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Renal disease
Published in Kaji Sritharan, Jonathan Rohrer, Alexandra C Rankin, Sachi Sivananthan, Essential Notes for Medical and Surgical Finals, 2021
Kaji Sritharan, Jonathan Rohrer, Alexandra C Rankin, Sachi Sivananthan
Causes: can be due to either renal losses (e.g. diuretics, Cushing’s syndrome, Conn’s syndrome, renal tubular losses, Liddle’s/Bartter’s/Gitelman’s syndrome) or extrarenal losses (e.g. vomiting, diarrhoea, alkalosis). Clinical features: weakness, lethargy, cramps. Investigations: ECG may demonstrate small/inverted T waves, U waves. Management: correct Mg+ as well as K+ (otherwise K+ will be difficult to correct). With IV or PO supplementation depending on severity.
Medicine
Published in Seema Khan, Get Through, 2020
For each presentation below, choose the SINGLE most likely diagnosis from the list of options. Each option may be used once, more than once or not at all. A 60-year-old man presents with chest pain radiating down the left arm. A 12-lead ECG reveals Q waves in II, III and AVf, with T-wave changes in V5 and V6.A 50-year-old woman presents with a fast heart rate with an irregular rhythm. There are no P waves on the ECG. She states that she has lost weight recently and is ‘nervous’. She also suffers from palpitations.On auscultation a patient is noted to have a rumbling diastolic murmur at the apex. The murmur is accentuated during exercise.A 60-year-old man on digitalis and diuretics presents with weakness and lethargy. ECG shows flat T waves and prominent U waves.A 65-year-old man with chronic bronchitis presents with a raised JVP, hepatomegaly, and ankle and sacral oedema.
The U wave
Published in Andrew R Houghton, Making Sense of the ECG, 2019
It has been suggested that the U wave represents repolarization of the interventricular septum, or of the Purkinje fibres, or of the papillary muscles or of myocytes in the mid-myocardium (so-called M cells). It has also been suggested that the U wave is caused by after-potentials following the cardiac action potential, or that it is really just a continuation of the T wave, and that T and U waves should both be considered together as part of the overall process of ventricular repolarization.
Thyrotoxic periodic paralysis: a presentation of hyperthyroidism increasing in frequency around the world
Published in Journal of Endocrinology, Metabolism and Diabetes of South Africa, 2023
Laboratory results include a very low serum potassium level without any acid-base disturbance.21,22 Renal excretion of potassium is also low, thus excluding renal potassium wasting. A high urinary calcium-to-phosphate ratio has been proposed to distinguish thyrotoxic periodic paralysis patients from those with familial hypokalaemic periodic paralysis.5 Suppressed thyroid stimulating hormone levels with raised T3 and T4 levels are pathognomonic of the disease. Unsurprisingly, Graves’ disease is most commonly diagnosed in patients with thyrotoxic periodic paralysis; however, thyroiditis, toxic multinodular goitre and TSH-producing pituitary tumours have also been reported.21,22,24 The ECG may show U-waves, prolonged PR interval and both supraventricular and ventricular ectopic beats. The risk for life-threatening ventricular tachycardias or fibrillation remains high until the hypokalaemia is corrected.25,26
The effect of Systolic and diastolic blood pressure on Tp-e interval in patients divided according to World Health Organization classification for body mass index
Published in Clinical and Experimental Hypertension, 2021
Ali Bağcı, Fatih Aksoy, Hasan Aydin Baş, İsmail Barkin Işık, Hikmet Orhan
A 12-lead ECG was performed on all patients at a speed of 50 mm/s in the supine position (Nihon Kohden, Tokyo, Japan). To reduce the error rate, all ECGs were scanned, recorded on a computer and evaluated by two cardiologists at 200% magnification using Adobe Photoshop software. Patients with U waves in their ECGs were excluded from the study. The QT interval was measured from the beginning of the QRS complex to the end of the T wave and corrected with the Bazett formula [cQT = QT√ (R-R interval)]. The Tp-e interval was defined and measured as the interval from the peak of the T wave to the end of the T wave using precordial leads. Precordial leads were used in measurements of the Tp-e interval (9,12,13). While calculations were performed, the average of three values obtained from each lead was used. The Tp-e/QT ratio and Tp-e/QTc ratio were determined by dividing the Tp-e value with the QT and QTc values, respectively. Lastly, the Tp-e/QT ratio was calculated from these measurements (Figure 1).
The frontal plane QRS-T angle may affect our perspective on prehypertension: A prospective study
Published in Clinical and Experimental Hypertension, 2021
A 12-lead ECG was performed on all patients at a speed of 50 mm/s in the supine position (Nihon Kohden, Tokyo, Japan). To reduce the error rate, all ECGs were scanned, recorded on a computer and evaluated by two cardiologists at 200% magnification using Adobe Photoshop software. Patients with U waves on their ECGs were excluded from the study. The QT interval was measured from the beginning of the QRS complex to the end of the T wave and corrected with the Bazett formula: cQT = QT√ (R-R interval). Tp-e interval was defined and measured as the interval from the peak of the T wave to the end of the T wave using precordial leads (12). Frontal QRS and T-wave axes were recorded in the automatic reports of the ECG machine. The angle f (QRS-T) was calculated from these axes as the absolute difference between the frontal plane QRS axis and the frontal plane T axis (Figure 1)(10).. In case the angle exceeded 180°, it was calculated by subtracting from 360° (9,13).