George Andrikopoulos

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.

Effects of Ischemia on P Wave Dispersion and Maximum P Wave Duration During Spontaneous Anginal Episodes

P wave dispersion (P dispersion), defined as the difference between the maximum and the minimum P wave duration, and maximum P wave duration (P maximum) are electrocardiographic (ECG) markers that have been used to evaluate the discontinuous propagation of sinus impulses and the prolongation of atrial conduction time, respectively. To study the effects of myocardial ischemia on P dispersion and P maximum, 95 patients with coronary artery disease (CAD) and typical angina pectoris and 15 controls with anginalike symptoms underwent 12‐lead surface ECG during and after the relief of pain. During pain and during the asymptomatic period, P maximum and P dispersion were calculated from the averaged complexes of all 12 leads. P dispersion increased significantly during spontaneous angina (45 ± 17 ms) compared to the asymptomatic period (40 ± 15 ms), P < 0.001 only in the patient group. Both P maximum and P dispersion showed higher values during angina in those patients who developed diffuse ischemia, as estimated with ST segment changes in multiple ECG leads. P dispersion showed higher values during the anginal episode in patients with left ventricular dysfunction, independently of the presence of a previous myocardial infarction. Atrial conduction abnormalities, as estimated with P maximum and particularly P dispersion, are significantly influenced by myocardial ischemia in patients with CAD and spontaneous angina.

Improved Detection of Coronary Artery Disease by Exercise Electrocardiography with the Use of Right Precordial Leads

BACKGROUND Exercise electrocardiography is an perfect test for the detection of coronary artery disease. We attempted to improve the diagnostic accuracy of exercise testing as a noninvasive method for the detection of coronary artery disease by using a combination of the left and right precordial leads. METHODS We studied 245 patients (218 men and 27 women) ranging from 32 to 74 years of age (mean [+/-SD], 52+/-8) who underwent treadmill exercise testing, thallium-201 scintigraphy, and coronary arteriography. During exercise testing, each patient had one electrocardiogram recorded with the standard 12 leads and 3 right precordial leads (V3R, V4R, and V5R), with the results for each set of leads recorded and analyzed separately. RESULTS On the basis of coronary arteriography, 34 patients had normal coronary arteries, 85 had single-vessel disease, 84 had two-vessel disease, and 42 had three-vessel disease. The sensitivities of the standard 12-lead exercise electrocardiogram, exercise electrocardiography incorporating right precordial leads, and thallium-201 scintigraphy were 52 percent, 89 percent, and 87 percent, respectively, for the detection of single-vessel disease; 71 percent, 94 percent, and 96 percent for the detection of two-vessel disease; 83 percent, 95 percent, and 98 percent for the detection of three-vessel disease; and 66 percent, 92 percent, and 93 percent for the detection of any coronary artery disease. The specificities of the three methods for the detection of any coronary artery disease were 88 percent, 88 percent, and 82 percent, respectively. CONCLUSIONS Use of right precordial leads along with the standard six left precordial leads during exercise electrocardiography greatly improves the sensitivity of exercise testing for the diagnosis of coronary artery disease.

Detection of hypertensive patients at risk for paroxysmal atrial fibrillation during sinus rhythm by computer-assisted P wave analysis

OBJECTIVE AND METHODS To determine whether hypertensive patients at risk for paroxysmal atrial fibrillation (AF) could be detected while in sinus rhythm, a computer-based 12-lead surface electrocardiogram was recorded in 50 hypertensive patients with history of paroxysmal AF (group A) and in 60 hypertensive patients without history of AF (group B). The maximum P-wave duration (P(maximum)), the minimum P-wave duration (P(minimum)), P-wave dispersion (Pdispersion = Pmaximum Pminimum), adjusted P-wave dispersion (APdispersion = Pdispersion/square root of the number of measurable leads), mean P-wave duration (mean P) and the standard deviation of the P-wave duration in all measured leads (SDP) were calculated. RESULTS Pdispersion, APdispersion and SDP were significantly higher in group A than in group B (Pdispersion, 52 +/- 19 versus 41 +/- 15 ms, P< 0.001; APdispersion, 15.2 +/- 5.5 versus 11.9 +/- 4.6 ms, P< 0.001; SDP, 16 +/- 5 versus 13 +/- 5 ms, P < 0.001). P(minimum), mean P and left ventricle ejection fraction (LVEF) were significantly lower in group A than in group B (Pminimum, 79 +/- 18 versus 91 +/- 13 ms, P < 0.001; mean P, 108 +/- 18 versus 116 +/- 13 ms, P= 0.005; LVEF, 64 +/- 5 versus 69 +/- 8%, P< 0.001). Pminimum, Pdispersion, mean P, SDP, APdispersion and LVEF were found to be significant univariate predictors of paroxysmal AF, whereas only Pminimum (P< 0.001) remained a significant independent predictor of paroxysmal AF in the multivariate analysis. CONCLUSION Hypertensive patients at risk for paroxysmal AF could be detected while in sinus rhythm by computer-assisted electrocardiographic P-wave analysis.

P Wave Dispersion: A Valuable Electrocardiographic Marker for the Prediction of Paroxysmal Lone Atrial Fibrillation

Background: The prolongation of atrial conduction time and the inhomogeneous propagation of sinus impulses are well known electrophysiological characteristics in patients with paroxysmal atrial fibrillation.

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, hypercholesterolemia, 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 MI, either in univariate (6.2 vs. 6.4%, P = 0.856), or in multivariate analysis adjusted for the same confounders (RR = 0.743, 95% CI = 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.

Improved myocardial performance during repetitive exercise testing: The role of extracellular superoxide dismutase activity in a model of exercise-induced myocardial preconditioning

BACKGROUND The aim of this study was to investigate whether endogenous antioxidant defense is involved in adaptation to myocardial ischemia in patients with coronary artery disease and severe exercise-induced myocardial ischemia. METHODS Fifty patients, aged 50 to 72 years (mean, 58 +/- 6 years), with positive exercise test results underwent 4 treadmill exercise tests. Thallium-201 scintigraphy was performed during the first and the fourth testing. The second, the third, and the fourth tests were performed the next day. The time interval between the second and the third test was 15 minutes, and between the third and the fourth test, the interval was 45 minutes. Extracellular superoxide dismutase activity was measured just before and at the peak of the first and the fourth exercise test. RESULTS The patients were divided in 2 groups according to the extent of myocardial ischemia at peak exercise of the fourth test compared with the first test. Most of the patients studied (37/50) showed improved myocardial performance during the last of the sequential exercise tests, as demonstrated with the studied exercise parameters and the extent of myocardial ischemia in thallium-scintigraphy. Extracellular superoxide dismutase activity before the last exercise test was found to be significantly increased only in the patients who had improved myocardial performance at the last of the sequential exercise tests. CONCLUSION The beneficial effects of sequential episodes of exercise-induced myocardial ischemia seem to be strongly related to extracellular superoxide dismutase activity. Although there is still lack of direct evidence, our data support the theory that the favorable adaptation to repetitive exercise may represent an aspect of the clinical relevance of ischemic preconditioning in humans.

Significance of exercise-induced simultaneous ST-segment changes in lead aVR and V5

This study was undertaken to investigate the ability of the exercise-induced ST depression in lead V5 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 V5 and ST elevation in aVR, in group B 149 patients with ST depression in V5 without ST elevation in aVR, and in group C 22 patients with ST elevation in aVR without ST depression in V5 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 V5 and concomitant ST elevation in aVR, may detect left anterior descending artery significant stenosis in patients with single vessel disease.

Short-term outcome and attainment of secondary prevention goals in patients with acute coronary syndrome--results from the countrywide TARGET study.

BACKGROUND/OBJECTIVES Acute coronary syndromes (ACS) continue to pose a significant medical and socioeconomic burden worldwide. Optimal management strategy aims to improve short and long-term outcome. The present study aims to assess short-term outcome of real-world ACS patients and evaluate the achievement rate of secondary prevention goals. METHODS The TARGET study is an observational study enrolling 418 consecutive ACS patients from 17 centers countrywide (78.0% males, 63.9 ± 12.9 years). After the in-hospital phase, patients were followed for 6 months. In total, 366 patients were included in the prospective phase of the study. At the end of the follow-up, mortality, major adverse cardiovascular events (MACE), prescription pattern of cardiovascular medications, lipid levels, adherence rate to treatment and behavioral recommendations were measured. RESULTS The overall mortality was 4.8% and the rate of MACE was 17.5%. At 6 months, a significantly lower proportion of patients received antiplatelet agents and statins as compared to hospital discharge. At the end of the follow-up, 87.7% of patients remained on statin treatment, yet only 18.2% of patients had LDL cholesterol levels less than 70 mg/dL. The adherence pattern to lifestyle and dietary recommendations remained low (66.2% quit smoking, 55.8% and 81.3% followed physical activity and dietary recommendations respectively). CONCLUSION Despite the low rate of mortality and MACE occurrence rate in this countrywide observational study, the attainment rate of secondary prevention goals is relatively poor. Improvement interventions focusing in these gaps of optimal care provision are expected to have a favorable impact on the prognosis of real world ACS patients.

Association of the 894G>T polymorphism in the endothelial nitric oxide synthase gene with risk of acute myocardial infarction.

BackgroundThis study was designed to investigate the association of the 894G>T polymorphism in the eNOS gene with risk of acute myocardial infarction (AMI), extent of coronary artery disease (CAD) on coronary angiography, and in-hospital mortality after AMI.MethodsWe studied 1602 consecutive patients who were enrolled in the GEMIG study. The control group was comprised by 727 individuals, who were randomly selected from the general adult population.ResultsThe prevalence of the Asp298 variant of eNOS was not found to be significantly and independently associated with risk of AMI (RR = 1.08, 95%CI = 0.77–1.51, P = 0.663), extent of CAD on angiography (OR = 1.18, 95%CI = 0.63–2.23, P = 0.605) and in-hospital mortality (RR = 1.08, 95%CI = 0.29–4.04, P = 0.908).ConclusionIn contrast to previous reports, homozygosity for the Asp298 variant of the 894G>T polymorphism in the eNOS gene was not found to be associated with risk of AMI, extent of CAD and in-hospital mortality after AMI