ECG in Pregnancy

Introduction

Electrocardiography (ECG) is a critical tool in evaluating the heart's electrical activity. However, during pregnancy, physiological changes can affect ECG readings. Understanding these changes is essential to differentiate normal adaptations from pathological conditions.

Physiological Changes in Pregnancy Affecting ECG

Pregnancy leads to significant cardiovascular adaptations due to hormonal and hemodynamic shifts, which may manifest in ECG changes:

1. Increased Heart Rate: A mild increase in resting heart rate (by 10-20 bpm) is common.
2. Left Axis Deviation: The growing uterus shifts the diaphragm upwards, causing a slight leftward shift of the heart’s electrical axis.
3. Shortened PR and QT Intervals: Due to increased blood volume and sympathetic activity.
4. Increased R-wave Amplitude in Lead V1: As the heart rotates slightly.
5. Non-Specific ST and T Wave Changes: Minor ST-segment depressions and T-wave inversions in inferior and lateral leads can occur, often without clinical significance.

Differentiating Normal Changes from Pathology

While most ECG changes during pregnancy are benign, it is crucial to recognize possible pathological conditions:

• Peripartum Cardiomyopathy: This can present with abnormalities like prolonged QT, left bundle branch block (LBBB), or ST-segment elevations.
• Arrhythmias: Pregnancy may predispose individuals to supraventricular and ventricular arrhythmias due to increased adrenergic tone.
• Pre-existing Heart Disease: Some ECG findings may indicate undiagnosed congenital or acquired heart disease.

Clinical Recommendations

When evaluating ECG in pregnancy: - Always correlate findings with clinical symptoms. - Consider an echocardiogram if the ECG suggests structural heart disease. - Monitor pre-existing cardiac conditions closely, as pregnancy increases cardiovascular strain. - Recognize when urgent interventions (e.g., in cases of ischemia, severe arrhythmias) are needed.

Conclusion

ECG findings in pregnancy may differ from the non-pregnant state due to physiological changes. Understanding these variations helps differentiate between normal adaptations and potential cardiac pathology.

Source recommendations

1. European Society of Cardiology (ESC) Guidelines on the Management of Cardiovascular Diseases During Pregnancy

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Cardiovascular-Diseases-during-Pregnancy-Management-of
2. https://pubmed.ncbi.nlm.nih.gov/30165544/
3. https://www.escardio.org/static-file/Escardio/Guidelines/publications/PREGN%20Guidelines-Pregnancy-FT.pdf
4. https://pubmed.ncbi.nlm.nih.gov/21873418/
5. https://academic.oup.com/eurheartj/article/39/34/3165/5078465

2. American Heart Association (AHA) Guidelines on Pregnancy and Heart Disease

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000772
2. https://www.heart.org/en/news/2023/02/13/to-improve-maternal-health-report-says-to-start-before-pregnancy
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001121
4. https://www.heart.org/en/healthy-living/fitness/fitness-basics/aha-recs-for-physical-activity-in-adults
5. https://newsroom.heart.org/news/aha-statement-pregnant-women-with-cvd-need-specialized-care-before-during-and-postpartum