Prognostic implications of intraventricular conduction delays in a general population: the Health 2000 Survey.

AIMS: We examined the prognostic impact of eight different intraventricular conduction delays (IVCD) in the standard electrocardiogram (ECG) in a community cohort. METHODS AND RESULTS: Data were collected from 6299 Finnish individuals. During a mean 8.2 years (interquartile range 8.1 to 8.3) of follow-up 640 subjects died (10.2%); 277 (4.4%) were cardiovascular deaths. For both sexes, all-cause and cardiovascular mortality was higher in subjects with IVCD than in those without. In Cox regression analysis after adjustment for age and gender, the hazard ratio for cardiovascular mortality for non-specific IVCD was 4.25 (95% confidence interval [CI] 1.95-9.26, P < 0.0001) and for left bundle branch block (LBBB) 2.11 (95% CI 1.31-3.41, P = 0.002). Right bundle branch block (RBBB) was not related to additional mortality, while incomplete RBBB (IRBBB) presented a hazard ratio of 2.24 (95% CI 1.064-4.77, P = 0.036). CONCLUSIONS: In the general population, non-specific IVCD, LBBB, and IRBBB were associated with increased relative risk for all-cause and cardiovascular mortality. RBBB did not have an impact on cardiovascular mortality either in subjects with or without previous heart disease.

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.

Updated electrocardiographic classification of acute coronary syndromes.

The electrocardiogram (ECG) findings in acute coronary syndrome should always be interpreted in the context of the clinical findings and symptoms of the patient, when these data are available. It is important to acknowledge the dynamic nature of ECG changes in acute coronary syndrome. The ECG pattern changes over time and may be different if recorded when the patient is symptomatic or after symptoms have resolved. Temporal changes are most striking in cases of ST-elevation myocardial infarction. With the emerging concept of acute reperfusion therapy, the concept ST-elevation/ non-ST elevation has replaced the traditional division into Q-wave/non-Q wave in the classification of acute coronary syndrome in the acute phase. KEYPOINTS: In acute coronary syndrome, in addition to the traditional electrocardiographic risk markers, such as ST depression, the 12-lead ECG contains additional, important diagnostic and prognostic information. Clinical guidelines need to acknowledge certain high-risk ECG patterns to improve patient care.

Physiological and pathological remodeling in acute inferior wall myocardial infarction.

In acute myocardial ischemic syndrome the electrocardiogram is capable of providing sophisticated information on coronary artery anatomy (the culprit artery, the level of obstruction, the arterial dimension), along with the hemodynamics, molecular biological characteristics and ionic changes that occur in the involved and uninvolved ischemic musculature. In acute myocardial ischemia, during a sudden obstruction of a distal co-dominant right coronary artery the ECG may be able to discriminate between physiological and pathological remodeling, providing predictive information to differentiate low from high risk cases during acute inferior wall infarction.

Correlation between ECG presentation and cardiovascular magnetic resonance imaging in Takotsubo cardiomyopathy.

Takotsubo cardiomyopathy (TTC) is characterized by acute and reversible ventricular dysfunction in the absence of significant coronary artery disease, typically triggered by acute emotional or physical stress. In the acute phase of TTC, the electrocardiogram (ECG) shows ST-segment elevation, which rapidly evolves into negative T waves and QT prolongation. However, different types of ventricular dysfunction may be associated with different patterns of ECG presentation. In this paper, we discuss the correlation between ECG presentation and cardiovascular magnetic resonance imaging in TTC.

ST-segment deviation pattern of takotsubo cardiomyopathy similar to acute pericarditis: diffuse ST-segment elevation.

BACKGROUND: Possible similarities or differences in the ST- and PR-segment deviations in the electrocardiogram of takotsubo cardiomyopathy (TTC) and acute pericarditis (AP) are not well defined. METHODS: We compared different parameters of the admission electrocardiogram in eight patients with TTC and eight patients with AP with ST-segment elevation in the acute phase. RESULTS: We found significant differences in the maximal magnitude of the T wave in the precordial leads, but not in the ST- and PR-segment deviation patterns between the two patient groups. All the patients in the two groups showed consistent ST-segment depression in lead aVR and absence of ST-segment elevation in lead V1. CONCLUSIONS: The ST- and PR-segment deviation patterns in TTC are similar to that of AP, namely diffuse ST-segment elevations with reciprocal changes in aVR and V1 and PR-segment elevation in aVR accompanied by PR-segment depression in the inferior leads, possibly indicating that TTC has ECG characteristics of circumferential subepicardial ischemia in the acute phase.

Prevalence of ventricular conduction blocks in the resting electrocardiogram in a general population: the Health 2000 Survey.

AIMS: The prevalence of eight different ventricular conduction blocks and their association with risk factors and major cardiovascular diseases were studied in a major Finnish population study. METHODS: Data, including 12-lead electrocardiograms, were collected from 6315 subjects. The prevalence of left bundle branch block (LBBB), right bundle branch block (RBBB), non-specific ventricular block, incomplete LBBB, incomplete RBBB, R-R'-pattern, left anterior hemiblock (LAHB), and left posterior hemiblock (LPHB) was calculated for both genders in three age groups. Their association with risk factors and cardiovascular diseases was studied. RESULTS: R-R'-pattern was the most common ventricular conduction block in all age groups (3.9%, p<0.001 for comparison between groups), but it showed no association with cardiovascular diseases. Males had more RBBB (1.5% vs. 0.7%, p<0.001), incomplete LBBB (1.8 vs. 0.4, p<0.001) and non-specific ventricular block (1.1% vs. 0.1%, p<0.001). With increasing age (<45 years vs. >55 years) LBBB, RBBB and LAHB (0 vs. 2.2%, 0.3 vs. 2.2%, 0.2 vs. 1.9% respectively, p-values<0.001) became more prevalent. LBBB, RBBB and non-specific ventricular conduction block were associated with coronary heart disease (angina pectoris in 28.3, 20.3 and 22.9%, respectively) and heart failure (25.0, 10.1 and 11.4%, respectively). LBBB and RBBB were also associated with peripheral vascular disease (8.8%). CONCLUSIONS: Ventricular conduction blocks differ in prevalence between sexes and age groups. They also show disparate association with cardiovascular diseases. These differences need to be taken into consideration in everyday clinical practice.

Common pitfalls in the interpretation of electrocardiograms from patients with acute coronary syndromes with narrow QRS: a consensus report.

Acute coronary syndromes (ACS) with narrow QRS are divided into 2 groups: ST-elevation ACS that requires emergency percutaneous coronary intervention, and non-ST elevation ACS. The classification of ACS into these 2 groups is not always straightforward. In this document, we discuss several electrocardiogram patterns of acute ischemia that are often misinterpreted. We suggest that any new recommendations or guidelines from the Scientific Societies should acknowledge these aspects of electrocardiogram interpretation by including appropriate diagnostic criteria that should prove helpful for the optimal management of patients with ACS.

Severe hypocalcemia simulating ST-elevation myocardial infarction.

ST-elevation myocardial infarction (STEMI) is an emergency situation in which immediate measures for myocardial reperfusion are needed. The diagnosis is based on the recognition of ST-segment elevation in the electrocardiogram (ECG). In case of coronary artery occlusion, ST-segment elevation is caused by an injury current from the ischemic myocardium. Rarely, other mechanisms may lead to ECG changes mimicking STEMI. In our case, a 65-year-old man was presented to our institution with ECG abnormalities suggestive of STEMI. However, coronary angiography showed open arteries. Laboratory tests revealed severe hypocalcemia caused by a deficiency of vitamin D. After calcium replacement therapy, the ECG normalized, and the patient was discharged in good condition. Only a few case reports on hypocalcemia-induced ST-segment elevation exist, and the mechanism remains unknown.

Electrocardiographic presentation of global ischemia in acute coronary syndrome predicts poor outcome.

BACKGROUND: Global ischemia (GI) electrocardiogram (ECG), wide-spread ST depression with inverted T waves maximally in leads V(4-5), and lead aVR ST elevation (STE), is a marker of an adverse outcome in patients with non-ST elevation acute coronary syndromes (ACS), perhaps because this pattern is indicative of left main stenosis. The prognostic value of this ECG pattern has not been established. AIMS: The distribution of ECG changes and the prognostic value of the GI ECG were studied. METHODS: ECGs of consecutive patients admitted with suspected ACS (n = 1,188) were classified into seven ECG categories: STE, Q waves without STE, left bundle branch block, left ventricular hypertrophy, GI ECG, other ST depression and/or T wave inversion, and other findings. RESULTS: The GI ECG pattern predicted a high rate (48%) of composite end-points (mortality, re-infarction, unstable angina, resuscitation, or stroke) at 10-month follow-up compared to the other ECG categories (36%) (HR 1.78; CI 95% 1.31-2.41; P < 0.001). In multivariate analysis, the GI ECG pattern was associated with a higher rate of composite end-points (HR 1.40; CI 95% 1.02-1.91; P = 0.035). The multivariate analysis furthermore identified age, creatinine level, and diabetes as independent predictors of prognosis. CONCLUSIONS: The GI ECG pattern predicted an unfavorable outcome, when compared to other ECG patterns in patients with ACS.

Prominent precordial T waves as a sign of acute anterior myocardial infarction: electrocardiographic and angiographic correlations.

In clinical practice, one occasionally encounters patients with symptoms lasting for relatively long time showing prominent positive T waves combined with minor ST elevation, or ST depression in the precordial leads. This electrocardiographic pattern has been described as Sclarovsky-Birnbaum grade 1 ischemia. We present 3 cases of patients with predominantly grade 1 ischemia, in whom the culprit site was in the left anterior descending coronary artery. The electro/pathophysiologic mechanisms of these electrocardiographic patterns are discussed.

Factors associated with failure to identify the culprit artery by the electrocardiogram in inferior ST-elevation myocardial infarction.

BACKGROUND: Right and left circumflex coronary artery occlusions cause inferior myocardial infarction. To improve the targeting of diagnostic and therapeutic measures individually, factors interfering with identification of the culprit artery by the electrocardiogram (ECG) were explored. METHODS: Patients with inferior preinfarction syndrome (n = 266) were included to the Danish Trial in Acute Myocardial Infarction-2 substudy. The culprit vessel was predicted by the ECG, and findings were correlated with angiography. Factors associated with false identification of the culprit artery by the ECG were examined. RESULTS: Electrocardiogram criteria for right coronary artery occlusion to predict coronary angiography findings had sensitivity, specificity, and positive and negative predictive values of 95%, 52%, 84%, and 81%. For left circumflex coronary artery occlusion, the corresponding values were 51%, 93%, 70%, and 85%, respectively. False ECG identification of the culprit artery was independently associated with left coronary dominance (P < .001; odds ratio [OR], 22.0; 95% confidence interval [CI], 7.2-67.0), multivessel disease (P = .035; OR, 2.2; 95% CI, 1.1-4.7), and absence of proximal occlusion pattern in the ECG (P = .003; OR, 4.0; 95% CI, 1.6-9.8). CONCLUSIONS: Left coronary artery dominance, multivessel disease, and absence of ECG signs of proximal culprit lesion are associated with failure to predict the culprit artery of inferior myocardial infarction by the 12-lead ECG.

Electrocardiographic presentation of left main disease in patients undergoing urgent or emergent coronary artery bypass grafting.

BACKGROUND: Widespread ST-segment depression with inverted T waves maximally in leads V4-V5 (ie, the global ischemia electrocardiogram [ECG] pattern) is a marker of adverse outcome in patients with non-ST-segment elevation acute coronary syndrome (ACS), perhaps because this pattern is indicative of left main stem stenosis. However, the prognostic value of this ECG pattern has not yet been established. OBJECTIVE: We studied the predictive value of a prespecified ECG pattern in patients who underwent urgent or emergent coronary artery bypass grafting (CABG). METHODS: We studied the sensitivity, specificity, and predictive values for the global ischemia ECG to predict angiographic left main coronary artery disease. Patients with a 12-lead ECG recorded during anginal symptoms before CABG were included. RESULTS: The global ischemia ECG pattern was found in 61 (76%) of 80 patients with and 12 (19%) of 65 patients without left main disease. The sensitivity, specificity, and positive and negative predictive values for left main coronary artery disease in patients with the global ischemia ECG pattern were 76%, 81%, 84%, and 74%, respectively. In multivariate analysis, the global ischemia ECG pattern was strongly associated with angiographic left main coronary artery disease after adjusting for age, gender, diabetes, hypertension, and smoking (hazard ratio, 16.0; 95% confidence interval, 6.5-39.5; P < 0.001). CONCLUSION: The global ischemia ECG pattern was strongly associated with angiographic left main coronary artery disease in patients who underwent urgent or emergent CABG.

Prognostic implications of quantitative ST-segment characteristics and T-wave amplitude for cardiovascular mortality in a general population from the Health 2000 Survey.

AIMS: We determined the gender-specific prognostic importance of quantitative measures of the ST segment and T wave in a community cohort. METHODS: Data were collected from 5613 Finnish individuals. Four electrocardiogram (ECG) lead groups were used: anterior, lateral, inferior, and lead V5. ST-segment depression, determined at four points along the ST segment, and T-wave amplitude were treated as continuous variables in Cox regression analyses. RESULTS: During a median follow-up period of 72.4 months, 120 cardiovascular deaths were registered. Among women, lateral lead group as well as lead V5 showed highly significant adjusted hazard ratios at all four ST-depression assessment points. This significance was lost in women ≥ 55 years when those with ECG-based criteria of left ventricular hypertrophy (LVH) were excluded. Results for ST-segment depression were not significant among men. As those with LVH were excluded, men ≥ 55 years showed borderline significance. T-wave amplitude did not reach significance among men, while lateral leads and lead V5 bore prognostic information among women. CONCLUSION: Quantitative ST-segment depression, regardless of the measurement point, allows prediction of cardiovascular death in women within a general population. However, the effect disappears as those with LVH are excluded. This observation highlights the need for consideration of LVH when depressed ST segments are clinically observed.

Prevalence and prognostic value of poor R-wave progression in standard resting electrocardiogram in a general adult population. The Health 2000 Survey.

AIMS: We examined the prevalence and prognostic impact of poor R-wave progression (PRWP) in a standard electrocardiogram (ECG) in a general population. METHODS: Data and standard resting ECG recording were collected from a large nationally representative (random sample) health examination survey conducted in Finland in 2000-2001. The final study population consisted of 5613 individuals. RESULTS: The prevalence of PRWP (defined as RV3 < or = 3 mm and RV2 < or = RV3) was 7.0% in women and 2.7% in men (P< or = 0.001 for difference). During follow-up of 70 +/- 9 months (mean +/- SD), 317 patients died (5.6%). Both all-cause and cardiovascular mortality was higher in the group with PRWP than in those without PRWP in both women and men. In Cox regression analysis after adjustment for age, hypertension, diabetes, previous myocardial infarction, and coronary heart disease, the relative risk for all-cause mortality for PRWP was 1.69 (95% CI 0.89-3.22, P=0.112) for men and 2.00 (95% CI 1.28-3.13, P=0.002) for women. For cardiovascular mortality the relative risk for individuals with PRWP was 1.85 (0.74-4.65, P=0.19) for men and 3.02 (1.54-5.93, P=0.001) for women. CONCLUSIONS: PRWP is a common ECG finding and predicts risk for total and cardiovascular mortality in women in a general population.

The electrocardiographic paradox of tako-tsubo cardiomyopathy-comparison with acute ischemic syndromes and consideration of molecular biology and electrophysiology to understand the electrical-mechanical mismatching.

From the electrocardiographic (ECG) point of view, the tako-tsubo cardiomyopathy (TTC) behaves like an acute subepicardial circumferential ischemic syndrome. The electrical manifestations are significantly different from those of acute transmural segmental ischemia, in which the ECG primarily expresses the electrophysiologic and metabolic changes occurring in the subepicardial layer. In comparison with transmural anterior ischemia and despite acute contraction impairment (circumferential middle and apical dyskinesis and basal hyperkinesis), in TTC there is typically only moderate ST elevation in the precordial leads. This paradox can be understood by taking into consideration the molecular biology and basic electrophysiology. In the senescent female with hypoestrogenemia, the subepicardium is almost totally unprotected against "adrenergic storm." In the fertile female, estrogen plays the pivotal role of protecting the myocardium at many levels of the metabolic cascade, such as in the regulation of the presynaptic release of adrenergic substances and by increasing the release of adenosine. There is consequential increase of the adenosine triphosphate (ATP)-sensitive K+ channels, thus regulating the inward flow of Ca2+ toward the sarcoplasmic reticulum. The ATP-sensitive K+ channels hyperpolarize the subepicardial cells during extremely aggressive situations such as ischemia and adrenergic storm. The hyperpolarization of the subepicardium is manifested in the ECG by tall, peaked T waves, indicating an increase of the repolarization gradient between the subendocardial and subepicardial layers. In the absence of estrogen, there are severe decreases in the concentration of adenosine and in the density of the ATP-sensitive K+ channels. The subepicardial myocytes cannot be hyperpolarized, and the adrenergic storm is manifested by moderate ST-T elevation. Furthermore, the very rapid appearance and disappearance of a Q wave are "against the rules." This is a classical example of electrical stunning, that disappears before mechanical stunning in which contraction is typically recovered only after 1 week.