Identifying EKG Rhythms

Introduction

Electrocardiography (EKG or ECG) is a fundamental tool in cardiology used to assess the electrical activity of the heart. Being able to identify different EKG rhythms is crucial for diagnosing cardiac conditions accurately.

Basic EKG Interpretation

To interpret an EKG, we analyze several components: - Rate: Determines if the heart rate is normal (60-100 bpm), tachycardic (>100 bpm), or bradycardic (<60 bpm). - Rhythm: Evaluates whether the heartbeat is regular or irregular. - P wave: Represents atrial depolarization and helps distinguish sinus rhythm from other rhythms. - PR interval: Normally between 120-200 ms, any deviation may suggest conduction abnormalities. - QRS complex: Indicates ventricular depolarization; a wide QRS may suggest bundle branch blocks. - ST segment & T wave: Help identify ischemia, infarction, and electrolyte imbalances.

Common EKG Rhythms

1. Normal Sinus Rhythm (NSR)

• Regular rhythm, 60-100 bpm
• P waves before each QRS
• Normal PR interval and QRS duration

2. Sinus Bradycardia

• Regular rhythm, heart rate <60 bpm
• Often seen in athletes, during sleep, or due to medications

3. Sinus Tachycardia

• Regular rhythm, heart rate >100 bpm
• Can be due to fever, anxiety, dehydration, etc.

4. Atrial Fibrillation (AFib)

• Irregularly irregular rhythm
• No distinct P waves
• Common in older adults and those with hypertension or heart disease

5. Atrial Flutter

• Sawtooth P waves (flutter waves)
• Regular or irregular rhythm

6. Supraventricular Tachycardia (SVT)

• Rapid, regular rhythm (>150 bpm)
• Sudden onset and termination

7. Ventricular Tachycardia (VT)

• Wide QRS complexes
• Can be life-threatening

8. Ventricular Fibrillation (VFib)

• Chaotic, irregular pattern
• No effective pumping of blood (needs immediate defibrillation)

Clinical Relevance

Recognizing these rhythms is essential, especially for emergency situations like VT or VFib. Proper interpretation helps guide treatment strategies such as antiarrhythmic medications, pacemakers, or defibrillators.

Conclusion

EKG rhythm identification is a vital skill in cardiology. Understanding fundamental characteristics of each rhythm can help diagnose and manage cardiac conditions effectively.

Source recommendations

1. American Heart Association ECG Interpretation Guidelines

1. https://www.heart.org/en/health-topics/heart-attack/diagnosing-a-heart-attack/electrocardiogram-ecg-or-ekg
2. https://www.ahajournals.org/doi/10.1161/circulationaha.108.191095
3. https://www.heart.org/-/media/files/affiliates/mwa/kansas-city/kc-cardiac-and-stroke-symposium/2020-event-documents/cardiac-presentations/2-ecg-hockstad.pdf?la=en
4. https://www.ahajournals.org/doi/10.1161/circulationaha.108.191098
5. https://pubmed.ncbi.nlm.nih.gov/19281931/

2. European Society of Cardiology Guidelines on Arrhythmias

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Ventricular-Arrhythmias-and-the-Prevention-of-Sudden-Cardiac-Death
2. https://academic.oup.com/eurheartj/article/43/40/3997/6675633
3. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Supraventricular-Tachycardia
4. https://pubmed.ncbi.nlm.nih.gov/36017572/
5. https://www.ahajournals.org/doi/10.1161/01.cir.0000091380.04100.84