The importance of ST elevation in V2-4 ECG leads in athletes.

BACKGROUND: Early repolarization in the anterior ECG leads (ERV2-4) is considered to be a sign of right ventricular (RV) remodeling, but its etiology and importance are unclear. METHODS: A total of 243 top-level endurance-trained athletes (ETA; 183 men and 60 women, weekly training hours: 15-20) and 120 leisure-time athletes (LTA; 71 men and 49 women, weekly training hours: 5-6) were investigated. The ERV2-4 sign was evaluated concerning type of sport, gender, transthoracic echocardiographic parameters, and ECG changes, which can indicate elevated RV systolic pressure [left atrium enlargement (LAE), right atrium enlargement (RAE), RV conduction defect (RVcd)]. RESULTS: Stroke volume and left ventricular mass were higher in ETAs vs. LTAs in both genders (p < 0.01). Prevalence of the ERV2-4 sign was significantly higher in men than in women [p = 0.000, odds ratio (OR) = 36.4] and in ETAs than in LTAs (p = 0.000). The highest ERV2-4 prevalence appeared in the most highly trained triathlonists and canoe and kayak paddlers (OR = 13.8 and 5.2, respectively). Within the ETA group, the post-exercise LAE, RAE, and RVcd changes developed more frequently in cases with than without ERV2-4 (LAE: men: p < 0.05, females: p < 0.005; RAE: men: p < 0.05, females: p < 0.005; RVcd: N.S.). These post-exercise appearing LAE, RAE, and RVcd are associated with the ERV2-4 sign (OR = 4.0, 3.7, and 3.8, respectively). CONCLUSIONS: According to these results, ERV2-4 develops mainly in male ETAs due to long-lasting and repeated endurance training. The ERV2-4 sign indicates RV's adaptation to maintain higher compensatory pulmonary pressure and flow during exercise but its danger regarding malignant arrhythmias is unclear.

New body surface isopotential map evaluation method to detect minor potential losses in non-Q-wave myocardial infarction.

BACKGROUND: Potential losses caused by stable non-Q-wave myocardial infarction (MI) are too small to diagnose with the use of standard ECG. The aim of the present study was to obtain accurate diagnostic criteria for this prognostically important disease with the help of body surface mapping. METHODS AND RESULTS: Body surface potentials were recorded with the use of 63 unipolar leads in 45 patients with a non-Q-wave MI (41 to 75 years old); 24 healthy adults, 42 patients with unstable angina, and 70 patients with Q-wave MI served as reference groups. Qualitative pathological features of the isopotential maps, such as onset time and site and magnitude of the first right-anterior/anterior minimum, as well as pathological negativities at that time, were defined in non-Q-wave MI cases. These features, which account for the activation sequence and the body surface projections of specific cardiac regions (Selvester classification), showed a 91% sensitivity and an 88% specificity for the detection of non-Q-wave MI. In comparison, the different departure maps (first third QRS, QRS, and QRST isoarea) resulted in less favorable specificities (50% to 58%). Concordance between the isopotential maps and the acute-phase ECG (90%), hypokinesis (64%), fixed perfusion defects (59%), and significant stenosis of the infarct-related coronary artery (87%) supported the concept that these isopotential map changes correspond to the supposed sites of MI. There were pathological features in 69% of patients with unstable angina, with similar concordances as in non-Q-wave MI. CONCLUSIONS: Isopotential maps revealed characteristic features that were suitable for the detection and localization of non-Q-wave MI in the clinical setting of unstable coronary artery disease.

Connection between right ventricular pressure and the ECG.

According to the literature, electrocardiographic signs of right ventricular hypertrophy have low sensitivity. The cause of this low sensitivity may be attributed to the original studies that were performed mostly in children with hypoplastic left ventricles or congenital heart abnormalities. In adulthood cases of normal or hypertrophic left ventricles, electrocardiographic right ventricular hypertrophy can only be detected during the late phase of ventricular depolarization. Two hundred four adult cardiac patients with complete noninvasive and invasive records were systematically studied by conventional and vectocardiographic methods. The terminal QRS (S wave) of the standard lead I has proved to be informative for detecting electrocardiographic signs in the presence of elevated right ventricular pressure. In cases of chronic right ventricular pressure overload (right ventricular hypertrophy) the terminal depolarization QRS vectors pointed posteriorly and to the right; therefore, a characteristic terminal S wave was represented in the standard lead I. If right and left ventricular hypertrophy were simultaneously present, the same resultant vectors pointed posteriorly and slightly to the left. In these cases, notching of the declining phase of the R wave was frequent, and a flatness of the terminal R wave portion was characteristic. The latter electrocardiographic sign has been called "simultaneous overloading of both ventricles" by the authors. The clinical utility of the new signs have also been proved by statistical methods.

[Clinical significance of incomplete right bundle branch block]. / Az inkomplett jobbszárblokkok klinikai jelentösége.

In authors' opinion the majority of the physicians speak about an incomplete right bundle branch block in cases of a terminal r'wave in lead V1 of the ECG, when the QRS complex is not wider than 0.12 sec. These ECG anomalies are not properly separated in the literature, either. Authors define 4 groups whose separation is possible by the analysis of leads V1 and V2. 1. Right ventricular conduction defect--the ECG width is 0.09-0.13 sec. This picture generally signs normal or only slight higher right ventricular pressure. 2. Real incomplete right bundle branch block--the terminal vector directs forward only in this group and it causes also an r' in V2 next to the high R' in lead V1. This group can be harmless, only a conduction defect, but it can mean an advanced stadium of serious right ventricular systolic or diastolic overloading, too. 3. Right ventricular diastolic overloading--the QRS width is normal. We saw this picture in slight forms of atrial septal defect. One of our conclusions was that in case of normal V1 a haemodynamic significant ASD I or ASD II can be excluded. 4. Normal variant: normal QRS width and only a very low r' in lead V1. It was seen in young patients or in patients with flat chest. Authors remark that this pattern can possibly be seen in childhood or in case of inexact ECG (V1) registration.

A new possibility in the study of heart activation: the nondipolar body surface map.

The main goal of the present paper is to study the temporal and spatial course of cardiac electrical activation noninvasively, and to acquire more information than can be obtained from conventional methods, such as electrocardiography or vectorcardiography. The single moving resultant heart dipole is determined from a set of measured body surface potential maps before dipolar and nondipolar theoretical body surface potential maps are calculated. These three kinds of maps are studied together in different electro-cardiological situations (normal, left and right bundle branch block, and necrosis) during the entire cardiac cycle. The set of nondipolar maps is suitable for localizing and following the changes of minor positivity and negativity to detect small extensions of infarcts.