Diagnostic image showing a standard 12-lead electrocardiogram (ECG) recorded at a speed of 25 mm/s and calibration of 10 mm/mV. The tracing demonstrates features of biventricular hypertrophy. Key findings include tall R-waves in the mid-to-left precordial leads (V3-V6) with very high amplitude, suggestive of left ventricular hypertrophy, and a slight right-axis deviation in the frontal plane. Lead V1 exhibits a fractionated QRS complex and prominent S-waves. Secondary repolarization abnormalities are present, characterized by ST-segment depression and T-wave inversion across the precordial leads V3-V6 and in lead III, indicating ventricular strain. The rhythm is sinus with a regular rate; P-waves are visible and positive in leads I and II. This ECG provides a classic clinical example of biventricular enlargement often associated with congenital heart diseases like ventricular septal defects with significant shunting.

A standard 12-lead electrocardiogram (ECG) recorded on pink grid paper, showing a sinus rhythm. The tracing demonstrates several abnormal waveform morphologies characteristic of cardiac involvement in Duchenne Muscular Dystrophy (DMD). Notable features include significantly tall R waves in the right precordial leads (V1, V2, and V3), with an R/S ratio greater than 1 in V1, which may mimic right ventricular hypertrophy or posterior wall involvement. The limb leads reveal a left axis deviation consistent with a left anterior fascicular block (LAFB), characterized by small q waves with tall R waves in leads I and aVL, and small r waves with deep S waves in leads II, III, and aVF. There is poor R-wave progression across the precordial leads, and the QRS complexes in V4–V6 show relatively lower voltages compared to the prominent right precordial R waves. These findings are clinically significant for identifying cardiomyopathy and conduction system abnormalities in patients with progressive muscular dystrophies.

A standard 12-lead electrocardiogram (ECG) displayed in a traditional 3x4 grid layout with a rhythm strip (Lead II) at the bottom. The tracing exhibits sinus tachycardia, characterized by a rapid heart rate with narrow QRS complexes and visible P-waves preceding each complex. Key morphological findings include prominent Q-waves in the inferior leads (II, III, and aVF), consistent with an old inferior wall myocardial infarction. There are signs of left ventricular hypertrophy (LVH), indicated by high QRS voltage in the precordial leads (specifically tall R-waves in V4-V6 and deep S-waves in V1-V3). The QTc interval is prolonged, measured at 484 ms. The P-waves in the inferior leads show increased amplitude, suggesting right atrial enlargement. These findings provide critical clinical context for evaluating cardiovascular pathology, including prior ischemia, structural chamber remodeling, and repolarization abnormalities.

This diagnostic image is a 12-lead electrocardiogram (ECG) demonstrating secondary repolarization abnormalities associated with Left Ventricular Hypertrophy (LVH). Key diagnostic findings include voltage criteria for LVH, characterized by high-amplitude QRS complexes in the precordial leads. Distinct ST-segment and T-wave changes are present: non-ischemic ST elevation (STE) is visible in lead aVR and the right precordial leads V1-V3. Conversely, prominent ST-segment depression with concomitant T-wave inversion (strain pattern) is observed in the lateral and inferior leads, specifically leads I, II, III, aVF, and V4-V6. These findings illustrate the 'strain pattern' of LVH, which is a critical differential diagnosis for ST-segment elevation myocardial infarction (STEMI). The tracing serves as an educational example of how chronic structural heart changes can mimic or mask acute coronary syndromes, emphasizing the importance of recognizing voltage criteria and the distribution of repolarization deviations in clinical cardiology.

This comparative medical illustration presents short-axis Cardiac Magnetic Resonance (CMR) images and corresponding Electrocardiogram (ECG) tracings for two types of Left Ventricular Hypertrophy (LVH). Panel A demonstrates concentric LVH, characterized by a significantly thickened myocardial wall and a reduced left ventricular (LV) end-diastolic cavity diameter (42 mm). The adjacent ECG shows high-voltage R waves in leads V5 and V6 with accompanying ST-segment depression and T-wave inversion, consistent with a left ventricular strain pattern. Panel B illustrates eccentric LVH, featuring a dilated LV cavity (end-diastolic diameter 60 mm) and relatively thinner myocardial walls compared to the concentric model. The corresponding ECG in panel B shows high-voltage R waves but with upright T waves and less pronounced ST-segment changes. The visual comparison highlights the structural differences between pressure-overload (concentric) and volume-overload (eccentric) remodeling and their respective electrophysiological manifestations, facilitating the study of cardiac morphology and ECG-LVH correlation criteria.

This diagnostic image is a 12-lead electrocardiogram (ECG) including right-sided lead V4R, obtained from a 4-month-old infant with dilated cardiomyopathy. The tracing demonstrates sinus tachycardia with a high ventricular rate. Key pathological features include markedly enlarged QRS amplitudes, particularly evident in the precordial leads (V1-V6) and limb leads (I, aVL), consistent with severe left ventricular hypertrophy. There are widespread ST-segment abnormalities characterized by down-sloping ST-segment depression and T-wave inversion/flattening in the lateral and inferior leads (I, aVL, II, aVF, V4-V6), representing a ventricular strain pattern. The P-waves are enlarged, suggesting atrial enlargement. Additionally, the QT interval is corrected (QTc) and appears prolonged. This ECG illustrates significant myocardial stress and structural remodeling associated with severe heart failure and pediatric cardiomyopathy.

This diagnostic image is a standard 12-lead electrocardiogram (ECG) displayed on a red grid background, illustrating significant ischemic changes. The tracing demonstrates a sinus rhythm with a normal heart rate. Pathological findings include diffuse ST-segment and T-wave abnormalities across multiple leads. Specifically, deep T-wave inversions are evident in the lateral leads (I, aVL, V4-V6), inferior leads (II, III, aVF), and anterior leads (V2-V3). ST-segment depression is visible in leads I, aVL, and V4-V6, while slight ST-segment elevation is noted in lead V2. Additionally, the precordial leads (V1-V6) show poor R-wave progression, characterized by low R-wave amplitude in V1-V3 that does not appropriately increase toward the lateral leads. These findings are clinically significant for suggesting myocardial ischemia or injury, often associated with coronary artery pathology such as a left anterior descending (LAD) artery lesion. The ECG serves as a critical educational tool for identifying widespread ischemic patterns and abnormal ventricular depolarization.

A standard 12-lead preoperative electrocardiogram (ECG) printed on grid paper, displaying limb leads (I, II, III, aVR, aVL, aVF) and precordial leads (V1-V6). The tracing demonstrates several ischemic findings. In the anterior precordial leads (V1-V3), there is a slight elevation of the ST segment above the isoelectric baseline. The morphology of the T-waves in these leads appears flattened or slightly inverted. In the lateral leads (V4-V6), the ST segment becomes more isoelectric, though abnormal ST-T wave morphology persists across V2-V6. Additionally, lead aVL shows a prominent T-wave inversion. The limb leads (II, III, aVF) demonstrate minor ST-segment abnormalities and non-specific T-wave changes. The QRS complexes exhibit relatively normal duration and voltage, though poor R-wave progression is noted in the early precordial leads. These findings are clinically significant as they suggest possible myocardial ischemia or injury affecting the anteroseptal and lateral regions of the heart, consistent with the patient's history of coronary artery disease.

This diagnostic image is a 12-lead electrocardiogram (ECG) recorded at a standard paper speed of 25 mm/s and voltage of 10 mm/mV. The tracing demonstrates significant acute electrophysiological changes across multiple vascular territories. Notably, there is ST-segment elevation visible in the inferior leads (II, III, and aVF) and the anterior precordial leads (V1 through V4), indicating transmural myocardial injury. The precordial leads also show a pattern of poor R-wave progression and deep S-waves in V2-V3. The presence of concurrent inferior and anterior ST-segment elevation is a clinically significant finding that may suggest a large territory of ischemia or multivessel coronary artery spasm (CAS), as seen in Prinzmetal angina or Takotsubo cardiomyopathy variants. The rhythm appears to be sinus, and the visual focus is on the repolarization abnormalities that characterize the acute episode. This ECG serves as a critical educational tool for identifying extensive ST-segment elevation myocardial infarction (STEMI) patterns and differentiating coronary vasospasm from fixed atherosclerotic occlusion.