Introduction to EKG Rhythms

Introduction to EKG Rhythms

  • Variety of knowledge levels in the classroom regarding rhythms.

  • Focus on foundational concepts starting with the P wave.

  • Use of a worksheet for labeling and understanding key components of EKGs.

Basics of EKGs

Lead Placement

  • Importance of where to place leads on the patient:

    • Avoid very hairy spots to ensure good contact and readings.

    • Avoid placing leads on wet skin to prevent poor readings.

    • For skinny patients, place leads in the intercostal spaces between ribs.

Graph Paper and Measuring Intervals

  • The graph paper used has big and small squares for measurement:

    • A big box represents 0.2 seconds.

    • A little box represents 0.04 seconds.

  • Each EKG strip analyzed will be a six-second strip to calculate heart rate.

Understanding P Waves

Identifying the P Wave

  • Definition and characteristics:

    • The P wave is represented as a tiny bump on the EKG strip.

    • Label it appropriately on your worksheet.

QRS Complex

  • Components of the QRS complex:

    • Begins with the Q wave, where it leaves the baseline.

    • The tallest point is the R wave.

    • Returns to baseline at the S wave.

  • Importance of QRS:

    • Represents ventricular depolarization.

The Heart's Electrical System

SA Node and Heart Functioning

  • SA Node (Sinoatrial Node):

    • Fires impulses to activate heartbeats, intrinsic heart rate averages around 60-100 beats per minute.

  • The sequence of the heart's electrical conduction:

    • Impulses travel from the SA node to the AV node, then through the Bundle of His to the right and left bundle branches, and finally to the ventricles.

Depolarization and Repolarization

  • The P wave represents atrial depolarization:

    • Indicates the firing of the SA node.

  • The T wave represents ventricular repolarization:

    • It shows the heart resting to get ready for the next beat.

Steps for EKG Interpretation

Evaluating the Rhythm

  1. Baseline: Should be steady and smooth.

  2. Rate Calculation: Count the number of QRS complexes in the six-second strip and multiply by 10 for the heart rate per minute:

    • Example: 8 QRS complexes in six seconds → 8 x 10 = 80 BPM.

  3. Regularity: Assess if the QRS complexes are spaced evenly.

  4. P waves: Ensure there is a P wave for every QRS:

    • Should be rounded and directed upward for sinus rhythm.

  5. QRS Duration: Fits within a big box = narrow complex; breaks this rule = wide complex.

  6. PR Interval: Normal is less than 0.2 seconds (i.e., fits within a big box).

  7. T Wave Evaluation: Basic recognition; detailed evaluation not covered in initial lessons.

Sinus Rhythms

Types of Sinus Rhythms

  • Normal Sinus Rhythm: Heart rate of 60-100 BPM with normal characteristics.

  • Sinus Bradycardia: Heart rate below 60 BPM.

  • Sinus Tachycardia: Heart rate above 100 BPM.

Atrial Issues

  • Key rhythms to know:

    • Supraventricular Tachycardia (SVT): Fast rate above 100, no visible P waves.

    • Atrial Fibrillation (A-Fib): Irregularly irregular rhythm, chaotic baseline without recognizable P waves.

    • Atrial Flutter: Regular rhythm with distinctive flutter waves.

Important Characteristics of A-Fib

  • Risk of blood clots due to non-effective atrial contraction.

  • When the AV node fails to block excessive impulses, it can lead to rapid heart rates.

Ventricular Issues and Risks

Premature Ventricular Contractions (PVCs)

  • Characteristics:

    • Each PVC results in a wide and bizarre QRS complex.

    • Types include unifocal (same appearance) and multifocal (different appearances).

  • If PVCs begin to join (couplets), there’s an increased risk of more severe arrhythmias.

Lethal Rhythms

  • Ventricular Tachycardia (VT): Sustained heart rate above 100 BPM with visible QRS complexes but bypassing atrial function. Can be lethal.

  • Ventricular Fibrillation (V-Fib): Chaotic electrical activity without QRS complexes, resulting in lost heartbeat - fatal without immediate CPR or defibrillation.

R on T Phenomenon

  • Dangerous event where a PVC occurs during the T wave of another heartbeat, leading to potential ventricular tachycardia.

Conclusion

  • Focus on frequency and characteristic identification of various rhythms to understand EKG readings effectively.

  • Emphasize the importance of assessment skills and systematic evaluation of heart rhythms.

  • Engage in practice to solidify understanding of rhythms and their implications for patient care, ensuring safety and readiness for clinical application.