Isoelectric ST Segment Research Articles

Prognostic Value of ST-segment Deviation in Lead aVR in Electrocardiogram in Acute Myocardial Infarction

Background: Acute myocardial infarction (AMI) remains a significant cause of morbidity and mortality worldwide, necessitating effective risk stratification tools for improved management. ST-segment deviation in lead augmented vector right (aVR) has emerged as a potential prognostic marker in AMI, but its clinical relevance in the Indian context requires further investigation. Materials and Methods: We conducted a single-center prospective observational study among patients admitted with AMI to assess the prognostic value of ST-segment deviation in lead aVR. Patients were categorized based on the presence or absence of ST-segment deviation in lead aVR, and demographic, clinical, and angiographic characteristics were compared between groups. Follow-up evaluations were performed to assess left ventricular ejection fraction (LVEF) and the incidence of ventricular tachycardia (VT). Results: The study enrolled 110 patients, categorizing them by ST-segment deviation in lead aVR. Patients with ST elevation in lead aVR showed higher moderate LVEF dysfunction (31%–40%) than those with isoelectric ST segments (P = 0.0058). Conversely, patients with ST depression in lead aVR had increased preserved ejection fraction compared to those with an isoelectric ST segment (P = 0.0414). <50% ST-segment resolution postpercutaneous coronary intervention (PCI) was more common among non-ST-segment elevation myocardial infarction (NSTEMI) patients. The incidence of VT was higher in ST elevation in lead aVR (P = 0.0045). Significant differences in ST-segment resolution after PCI (P = 0.0117) between STEMI and NSTEMI patients were noted. Conclusion: ST-segment deviation in lead aVR serves as a valuable prognostic marker in AMI, correlating with adverse outcomes such as moderate LVEF dysfunction and increased risk of VT. Furthermore, its association with ST-segment resolution post-PCI highlights its role in assessing reperfusion success and guiding management strategies. These findings underscore the importance of ST-segment deviation in lead aVR for risk stratification and personalized management in AMI patients.

Is It ST-Segment-Elevation Myocardial Infarction?

A 76-year-old man presented with acute-onset chest pain and dyspnea. He had a history of coronary artery disease, ischemic cardiomyopathy (left ventricular ejection fraction, 25%), recent non-ST-segment-elevation myocardial infarction (NSTEMI), and stenting of the left anterior descending coronary artery (LAD) one month before the current presentation. Soon thereafter, he underwent stenting of the left main coronary artery (LMCA), obtuse marginal branch (OMB), and left circumflex coronary artery. His chest pain subsided soon after arrival at the emergency department. His cardiac troponin I level was 22 ng/mL (normal level, <0.03 ng/mL), and his brain natriuretic peptide level was 841 pg/mL (normal level, <100 pg/mL). Figure 1 shows his electrocardiogram (ECG).What is the diagnosis?C) STEMI due to first OMB or ramus intermedius occlusionThe ECG shows sinus rhythm, mild ST-segment elevation (STE) with T-wave inversion in lead aVL, ST-segment depression with positive T waves in leads II, III, aVF, and V3 through V6, and an isoelectric ST segment in leads I and V1 through V2. The Fourth Universal Definition of Myocardial Infarction1 says, “More profound ST-segment shifts or T-wave inversions involving multiple leads/territories are associated with a greater degree of myocardial ischaemia, and a worse prognosis. For example, ST-segment depression ≥1 mm in 6 leads, which may be associated with STE in lead aVR or lead V1 and hemodynamic compromise, is suggestive evidence of multivessel disease or left main disease” (eliminating answer A). This is considered a high-risk ECG pattern for which invasive intervention within 2 hours is recommended, in accordance with the 2020 European Society of Cardiology guidelines for managing acute coronary syndromes without persistent STE.2 Our patient's ECG shows ST-segment depression in 7 leads but no significant STE in lead aVR or V1. In contrast, STE with negative T waves is seen in lead aVL.Patients with a nonischemic early repolarization pattern can have STE in lead aVL. However, the T waves are usually positive, and there is often a J-point notch. The pattern here suggests a reperfused or more advanced stage of STEMI,3 and the patient's clinical presentation (symptom resolution after hospital arrival) supports this diagnosis.New STE in 2 contiguous leads is necessary for the diagnosis of STEMI.1 However, this is an epidemiologic (not pathophysiologic) criterion, to minimize false-positive diagnosis. Acutely occluded arterial branches may cause STE in only one lead with diffuse ST-segment depression.4 The STE in leads aVL and V2 through V5 is caused by LAD occlusion proximal to the first diagonal branch (eliminating answer B),4 and STE in leads aVL and V2 without STE in leads V3 through V5 suggests an occluded first diagonal branch. The ST-segment depression in the anterolateral and inferior leads is incompatible with the typical presentation of takotsubo cardiomyopathy (answer D). The STE in lead aVL, incompatible with ischemic cardiomyopathy (answer E), is accompanied by ST-segment depression in lead V2, suggesting obstruction of the first OMB. Our patient had an isoelectric ST segment in lead V2, so the differential diagnosis is an occluded OMB or ramus intermedius.4 A coronary angiogram on the second day of admission showed subacute thrombotic occlusion of the first OMB (Fig. 2, arrow), and stenting restored patent flow.Disclosures: NoneFunding/support: None

Acute Coronary Syndrome with ST Segment Elevation: New Electrocardiographic Pattern

A 58-year-old man with a history of hypertension and diabetes, presented to the emergency department (ED) after 2 hours of oppressive, severe chest pain radiating to the left arm and associated with dyspnea. Upon arrival he was stable, an ECG was performed that demonstrated an isolated elevation of the J point in DIII, with depression of the J point in DI, DII, AVL, V4 to V6, with isoelectric ST segment in AVF. Troponine was not expected because an ST equivalent pattern was suspected. Should the patient be treated for an acute coronary syndrome with elevation of the ST or non-ST elevation based on the ECG findings?

Primary percutaneous coronary intervention is appropriate in transient ST-elevation myocardial infarction.

Reperfusion therapy by primary percutaneous coronary intervention (PPCI) is generally indicated in patients suffering from acute myocardial infarction (MI) with ST-segment elevation (STEMI). Prior to hospital admission, full ST-segment resolution (fSTR) may occur. Optimal management of such patients with transient STEMI (TSTEMI) is potentially challenging. Our aim was to evaluate the hypothesis that in TSTEMI patients, patency of infarct related artery (IRA) is achieved before PPCI, and to compare the outcome of TSTEMI and STEMI patients during a prolonged follow-up. Three hundred consecutive adult STEMI patients were referred to catheterization laboratory. In all patients, standard 12 lead ECGs were obtained both at the time of the first medical contact, and on catheterization laboratory admission. TSTEMI occurred in 20 patients (6.7%). Despite fSTR (isoelectric ST segment), occluded IRA was found in 5 of these patients (25%). Pre-PPCI TIMI flow grade 2 was found in 6 TSTEMI patients (30%). Troponin T value at 24 h after symptom onset was lower in the TSTEMI group (1.8±2.5 mg/L vs. 3.6±3.5 mg/L, P=0.008). These patients also had a lower value of brain natriuretic peptide (156.3±119.5 ng/L vs. 438.5±429.0 ng/L, P<0.001) and higher left ventricular ejection fraction (59.9±6.3% vs. 51.6±10.2%, P<0.001). All patients were followed for a median of 5.6 years during which the overall survival did not differ between the TSTEMI and STEMI groups. Primary PCI is strongly recommended in TSTEMI patients because of a relatively high incidence of occluded infarct related arteries. The rate of patients with TSTEMI is relatively low.

Significance of Lead aVR ST Segment Elevation in Patients Presenting with NSTEMI Acute Coronary Syndrome as a Predictor of Left Main Coronary Artery Lesions

Abstract Background: Left main coronary artery (LMCA) occlusion is a serious clinical condition. Despite its low incidence, the prognosis is grave. It may present as sudden death, complete heart block, shock and/or acute coronary syndrome (ACS). Aim of Study: The study aimed to investigate the value of ST-segment elevation in lead aVR in the surface ECG as a predictor of LMCA lesions in patients suffering from non-ST-segment elevation myocardial infarction (NSTEMI) and its relation to the severity of LMCA. Material and Methods: It is a retrospective study including patients admitted to CCU in Banha University Hospital, Shebin El-Kom Teaching Hospital and National Heart Institute. A total number of 100 patients with the diagnosis of NSTEMI ACS who had significant LMCAD on coronary angiography were included in this study; the patients were classified according to the presence or absence of ST-segment elevation of >!0.05mV in lead aVR into two groups: - Group 1: Patients with isoelectric ST-segment in lead aVR or with ST-segment elevation of less than 0.05mV. - Group 2: Patients with ST-segment elevation of 0.05mV or more in aVR. Results: Patients with elevated ST segment more than 1 is significantly higher among patients who died than those who are still alive (p<0.001). Twenty eight patients (37.8%) had Left Main coronary disease in group 2, less than 80% stenosis compared to 18 (75%) patients in group 1. While 46 patients (62,2%) had Left Main stenosis more than 80% In group 2, compared to 6 patients (25%) in group 1, the differences between subgroups were statistically signif-icant difference (p-value <0.001). Conclusion: ST-segment elevation in lead aVR is a sen-sitive prognostic indicator in detecting left main coronary artery lesions of patients suffering from non-ST-segment elevation myocardial infarction (NSTEMI).

Variability Inter-observer between Three Methods of Electrocardiographic (Conventional, Computerized and Computerized Printed) on Healthy Cats

Background: Electrocardiography is an exam widely used in feline medicine. It consists of recording the electrical activity of the heart in waves representing myocardial depolarization and repolarization. Two electrocardiographic evaluation methods are employed in dogs and cats: computerized and conventional. However, possible differences in ECG results performed by the different methods have been reported. This paper aims to evaluate the observer's interference in the interpretation of the electrocardiographic exams and possible differences between the methods: conventional single channel, computerized screen and computerized printed of healthy cats.Materials, Methods &amp; Results: Electrocardiographic tracings were obtained from 58 healthy cats, aged between 1 and 10 years-old, of both sexes, of the Persian and mixed breed and therefore interpreted by four observers with similar degree of experience. The examinations were performed in a sequential manner, the computerized method first, and then the conventional method. The animals were gently contained in the right lateral decubitus position. The tracings obtained by the conventional method were printed on thermally sensitive graph paper. The computerized method was performed in computer by means of specific software (TEB® ECGPC version 6.2), being the waves delimited by the observer. The tracings were also printed by means of a jet printer, and also interpreted. The morphology of P waves, QRS complexes and T waves were analyzed in the derivations: I, II, III, aVR, aVL and aVF. Heart rate, amplitude and duration of the P, QRS and T waves, PR, QT and heart rate (HR) intervals were calculated in derivation II. Mean electric axis was determined in leads I and III. Comparing the methods, there was a difference observed in the values of P and R waves, QRS complex, QT and PR intervals and T wave polarity. The interpretation of the evaluators presented statistical differences in the duration of the P wave, QRS, QT and HR. The three methods used presented differences during the mean of the interpretation of the evaluators.Discussion: Some factors such as the positioning of the animal and the use of chemical containment may influence the electrocardiographic tracings, as well as variations between electrocardiographic devices. In our study, the non-use of sedation and the use of the same equipment in all animals reduced the variability of the results. The interpretation of the computerized method printed and on the screen presented different results which can be explained by the reduced human visual capacity when compared to the computers. It is known that the interpretation of different tracings by the observers might influence the results of the examination. The evaluators of the present study evaluated the same tracings, but there was a difference in the interpretation of the observers. Regarding the methods, there was a difference between the three methods evaluated in relation to the ST segment. The computerized on-screen method demonstrated in its totality isoelectric ST segments that represent normal pattern for the species. The conventional and computerized printed methods presented results of elevation in ST segments that represent alterations in the diagnosis. There was a difference between the measurements performed by different observers, however this fact did not influence the results of the tests, since the parameters remained within the normality standards for species. It can be concluded that the variation between observers and among the three methods evaluated suggests that the ST segment interpretation is subtle and less influenced when performed in the computerized method.

Comparison of ST segment Changes in Lead aVR with in-Hospital Outcomes in Patients with First attack of Acute Inferior ST Segment Elevation Myocardial Infarction

Background: Inferior wall ST segment elevation myocardial infarction is considered to be at lower risk than anterior wall STEMI except in some cases. The aim of our study was to evaluate the relationships between on admission ST segment changes in lead aVR and short term in-hospital outcomes in acute isolated inferior myocardial infarction undergoing thrombolysis.&#x0D; Methods: Total 107 of first attack of inferior STEMI patients were included and all were thrombolysed by streptokinase. The sample population were divided into three groups based on the condition of ST segment in lead aVR on admission and in hospital outcomes were observed: Group –A: ST segment elevation ≥0.5 mm; Group –B: ST segment depression ≥0.5 mm; Group-C: Iso-electric ST segment.&#x0D; Results: 6.54% of study population had ST segment elevation in lead aVR, 53.27% had ST segment depression in lead aVR and 41.12% had isoelectric ST segment in lead aVR. During hospital stay mortality rates of patients of Group A, Group B and Group C were 33.3%, 5.3% and 4.5 % respectively; rates of cardiogenic shock were 33.3%, 8.8% and 2.3% respectively; heart failure rates were 50.0%, 15.8% and 4.5% respectively; rates of recurrent angina after thrombolysis were 66.7%, 33.3% and 6.8% respectively in three groups and the mean LVEF were 40.17, 48.61 and 52.50 respectively.&#x0D; Conclusion: The on admission-isoelectric ST segment in lead aVR in acute inferior myocardial infarction predicted better in-hospital outcomes in comparison to ST segment elevation and ST segment depression in aVR. On the other hand, ST segment elevation in lead aVR predicted worse in-hospital outcomes than ST segment depression in acute inferior myocardial infarction in spite of reperfusion by thrombolytic.&#x0D; Cardiovasc. j. 2019; 11(2): 123-128

No effect of season on the electrocardiogram of long-eared bats (Nyctophilus gouldi) during torpor.

Heterothermic animals regularly undergo profound alterations of cardiac function associated with torpor. These animals have specialised tissues capable of withstanding fluctuations in body temperature > 30°C without adverse effects. In particular, the hearts of heterotherms are able to resist fibrillation and discontinuity of the cardiac conduction system common in homeotherms during hypothermia. To investigate the patterns ofcardiac conduction in small insectivorous bats which enter torpor year round, I simultaneously measured ECG and subcutaneous temperature (Tsub) of 21 Nyctophilus gouldi (11g) during torpor at a range of ambient temperatures (Ta 1-28°C). During torpor cardiac conduction slowed in a temperature dependent manner, primarily via prolongation along the atrioventricular pathway (PR interval). A close coupling of depolarisation and repolarisation was retained in torpid bats, with no isoelectric ST segment visible until animals reached Tsub <6°C. There was little change in ventricular repolarisation (JT interval) with decreasing Tsub, or between rest and torpor at mild Ta. Bats retained a more rapid rate of ventricular conduction and repolarisation during torpor relative to other hibernators. Throughout all recordings across seasons (> 2500h), there was no difference in ECG morphology or heart rate during torpor, and no manifestations of significant conduction blocks or ventricular tachyarrhythmias were observed. My results demonstrate the capacity of bat hearts to withstand extreme fluctuations in rate and temperature throughout the year without detrimental arrhythmogenesis. I suggest that this conduction reserve may be related to flight and the daily extremes in metabolism experienced by these animals, and warrants further investigation of cardiac electrophysiology in other flying hibernators.

Evaluation of baseline ECG in patients undergoing Oral Flecainide Challenge test for suspected Brugada Syndrome: An analysis of lead II

Background and ObjectivesWe analyzed Lead II in patients undergoing an Oral Flecainide Challenge test (FCT), to identify any pointers that could predict a positive FCT and thereby help in recognition of latent BS. MethodsThe following parameters in lead II were retrospectively analyzed from the pre-test ECG in 62 patients undergoing FCT for suspected BS: The presence or absence of S waves, S wave amplitude, duration and upslope duration; J point parameters- Early repolarization, QRS notch, and QRS Slur; ST segment parameters-lack of isoelectric ST segment, ST duration and QT interval. Results48 had positive FCT (Group-1) while 14 were negative for FCT(Group-2). Lack of an isoelectric ST segment (50% vs 14.29%, p = 0.018) and slurring of QRS (33.33% vs 0%, p = 0.014) was more common in Group-1 than Group-2. Group-1 had shorter ST segment duration (median 81.5 (IQR 64–103.5) vs 110 (IQR 90–132), p = 0.002) and shorter ST: QT ratio (median 0.28 (IQR 0.22–0.35) vs 0.23 (0.18–0.27), p = 0.007). QRS notch/depressed J point (87.5%), QRS slur (100%), and lack of isoelectric ST segment (92.31%) had high sensitivity for predicting an inducible Type 1 Brugada pattern. Combining two parameters- ST: QT ratio<0.24 and lack of isoelectric ST segment-considerably improved the specificity (73.3%), and the positive predictive value of the test to 76%. The results remained accurate when validated in a small prospective cohort. ConclusionShortened ST segment in Lead II, lack of isoelectric ST segment, slurred QRS and ST/QT ratio <0.24 are predictive of underlying Brugada pattern in baseline ECG.

Electrocardiographic parameters of red-eared slider (Trachemys scripta elegans) in two temperatures

The objective of this research is to evaluate the electrocardiographic parameters of red-eared slider (Trachemys scripta elegans) in order to promote reference values for the species, and to compare the results of the examinations in two different temperatures (24º C in stage 1 and 16º C in stage 2). Thirty healthy adults animals were used (17 males and 13 females) with average weight of 1.467 ± 0.312 kg. The measurements obtained in Stage 1 were: heart rate of 37 ± 8 beats/min, variation of mean cardiac axis between 60° and 90° in most animals; P wave amplitude of 0.041 ± 0.022 mV and duration 70 ± 26 ms, duration of the PR interval of 356 ± 167 ms, QRS complex du ration of 124 ± 21 ms and amplitude of 0.357 ± 0.167 mV, QT interval of 1002 ± 170 ms; isoelectric ST segment, with a mean TP duration of 348 ± 205 ms, positive T waves deflection in 20 animals and negative in 10 animals, with an amplitude of 0.118 ± 0.085 mV. However, the results observed In Stage 2 were a reduction in the heart rate (19 ± 6 beats/min). It was not possible to observe P waves in most of the animals, however, in the subjects in which it was possible to observe such waves, the amplitude was similar to the one of Stage 1, but with longer duration (120 ± 32 ms). There was an increase in the (duration of) PR interval duration (524 ± 162 ms), in QRS complex (175 ± 30 ms) and QRS complex amplitude (0.332 ± 0.138 mV); there was also an increase in the QT (1832 ± 410 ms) and TP intervals (1385 ± 861 ms), in the ST segment remained isoelectric and in T wave amplitude as well (0.218 ± 0.173 mV). Positive polarity was observed in most animals (20 animals) but the T wave was not observed in 10 animals. There was no statistical difference between males and females in two stages.

An incidental case of Wellens' syndrome in a community emergency department.

Wellens’ syndrome, also called left anterior descending (LAD) coronary T-wave syndrome, is a characteristic electrocardiographic (ECG) pattern suggestive of coronary artery disease in the preinfarction stage.[1–3] ECG changes in Wellens’ syndrome may signify critical stenosis in the proximal LAD coronary artery.[1–5] Furthermore, ECG changes may occur during a pain-free period with no other evidence of ischemia or unstable angina and none to minimal elevation of cardiac enzyme levels.[3,5] Hence, recognition of the aforementioned pattern is important in preventing the development of a devastating anterior wall myocardial infarction.[2–5] There are two patterns of ECG changes related to Wellens’ syndrome. The first involves a minimally elevated or isoelectric ST segment with inverted T waves in leads V2 and V3, often in leads V1 and V4, and occasionally in leads V5 and V6.[1–3,5] This pattern accounts for approximately 75% of Wellens’ syndrome cases.[3,5] The second pattern involves biphasic T waves in leads V2 and V3[1–3,5] and accounts for roughly 25% of Wellens’ syndrome cases.[3,5]

Significance of ST-segment deviation in lead aVR for prediction of culprit artery and infarct size in acute inferior wall ST-elevation myocardial infarction

Abstract Background In patients with acute ST-segment elevation myocardial infarction identification of the culprit artery either due to right coronary artery or left circumflex artery was studied. The electrocardiogram can help in earlier risk stratification and better guidance of therapy for reperfusion. Patients and methods 50 patients with acute inferior myocardial infarction were divided into two groups. Group A: patients with ST segment depression in lead aVR ⩾ 1 mv. Group B: patients with isoelectric ST segment or with ST segment depression in lead aVR Results Fifty patients with acute inferior myocardial infarction were included in the present study. There were 35 males (70%) and 15 females (30%), with a mean age 55.6 ± 8.8. In Group A, left circumflex artery was the culprit artery in 8 (47%) and right coronary artery was the culprit artery in 9 (53%). Group B, left circumflex artery was the culprit artery in 4 (12%) and right coronary artery was the culprit artery in 29 (88%) patients with aVR depression had significantly larger infarctions (estimated by peak creatine phosphokinase (CPK-MB) levels and transthoracic echocardiography) than patients without aVR depression. Conclusion In patients with inferior wall STEMI, ST-segment depression in aVR was more common in LCX infarcts than RCA infarcts. Patients with aVR depression had significantly larger infarctions, (estimated by peak creatine phosphokinase (CPK-MB) levels and transthoracic echocardiography) than patients without aVR depression.

New Electrocardiographic Criteria to Differentiate Acute Pericarditis and Myocardial Infarction

ObjectiveTransmural myocardial ischemia induces changes in QRS complex and QT interval duration but, theoretically, these changes might not occur in acute pericarditis provided that the injury is not transmural. This study aims to assess whether QRS and QT duration permit distinguishing acute pericarditis and acute transmural myocardial ischemia. MethodsClinical records and 12-lead electrocardiogram (ECG) at ×2 magnification were analyzed in 79 patients with acute pericarditis and in 71 with acute ST-segment elevation myocardial infarction (STEMI). ResultsECG leads with maximal ST-segment elevation showed longer QRS complex and shorter QT interval than leads with isoelectric ST segment in patients with STEMI (QRS: 85.9 ± 13.6 ms vs 81.3 ± 10.4 ms, P = .01; QT: 364.4 ± 38.6 vs 370.9 ± 37.0 ms, P = .04), but not in patients with pericarditis (QRS: 81.5 ± 12.5 ms vs 81.0 ± 7.9 ms, P = .69; QT: 347.9 ± 32.4 vs 347.3 ± 35.1 ms, P = .83). QT interval dispersion among the 12-ECG leads was greater in STEMI than in patients with pericarditis (69.8 ± 20.8 ms vs 50.6 ± 20.2 ms, P <.001). The diagnostic yield of classical ECG criteria (PR deviation and J point level in lead aVR and the number of leads with ST-segment elevation, ST-segment depression, and PR-segment depression) increased significantly (P = .012) when the QRS and QT changes were added to the diagnostic algorithm. ConclusionsPatients with acute STEMI, but not those with acute pericarditis, show prolongation of QRS complex and shortening of QT interval in ECG leads with ST-segment elevation. These new findings may improve the differential diagnostic yield of the classical ECG criteria.

Electrocardiographic ST-segment deviations and risk of death: significant age and gender differences in a large primary care population

Purpose: ST-segment abnormalities are known to be common, but little more is known about their prevalence and possible prognostic implications. Therefore, we aimed to perform a reference study quantitatively assessing the age- and gender specific consequences of having ST-segment deviations. Methods: We evaluated precordial ST-segment deviations using computerized analysis of ECGs from 301,852 subjects (44.2% men) recorded in a primary care core laboratory. ST-segment deviations were divided into three categories of depression and three of elevation. Separate analyses were performed for men and women above and under the age of 65. Baseline data regarding medication and comorbidity as well as follow-up data were gathered with the use of Danish registries. Our end point was death from cardiovascular disease. Multivariable-adjusted hazard ratios for the different voltage-categories, in each of the precordial leads, were calculated using Cox P.H. model. All hazard ratios (HR) reported are with reference to an isoelectric ST-segment. Results: After a median follow-up period of 5.8 years, there were 8,282 cardiovascular deaths (CVD) and 25,574 deaths from non-cardiovascular causes. In general, increasing ST-depression was associated with an increased mortality in a dose-response manner in all precordial leads. This was most pronounced for women <65 years of age in lead V3, where an ST-depression from 100μV to 150μV was associated with a HR of 12.4 (4.6-33.8). ST-elevations in young women were generally associated with increased mortality such as in lead V4, where ST-elevation >150μV was associated with a HR of 10.48 (3.28-33.53). The same elevation in young men was associated with a HR of 0.76 (0.42-1.38). This gender difference was present in all leads except lead V1, where ST-elevation was associated with increased mortality for both men and women. ST-elevation >150μV in V1 was associated with a HR of 2.18 (1.15-4.14) for men >65 years of age and a HR of 2.34 (1.75-3.12) for women >65 years of age. Additionally, ST-elevations in lead V2 and V3 had a certain protective effect in men <65 years. Elevations from 100μV to 150μV in lead V2 was associated with a HR of 0.65 (0.52-0.80) and a HR of 0.76 (0.62-0.92) in lead V3. Conclusion: ST-depression is generally associated with increased mortality in a dose-response manner in all precordial leads and for both genders, with the strongest effect for the young subjects. ST-elevations were associated with increased mortality in women but not in men, except in lead V1. We saw a certain protective effect of ST-elevation in lead V2 and V3 for young male subjects.

A special case of Wellens' syndrome

Wellens' syndrome is a pattern of electrocardiographic T-wave changes associated with critical stenosis of proximal left anterior descending artery (LAD). T-waves abnormalities were found in precordial leads, especially in V2–V3 during pain-free periods, and ECG obtained during episodes of pain demonstrates upright T-waves with possible elevated or isoelectric ST segments. Early recognition and appropriate intervention carries significant diagnostic and prognostic value. We reported a case of Wellens' syndrome with different etiology and prognosis. Although the ECG showed typical T-wave changes in V2–V5 leads, patient's coronary angiography revealed moderate stenosis in proximal LAD, and coronary artery spasm was suggested. Unlike the classic Wellens' syndrome, which needs aggressive coronary intervention, our patient fared well with conservative medical therapy (diltiazem and nitrates) and showed favorable prognosis.

Presence of a critical stenosis in left anterior descending coronary artery alongside a short “P-R” and “Q-T” pattern, in the same electrocardiographic record

The knowledge of the heart and its functions is increasing every day. However, many cardiac dysfunctions remain undocumented. One of them might be the presence of the Wellens' sign, minimally elevated or isoelectric ST segments, and inverted T waves in the precordial leads, without changes in the QRS complex, together with a shortened of “P-R and Q-T intervals” in the same electrocardiographic record. Both patterns are greatly underdiagnosed. The key to an accurate diagnosis of both dysfunctions must begin with a detailed analysis of all the symptoms reported by the patient. The ECG recording provides an almost definitive confirmation: The T-wave characteristics in precordial derivations. The duration of P-R and Q-T intervals.

Rechtsseitige Kunstklappenthrombose

A 33-year-old woman (Pt. A) with a prosthetic cardiac valve in the pulmonary position [CarboMedics bileaflet valve, diameter 23 mm] as part of the repair of a tetralogy of Fallot 4 years previously, and a 51-year-old woman (Pt. B) with a prosthetic cardiac valve [St. Jude Medical bileaflet valve, diameter 31 mm] inserted in tricuspid position as replacement of a degenerated Hancock bioprosthetic valve inserted 15 years previously, 10 years after an episode of endocarditis, were admitted to hospital with dyspnea and chest pain and dyspnea and tachycardia, respectively. Pt. A had a 3 - 4/6 crescendo-decrescendo systolic murmur and a 2/6 early diastolic decrescendo murmur over the 2nd to 4th right intercostal space (ICS), while Pt. B had a 3/6 holosystolic murmur and a 2 - 3/6 diastolic murmur over the 4th right ICS. Closing click was missing in both patients. Blood tests demonstrated an elevated LDH (404 U/l) in Pt. A and an elevated GGT (108 U/l) and fibrinogen (449 mg/dl) in Pt. B. Anticoagulation was below the therapeutic level, with an INR value of 1,65 and 1,93, respectively. The electrocardiogram showed sinus rhythm, right bundle branch block and an isoelectric ST-segment (Pt. A) and a typical high-frequency atrial flutter with a 2:1 block, right bundle branch block and terminal T-wave inversions in leads V1 to V5 (Pt. B). Cinefluoroscopy showed rigid and hypomobile leaflets as a result of prosthetic cardiac valve thrombosis. Doppler echocardiography confirmed the stenosis of the prosthetic valve in the pulmonary position (peak gradient 73 mm Hg, mean gradient 34 mm Hg) and the tricuspid position (mean gradient 8.48 mm Hg, peak gradient 16.73 mm Hg). Both patients were treated with unfractionated heparin and urokinase single-bolus injection of 4400 U/kg over 10 min followed by an infusion of 4400 U/kg/h over 12 h. Both patients had an abnormal opening angle, which improved to a normal opening and closing angle. Doppler echocardiography demonstrated decreased peak (18.0 and 6.6 mm Hg, respectively) and median gradients (9.0 and 2.6 mm Hg, respectively). No further complications (such as bleeding, embolism, delayed surgical treatment, rethrombosis) had occurred, and both patients became asymptomatic. After oral anticoagulation in a therapeutic INR range for 12 and 4 months, respectively, prosthetic heart valve function continued to be normal in both patients. Thrombolysis appears to be an efficacious and safe treatment in patients with thrombosis of a prosthetic cardiac valve in the pulmonary or tricuspid position, and it may be used as first-line therapy. Cinefluoroscopy is a simple and accurate method both in the diagnosis of prosthetic cardiac valve thrombosis and in following the response to thrombolytic treatment.

The efficacy and safety of external biphasic defibrillation in toy breed dogs

AbstractObjective: To evaluate the efficacy and safety of biphasic (BP) defibrillation in toy breed dogs (&lt;5 kg of body weight).Design: Prospective, clinical experimental study.Setting: Veterinary teaching hospital.Animals: Five dogs (pilot study) and 10 dogs (comparison study of biphasic versus monophasic defibrillation).Measurements and main results: The efficacy of defibrillation was compared by estimating E80 (80% probability of successful defibrillation) after biphasic (BP) and monophasic (MP) defibrillations. The E80 for BP defibrillation was 7.24±1.33 J (2.24±0.41 J/kg) and 10.24±1.34 J (3.18±0.12 J/kg) for MP defibrillation. BP waveform required 30% less shock energy for a successful defibrillation. In order to compare the safety of defibrillation, we evaluated changes in cardiac biomarkers, electrocardiogram, echocardiographical left ventricular index, and aortic pressure during and after BP and MP defibrillation. All dogs treated by either BP or MP defibrillation survived. Pulseless electrical activity occurred in 2 of 5 dogs during MP defibrillation. The levels of cardiac biomarkers were elevated and sustained for longer periods in the MP defibrillation group. Electrocardiographic changes (e.g., QT prolongation, the time to return to an isoelectric ST segment after shocks) were more severe and longer in the MP defibrillation group. In addition, overall left ventricular cardiac performance was severely depressed in the MP group compared with the BP group.Conclusion: Our findings suggest that BP defibrillation is more effective and safer than MP defibrillation. We determined the acceptable shock energy to be 2–4 J/kg for toy breed dogs.

Initial Presenting Electrocardiogram as Determinant for Hospital Admission in Patients Presenting to the Emergency Department with Chest Pain: A Pilot Investigation

Evaluation of chest pain accounts for millions of costly Emergency Department (ED) visits and hospital admissions annually. Of these, approximately 10-20% are myocardial infarctions (MI). Patients with chest pain whose initial electrocardiogram (ECG) is normal do not require hospital admission for evaluation and management of a possible myocardial infarction. The medical records of a consecutive cohort of 250 patients who presented to the ED with chest pain and were admitted by the ED physician to a cardiology inpatient service of an academic tertiary care medical center were reviewed. Reasons for admission to hospital was to rule out an acute coronary syndrome, specifically, myocardial infarction. The initial ECG of each patient was evaluated for abnormalities and compared with the final diagnosis. Of the 75 patients presenting with normal ECGs (normal, upright T waves and isoelectric ST segments), 1 (1.3%) was subsequently diagnosed with a myocardial infarction by Troponin I elevation alone. Of the 55 patients presenting with abnormal ECGs but no clear evidence of ischemia [i.e., left bundle branch block (LBBB), right bundle branch block (RBBB), left anterior hemiblock (LAH)], 2 (3.6%) were diagnosed with MI. Of the 48 patients presenting with abnormal ECGs questionable for ischemia (nonspecific ST and T wave changes that were not clearly ST segment elevation or depression), 7 (14.6%) were diagnosed with an MI. Of the 72 patients who presented with abnormal ECGs showing ischemia (acute ST segment elevation and/or depression), 39 (54.2%) were shown to have evidence for MI. Patients who presented with normal ECGs (category 1) were extremely low risk for acute myocardial infarction. Patients with abnormal ECGs but no evidence of definite ischemia (category 2) had a relatively low incidence of MI. Patients with abnormal ECGs questionable for ischemia (category 3) had an intermediate risk of acute myocardial infarction. The majority of patients with abnormal ECGs demonstrating ischemia (category 4) were subsequently shown to evolve an acute myocardial infarction. Patients with chest pain and initial ECGs with ST segment abnormalities suggestive or diagnostic for ischemia, should be admitted to the hospital for further evaluation and management. Patients with ECGs that do not display acute ST segment changes are at a lower risk for acute myocardial infarction than those with acute ST segment changes and should be admitted on the basis of cardiac risk profile. (i.e., age, gender, hypertension, diabetes, smoking, known coronary artery disease, etc.) Patients with normal ECGs (category 1) are at extremely low risk, and it may be acceptable to consider further evaluation on an outpatient basis.

Electrocardiographic characteristics of patients with inferior myocardial infarction but angiographically normal coronary arteries

Normal coronary arteries were found in 22 (5.8%) of 379 patients presented with acute inferior myocardial infarction. These patients were significantly younger, had less cardiovascular risk factors, better systolic heart function, and lower cardiac enzymes level. Electrocardiography significantly showed more (1) ratio of ST-segment elevation in II/ III ≥ 1; (2) isoelectric ST-segment in I; (3) ST-segment elevation in I; and less (4) paroxysmal atrial fibrillation; (5) ST-segment depression in I; and (6) ST-segment elevation in V4R. In conclusion, this subset of patients had clinical features suggestive of smaller infarct size compared with those suffering from atherosclerotic disease. They may have more left circumflex artery involvement and distal right coronary artery occlusion, as deduced from electrocardiography.