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- Bayes de Luna, Antonio, et al.
(author)
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Interatrial blocks. A separate entity from left atrial enlargement: a consensus report
- 2012
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In: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 45:5, s. 445-451
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Journal article (peer-reviewed)abstract
- Impaired interatrial conduction or interatrial block is well documented but is not described as an individual electrocardiographic (ECG) pattern in most of ECG books, although the term atrial abnormalities to encompass both concepts, left atrial enlargement (LAE) and interatrial block, has been coined. In fact, LAE and interatrial block are often associated, similarly to what happens with ventricular enlargement and ventricular block. The interatrial blocks, that is, the presence of delay of conduction between the right and left atria, are the most frequent atrial blocks. These may be of first degree (P-wave duration > 120 milliseconds), third degree (longer P wave with biphasic [+/-] morphology in inferior leads), and second degree when these patterns appear transiently in the same ECG recording (atrial aberrancy). There are evidences that these electrocardiographic P-wave patterns are due to a block because they may (a) appear transiently, (b) be without associated atrial enlargement, and (c) may be reproduced experimentally. The presence of interatrial blocks may be seen in the absence of atrial enlargement but often are present in case of LAE. The most important clinical implications of interatrial block are the following: (a) the first degree interatrial blocks are very common, and their relation with atrial fibrillation and an increased risk for global and cardiovascular mortality has been demonstrated; (b) the third degree interatrial blocks are less frequent but are strong markers of LAE and paroxysmal supraventricular tachyarrhythmias. Their presence has been considered a true arrhythmological syndrome. (C) 2012 Elsevier Inc. All rights reserved.
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- Nikus, Kjell, et al.
(author)
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Electrocardiographic classification of acute coronary syndromes: a review by a committee of the International Society for Holter and Non-Invasive Electrocardiology
- 2010
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In: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 43:2, s. 91-103
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Journal article (peer-reviewed)abstract
- The electrocardiogram (ECG) remains the most immediately accessible and widely used diagnostic tool for guiding emergency treatment strategies. The ECG recorded during acute myocardial ischemia is of diagnostic, therapeutic, and prognostic significance. In patients with myocardial ischemia as a result of decreased blood supply, the initial 12-lead ECG typically shows (1) predominant ST-segment elevation (STE) as part of STE acute coronary syndrome (STE-ACS), or (2) no predominant STE, that is, non STE ACS (NSTE-ACS). Patients with predominant STE are classified as having either aborted myocardial infarction (MI) or ST-elevation MI (STEMI) based on the absence or presence of biomarkers of myocardial necrosis. The MI may be aborted either by spontaneous or therapeutic reperfusion of the ischemic myocardium before development of myocardial cell necrosis. NSTE-ACS patients are classified as having either unstable angina or NSTE-MI, based also on the absence or presence of biomarkers of mycardial necrosis. The information obtained from the 12-lead ECG at presentation should be complemented by repeated ECGs especially during symptoms indicative of ischemia and, if applicable, by comparing the findings with reference ECGs. Also, continuous ECG recording in a coronary care setting, including the comparison of ECGs with and without pain, adds to the information gained at patient presentation. In this article, mechanisms of ischemic ECG changes and the ECG patterns recorded in both STE-ACS and NSTE-ACS are described. ECG patterns of NSTE-ACS, which include ST depression, negative T wave, and even normal ECG, need to be better defined in future studies to correlate them with the severity and extent of ischemia and to explore to what extent they are explained by acute active ischemia or represent consequences of ischemia. One of the aims of this article is to propose a classification of the ECG patterns encountered in different clinical scenarios of ACS. How these patterns will aid in guiding the diagnostic and therapeutic process is discussed. (c) 2010 Elsevier Inc. All rights reserved.
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