A counterpoint paper: Comments on the electrocardiographic part of the 2018 Fourth Universal Definition of Myocardial Infarction.

The Fourth Universal Definition of Myocardial Infarction (FUDMI) [published simultaneously in 2018 in numerous journals including Circulation, Journal of the American College of Cardiology and European Heart Journal] focuses mainly on the distinction between non-ischemic myocardial injury and myocardial infarction (MI), along with the role of cardiovascular magnetic resonance, in order to define the etiology of myocardial injury. As a consequence, there is less emphasis on updating the parts of the definition concerning the electrocardiographic (ECG) changes related to MI. Evidence of myocardial ischemia is a prerequisite for the diagnosis of MI and the ECG is the main available tool for i) detecting acute ischemia, ii) triage and iii) risk stratification upon presentation. This review focuses on multiple aspects of ECG interpretation that we firmly believe should be considered for incorporation in any future update to the Universal Definition of MI. Our counterpoint view is that: a) the use of the ECG following coronary artery bypass surgery should be better explored and defined; b) the emphasis in the FUDMI on convex versus concave ST-elevation, which is questionable, should be balanced by the fact that many patients with true ST-elevation MI (STEMI) present with a concave form of ST elevation; c) reciprocal ST-depression in STEMI caused by right coronary artery or left circumflex artery occlusion, should be set against the fact that not all anterior STEMIs present with reciprocal ST-depression which can also be seen in cardiomyopathy and left ventricular hypertrophy; d) the "posterior" leads V7-V9 should be placed on a horizontal line from V4, rather than follow the 5th intercostal space; e) ST-depression in V1-V3 is not a manifestation of ischemia of the basal inferior segment, placed horizontally; f) Interpreting ST-T changes in patients with conduction abnormalities and pacemakers should be further defined.

Expert cardiologists cannot distinguish between Brugada phenocopy and Brugada syndrome electrocardiogram patterns.

AIMS: Brugada phenocopies (BrPs) are electrocardiogram (ECG) patterns that are identical to true Brugada syndrome (BrS) but are induced by various clinical conditions. The concept that both ECG patterns are visually identical has not been formally demonstrated. The aim of our study was to determine if experts on BrS were able to accurately distinguish between the BrS and BrP ECG patterns. METHODS AND RESULTS: Six ECGs from confirmed cases of BrS and six ECGs from previously published cases of BrP were included in the study. Surface 12-lead ECGs were scanned, saved in JPEG format, and sent to 10 international experts on BrS for evaluation (no clinical history provided). Evaluators were asked to label each case as a Brugada ECG pattern or non-Brugada ECG pattern by visual interpretation alone. The overall accuracy was 53 ± 33% for all cases. Within the BrS cases, the mean accuracy was 63 ± 34% and within the BrP cases, the mean accuracy was 43 ± 33%. Intra-observer repeatability was moderate (κ = 0.56) and inter-observer agreement was fair (κ = 0.36) while evaluator accuracy vs. the true diagnosis was only marginally better than chance (κ = 0.05). Similarly, diagnostic operating characteristics were poor (sensitivity 62%, specificity 43%, +LR 1.1, -LR 0.9). CONCLUSION: Our results provide strong evidence that BrP and BrS ECG patterns are visually identical and indistinguishable. These findings support the use of systematic diagnostic criteria for differentiating BrP vs. BrS as an erroneous diagnosis may have a negative impact on patient morbidity and mortality.

New methodologies for measuring Brugada ECG patterns cannot differentiate the ECG pattern of Brugada syndrome from Brugada phenocopy.

BACKGROUND: Brugada phenocopies (BrP) are clinical entities characterized by ECG patterns that are identical to true Brugada syndrome (BrS), but are elicited by various clinical circumstances. A recent study demonstrated that the patterns of BrP and BrS are indistinguishable under the naked eye, thereby validating the concept that the patterns are identical. OBJECTIVE: The aim of our study was to determine whether recently developed ECG criteria would allow for discrimination between type-2 BrS ECG pattern and type-2 BrP ECG pattern. METHODS: Ten ECGs from confirmed BrS (aborted sudden death, transformation into type 1 upon sodium channel blocking test and/or ventricular arrhythmias, positive genetics) cases and 9 ECGs from confirmed BrP were included in the study. Surface 12-lead ECGs were scanned, saved in JPEG format for blind measurement of two values: (i) ß-angle; and (ii) the base of the triangle. Cut-off values of ≥58° for the ß-angle and ≥4mm for the base of the triangle were used to determine the BrS ECG pattern. RESULTS: Mean values for the ß-angle in leads V1 and V2 were 66.7±25.5 and 55.4±28.1 for BrS and 54.1±26.5 and 43.1±16.1 for BrP respectively (p=NS). Mean values for the base of the triangle in V1 and V2 were 7.5±3.9 and 5.7±3.9 for BrS and 5.6±3.2 and 4.7±2.7 for BrP respectively (p=NS). The ß-angle had a sensitivity of 60%, specificity of 78% (LR+ 2.7, LR- 0.5). The base of the triangle had a sensitivity of 80%, specificity of 40% (LR+ 1.4, LR- 0.5). CONCLUSIONS: New ECG criteria presented relatively low sensitivity and specificity, positive and negative predictive values to discriminate between BrS and BrP ECG patterns, providing further evidence that the two patterns are identical.

New-onset atrial fibrillation after cavotricuspid isthmus ablation: identification of advanced interatrial block is key.

AIMS: A significant proportion of patients develop atrial fibrillation (AF) following cavotricuspid isthmus (CTI) ablation for typical atrial flutter (AFl). The objective of this study was to assess whether the presence of advanced interatrial block (aIAB) was associated with an elevated risk of AF after CTI ablation in patients with typical AFl and no prior history of AF. METHODS AND RESULTS: This study included patients with typical AFl and no prior history of AF that were referred for CTI ablation. Patients were excluded when they had received repeat ablations or did not demonstrate a bidirectional block. In all patients, a post-ablation electrocardiogram (ECG) in sinus rhythm was evaluated for the presence of aIAB, defined as a P-wave duration ≥120 ms and biphasic morphology in the inferior leads. New-onset AF was identified from 12-lead ECGs, Holter monitoring, and device interrogations. The cohort comprised 187 patients (age 67 ± 10.7 years; ejection fraction 55.8 ± 11.2%). Advanced interatrial block was detected in 18.2% of patients, and left atrium was larger in patients with aIAB compared with those without aIAB (46.2 ± 5.9 vs. 43.1 ± 6.0 mm; P = 0.01). Over a median follow-up of 24.2 months, 67 patients (35.8%) developed new-onset AF. The incidence of new-onset AF was greater in patients with aIAB compared with those without aIAB (64.7 vs. 29.4%; P < 0.001). After a comprehensive multivariate analysis, aIAB emerged as the strongest predictor of new-onset AF [odds ratio (OR) 4.2, 95% confidence interval (CI): 1.9-9.3; P < 0.001]. CONCLUSION: Advanced interatrial block is a key predictor for high risk of new-onset AF after a successful CTI ablation in patients with typical AFl.

Obesity paradox and risk of sudden death in heart failure results from the MUerte Subita en Insuficiencia cardiaca (MUSIC) study.

BACKGROUND: among patients with heart failure (HF), body mass index (BMI) has been inversely associated with mortality, giving rise to the so-called obesity paradox. The aim of this study was to examine the relationship between BMI and two modes of cardiac death: pump failure death and sudden death. METHODS: nine hundred seventy-nine patients with mild to moderate chronic symptomatic HF from the MUSIC (MUerte Subita en Insuficiencia Cardiaca) Study, a prospective, multicenter, and longitudinal study designed to assess risk predictors of cardiac mortality, were followed up during a median of 44 months. Independent predictors of death were identified by a multivariable Cox proportional hazards model. RESULTS: higher BMI emerged as an independent predictor of all-cause mortality (hazard ratio [HR] = 0.94, 95% confidence interval [CI] = 0.91-0.97, P = .0003) and pump failure death (HR = 0.93, 95% CI = 0.88-0.98, P = .004). Sudden death accounted for 45% of deaths in obese patients, 53% in overweight patients, and 37% in lean patients. No significant relationship between BMI and sudden death was observed (HR = 0.97, 95% CI = 0.92-1.02, P = .28). The only independent predictors of sudden death were prior history of myocardial infarction (HR = 1.89, 95% CI = 1.23-2.90, P = .004), hypertension (HR = 1.66, 95% CI = 1.05-2.63, P = .03), left ventricular ejection fraction (HR = 0.88, 95% CI = 0.79-0.96, P = .006), and N-terminal pro-B-type natriuretic peptide (HR = 1.01, 95% CI = 1.00-1.02, P = .048). CONCLUSIONS: the obesity paradox in HF affects all-cause mortality and pump failure death but not sudden death. The risk of dying suddenly was similar across BMI categories in this cohort of ambulatory patients with HF.

Conduction Disorders in the Setting of Acute STEMI.

ST-elevation myocardial (STEMI) is frequently associated with conduction disorders. Regional myocardial ischemia or injury may affect the cardiac conduction system at various locations, and neural reflexes or changes in the balance of the autonomous nervous system may be involved. Sinoatrial and atrioventricular blocks are more frequent in inferior than anterior STEMI, while new left anterior fascicular block and right bundle branch block indicate proximal occlusion of the left anterior descending coronary artery. New left bundle branch block is associated with multi-vessel disease. Most conduction disorders associated with STEMI are reversible with reperfusion therapy, but they may still impair prognosis because they indicate a large area at risk, extensive myocardial infarction or severe coronary artery disease. Acute STEMI recognition is possible in patients with a fascicular or right bundle branch block, but future studies need to define the cut-off values for ST depression in the leads V1-V3 in inferolateral MI and for ST elevation in the same leads in anterior STEMI. In the left bundle branch block, concordant ST elevation is a specific sign of acute coronary artery occlusion, but the ECG feature has low sensitivity.

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.

The MUSIC Risk score: a simple method for predicting mortality in ambulatory patients with chronic heart failure.

AIMS: The prognosis of chronic heart failure (CHF) is extremely variable, although generally poor. The purpose of this study was to develop prognostic models for CHF patients. METHODS AND RESULTS: A cohort of 992 consecutive ambulatory CHF patients was prospectively followed for a median of 44 months. Multivariable Cox models were developed to predict all-cause mortality (n = 267), cardiac mortality (primary end-point, n = 213), pump-failure death (n = 123), and sudden death (n = 90). The four final models included several combinations of the same 10 independent predictors: prior atherosclerotic vascular event, left atrial size >26 mm/m(2), ejection fraction < or =35%, atrial fibrillation, left bundle-branch block or intraventricular conduction delay, non-sustained ventricular tachycardia and frequent ventricular premature beats, estimated glomerular filtration rate <60 mL/min/1.73 m(2), hyponatremia < or =138 mEq/L, NT-proBNP >1.000 ng/L, and troponin-positive. On the basis of Cox models, the MUSIC Risk scores were calculated. A cardiac mortality score >20 points identified a high-risk subgroup with a four-fold cardiac mortality risk. CONCLUSION: A simple score with a limited number of non-invasive variables successfully predicted cardiac mortality in a real-life cohort of CHF patients. The use of this model in clinical practice identifies a subgroup of high-risk patients that should be closely managed.

Association of blood pressure and its evolving changes with the survival of patients with heart failure.

OBJECTIVE: The association between low blood pressure (BP) levels and increased mortality has been established in several studies of heart failure (HF). Although many drugs administered to these patients decrease BP, the relationship between changes in BP and survival has not been investigated. Nor have previous analyses distinguished among different forms of death. We investigated the influence of baseline BP and changes in BP during a 1-year period on the survival of patients with HF, distinguishing among sudden cardiac death, nonsudden cardiac death, and noncardiac death. We also identified the possible relationship with the baseline values of and changes in other clinical and treatment variables, including pharmacologic treatments. METHOD AND RESULTS: A total of 1062 patients with chronic HF included in the Spanish National Registry of Sudden Death (mean age of 64.5 +/- 11.8 years, 72% were men, and 21% were in New York Heart Association class III with a mean left ventricular ejection fraction of 36.7% +/- 14.2%) were prospectively investigated for a mean of 1.9 +/- 0.6 years. A multivariable Cox proportional hazards model adjusting for clinical and therapeutic variables showed an independent association between low baseline systolic blood pressure (SBP) and nonsudden cardiac death (hazard ratio [HR] 0.96, 95% confidence interval [CI] 0.93-0.98), but changes in SBP during the following year did not influence survival, regardless of the baseline SBP level (P = .55). Contrariwise, baseline diastolic BP was not associated with mortality, but an increase in diastolic BP during the following year showed a borderline independent significant association with lower nonsudden cardiac death (HR 0.90, 95% CI 0.82-1.00). Treatment with angiotensin-converting enzyme inhibitors or beta-blockers at baseline was also associated with lower nonsudden cardiac mortality, as was an increase in left ventricular ejection fraction during the following year (HR 0.69, 95% CI 0.51-0.93; P = .015). CONCLUSION: Among patients with stable HF, low SBP is associated with a greater risk of nonsudden cardiac death. The change in SBP during a 1-year period has no prognostic value. Because the beneficial effects of drugs associated with increased survival (in this study, angiotensin-converting enzyme inhibitors and beta-blockers) thus seem to be independent of their effects on BP, changes in BP should probably not influence the decision to use such drugs or continue their administration.

Wellens syndrome associated with prominent anterior QRS forces: an expression of left septal fascicular block?

Wellens syndrome is a clinical-electrocardiographic entity also referred to as left anterior descending (LAD) coronary T-wave syndrome or acute coronary T-wave syndrome. It is a complex of symptoms and signals indicating the existence of an undesirable condition secondary to critical high-grade proximal stenosis of the LAD coronary artery characterized by the association of prior history of acute coronary syndrome with little or no elevation of markers of myocardial damage (unstable angina) and characteristic electrocardiographic changes consistent with subepicardial anterior ischemic pattern (persistently symmetrical, deep negative and broad-based T waves) or plus-minus T waves with inversion of the terminal portion in the LAD coronary artery territory (V1 through V5 or V6). We present a case of a variant of Wellens syndrome that reveals association and, transitorily, the criteria described in literature for left septal fascicular block.

Kearns-Sayre syndrome: electro-vectorcardiographic evolution for left septal fascicular block of the his bundle.

The Kearns-Sayre syndrome is a neuromyopathic disorder associated with mitochondrial abnormalities and characterized by the triad of chronic external ophthalmoplegia, atypical pigmentary retinopathy, and progressive conduction system disorders. Ragged red muscle fibers that seem to contain an excess of altered mitochondria are observed. The disease affects both sexes alike, during the first or the second decade of life. The following manifestations are observed: central bilateral sensorineural deafness, pyramidal signs, ataxia, asymmetrical ptosis, external ophthalmoplegia, and progressive muscular weakness secondary to myopathy associated with a significant increase of proteins of cephalorachidian liquid. A variety of endocrinopathies may occur.