Tall upright T waves in the precordial leads

Serial Electrocardiograms-An Unsung Hero

This case report describes a patient in their 60s with diabetes and hypertension who presented to the emergency department with retrosternal chest pain.

Evaluating value of positive T wave in lead V1 and TV1 > TV6 pattern in predicting significant coronary artery disease in patients undergoing coronary angiography

BACKGROUND

The aim of this study was to predict significant coronary artery disease (CAD) in patients undergoing coronary angiography.

METHODS

In this cross-sectional study, data of 384 patients who underwent angiography during 2015-2017 were reviewed. Electrocardiograms (ECGs) were evaluated in terms of having positive T wave in lead V1 (TV1) described as T wave with amplitude of more than 0.15 mV and angiography records were assessed for presence of significant CAD defined as presence of ≥ 70% internal diameter stenosis in at least one major epicardial coronary artery or more than 50% stenosis in left main artery (LMA).

RESULTS

Out of 384 patients who participated in this study with mean age of 63.6 ± 10.2 years (40-89 years), 71.6% showed positive TV1 and significant CAD simultaneously and left anterior descending artery (LAD) and left circumflex artery (LCX) lesions were more frequently reported in coronary angiography. Based on chi-square test, the prevalence of significant CAD was obviously more in those with positive TV1 as compared to those without this finding [odds ratio (OR) = 2.74, 95% confidence interval (CI): 1.80-4.19, P < 0.001]. Mann-Whitney test showed significant difference in number of coronary arteries involved in CAD between presence of positive and negative T wave in lead V1 (P < 0.001). Great number of patients with significant CAD had remarkably higher T wave amplitude in lead V1 in comparison to lead V6 (OR = 6.22, 95% CI: 3.14-12.30, P < 0.001).

CONCLUSION

Positive TV1 and TV1 > TV6 pattern can be considered as a predictor for significant CAD in patients with otherwise normal ECG.

Evaluation of Electrocardiographic Parameters Predicting Cardiovascular Events in Patients with End-Stage Renal Disease before and after Transplantation

BACKGROUND AND OBJECTIVES

Cardiovascular (CV) mortality represents the leading cause of death in patients with end-stage renal disease (ESRD). Efficient screening is required to detect CV disease at an early stage, but the best diagnostic work-up is uncertain. The aim of this study was to identify electrocardiographic parameters in dialysis patients associated with an increased frequency of CV events.

METHODS

A 12-lead electrocardiogram was performed in 139 patients who were on the renal transplant waiting list and who subsequently received a kidney transplant. CV events were analyzed from the day of listing for kidney transplantation until 1 year after renal transplantation.

RESULTS

Multivariate Cox regression analysis showed that an elevated T:R ratio in anterior and inferior leads was independently associated with CV events (T:R ratio of anterior leads hazard ratio [HR] 1.32 [95% CI 1.09-1.59; p = 0.004] and inferior leads HR 2.15 [95% CI 1.23-3.77; p = 0.008]). In particular, a T:R ratio in inferior leads exceeding 0.6 was associated with CV events in a Kaplan-Meier analysis.

CONCLUSIONS

Taken together, we found an increased T:R ratio in ESRD patients to be a predictive marker for CV events.

Pitfalls in Electrocardiographic Diagnosis of Acute Coronary Syndrome in Low-Risk Chest Pain

Less than half of patients with a chest pain history indicative of acute coronary syndrome have a diagnostic electrocardiogram (ECG) on initial presentation to the emergency department. The physician must dissect the ECG for elusive, but perilous, characteristics that are often missed by machine analysis. ST depression is interpreted and often suggestive of ischemia; however, when exclusive to leads V1–V3 with concomitant tall R waves and upright T waves, a posterior infarction should first and foremost be suspected. Likewise, diffuse ST depression with elevation in aVR should raise concern for left main- or triple-vessel disease and, as with the aforementioned, these ECG findings are grounds for acute reperfusion therapy. Even in isolation, certain electrocardiographic findings can suggest danger. Such is true of the lone T-wave inversion in aVL, known to precede an inferior myocardial infarction. Similarly, something as ordinary as an upright and tall T wave or a biphasic T wave can be the only marker of ischemia. ECG abnormalities, however subtle, should give pause and merit careful inspection since misinterpretation occurs in 20–40% of misdiagnosed myocardial infarctions.

Acute coronary syndromes

Despite technologic advances in many diagnostic fields, the 12-lead ECG remains the basis for early identification and management of an acute coronary syndrome. This article reviews the use of the ECG in acute coronary syndromes.

T/QRS ratio best distinguishes ventricular aneurysm from anterior myocardial infarction

OBJECTIVES

Reperfusion therapy for acute myocardial infarction (AMI) is indicated in the presence of ST elevation (STE) and ischemic symptoms. Previous MI may present with persistent STE or "left ventricular aneurysm" (LVA) morphology that mimics AMI. Hypothesis A high ratio of T amplitude to QRS amplitude best distinguishes AMI from LVA.

METHODS

This was a retrospective cohort analysis. Patients with anatomical LVA by echocardiography were identified and those who presented to the ED with ischemic symptoms and STE of at least 1 mm in 2 consecutive leads and ruled out for acute left anterior descending coronary artery (LAD) occlusion were selected. Electrocardiograms (ECGs) were compared with a control group of 37 consecutive anterior AMI (aAMI) with proven acute LAD occlusion. Bundle-branch block was excluded. Various ECG measurements and ratios were compared.

RESULTS

Twenty patients with LVA met the inclusion criteria. The best discriminator was T amplitude sum to QRS amplitude sum ratio V1-V4, misclassifying only 4 (6.8%) of 59 cases at a cutoff of >0.22 for AMI. For aAMI and LVA, respectively, mean (+/-95% CI) ratio of the sum of T amplitudes in V 1 to V 4 to the sum of QRS amplitude in V1-V4 was 0.54+/-0.085 and 0.16+/-0.021 (P<.00012). Thirty-five of 37 aAMI had a ratio>0.22; the false negatives (ratio<0.22) had 11.5 and 6 hours of symptoms before the ECG. Twenty of 22 LVA had a ratio<or=0.22. Mean highest T/QRS ratio in V1-V4 was 1.1+/-0.29 for an AMI and 0.26+/-0.056 for LVA (P<10(-7)).

CONCLUSION

T amplitude/QRS amplitude ratio best distinguishes aAMI from LVA in ECGs that meet STE criteria for reperfusion therapy. A high ratio is associated with an AMI.

Higher T-wave amplitude associated with better prognosis in patients receiving thrombolytic therapy for acute myocardial infarction (a GUSTO-I substudy). Global Utilization of Streptokinase and Tissue plasminogen Activator for Occluded Coronary Arteries

Increased T-wave amplitude is one of the earliest electrocardiographic (ECG) changes following coronary artery occlusion. Therefore, higher T waves in the presenting electrocardiogram should represent earlier time to treatment and thus be associated with lower mortality following thrombolytic therapy. However, T-wave amplitude has never been evaluated as a prognostic marker in this setting. We examined clinical outcomes in 3,317 patients with acute myocardial infarction (AMI) who underwent thrombolysis in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO-I) Study. Patients were classified as either those with high T waves or those with low T waves. Higher T waves were defined as those >98th percentile of the upper limit of normal. T-wave amplitude was also evaluated as a continuous variable according to infarct location (maximum T-wave amplitude) and as the amount of excess T-wave amplitude above normal (excess T-wave amplitude). Patients with higher T waves had lower 30-day mortality than those without (5.2% vs 8.6%, p = 0.001) and were less likely to develop congestive heart failure (15% vs 24%, p <0.001) or cardiogenic shock (6.1% vs 8.6%, p = 0.023). Higher maximum T-wave amplitude and excess T-wave amplitude were predictive of lower 30-day mortality (chi-square = 67, p <0.001 and chi-square = 33, p <0.001, respectively). These differences remain significant after controlling for other prognostic baseline ECG variables. In addition, T-wave amplitude added prognostic significance after controlling for time to treatment. T-wave amplitude, an often-overlooked component of the electrocardiogram, can add significant prognostic information in initial evaluation of patients with AMI.

Hyperacute T-wave criteria using computer ECG analysis

Hyperacute T waves (HATWs) have been described as tall-amplitude, primary T-wave abnormalities sometimes seen in the early phases of transmural myocardial infarction. Despite numerous human and animal studies addressing the presence and significance of HATWs, there are no widely held, reliable ECG criteria for their accurate identification. Using a specially designed computer program on a Hewlett-Packard Realm ECG analysis system, we screened 13,393 adult ECGs to identify those having T-wave amplitudes greater than accepted standards (limb leads, greater than 0.5 mV; precordial leads, greater than 1.0 mV). Patients with other known causes of primary and secondary tall T waves were excluded from the study sample. Patients with tall-amplitude T-waves who then developed clinically verifiable myocardial infarction were labeled the HATW group. The HATW group (21) represented 4.1% of the tall T wave group (513) and 0.16% of the entire sample. The remaining patients, who did not meet HATW criteria, were called the early repolarization variant (ERV) group (51). Both groups underwent comparative computer morphology analysis. Nine parameters were statistically significant in discriminating HATWs from early repolarization variants. A combination of J-point position/T-wave amplitude of more than 25%, T-wave amplitude/QRS amplitude of more than 75%, J-point position of more than 0.30 mV, and age of more than 45 years predicted HATWs from a control group with a specificity of 98.0% and a sensitivity of 61.9% and with positive and negative predictive values of 92.9% and 86.2%, respectively. We conclude that HATWs have characterizable discriminating ECG morphology as determined by computer ECG analysis compared with a control group.