus IC enalaprilat), and LV outflow gradient, coronary blood flow, and coronary flow reserve values returned to baseline (45.5+/-5.3 mm Hg, 107+/-12 mL/min, and 2.2+/-0.5, respectively; P=NS versus baseline). Conclusions-Activation of the cardiac renin-angiotensin system contributes to LV diastolic dysfunction as well as to the decreased coronary blood flow and coronary flow reserve in HOCM. Cardiac ACE inhibition restores and circulatory ACE inhibition aggravates the above derangements

In-hospital mortality of habitual cigarette smokers after acute myocardial infarction - The `smoker's paradox' in a countrywide study

Aims Habitual cigarette smokers, paradoxically, present improved short-term prognosis after acute myocardial infarction, a phenomenon often termed ‘smoker’s paradox’. We sought to examine cigarette smokers’ post-infarction survival advantage in a countrywide survey of unselected, consecutive patients presenting with acute myocardial infarction. Methods and Results The study population was derived from the registry of the Hellenic study of acute myocardial infarction, which recruited 7433 consecutive patients with acute myocardial infarction from 76, out of a total of 86, hospitals countrywide. Cigarette smokers presented with lower unadjusted mortality rates (7.4% vs 14.5%,, P<0.001), were younger, predominantly of male gender and were less likely to suffer from diabetes mellitus and arterial hypertension. When all univariate predictors of poor outcome were included as covariates in multivariate analysis, smoking status was not significantly associated with inhospital mortality (relative risk = 1.12. 95% CI=0.86 1.44, P=0.399). The beneficial effect of thrombolytic therapy was independent of the smoking status ill both univariate and multivariate analysis. Conclusion Unadjusted mortality rates are significantly lower in smokers, but age accounted for much of their seemingly improved outcome. When a number of additional clinical variables were taken into consideration, no significant influence of habitual smoking on early outcome following acute myocardial infarction was observed. (Eur Heart. J 2001; 22: 776-784, doi: 10053/euhj.2000.2315) (C) 2001 The European Society of Cardiology

Significance of exercise-induced simultaneous ST-segment changes in lead aVR and V-5

This study was undertaken to investigate the ability of the exercise-induced ST depression in lead V-5 and concomitant ST elevation in lead aVR for the identification of the significantly narrowed coronary artery in patients with single vessel disease. We studied 229 consecutive patients who developed the aforementioned exercise-induced electrocardiographic changes. All underwent Thallium-201 scintigraphy and coronary arteriography. Patients were divided into three groups. In group A, 58 patients with ST depression in V-5 and ST elevation in aVR, in group B 149 patients with ST depression in V-5 without ST elevation in aVR, and in group C 22 patients with ST elevation in aVR without ST depression in V-5 induced with exercise, were included. In group A, 81% of the patients while in group B, 29% and in group C only 18% of the patients had left anterior descending artery disease. According to Thallium-201 scintigraphy, 80% of the group A, 27% of the group B and 12% of the group C patients developed myocardial ischemia in areas supplied by the left anterior descending artery. Thus, exercise-induced ST depression in V-5 and concomitant ST elevation in aVR, may detect left anterior descending artery significant stenosis in patients with single vessel disease. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved

The paradoxical association of common polymorphisms of the renin-angiotensin system genes with risk of myocardial infarction

Background The insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE) and the A1166C polymorphism of the angiotensin-II AT1 receptor (AT1R) have been extensively investigated as possible risk factors for myocardial infarction (MI). Design and methods Genetic association, case-control study, specifically designed to investigate the association of the above-mentioned polymorphisms with risk of MI in a homogeneous, low coronary risk, Caucasian population. The study population consisted of 1603 consecutive patients with acute MI who were recruited from nine clinics, located in three cities, and 699 unrelated adults who were randomly selected from the city catalogues. Results In univariate analysis, the DD genotype was found to be more prevalent among controls (40.8 vs. 35.2%, P=0.011). In multivariate analysis adjusted for age, gender, smoking status, diabetes mellitus, hypercholesterolaemia, hypertension and family history of coronary artery disease, the presence of the DD genotype was independently and negatively associated with risk of AMI (RR = 0.743,95% CI = 0.595-0.927, P= 0.008). The CC genotype was not found to be significantly associated with risk of M I, either in univariate (6.2 vs. 6.4%, P=0.856), or in multivariate analysis adjusted for the same confounders (RR = 0.743, 95% Cl = 0.473-1.167, P= 0.197). Conclusions Contrary to previous reports, in this study the DD genotype of the ACE gene, but not the CC genotype of the AT1R gene, was associated with a lower risk of MI. Our results emphasize the complexity of genotype-phenotype interactions in the pathogenesis of ischaemic heart disease and question the previously hypothesized role of the DD genotype on risk of acute myocardial infarction. (C) 2004 The European Society of Cardiology

Exercise-induced ST-segment changes in lead V-1 identify the significantly narrowed coronary artery in patients with single-vessel disease - Correlation with thallium-201 scintigraphy and coronary arteriography data

We investigated the correlation of exercise-induced ST-segment changes in lead V-1, with the detection of the significantly narrowed vessel that induced ischemia during exercise in myocardial areas supplied by this vessel. We studied 198 patients who underwent exercise testing, thallium-201 scintigraphy, and coronary arteriography. The patients were divided into three groups. In group 1 (ST-segment elevation in lead V-1), 84% had left anterior descending coronary artery disease (P < .001); in group 2 (ST-segment depression in lead V-1), 76% had right coronary artery disease (P < .001); and in group 3 (no ST-segment changes in lead V-1), there were no significant differences concerning the narrowed vessel. Thallium-201 scintigraphy data confirmed the existence of the reversible perfusion defect(s) in an area(s) of myocardium supplied by the respective coronary arteries (P < .001). Exercise-induced ST-segment elevation or depresssion in V-1 may identify the obstructed vessel in patients with single-vessel disease and without prior myocardial infarction

The role of carotid atherosclerosis in the distinction between ischaemic and non-ischaemic cardiomyopathy

Aim Sometimes ischaemic cardiomyopathy is a result of severe coronary artery disease of an occult course, without typical symptoms or evidence of myocardial infarction. This form of presentation is usually indistinguishable from non-ischaemic dilated cardiomyopathy. Carotid bifurcation atherosclerosis and coronary artery disease have been shown to be strongly associated. We prospectively examined the value of extracranial carotid atherosclerosis in the distinction between ischaemic and non-ischaemic aetiology in patients with clinically unexplained cardiomyopathy. Methods and Results Seventy-eight patients with undetermined dilatation and diffuse impairment of the left ventricular contraction were studied within 28 months. They underwent carotid scan and coronary arteriography. Carotid atherosclerosis was found to be very common in ischaemic and rare in non-ischaemic cardiomyopathy. The presence of at least one abnormal carotid finding (intimamedia thickness >1 mm, plaques, severe carotid stenosis) was 96% sensitive and 89% specific for ischaemic cardiomyopathy. Conclusion Carotid scanning may be a useful screening and decision making tool in patients with cardiomyopathy of indecisive cause. Patients with carotid atherosclerosis are likely to suffer from severe coronary artery disease. Coronary angiography and subsequent myocardial viability studies, when indicated, could be considered early during their evaluation. In contrast, a negative carotid scan predicts non-ischaemic cardiomyopathy. (Eur Heart J 2000; 21: 919-926) (C) 2000 The European Society of Cardiology