Impact of quantitative ST-T analysis in patients with suspected myocardial infarction presenting with right bundle branch block

BACKGROUND

While left bundle branch block (LBBB) is a well-known risk feature in patients with acute myocardial infarction and a rapid invasive management is recommended, data supporting this strategy for patients with right bundle branch block (RBBB) is less robust.

METHODS

In total, 2,139 patients with suspected ST-elevation myocardial infarction (STEMI) were triaged to acute coronary angiography based on a prehospital 12-lead ECG. Sensitivity and specificity for STEMI-ECG-criteria were compared in RBBB and non-BBB patients. Adjusted hazard ratios for 1-year overall mortality were computed.

RESULTS

STEMI was adjudicated in 1,832/2,139 (85.6%) of all patients and in 102/117 (87.2%) of RBBB patients. ST-segment deviation followed typical ST-T patterns in most RBBB patients. Out of 17 RBBB patients without significant ST-changes STEMI was adjudicated in 14 (82%). Diagnostic accuracy of STEMI-criteria was comparable in RBBB and non-RBBB patients for inferior (sensitivity: 51.1% vs 59.1%, p=0.14; specificity: 66.7% vs 52.1%, p=0.33) and anterior STEMI (sensitivity: 35.2% vs 36.6%, p=0.80; specificity: 58.3% vs 49.5%, p=0.55). Diagnostic performance was lower for lateral STEMI in RBBB patients (sensitivity: 14.8% vs 4.4%, p=0.001; specificity: 75.0% vs 98.4%, p<0.001). Patients with RBBB had higher 1-year mortality compared to non-BBB patients (hazard ratio 2.3% (95% CI 1.25-4.21).

CONCLUSION

ECG-criteria used for detection of STEMI showed comparable diagnostic accuracy in RBBB and non-BBB patients. However, STEMI was frequently present in RBBB patients not fulfilling diagnostic ECG-criteria. RBBB-patients showed poorer outcome after 1 year. Consequently, the presence of RBBB in suspected STEMI cases signifies a high-risk feature, aligning with established guidelines.

Sustained mitigation of ST-segment elevation in a patient with Brugada syndrome type 1 during sevoflurane and remifentanil anesthesia: a case report

BACKGROUND

During general anesthesia, patients with Brugada syndrome are at risk of malignant arrhythmias following worsened ST-segment elevation, potentially leading to sudden cardiac death. The protocol for safe anesthetic management of patients with Brugada syndrome has not yet been established.

CASE PRESENTATION

A 63-year-old man, diagnosed with a spontaneous Brugada type 1 pattern, was scheduled for a pleural biopsy using video-assisted thoracoscopic surgery under general anesthesia. We planned general anesthesia using volatile induction and maintenance anesthesia with sevoflurane and remifentanil. We monitored ST-segment morphology and observed sustained mitigation of ST-segment elevation throughout general anesthesia.

CONCLUSION

The present case may indicate that safe anesthetic management of patients with Brugada syndrome depends on whether the anesthetics used can reduce ST-segment elevation.

A cross-sectional study determining prevalence and factors associated with ST-segment elevation myocardial infarction and non-ST segment elevation myocardial infarction in Iran: results from fasa registry on acute myocardial infarction (FaRMI)

BACKGROUND

Acute myocardial infarction is still a leading cause of death worldwide, accounting for roughly three million deaths yearly. This study aimed to investigate the prevalence and factors associated with ST-Segment Elevation Myocardial Infarction and Non-ST Segment Elevation Myocardial Infarction in Iran.

METHODS

This cross-sectional study was conducted using the databases of the Fasa Registry on Acute Myocardial Infarction (FaRMI) and the Fasa Adult Cohort Study (FACS). chi-squared and one-way ANOVA tests were utilized to calculate the unadjusted associations between the study variables. A multivariate multinomial logistic regression model was also employed to determine the adjusted association of each independent variable with the risk of ST-elevation myocardial infarction (STEMI).

RESULTS

The prevalence of STEMI and non-STEMI was 31.60% and 11.80%, respectively. Multinomial logistic regression showed that older age, anemia, high WBC, and high creatinine levels were associated with higher odds of STEMI and non-STEMI compared to healthy individuals. In addition, based on the analysis being a woman(OR = 0.63,95%CI:0.51-0.78), anemia(OR = 0.67,95%CI:0.54-0.63)and hypertension (OR = 0.80,95%CI:0.65-0.97)decreased the likelihood of STEMI occurrence compared to non-STEMI, while high WBC(OR = 1.19,95%CI:1.15-1.23)increased the odds.

CONCLUSION

In this study, significant predictors of MI risk included age, gender, anemia, lipid profile, inflammation, and renal function. Subsequent investigations ought to prioritize the comprehensive understanding of the underlying mechanisms that drive these connections and assess the effectiveness of specific interventions aimed at diminishing the occurrence of MI and improving patient outcomes.

Dynamic changes in T-wave and QTc interval during tilt table testing: Innocent until proven otherwise

A16-year-old female underwent tilt table testing, which resulted positive for reflex vasodepressive syncope. 12‑lead ECG during syncope showed T-wave inversion in infero-lateral leads, along with QTc interval increase >100 msec compared to baseline. These abnormalities rapidly disappeared in supine position with resumption of consciousness. Complete cardiac evaluation excluded heart disease. T-wave changes and moderate QTc prolongation are relatively common in young (mainly female) patients undergoing tilt table testing and they appear benign in nature. However, in a minority of cases, on the basis of the clinical context and after an accurate ECG analysis, further examinations may be warranted.

ST-Segment Elevation: An Unexpected Culprit

The clinical presentation of pulmonary embolism (PE) and acute coronary syndrome can be similar. We report a case of a patient presenting with antero-septal ST-segment elevation after cardiac arrest, found to have acute-PE-mimicking ST-segment elevation myocardial infarction (STEMI), treated with aspiration thrombectomy and catheter-directed thrombolysis (CDT). A 78-year-old man was admitted with dyspnea, chest pain and tachycardia. During evaluation, cardiac arrest in pulseless electrical activity was documented. Advanced life support was started immediately. ECG post-ROSC revealed ST-segment elevation in V1-V4 and aVR. Echocardiography showed normal left ventricular function but right ventricular (RV) dilation and severe dysfunction. The patient was in shock and was promptly referred to cardiac catheterization that excluded significant CAD. Due to the discordant ECG and echocardiogram findings, acute PE was suspected, and immediate invasive pulmonary angiography revealed bilateral massive pulmonary embolism. Successful aspiration thrombectomy was performed followed by local alteplase infusion. At the end of the procedure, mPAP was reduced and blood pressure normalized allowing withdrawal of vasopressor support. Twenty-four-hour echocardiographic reassessment showed normal-sized cardiac chambers with preserved biventricular systolic function. Bedside echocardiography in patients with ST-segment elevation post-ROSC is instrumental in raising the suspicion of acute PE. In the absence of a culprit coronary lesion, prompt pulmonary angiography should be considered if immediately feasible. In these cases, CDT and aspiration in high-risk acute PE seem safe and effective in relieving obstructive shock and restoring hemodynamics.

Understanding the EKG changes in methemoglobinemia

Methemoglobin is a form of hemoglobin that has been oxidized, changing its heme iron configuration from the ferrous to the ferric state. Unlike normal hemoglobin, methemoglobin does not bind oxygen and as a result, cannot deliver oxygen to the tissues. At the presentation in the emergency department, an electrocardiogram (EKG) is usually performed as a reflex for patients admitted for shortness of breath to rule out acute coronary syndrome. Very limited data is available on EKG abnormalities in patients with methemoglobinemia. In this study, we retrospectively analyzed the pattern of EKG changes in patients with methemoglobinemia.

Evolution of Myocardial Tissue Injury: A CMR Study Over a Decade After STEMI

BACKGROUND

In patients with a first ST-segment elevation myocardial infarction (STEMI), the multi-annual evolution of myocardial tissue injury parameters, as assessed by cardiac magnetic resonance (CMR), has not yet been described.

OBJECTIVES

This study examined myocardial tissue injury dynamics over a decade after STEMI.

METHODS

Sequential CMR examinations (within the first week after STEMI, and at 4, 12, months, and 9 years thereafter) were conducted in 74 patients with STEMI treated with primary percutaneous coronary intervention. Left ventricular function, infarct size (IS), and microvascular obstruction (MVO) were assessed at all time points. T2∗, T2, and T1 mapping (n = 59) were added at 9-year scan to evaluate the presence of iron and edema within the infarct core, respectively.

RESULTS

IS decreased progressively and significantly between all CMR time points (all P < 0.001), with an average reduction rate of 5.8% per year (IQR: 3.5%-8.8%) and a relative reduction of 49% (IQR: 39%-76%) over a decade. MVO was present in 61% of patients at baseline, but was not present at the follow-up examinations. At 9-year CMR, 17 of 59 (29%) patients showed iron deposition within the infarct core, whereas 82% had persistent edema. Persistent iron and edema were associated with greater IS on any occasion (all P < 0.001), as well as the presence of MVO (P < 0.001). Patients with persistent iron and edema showed a lower relative regression of IS (P = 0.005 and P = 0.032, respectively) and greater end-systolic volumes over a decade (all P < 0.012 and P > 0.023, respectively). A T1 hypointense infarct core without evidence of T2∗ iron deposition (14 of 59 [24%] patients) was attributed to lipomatous metaplasia of the infarct.

CONCLUSIONS

The evolution of IS is a dynamic process that extends well beyond the first few months after STEMI. Persistence of iron and edema within the infarct core occurs up to a decade after STEMI and is associated with initial infarct severity and poor infarct healing.

Prognostic value of infarct-related-lead Tpeak-Tend/QT ratio in patients with ST-segment elevation myocardial infarction

Tpeak-Tend/QT ratio (Tp-e/QT) in patients with ST-segment elevation myocardial infarction (STEMI) is reportedly associated with major adverse cardiac events (MACEs). However, Tp-e/QT measurement methods are controversial, and few studies have clarified the effect of different Tp-e/QT measures on prognosis. Our study is the first to investigate the advantages of the Tp-e/QT measured by infarct-related-lead method in predicting MACEs during hospitalization and long-term mortality in patients with STEMI. A total of 427 STEMI patients undergoing primary percutaneous coronary intervention (PCI) were included in this study. The Tp-e/QT before PCI was measured by traditional 12-lead method and infarct-related-lead method. Outcomes were tested using comparative statistics, logistic regression, receiver operating characteristic (ROC) curve and Kaplan-Meier survival analysis. There were 62 (14.5%) patients who had MACEs in-hospital. Logistic regression showed that the Tp-e/QT in infarct-related-lead was an independent predictor (p < 0.001). The area under the ROC curve (AUC) of the Tp-e/QT in infarct-related-lead was larger than that in the Tp-e/QT in traditional 12-lead (0.889 vs 0.741), and the optimal cutoff value was 0.32. The three-year survival rate of patients in the infarct-related-lead Tp-e/QT < 0.32 group was better than Tp-e/QT ≥ 0.32 group in Kaplan-Meier survival analysis (93.9 vs 87.0%). When stratified according to infarct-related arteries, the results showed that the common odds ratio of patients in Tp-e/QT ≥ 0.32 group occurred MACEs was 1.562, P = 0.038. The infarct-related-lead Tp-e/QT performed better than the traditional 12-lead Tp-e/QT in predicting poor prognosis.

Electrocardiographic left ventricular strain pattern, ST-segment depression and atrial fibrillation at the time of diagnosis of systemic light chain amyloidosis: Incidence and clinical significance

BACKGROUND

ST/T abnormalities recognized as electrocardiographic (ECG) left ventricular (LV) strain pattern are known as a marker of myocyte death and reduced survival. The purpose of this study was to determine whether ECG LV strain pattern, its components and atrial fibrillation (AF) predict lower survival at the time of diagnosis of systemic light chain (AL) amyloidosis.

METHODS

12‑lead surface electrocardiogram (ECG), standard two-dimensional echocardiography, laboratory analyses were retrospectively evaluated within 2 months of diagnosis in 87 patients with biopsy-proven systemic AL amyloidosis from 2009 to 2017 in a single center. ECG strain pattern was defined as coexistence of ST-segment horizontal or downward sloping depression ≥0.05 mV at its most horizontal section and negative asymmetrical T-wave deeper than 0.1 mV in at least 1 of leads I,aVL,V1-V6. Patients with QRS >120 ms (BBB or major IVCD) were excluded from the analysis.

RESULTS

Kaplan-Meier survival analysis revealed a 1.8-fold shorter overall survival (OS) at 2 years in the ECG strain (21% of participants) group (p = 0.0078), 2.0-fold shorter OS in the ST-segment depression (STd) (isolated and strain related as one group) (34% of participants) group (p < 0.0001), and 3.9-fold shorter OS in AF (23% of participants) group (p < 0.0001) compared with those without. Median survival of patients with STd and AF were and 13.0 (range 1-74) and 9.5 (range 1-74) months respectively. In univariate analysis STd and AF were stronger predictors of inferior OS than relative wall thickness, average E/e' ratio, and LV ejection fraction, but weaker predictors of OS than B-type natriuretic peptide. In multivariate analysis STd and AF lost significance after adjustment for age, gender, number of organs involved and BNP.

CONCLUSIONS

ST-segment depression and AF were not significantly associated with reduced survival in AL amyloidosis at diagnosis.

Acute chest pain with ST-segment elevation in lead V1-V3: when you hear hoofbeats, also look for zebras

ST-segment elevation (STE) in the anterior precordial leads is the hallmark of anterior myocardial infarction. In rare cases, this ECG pattern may be due to isolated infarction of the right ventricle since leads V1-V3 directly overlie the right ventricular free wall. Herein, we aimed to provide clues to recognize and understand this diagnostic pitfall through a series of 4 patients presenting with STE in the anterior leads.

The effects of amiodarone prophylaxis on cardiac dysrhythmia in acute aluminium phosphide poisoning

Cardiovascular toxicity is the most common cause of fatality in the first 24 hours of poisoning with aluminium phosphide (AlP). Most often manifesting itself in cardiac dysrhythmias. The aim of this study was to evaluate the benefits of amiodarone prophylaxis against cardiac dysrhythmia in 46 patients with acute AlP poisoning. They were divided in two groups of 23: one receiving amiodarone and the other not (control). The treatment group received amiodarone prophylaxis in the initial intravenous bolus dose of 150 mg, followed by a drip of 1 mg/min for six hours and then of 0.5 mg/min for eighteen hours. Both groups were Holter-monitored for 24 hours since admission. Save for amiodarone, both groups received the same standard treatment. Amiodarone had a significant beneficial effect in reducing the frequency of ST-segment elevation and ventricular fibrillation plus atrial fibrillation (P=0.02 and P=0.01, respectively), but the groups did not differ significantly in mortality (9 vs 11 patients, respectively). The mean time between ICU admission and death (survival time) was significantly longer in the treatment group (22 vs 10 h, respectively; P=0.03). Regardless its obvious limitations, our study suggests that even though amiodarone alone did not reduce mortality, it may provide enough time for antioxidant therapy to tip the balance in favour of survival and we therefore advocate its prophylactic use within the first 24 h of AlP poisoning.

Summation and Cancellation Effects on QRS and ST-Segment Changes Induced by Simultaneous Regional Myocardial Ischemia

Simultaneous ischemia in two myocardial regions is a potentially lethal clinical condition often unrecognized whose corresponding electrocardiographic (ECG) patterns have not yet been characterized. Thus, this study aimed to determine the QRS complex and ST-segment changes induced by concurrent ischemia in different myocardial regions elicited by combined double occlusion of the three main coronary arteries. For this purpose, 12 swine were randomized to combination of 5-min single and double coronary artery occlusion: Group 1: left Circumflex (LCX) and right (RCA) coronary arteries (n = 4); Group 2: left anterior descending artery (LAD) and LCX (n = 4) and; Group 3: LAD and RCA (n = 4). QRS duration and ST-segment displacement were measured in 15-lead ECG. As compared with single occlusion, double LCX+RCA blockade induced significant QRS widening of about 40 ms in nearly all ECG leads and magnification of the ST-segment depression in leads V1-V3 (maximal 228% in lead V3, p < 0.05). In contrast, LAD+LCX or LAD+RCA did not induce significant QRS widening and markedly attenuated the ST-segment elevation in precordial leads (maximal attenuation of 60% in lead V3 in LAD+LCX and 86% in lead V5 in LAD+RCA, p < 0.05). ST-segment elevation in leads V7-V9 was a specific sign of single LCX occlusion. In conclusion, concurrent infero-lateral ischemia was associated with a marked summation effect of the ECG changes previously elicited by each single ischemic region. By contrast, a cancellation effect on ST-segment changes with no QRS widening was observed when the left anterior descending artery was involved.

Clinical Implications of Electrocardiograms for Patients With Type A Acute Aortic Dissection

Type A acute aortic dissection (AAD) is a serious cardiovascular emergency requiring urgent surgery. Timely accurate diagnosis is essential, but often challenging, because of the wide spectrum of clinical presentations. In patients with type A AAD, chest pain is the most common symptom; furthermore, ischemic ST-T changes such as ST-segment elevation or depression or negative T waves are frequently observed on presentation ECG. These clinical presentations of type A AAD are difficult to differentiate from those of acute coronary syndrome (ACS), which could lead to delayed diagnosis and treatment of type A AAD or misdiagnosis of ACS followed by inappropriate treatment. Of note, ischemic ST-T changes have been shown to be associated with poor outcomes in patients with type A AAD. Because ECG is simple, inexpensive, noninvasive, readily available, and rapidly interpretable at the time of presentation, risk stratification based on ECG findings is considered very useful clinically. ECG findings of type A AAD thus have clinically important diagnostic, therapeutic, and prognostic implications; however, the relationships among these factors remain poorly understood. We review the prevalence of ECG abnormalities, clinical features associated with such changes, and the prognostic importance in patients with type A AAD.

Diagnostic value of ST-segment deviations during cardiac exercise stress testing: Systematic comparison of different ECG leads and time-points

BACKGROUND

Exercise ECG stress testing is the most widely available method for evaluation of patients with suspected myocardial ischemia. Its major limitation is the relatively poor accuracy of ST-segment changes regarding ischemia detection. Little is known about the optimal method to assess ST-deviations.

METHODS

A total of 1558 consecutive patients undergoing bicycle exercise stress myocardial perfusion imaging (MPI) were enrolled. Presence of inducible myocardial ischemia was adjudicated using MPI results. The diagnostic value of ST-deviations for detection of exercise-induced myocardial ischemia was systematically analyzed 1) for each individual lead, 2) at three different intervals after the J-point (J+40ms, J+60ms, J+80ms), and 3) at different time points during the test (baseline, maximal workload, 2min into recovery).

RESULTS

Exercise-induced ischemia was detected in 481 (31%) patients. The diagnostic accuracy of ST-deviations was highest at +80ms after the J-point, and at 2min into recovery. At this point, ST-amplitude showed an AUC of 0.63 (95% CI 0.59-0.66) for the best-performing lead I. The combination of ST-amplitude and ST-slope in lead I did not increase the AUC. Lead I reached a sensitivity of 37% and a specificity of 83%, with similar sensitivity to manual ECG analysis (34%, p=0.31) but lower specificity (90%, p<0.001).

CONCLUSION

When using ECG stress testing for evaluation of patients with suspected myocardial ischemia, the diagnostic accuracy of ST-deviations is highest when evaluated at +80ms after the J-point, and at 2min into recovery.

Acute myocardial infarction due to left main coronary artery disease in men and women: does ST-segment elevation matter?

INTRODUCTION

Gender-specific issues regarding ST-segment elevation (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) due to unprotected left main coronary artery (ULMCA) disease were not sufficiently studied. We assessed the value of STEMI/NSTEMI initial classification on the management of men and women with acute MI due to critical stenosis or occlusion of the ULMCA.

MATERIAL AND METHODS

The study group consisted of 643 consecutive patients with acute MI with the ULMCA as the infarct-related artery. Data derive from an ongoing, nationwide, multicenter, prospective, observational registry.

RESULTS

Isolated ULMCA disease was more frequent in women and multivessel disease was more frequent in men in the NSTEMI group. The incidence of cardiogenic shock or pulmonary edema and cardiac arrest was higher in the STEMI group. Totally occluded ULMCA was more frequent in the STEMI group. Although the majority of patients underwent percutaneous coronary intervention (PCI), it was less frequently used in NSTEMI women and NSTEMI men. Although in-hospital and long-term mortality rates were higher in the STEMI group, there were no gender-related differences within groups. The initial ST-segment elevation was an independent predictor of in-hospital (OR = 2.37, 95% CI: 1.14-4.91, p = 0.02) and 12-month (OR = 1.52, 95% CI: 1.01-2.27, p = 0.045) mortality.

CONCLUSIONS

There were no gender-related differences in the management within the STEMI or NSTEMI group. Although acute myocardial infarction due to ULMCA disease is associated with high mortality in both genders, STEMI was a negative prognostic factor of in-hospital and 12-month mortality. Despite poor baseline characteristics and clinical presentation in women, female gender itself did not influence mortality.

Exploiting multi-lead electrocardiogram correlations using robust third-order tensor decomposition

In this Letter, a robust third-order tensor decomposition of multi-lead electrocardiogram (MECG) comprising of 12-leads is proposed to reduce the dimension of the storage data. An order-3 tensor structure is employed to represent the MECG data by rearranging the MECG information in three dimensions. The three-dimensions of the formed tensor represent the number of leads, beats and samples of some fixed ECG duration. Dimension reduction of such an arrangement exploits correlations present among the successive beats (intra-beat and inter-beat) and across the leads (inter-lead). The higher-order singular value decomposition is used to decompose the tensor data. In addition, multiscale analysis has been added for effective care of ECG information. It grossly segments the ECG characteristic waves (P-wave, QRS-complex, ST-segment and T-wave etc.) into different sub-bands. In the meantime, it separates high-frequency noise components into lower-order sub-bands which helps in removing noise from the original data. For evaluation purposes, we have used the publicly available PTB diagnostic database. The proposed method outperforms the existing algorithms where compression ratio is under 10 for MECG data. Results show that the original MECG data volume can be reduced by more than 45 times with acceptable diagnostic distortion level.

Precordial junctional ST-segment depression with tall symmetric T-waves signifying proximal LAD occlusion, case reports of STEMI equivalence. J Electrocardiol. 2016;49:76-80. [PMID: 26560436 DOI: 10.1016/j.jelectrocard.2015.10.005]

Timely reperfusion therapy by means of primary percutaneous coronary intervention (PCI) is the preferred treatment for patients with ST-segment elevation myocardial infarction. A significant number of patients with large acute myocardial infarction, caused by occlusion of an epicardial coronary artery, do not show ST-elevation on the electrocardiogram. Other ECG abnormalities may be present, the so called STEMI-equivalents. One such STEMI equivalent, junctional ST-segment depression followed by tall symmetrical T-waves in the precordial leads, often in combination with slight ST-elevation in lead AVR, has been associated with proximal occlusion of the left anterior descending coronary artery. Recognition of this ECG pattern by ambulance staff, emergency physicians and interventional cardiologists envolved in STEMI networks, is important to ensure timely reperfusion therapy in these patients. In this paper we present three patients with typical symptoms of acute myocardial infarction and the ECG pattern with slight J-point depression combined with tall, symmetrical T-waves.

Significance of lead aVR in acute coronary syndrome

The 12-lead electrocardiogram (ECG) is a crucial tool in the diagnosis and risk stratification of acute coronary syndrome (ACS). Unlike other 11 leads, lead aVR has been long neglected until recent years. However, recent investigations have shown that an analysis of ST-segment shift in lead aVR provides useful information on the coronary angiographic anatomy and risk stratification in ACS. ST-segment elevation in lead aVR can be caused by (1) transmural ischemia in the basal part of the interventricular septum caused by impaired coronary blood flow of the first major branch originating from the left anterior descending coronary artery; (2) transmural ischemia in the right ventricular outflow tract caused by impaired coronary blood flow of the large conal branch originating from the right coronary artery; and (3) reciprocal changes opposite to ischemic or non-ischemic ST-segment depression in the lateral limb and precordial leads. On the other hand, ST-segment depression in lead aVR can be caused by transmural ischemia in the inferolateral and apical regions. It has been recently shown that an analysis of T wave in lead aVR also provides useful prognostic information in the general population and patients with prior myocardial infarction. Cardiologists should pay more attention to the tracing of lead aVR when interpreting the 12-lead ECG in clinical practice.