Diego Goldwasser

Current electrocardiographic criteria for diagnosis of Brugada pattern: a consensus report ☆

Brugada syndrome is an inherited heart disease without structural abnormalities that is thought to arise as a result of accelerated inactivation of Na channels and predominance of transient outward K current (I(to)) to generate a voltage gradient in the right ventricular layers. This gradient triggers ventricular tachycardia/ventricular fibrillation possibly through a phase 2 reentrant mechanism. The Brugada electrocardiographic (ECG) pattern, which can be dynamic and is sometimes concealed, being only recorded in upper precordial leads, is the hallmark of Brugada syndrome. Because of limitations of previous consensus documents describing the Brugada ECG pattern, especially in relation to the differences between types 2 and 3, a new consensus report to establish a set of new ECG criteria with higher accuracy has been considered necessary. In the new ECG criteria, only 2 ECG patterns are considered: pattern 1 identical to classic type 1 of other consensus (coved pattern) and pattern 2 that joins patterns 2 and 3 of previous consensus (saddle-back pattern). This consensus document describes the most important characteristics of 2 patterns and also the key points of differential diagnosis with different conditions that lead to Brugada-like pattern in the right precordial leads, especially right bundle-branch block, athletes, pectus excavatum, and arrhythmogenic right ventricular dysplasia/cardiomyopathy. Also discussed is the concept of Brugada phenocopies that are ECG patterns characteristic of Brugada pattern that may appear and disappear in relation with multiple causes but are not related with Brugada syndrome.

Electrocardiographic classification of acute coronary syndromes: a review by a committee of the International Society for Holter and Non-Invasive Electrocardiology.

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.

Differentiating ST Elevation Myocardial Infarction and Nonischemic Causes of ST Elevation by Analyzing the Presenting Electrocardiogram

Guidelines recommend that patients with suggestive symptoms of myocardial ischemia and ST-segment elevation (STE) in > or =2 adjacent electrocardiographic leads should receive immediate reperfusion therapy. Novel strategies aimed to reduce door-to-balloon time, such as prehospital wireless electrocardiographic transmission, may be dependent on the interpretation accuracy of the electrocardiogram (ECG) readers. We assessed the ability of experienced electrocardiographers to differentiate among STE, acute STE myocardial infarction (STEMI), and nonischemic STE (NISTE). A total of 116 consecutive ECGs showing STE were studied. Fifteen experienced cardiologists were asked to decide, based on the ECG and assuming that the patient had compatible symptoms, whether they would send each patient for primary percutaneous coronary intervention (PPCI). If NISTE was chosen, the reader selected 1 or more 12 possible options to explain the choice. Of 116 patients, only 8 had STEMI. The percentage of ECGs for which PPCI was recommended for the patient by the individual readers varied widely (7.8% to 33%). There was no significant difference between the North American and Other Countries readers (p = 0.13). The sensitivity and specificity of the individual readers ranged from 50% to 100% (average 75%) and 73% to 97% (average 85%), respectively. There were broad inconsistencies among the readers in the chosen reasons used to classify NISTE. In conclusion, we found wide variations among experienced electrocardiographers in reading ECGs with STE and differentiating STEMI with need for PPCI from NISTE. There is a need to revise our current electrocardiographic criteria for differentiating STEMI from NISTE.

A New Electrocardiographic Algorithm to Locate the Occlusion in Left Anterior Descending Coronary Artery

Early prediction of proximal left anterior descending coronary artery (LAD) occlusion is essential from a clinical point of view

New electrocardiographic diagnostic criteria for the pathologic R waves in leads V1 and V2 of anatomically lateral myocardial infarction.

AIMS To study the different QRS patterns in leads V1 and V2 in first inferior, lateral, and combined inferolateral myocardial infarction (MI) to recognize which are the ECG criteria that best define the presence of lesions isolated to the anatomically lateral wall of the left ventricle. METHODS AND RESULTS We studied consecutive patients with first inferior (15), lateral (9), or inferolateral (21) MI with reference to contrast enhanced cardiac magnetic resonance (CE-CRM). We measured the R-wave amplitude and duration, the R/S ratio, and the T-wave amplitude and polarity in leads V1 and V2. The specificity of the V1 criteria for lateral MI, that is, R/S amplitude ratio 1 or greater and R duration 40 milliseconds or longer, is very high but its sensitivity is low. We defined 2 new criteria, R/S of 0.5 or greater and R amplitude in V1 greater than 3 mm, with each achieving a sensitivity of 73.3% and specificity of 93.3% for lateral/inferolateral MI location. CONCLUSIONS (1) New ECG criteria for lateral MI (R/S ratio in V1 > or =0.5 and R amplitude in V1 >3 mm) present very high specificity and lower but very acceptable sensitivity for lateral MI. (2) New criteria based on R waves in V2 or T waves in V1 to V2 do not discriminate between inferior and lateral MI. (3) The classical criteria (R/S amplitude ratio > or =1 and R duration > or =40 ms in V1) attain very high specificity but much lower sensitivity than the new criteria.

A new method of filtering T waves to detect hidden P waves in electrocardiogram signals

AIMS A correct identification of the P wave is crucial for the diagnosis of narrow QRS tachycardias. This is sometimes difficult because atrial activity is hidden in the T wave. The aim of this study is to evaluate the usefulness of a T wave filtering technique based on wavelet transformation to identify atrial activity. METHODS AND RESULTS Forty-two patients with narrow QRS tachycardias and regular atrial activity were studied. A surface electrocardiogram (ECG), intra-atrial recording, and the T wave filtering ECG were compared simultaneously to check the accuracy of the filtering system in detecting atrial activity. The sensitivity of the T wave filtering and P wave detection algorithm was 85.8% [95% confidence interval (CI): 81.2-89.4%] and the specificity was 89.4% (95% CI: 87.1-91.4%), with a global accuracy of 88.5% (95% CI: 86.5-90.3%). The expert cardiologists accuracy in distinguishing between atrioventricular nodal reentry tachycardia and atrioventricular reentry tachycardia was 75% in the surface ECG vs. 100% in the ECG with the T wave filtering process (P<0.01). CONCLUSIONS T wave filtering based on wavelet transformation improves the capacity of the surface ECG to identify atrial activity in cases of regular narrow QRS supraventricular tachycardias.

Negative T Wave in Ischemic Heart Disease: A Consensus Article

For many years was considered that negative T wave in ischemic heart disease represents ischemia and for many authors located in subepicardial area.

Advanced interatrial block: a well-defined electrocardiographic pattern with clinical arrhythmological implications

We read with interest Hinojar et al .1 case recently published in the journal. Their case wisely demonstrated the presence of P-wave with +/− morphology in leads II, III, and aVF as a pattern of advanced interatrial block (IAB). This pattern has been also called ‘block in the Bachmann bundle zone’ since Waldo obtained this electrocardiogram (ECG) pattern by cutting the Bachmann bundle at both sides of the septum [right and left atrium (LA)].2 The electroanatomical mapping (CARTO) showed by Hinojar et al. in sinus rhythm clearly shows that the atrial activation starts normally, but its propagation is blocked along the LA roof and the high lateral activation is delayed and directed caudocraneally starting at the posteroinferior LA region. Therefore, this type of atrial activation …

Prinzmetal Angina: ECG Changes and Clinical Considerations: A Consensus Paper

We will focus our attention in this article in the ECG changes of classical Prinzmetal angina that occur during occlusive proximal coronary spasm usually in patients with normal or noncritical coronary stenosis.

Chronic Myocardial Infarction: Where Is It Located?

This ECG was recorded during a routine checkup of a 77-year-old man who had a heart attack 8 months earlier. He was in the countryside when he felt constrictive chest pain lasting ≈2 hours but was not hospitalized until 20 hours later. A coronary angiogram was performed the following day. Based on ECG demonstrated in Figure 1, where is the culprit lesion? Where was the myocardial infarction (MI) located? Figure 1. The 12-lead ECG (see text for description). Please turn the page to read the diagnosis. This ECG shows sinus rhythm with left-axis deviation in the frontal plane (left anterior hemiblock) with notches in the S wave, a broad R>S in V1, and Rs with progressively decreased voltage until V6. In frontal plane leads, the voltage was low in all leads, and the T wave was flat in I leads and left …