Intro to EKG Interpretation - A Systematic Approach

Summary

In this comprehensive video, Eric from Stanford University provides a systematic approach to interpreting EKGs, aimed at medical, nursing, PA, or paramedic students. The method involves three main steps: assessing rhythm (including rate, regularity, and QRS morphology), evaluating the QRS complex (focusing on axis and abnormalities like hypertrophy and infarction), and reviewing the ST segments, T-waves, and QT interval. He emphasizes the importance of understanding waveform abnormalities and their causes over rigid diagnostic categories, offering a practical guide for accurate EKG interpretation.

Takeaways

• 😀 Always start by assessing the rhythm, as it sets the foundation for interpreting the rest of the EKG.
• 😀 The traditional sequence of interpreting an EKG (rate, rhythm, axis, hypertrophy, infarction) is not always the most logical or effective method, as suggested by the speaker.
• 😀 Focus on individual waveform abnormalities rather than grouping them under broad diagnoses like hypertrophy and infarction.
• 😀 Normal resting heart rate for adults is between 50 to 90 beats per minute, not 60 to 100 as commonly assumed.
• 😀 When assessing the rhythm, determine if it's regular, regularly irregular, or irregularly irregular. Each of these can indicate different underlying conditions.
• 😀 The QRS complex should be evaluated for its width, whether it's narrow or wide. A wide complex may suggest various causes like bundle branch block or ventricular arrhythmias.
• 😀 P-waves should be evaluated for their morphology, and their absence or abnormality could point to atrial fibrillation, flutter, or other arrhythmias.
• 😀 The relationship between the atrial and ventricular activities is crucial, especially in conditions like first- and second-degree AV block, where the PR interval is key.
• 😀 A normal QRS axis for adults is between -30 and +90 degrees, not 0 to 90 as often mistakenly believed. Axis deviations have various causes, such as right or left ventricular hypertrophy.
• 😀 Evaluate the ST segments, T-waves, and QT interval for abnormalities like ST elevation or depression, which could indicate conditions like myocardial infarction or pericarditis.
• 😀 QT interval prolongation can result from congenital long QT syndrome, certain medications, or electrolyte imbalances like hypocalcemia and hypothermia, and it's a risk for sudden cardiac death.

Q & A

What is the first step in Eric's systematic approach to interpreting an EKG?

The first step is to assess the rhythm, which includes determining the rate and whether the rhythm is regular, regularly irregular, or irregularly irregular.

Why does Eric emphasize the importance of a systematic approach to reading EKGs?

Eric recommends a systematic approach, especially for beginners, because it helps avoid missing critical diagnoses, especially since waveform abnormalities can be caused by various conditions other than hypertrophy and infarction.

What are the three main steps Eric uses in his approach to reading EKGs?

The three main steps are: 1) assess the rhythm (which includes the rate), 2) assess the QRS complex (including axis and morphology), and 3) assess the ST segments, T-waves, and QT interval.

What is the normal resting heart rate for adults, according to the script?

The normal resting heart rate for adults is between 50 and 90 beats per minute, not 60 to 100 as commonly believed.

How does Eric recommend determining if the rhythm is regular or irregular?

Eric suggests evaluating the consistency of the RR interval. If the interval is consistent, it is a regular rhythm. If it varies in a predictable pattern, it is regularly irregular, and if it varies without any predictable pattern, it is irregularly irregular.

What is the significance of a heart rate of 140 to 150 beats per minute?

A heart rate of 140 to 150 beats per minute specifically suggests the possibility of atrial flutter with 2:1 AV block, where only one in every two depolarizations passes through to the ventricles.

What should you look for when assessing the morphology of the P-waves?

When assessing the P-waves, you should check for their morphology, ensuring they are upright in Lead 1 and down in AVR. You should also check for evidence of atrial enlargement or the presence of fibrillation or flutter waves.

What is the normal range for the PR interval, and what does a prolonged PR interval indicate?

The normal PR interval is between 120 and 200 milliseconds. A PR interval consistently above 200 milliseconds indicates first-degree AV block.

What are delta waves, and what do they suggest?

Delta waves are a shallow upstroke before the QRS complex, causing it to widen. They are indicative of an accessory pathway, which is an abnormal tract of conductive myocardium that connects the atria to the ventricles without passing through the AV node.

What is the QT interval, and what should you look for when assessing it?

The QT interval represents the time it takes for the heart to contract and then recover. It should be corrected for heart rate and should be less than half the RR interval. Prolonged or shortened QT intervals can indicate conditions like congenital long QT syndrome or hypercalcemia, respectively.