mavii

History of the Epsilon Wave. Guy Hugues Fontaine (1936-2018) was a French cardiologist and electrophysiologist.In 1977 he defined and named arrhythmogenic right ventricular dysplasia ARVD; the epsilon wave; and the Fontaine lead placement to best amplify the waves on an ECG. The term “epsilon” was nice, because it occurs in the Greek alphabet after delta; thus, delta represents the pre ...

S wave: it is the second negative wave in the QRS complex, appearing after the R wave. QS wave: when a complex is completely negative, with absence of any positive wave, it is referred to as QS complex. It is usually a sign of necrosis. R' and S' waves: when more than a R or S wave are present, they are referred to as R’ wave and S’ wave.

The P-wave, PR interval and PR segment. ECG interpretation traditionally starts with an assessment of the P-wave. The P-wave reflects atrial depolarization (activation). The PR interval is the distance between the onset of the P-wave to the onset of the QRS complex. The PR interval is assessed in order to determine whether impulse conduction from the atria to the ventricles is normal.

Leads V5–V6 often display a small q-wave (called septal q-wave, explained in this article). An isolated QS complex is allowed in lead V1 (due to missing r-wave or misplaced electrode). Lead III occasionally displays a large isolated Q-wave; this is called a respiratory Q-wave, because its amplitude varies with respiration.

The Q Wave. A Q wave is any negative deflection that precedes an R wave. The Q wave represents the normal left-to-right depolarisation of the interventricular septum; Small ‘septal’ Q waves are typically seen in the left-sided leads (I, aVL, V5 and V6)

This is the “sine wave” rhythm of extreme hyperkalemia. This pattern usually appears when the serum potassium levels are well over 8.0 mEq/L. Had we seen the earlier ECGs, we might have had more warning, because the ECG in earlier stages of hyperkalemia shows us distinctive peaked, sharp T waves and a progressive intraventricular conduction ...

T-wave inversion without simultaneous ST-segment deviation: This is not a sign of ongoing ischemia, but may be post-ischemic. One type of post-ischemic T-wave inversion is especially acute, namely Wellen’s syndrome (characterized by deep T-wave inversions in V1–V6 in patients with recent episodes of chest pain ).

A new T wave flattening or inversion, except in lead aVR, must be considered a sign of myocardial ischemia (although normal inverted T waves may appear in leads III, aVF and V1). Chronic Myocardial Ischemia: An inverted T wave appears during the natural evolution of Q wave infarction, usually in the same leads as the Q wave.

One of these ECG changes is a sine wave pattern which is a manifestation of severe hyperkalemia. Different levels of hyperkalemia cause different electrophysiological changes, the first sign of which is inverted T waves that are the result of accentuation of repolarization .

Parts of the ECG explained P waves. P waves represent atrial depolarisation.. In healthy individuals, there should be a P wave preceding each QRS complex.. PR interval. The PR interval begins at the start of the P wave and ends at the beginning of the Q wave.. It represents the time for electrical activity to move between the atria and the ventricles.. QRS complex. The QRS complex represents ...

A guide to the normal ECG, including features of a normal 12-lead ECG and an image example. ... P waves: present, and each P wave is followed by a QRS complex; PR interval: 120-200 ms (3-5 small squares) QRS complex: width <0.12 seconds, normal morphology and normal progression in chest leads (R wave amplitude increases from V1 to V6)

The ECG pattern may vary over time — patients with symptomatic Brugada syndrome may have a non-diagnostic ECG at the time of assessment (e.g. Type 2 or 3 pattern; even a normal ECG). A diagnostic ECG may be produced in these patients by administration of a sodium-channel blocking agent, typically a class I antiarrhythmic such as flecainide.

A wave is a positive or negative stroke that represents a single electrical event in the heart. There are five primary waves in a standard ECG: P Wave: Represents the electrical activity in the atria (upper chambers of the heart). Q Wave: A downward deflection of the wave. R Wave: The first upward deflection of the wave.

The main EKG waves include: P wave. Q wave. R wave. S wave. T wave. U wave. Together the Q wave, R wave, and S wave form the QRS complex. The U wave is not always visible on a normal EKG, but would be located after the T wave if present and is usually in the same direction as the T wave.

The normal T-wave is somewhat asymmetric, with a steeper downward slope. The U-wave. The U-wave, which is a positive wave after the T-wave, appears occasionally on the ECG. Its height (amplitude) is approximately one fourth of the amplitude of the T-wave. The U-wave is most often seen in leads V2, V3 and V4.

Use this EKG interpretation cheat sheet that summarizes all heart arrhythmias in an easy-to-understand fashion. One of the most useful and commonly used diagnostic tools is electrocardiography (EKG) which measures the heart’s electrical activity as waveforms. An EKG uses electrodes attached to the skin to detect electric currents moving through the heart.

EKG 1. Rate: 14 X 6 = 84 bpm Rhythm: sinus Axis: (up in I, up in II, up in aVF) normal axis Waves: P: up and morphologically normal (<2.5 mm tall, uniphasic, < 3 small boxes in duration) in lead II: all normal findings. downgoing in V1 (should be upright or biphasic with the late segment downgoing, but should not be negative in totality)

Figure 1. The initial 12-lead ECG (25 mm/sec, 5 mm/mV) obtained on presentation to the emergency department demonstrates a sinus bradycardia with prolonged atrial conduction (flattened and broadened P waves, see arrows), a first-degree atrioventricular block (PQ, 300 ms), and an intraventricular conduction delay (QRS, 160 ms).

LITFL Further Reading. ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation; ECG A to Z by diagnosis – ECG interpretation in clinical context; ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases; 100 ECG Quiz – Self-assessment tool for examination practice; ECG Reference SITES and BOOKS – the best of the rest