This diagnostic image is a 6-lead electrocardiogram (ECG) trace focusing on the precordial leads (V1-V6). The tracing demonstrates classic features associated with hypokalemia, specifically in a clinical context of a 2.7 mM/l potassium level. In leads V1, V2, and V3, there is visible ST-segment depression and a reduction in T-wave amplitude. A prominent, marked U-wave is indicated by a black arrow in lead V2, following the T-wave. The right precordial leads (V4-V6) show tall R-waves with high voltage, meeting the voltage criteria for left ventricular hypertrophy (LVH). The combination of high-amplitude QRS complexes and the characteristic repolarization abnormalities (U-waves, ST depression, and flattened T-waves) provides a key educational example of how electrolyte imbalances and structural heart changes manifest on a standard ECG. This is an intermediate-level resource for cardiology and internal medicine training, illustrating the diagnostic findings of severe hypokalemia and hypertensive heart disease morphology.

This diagnostic image is a 12-lead electrocardiogram (ECG) recorded on standard grid paper. The tracing demonstrates hallmark visual findings associated with severe hypokalemia. Key electrocardiographic features include significant T-wave flattening across multiple leads, most notably in leads I, II, aVF, V5, and V6, where the T-waves appear almost isoelectric. There is a corresponding appearance of prominent, positive U-waves, which are particularly distinct in the precordial leads V3 through V6. In these leads, the U-wave amplitude is nearly equal to or exceeds the amplitude of the preceding flattened T-wave, creating a characteristic 'camel-hump' morphology or a false impression of a prolonged QT interval (often referred to as a QU interval). The rhythm is sinus, and the primary educational focus is the recognition of electrolyte-induced repolarization abnormalities. This ECG is clinically significant for identifying severe potassium depletion, such as that caused by diuretic use or pseudo-aldosteronism.

This diagnostic graphic illustrates various electrocardiogram (ECG) manifestations of electrolyte disturbances across four panels. Panel A demonstrates hypokalemia, characterized by flattened T waves and prominent U waves, which can lead to a pseudoprolonged QT interval. Panel B shows hyperkalemia, highlighted by classic tall, peaked 'tented' T waves and narrow QRS complexes. Panel C displays hypocalcemia, primarily showing a prolongation of the ST segment leading to a lengthened QT interval while T wave morphology remains relatively preserved. Panel D represents hypercalcemia, which is characterized by a shortened ST segment and a correspondingly shortened QT interval. The collection serves as an educational comparison chart for clinicians and medical students to recognize pathognomonic rhythm strip changes associated with potassium and calcium imbalances. Key educational concepts include repolarization abnormalities, interval duration changes, and the visual differentiation of metabolic derangements in a clinical cardiology context.