Occurrence of transient U-wave inversion during vasospastic anginal attack is not related to the direction of concurrent ST-segment shift

Bilateral isolated coronary ostial stenosis in a middle-aged premenopausal woman with vasospastic angina: a case report

Background

Vasospastic angina (VSA) is uncommon in premenopausal women who have less chronic endothelial injury causing vascular remodelling, considered to play a primary role in the pathogenesis for coronary vasospasms. Furthermore, vasospasms rarely occur in the bilateral coronary ostia. Isolated coronary ostial stenosis (ICOS), which often causes severe effort angina and requires surgical intervention, is more commonly reported in middle-aged women, with causes including fibromuscular dysplasia (FMD) and large-vessel vasculitis. However, ICOS associated with VSA is extremely rare.

Case summary

A 50-year-old premenopausal Japanese woman presented with a complaint of typical chest pain due to angina during light exertion daily in the early morning hours since 3 years. Coronary angiography (CAG) revealed bilateral mild-to-moderate ICOS in addition to multi-vessel spasms involving the bilateral coronary ostia confirmed by the vasospasm provocation test using intracoronary acetylcholine injection. Tests to determine the cause of ICOS did not identify FMD or any other disease. The angina attacks alleviated after calcium channel blocker (CCB) administration without intervention for bilateral ICOS for 24 years since the first presentation. Moreover, coronary computed tomography angiography (CTA) performed 24 years after the first presentation showed no ICOS.

Discussion

In our patient with typical and frequent VSA symptoms, CAG revealed both mild-to-moderate ICOS and the vasospasms in the bilateral coronary ostia. Fibromuscular dysplasia or large-vessel vasculitis was ruled out as the causes of ICOS. Vasospastic angina rarely occurred after the prescription of CCB, and coronary CTA 24 years after the first presentation showed no ICOS. Bilateral ICOS in our patient might be VSA related.

Identification of the Vessels Causing Myocardial Ischemia by a Synthesized 18-Lead Electrocardiogram Obtained After the Master Two-Step Exercise Test in a Patient With Effort Angina

A synthesized 18-lead electrocardiograph is a specialized technology that mathematically computes the virtual electrocardiographic waveforms of the right chest leads (V3R, V4R, and V5R) and posterior leads (V7, V8, and V9) based on a standard 12-lead electrocardiograph input without additional lead placement or techniques. Synthesized 18-lead electrocardiography is a useful test for the identification of the culprit coronary arteries in patients with ST-segment elevation myocardial infarction of the right ventricular wall or the posterior/lateral left ventricular wall, which are often missed on standard 12-lead electrocardiography. However, few studies have examined the usefulness of this modality during exercise stress testing. We present a case of a 78-year-old man with a two-month history of typical angina. The synthesized 18-lead electrocardiogram obtained just after the Master two-step exercise test revealed ST-segment shifts in multiple leads, including synthesized V4R, V5R, and V7-9 leads, and U-wave changes in some leads, including the synthesized V9 lead. The diagnosis of the culprit coronary arteries causing exercise-induced myocardial ischemia is discussed with reference to coronary angiographic findings. This modality could potentially increase the sensitivity and specificity for the detection of coronary artery disease and accurately pinpoint the site of the lesion. If an electrocardiograph can display a synthesized 18-lead electrocardiogram, it should be used when evaluating the waveform due to myocardial ischemia.

Inverted U Waves-Red Flags in Electrocardiograms

This case report presents the electrocardiogram findings of a patient in their 50s with intermittent compression-like pain in the chest and a history of hypertension and diabetes.

Vasospasm in the First Septal Perforator Branch and Late High-Grade Atrioventricular Block Following Successful Primary Percutaneous Coronary Intervention for the Proximal Left Anterior Descending Coronary Artery: A Case Report

We present a case of a high-degree advanced atrioventricular block (AVB), which occurred 24 hours after successful primary percutaneous coronary intervention (PCI) in the proximal left anterior descending coronary artery (LAD), the culprit of ST-segment elevation myocardial infarction (STEMI). The methylergometrine provocation test for coronary vasospasms, which was performed on the eighth hospital day, revealed transient total occlusion of the first septal perforator branch. After prescribing a calcium channel blocker to the patient, AVB did not recur for three years, as confirmed using an implantable loop recorder (ILR). In this patient, delayed high-grade AVB following primary PCI in the proximal LAD might be caused by the spasm of the first septal perforator branch. Documented cases of spasms in this branch are rare.

The U-wave: A remaining enigma of the electrocardiogram

The U-wave's electrophysiological origin remains unknown and is subject to debate. It is rarely used for diagnosis in clinical practice. The aim of this study was to review new information regarding the U-wave. Further to present the proposed theories behind the U-wave's origin along with potential pathophysiologic and prognostic implications related to its presence, polarity and morphology.

METHOD

Literature searches were conducted to retrieve publications related to the electrocardiogram U-wave in the literature database Embase.

RESULTS

The review of the literature revealed the following major theories that will be discussed; late depolarisation, delayed or prolonged repolarisation, electro-mechanical stretch and IK1 dependent intrinsic potential differences in the terminal part of the action potential. Various pathologic conditions were found to correlate with the presence and properties of the U-wave, such as its amplitude and polarity. Abnormal U-waves can, for example, be observed in coronary artery disease with ongoing myocardial ischemia or infarction, ventricular hypertrophy, congenital heart disease, primary cardiomyopathy and valvular defects. Negative U-waves are highly specific for the presence of heart diseases. Concordantly negative T- and U-waves are especially associated with cardiac disease. Patients with negative U-waves tend to have higher blood pressure and history of hypertension, higher heart rate, cardiac disease and left ventricular hypertrophy compared to subjects with normal U-waves. Negative U-waves have been found to be associated with increased risk of all-cause mortality, cardiac death and cardiac hospitalisation in men.

CONCLUSIONS

The origin of the U-wave is still not established. U-wave diagnostics may reveal cardiac disorders and the cardiovascular prognosis. Including the U-wave characteristics in the clinical ECG assessment may be useful.

Variant Angina with Spontaneously Documented Ischemia- and Tachycardia-induced "Lambda" Waves

In a patient with variant angina of the proximal left anterior descending coronary artery, myocardial ischemia changed the QRS-ST-T configurations without J-waves into those resembling "lambda" waves at maximal ST-segment elevation, and couplets or triplets of supraventricular extrasystole (SVE) changed the ischemia-induced "lambda" waves into QRS-ST-T configurations resembling a "tombstone" morphology or "monophasic QRS-ST complex." At the resolution phase of coronary spasm, the QRS-ST-T configurations returned to those without J-waves and were changed by SVE into "lambda" waves. Interestingly, neither ischemia- nor SVE-induced "lambda" waves or SVE-induced "tombstone" morphology or "monophasic QRS-ST complex" were complicated by ventricular tachyarrhythmia.

Significance of exercise induced U wave inversion as a marker for coronary artery disease

Exercise stress testing for detecting inducible ischaemia was first introduced in the 1950s and remained one of the only methods of stressing the heart for years to come. The presence of inducible ischaemia was assessed by ECG changes during exercise apart from other factors, namely, duration of exercise, blood pressure and heart rate response, metabolic equivalents achieved, etc. With the emergence of other tests to look for inducible ischaemia, for example, dobutamine stress echocardiography and myocardial perfusion scanning and also as the threshold for invasive evaluation has decreased, unusual and infrequently encountered ECG changes are not looked for during exercise stressing with the same degree of diligence. The authors describe below the case of a 49-year-old male whose left anterior descending artery stenosis was diagnosed on exercise stress test on the basis of a negative U wave.

Detection of U wave activity in healthy volunteers by high-resolution magnetocardiography

INTRODUCTION

The purpose of our study was to prove the existence of the U wave using magnetocardiograms (MCGs).

METHODS

The 31-channel MCGs of 25 healthy volunteers were recorded. The onset of the U wave was defined by newly developed spatial correlation analysis; and the end, by different approaches.

RESULTS

A U wave could be proved in all volunteers. In 10 volunteers (heart rate, 57 +/- 19 beats/min) in whom the U wave was found to be separated from the following P wave, the U wave's end could be determined as a threshold value (U wave duration, 310 +/- 24 milliseconds). In 15 volunteers (heart rate, 70 +/- 38 beats/min), the end of the U waves was concealed by a continuous transition of the U waves into the following P waves.

CONCLUSIONS

The U wave seems to be a regular phenomenon and has a distinct spatiotemporal assembly.