New pattern of atypical advanced interatrial block.

INTRODUCTION: Interatrial block (IAB) is defined as prolonged P-wave duration (≥ 120 ms) due to delayed conduction in the Bachmann bundle. This is readily identifiable using surface electrocardiogram (ECG). Advanced IAB can be classified as typical and atypical. Atypical IAB can be further categorized by (i) duration or (ii) morphology. In this report, we have identified a new pattern of atypical IAB with triphasic morphology of the P-wave in the inferior leads. METHODS: Two clinical cases were evaluated including surface ECGs. P-wave durations and amplitudes were measured with digital calipers using ECG analysis software (MUSE, GE HealthCare). Comparisons were made using prior data to evaluate IAB and P-wave duration and morphology. RESULTS: A new pattern of atypical advanced IAB shows prolonged P-wave duration (P wave >160 ms) and triphasic morphology in all inferior leads with P +/+/- and P +/-/+, respectively. We speculate that triphasic P-waves in the inferior leads represent three moments of atrial depolarization; from right to left. CONCLUSION: This study describes a novel pattern of atypical advanced IAB. Further investigation regarding the increased risk of atrial fibrillation and stroke associated with this new pattern is warranted in the future.

The S1S2S3 electrocardiographic pattern - Prevalence and relation to cardiovascular and pulmonary diseases in the general population.

BACKGROUND: There is lack of studies exploring the incidence and association with diseases of the S1S2S3 electrocardiogram (ECG) pattern in the general population. SUBJECTS AND METHODS: This population study included 6299 individuals aged 30+, and explored the prevalence and association between S1S2S3 and cardiovascular and pulmonary diseases. Criteria for the S1S2S3-I and S1S2S3-II ECG pattern were fulfilled when there was an S wave in the leads I, II and III, and the S-wave amplitude was greater than the R-wave amplitude in one or two of the leads, respectively. RESULTS: The S1S2S3-I ECG pattern was found in 2332 subjects (36.9%). After age adjustment, hypertension was associated with S1S2S3-I (Odds ratio [OR] 1.25, 95% CI 1.12-1.41, p < 0.001). This age-adjusted association was statistically significant among men but not among women (OR 1.37, 1.16-1.62, p < 0.001 and OR 1.13, 0.97-1.33, p = 0.126, respectively). The S1S2S3-II ECG pattern was present in 193 subjects (3.1%). After age adjustment, heart failure proved to be associated with S1S2S3-II (OR 1.85, 1.18-2.90, p = 0.007). Dividing the population by sex, resulted in a statistically significant age-adjusted association for men but not for women (OR 2.30, 1.22-4.33, p = 0.010 and OR 1.59, 0.83-3.03, p = 0.159, respectively). Interactions with sex were statistically non-significant. CONCLUSION: In the general adult population, the prevalence of the S1S2S3 ECG pattern is markedly affected by the diagnostic ECG criteria. The S1S2S3-I pattern was associated with hypertension, while S1S2S3-II was associated with heart failure, and both associations were enhanced in men. The associations with other studied cardiovascular and pulmonary diseases were minor and not clinically useful for risk stratification.

Rationale and design of the BAYES (Interatrial Block and Yearly Events) registry.

The prevalence of interatrial block (IAB) is high in the elderly, particularly in those with heart disease. Despite this high prevalence-and the association of IAB with the risk of atrial fibrillation (AF), stroke, and cognitive decline-little information exists about the prognosis of older patients with IAB. P-wave duration and morphology are associated with risk of developing AF, stroke, and cognitive decline in elderly patients with structural heart disease. The aim of the Interatrial Block and Yearly Events (BAYES) registry is to assess the impact of IAB on the risk of AF and stroke during 3 years of follow-up. A series of 654 ambulatory patients age ≥70 years with heart disease from 35 centers will be included in 3 similar-size groups of patients. Group A: normal P-wave duration (<120 ms); Group B: partial IAB (P-wave duration ≥120 ms without biphasic [plus/minus] morphology in the inferior leads II, III, and aVF); and Group C: advanced IAB (P-wave duration ≥120 ms with biphasic [plus/minus] morphology in the inferior leads II, III, and aVF). Patients will be managed according to current recommendations. The 2 primary endpoints are defined as (1) AF duration >5 minutes and documented in any form of electrocardiographic recording; and (2) stroke. Results from this study might significantly improve the knowledge of IAB and its impact on the outcome of elderly patients with heart disease and could open the door to the use of anticoagulation therapy in some elderly patients with IAB.

Evaluation of acceleration and deceleration cardiac processes using phase-rectified signal averaging in healthy and idiopathic dilated cardiomyopathy subjects.

The aim of the present study was to investigate the suitability of the Phase-Rectified Signal Averaging (PRSA) method for improved risk prediction in cardiac patients. Moreover, this technique, which separately evaluates acceleration and deceleration processes of cardiac rhythm, allows the effect of sympathetic and vagal modulations of beat-to-beat intervals to be characterized. Holter recordings of idiopathic dilated cardiomyopathy (IDC) patients were analyzed: high-risk (HR), who suffered sudden cardiac death (SCD) during the follow-up; and low-risk (LR), without any kind of cardiac-related death. Moreover, a control group of healthy subjects was analyzed. PRSA indexes were analyzed, for different time scales T and wavelet scales s, from RR series of 24 h-ECG recordings, awake periods and sleep periods. Also, the behavior of these indexes from simulated data was analyzed and compared with real data results. Outcomes demonstrated the PRSA capacity to significantly discriminate healthy subjects from IDC patients and HR from LR patients on a higher level than traditional temporal and spectral measures. The behavior of PRSA indexes agrees with experimental evidences related to cardiac autonomic modulations. Also, these parameters reflect more regularity of the autonomic nervous system (ANS) in HR patients.

The Diagnosis and Clinical Implications of Interatrial Block.

Impaired interatrial conduction or interatrial block is now well-documented but is not described as an individual electrocardiographic (ECG) pattern in the majority of ECG literature. In fact the term atrial abnormality has been adopted to encompass both left atrial enlargement (LAE) and interatrial block. In this paper, we maintain that interatrial blocks and atrial enlargement are separate entities, and that interatrial blocks, similar to other types of blocks at sinoatrial, AV junctional, and ventricular level, exhibit a specific ECG pattern that may present first, second, and third degree types of conduction block. The third degree or advanced interatrial block (A-IAB) is frequently associated with atrial fibrillation/atrial flutter (AF/AFl), and constitutes a true newly-described syndrome.

Symbolic dynamics to discriminate healthy and ischaemic dilated cardiomyopathy populations: an application to the variability of heart period and QT interval.

Myocardial ischaemia is hypothesized to stimulate the cardiac sympathetic excitatory afferents and, therefore, the spontaneous changes of heart period (approximated as the RR interval), and the QT interval in ischaemic dilated cardiomyopathy (IDC) patients might reflect this sympathetic activation. Symbolic analysis is a nonlinear and powerful tool for the extraction and classification of patterns in time-series analysis, which implies a transformation of the original series into symbols and the construction of patterns with the symbols. The aim of this work was to investigate whether symbolic transformations of RR and QT cardiac series can provide a better separation between IDC patients and healthy control (HC) subjects compared with traditional linear measures. The variability of these cardiac series was studied during daytime and night-time periods and also during the complete 24 h recording over windows of short data sequences of approximately 5 min. The IDC group was characterized by an increase in the occurrence rate of patterns without variations (0 V%) and a reduction in the occurrence rate of patterns with one variation (1 V%) and two variations (2 V%). Concerning the RR variability during the daytime, the highest number of patterns had 0 V%, whereas the rates of 1 V% and 2 V% were lower. During the night, 1 V% and 2 V% increased at the expense of diminishing 0 V%. Patterns with and without variations between consecutive symbols were able to increase the separation between the IDC and HC groups, allowing accuracies higher than 80%. With regard to entropy measures, an increase in RR regularity was associated with cardiac disease described by accuracy >70% in the RR series and by accuracy >60% in the QTc series. These results could be associated with an increase in the sympathetic tone in IDC patients.

The role of the ECG in diagnosis, risk estimation, and catheterization laboratory activation in patients with acute coronary syndromes: a consensus document.

The electrocardiogram (ECG) is the most widely used imaging tool helping in diagnosis and initial management of patients presenting with symptoms compatible with acute coronary syndrome. Acute ischemia affects the configuration of the QRS complexes, the ST segments and the T waves. The ECG should be read along with the clinical assessment of the patient. ST segment elevation (and ST depression in leads V1 -V3 ) in patients with active symptoms usually indicates acute occlusion of an epicardial artery with ongoing transmural ischemia. These patients should be triaged for emergent reperfusion therapy per current guidelines. However, many patients have ST segment elevation secondary to nonischemic causes. ST depression in leads other than V1 -V3 usually are indicative of subendocardial ischemia secondary to subocclusion of the epicardial artery, distal embolization to small arteries or spasm supply/demand mismatch. ST depression may also be secondary to nonischemic etiologies, such as left ventricular hypertrophy, cardiomyopathies, etc. Knowing the clinical scenario, comparison to previous ECG and subsequent ECGs (in cases that there are changes in the quality or severity of symptoms) may add in the diagnosis and interpretation in difficult cases. This review addresses the different ECG patterns, typically seen in patients with active symptoms, after resolution of symptoms and the significance of such changes when seen in asymptomatic patients.

Negative T wave in ischemic heart disease: a consensus article.

BACKGROUND: For many years was considered that negative T wave in ischemic heart disease represents ischemia and for many authors located in subepicardial area. METHODS: We performed a review based in the literature and in the experience of the authors commenting the real significance of the presence of negative T wave in patients with ischemic heart disease. RESULTS: The negative T wave may be of primary or secondary type. Negative T wave observed in ischemic heart disease are of primary origin, therefore not a consequence of abnormal repolarization pattern. The negative T wave of ischemic origin presents the following characteristics: (1) are symmetrical and of variable deepness; (2) present mirror patterns; (3) starts in the second part of repolarization; and (4) may be accompanied by positive or negative U wave. The negative T wave of ischemic origin may be seen in the following clinical settings: (1) postmyocardial infarction due to a window effect of necrotic zone and (2) as a consequence of reperfusion in case of aborted MI when the artery has opened spontaneously, or after fibrinolysis, PCI, or coronary spasm. CONCLUSION: Acute ongoing ischemia do not cause negative T wave. This pattern appears when the ongoing ischemia is vanishing or in the chronic phase. In all these cases the cause of negative T wave is not located in the subepicardial area. Furthermore, positive exercise testing is expressed by ST depression never by isolated negative T wave. There are many circumstances that may present negative T wave outside ischemic heart disease and that have been discussed in this paper.

Prinzmetal angina: ECG changes and clinical considerations: a consensus paper.

BACKGROUND: 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. RESULTS: The most important ECG change during a focal proximal coronary spasm is in around 50% of cases the appearance of peaked and symmetrical T wave that is followed, if the spasm persist, by progressive ST-segment elevation that last for a few minutes, and later progressively resolve. The most frequent ECG changes associated with ST-segment elevation are: (a) increased height of the R wave, (b) coincident S-wave diminution, (c) upsloping TQ in many cases, and (d) alternans of the elevated ST-segment and negative T wave deepness in 20% of cases. The presence of arrhythmias is very frequent during Prinzmetal angina crises, especially ventricular arrhythmias. The prevalence and importance of ventricular arrhythmias were related to: (a) duration of episodes, (b) degree of ST-segment elevation, (c) presence of ST-T wave alternans, and (d) the presence of >25% increase of the R wave. CONCLUSIONS: The incidence of Prinzmetal angina is much lower then 50 years ago for many reasons including treatment with calcium channel blocks to treat hypertension and ischemia heart disease and the decrease of smoking habits.

ECG diagnosis and classification of acute coronary syndromes.

In acute coronary syndromes, the electrocardiogram (ECG) provides important information about the presence, extent, and severity of myocardial ischemia. At times, the changes are typical and clear. In other instances, changes are subtle and might be recognized only when ECG recording is repeated after changes in the severity of symptoms. ECG interpretation is an essential part of the initial evaluation of patients with symptoms suspected to be related to myocardial ischemia, along with focused history and physical examination. Patients with ST-segment elevation on their electrocardiogram and symptoms compatible with acute myocardial ischemia/infarction should be referred for emergent reperfusion therapy. However, it should be emphasized that a large number of patients may have ST-elevation without having acute ST-elevation acute coronary syndrome, while acute ongoing transmural ischemia due to an abrupt occlusion of an epicardial coronary artery may occur in patients with ST-elevation less than the thresholds defined by the guidelines. Up-sloping ST-segment depression with positive T waves is increasingly recognized as a sign of regional subendocardial ischemia associated with severe obstruction of the left anterior descending coronary artery. Widespread ST-segment depression, often associated with inverted T waves and ST-segment elevation in lead aVR during episodes of chest pain, may represent diffuse subendocardial ischemia caused by severe coronary artery disease. In case of hemodynamic compromise, urgent coronary angiography has been increasingly recommended for these patients.

Low atrial fibrillatory rate is associated with poor outcome in patients with mild to moderate heart failure.

BACKGROUND: Atrial fibrillatory rate (AFR) is a measure of atrial remodeling caused by atrial fibrillation (AF), and its acceleration negatively affects outcome of interventions for persistent AF. However, the prognostic value of AFR in patients with congestive heart failure (CHF) has not been studied. We sought to evaluate whether AFR can predict outcome in patients with mild to moderate (New York Health Association II-III) CHF. METHODS AND RESULTS: High-resolution 20-minute long Holter ECGs obtained from 169 CHF patients with AF at enrollment were analyzed. AFR was estimated using spatiotemporal QRST cancellation and time-frequency analysis. The patients were followed for a median of 44 months, with primary end point defined as total mortality and secondary end points as sudden death and heart failure death. Atrial signal quality was sufficient for AFR estimation in 142 patients (mean age 69±11 years, 101 male). Of those, 48 patients died during follow-up, including 18 because of CHF progression. Mean AFR was 390±60 fpm and decreased with age (r=-0.3, P<0.001). Patients with AFR ≤371 fpm (lower tertile) had 44% 3-year mortality as compared with 26% with higher AFR. Lower AFR was an independent predictor of all cause mortality (HR=1.99, 95% CI=1.09-3.63, P=0.025) and CHF death (HR=3.74, 95% CI=1.38-10.14, P=0.010) after adjustment for significant clinical covariates in multivariable Cox analysis. CONCLUSIONS: In CHF patients with AF, reduced AFR assessed using noninvasive approach is associated with increased risk of death because of heart failure progression, and may be considered a predictor of outcome.

Specific characteristics of sudden death in a mediterranean Spanish population.

Most of the data reported on sudden cardiac death has been from studies of Anglo-Saxon patients. We conducted a study to ascertain the relation between sudden death (SD) and some epidemiologic, clinical, and biochemical parameters and to assess the coronary histopathologic aspects of subjects in a Spanish population who had died suddenly. A total of 204 subjects (86% men), aged 12 to 80 years (mean 54 ± 15), who had died from out-of-hospital natural SD were evaluated. Only 15% of subjects had been previously diagnosed with heart disease. Pathologic evidence of underlying cardiovascular disease was found in 90% of cases, with coronary heart disease (CHD) the most frequent (58%). The CHD was acute coronary thrombosis in 41% and a stable plaque with luminal narrowing of ≥75% in 59%. An old myocardial infarction was found in 31% of the SD victims. Cardiac hypertrophy was found in 48%, with no relation between the presence of cardiac hypertrophy and CHD. Patients with stable plaques had a greater heart weight than did those with acute coronary thrombosis (p = 0.02). Male gender, older age, smoking, and low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio of ≥3 were associated with CHD. A greater percentage of patients with an eroded and/or ruptured plaque than patients with a stable plaque were smokers. Only smoking and a low-density lipoprotein/high-density lipoprotein cholesterol ratio of ≥3 were associated with an eroded and/or ruptured plaque. In conclusion, compared with the findings from studies of Anglo-Saxon patients, a lower incidence of CHD and acute coronary thrombosis and a greater incidence of cardiac hypertrophy were found in SD victims of a Mediterranean Spanish population.

Technical mistakes during the acquisition of the electrocardiogram.

In addition to knowledge of normal and pathological patterns, the correct interpretation of electrocardiographic (ECG) recordings requires the use of acquisition procedures according to approved standards. Most manuals on standard electrocardiography devote little attention to inadequate ECG recordings. In this article, we present the most frequent ECG patterns resulting from errors in limb and precordial lead placement, artifacts in 12-lead ECG as well as inadequate filter application; we also review alternative systems to the standard ECG, which may help minimize errors.