Significance of Negative U Waves in the Precordial Leads During Anterior Wall Acute Myocardial Infarction

Tamura, Akira; Watanabe, Tôru; Nagase, Kimiaki; Mikuriya, Yoshiaki; Nasu, Masaru

doi:10.1016/s0002-9149(97)00011-8

Cited by 15 publications

(11 citation statements)

References 19 publications

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“…7 Moreover, the presence of a negative U wave in acute myocardial infarction has been reported to possibly reflect a smaller mass of necrotic myocardium and, hence, an infarction more responsive to reperfusion therapy. 8 Notably, unlike its better-known counterpart, the prominent upright U wave, the negative U wave has no clear association with abnormal electrolyte levels.…”

Section: Discussionmentioning

confidence: 99%

The Negative U Wave

Salazar

Goldschlager

2020

JAMA Intern Med

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A woman in her 60s with a history of hypertension, seizure disorder, and polysubstance use was brought to the hospital because of altered mental status. On arrival to the emergency department, she demonstrated nonpurposeful lower extremity movements and was nonresponsive; her Glasgow Coma Scale score was 6. Vital signs were notable for normal body temperature, normal heart rate (85 beats/ min), and markedly elevated blood pressure (220/122 mm Hg). Physical examination findings revealed an ill-appearing, normocephalic woman with asymmetric pupils-the left pupil was 4 mm in diameter and her right pupil was described as pinpoint. Stroke was suspected, and she was intubated because of concern for inability to protect the airway. Computed tomography of the head did not demonstrate hemorrhage, herniation, large-vessel occlusion, or perfusion mismatch. Initial laboratory workup findings were largely unremarkable, with lactate, creatinine, glucose, and highsensitivity troponin levels all within normal limits. Serum electrolyte levels, including potassium and magnesium, were grossly normal. An electrocardiogram (ECG) was obtained (Figure).Question: What are the notable findings of the ECG?

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Section: Discussionmentioning

confidence: 99%

The Negative U Wave

Salazar

Goldschlager

2020

JAMA Intern Med

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“…The algorithm satisfies an unmet clinical need because until now it has not been possible to report U waves in AF. Many studies have noted the diagnostic value of U wave abnormalities, particularly inverted U waves 17 – 19 . Although we did not detect any abnormal U waves in our cohort the algorithm facilitates the reporting of U wave abnormalities in AF patients as recommended by the important cardiac associations 2 , 7 .…”

Section: Discussionmentioning

confidence: 99%

Validation of an algorithm to reveal the U wave in atrial fibrillation

Al-Karadi

Wilkinson

Caldwell

et al. 2018

Sci Rep

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Major cardiac organisations recommend U wave abnormalities should be reported during ECG interpretation. However, U waves cannot be measured in patients with atrial fibrillation (AF) due to the obscuring fibrillatory wave. The aim was to validate a U wave measurement algorithm for AF patients. Multi-beat averaging was applied to ECGs of 25 patients during paroxysms of AF and the presence of U waves compared to those from the same patients during sinus rhythm (SR). In a further database of 10 long-term AF recordings, the number of beats for effective U wave extraction by the algorithm was calculated. U waves were revealed in all AF recordings and there was no significant difference between the presence of U waves in AF and SR (p = 0.88). U wave amplitude was significantly increased in AF (mean (s.d.) amplitude 55 (39) AF vs 37 (28) μV SR, p = 0.005). The presence of U waves could easily be discerned when as few as 10 beats were used in the algorithm. The study demonstrates the validity of the algorithm to reveal U waves in AF recordings. The algorithm offers the potential to detect U wave abnormalities in patients with AF.

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“…27 Tamura et al noted that patients with exerciseinduced U wave changes following acute anterior wall myocardial infarction were less likely to have had ST elevation on the presenting ECG, had better collateral circulation, greater left ventricular ejection fraction, and better regional wall motion. 24 These observations suggest that U waves point not only to the presence of severe coronary narrowing but also more robust collateral circulation. It is thought that well collateralized ischemic myocardium provides the necessary substrate to produce heterogeneous repolarization, and thus apparent U waves, under conditions of physical stress.…”

Section: Exercise-induced U Wavesmentioning

confidence: 97%

“…Negative U waves usually appear when a large myocardial territory is involved and can help locate the coronary artery involved. [21][22][23][24] Negative U waves may be the only ECG sign of ischemia. Kanemoto et al studied the significance of U wave polarity in V4-V6 in patients with anterior MI 6 to 8 weeks prior to enrollment.…”

Section: Myocardial Infarction (Mi)mentioning

confidence: 99%

Giant U waves: an important clinical clue

Verma

Figueredo

Greenspan³

et al. 2011

RRCC

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Electrocardiographic U waves are a common clinical finding, and yet are poorly understood by many physicians. They can be seen in many clinical conditions, most importantly hypokalemia and ischemic heart disease. Over the years, many theories have been put forth to explain their origin. While still not completely understood, it now appears that mechanoelectrical interactions are responsible for normal U waves. Pathologic U waves may be seen in ischemic heart disease where they sometimes point to acute ischemic events. The large U waves of hypokalemia are most likely not true U waves but rather the terminal deflection in a bifid T wave.

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Significance of Negative U Waves in the Precordial Leads During Anterior Wall Acute Myocardial Infarction

Cited by 15 publications

References 19 publications

The Negative U Wave

The Negative U Wave

Validation of an algorithm to reveal the U wave in atrial fibrillation

Giant U waves: an important clinical clue

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