From the Guidelines
Tachycardia in pregnancy should be managed with caution, prioritizing the health and safety of both the mother and the fetus, and beta-blockers like metoprolol or labetalol are generally considered safe after the first trimester. During pregnancy, resting heart rate typically increases by 10-20 beats per minute due to increased blood volume, cardiac output, and metabolic demands 1. For mild to moderate sinus tachycardia (heart rate 100-120 bpm) without symptoms, reassurance and monitoring are usually sufficient. However, persistent tachycardia over 120 bpm or accompanied by symptoms like dizziness, shortness of breath, or chest pain warrants further investigation.
Key Considerations
- First-line management includes identifying and treating underlying causes such as anemia, dehydration, hyperthyroidism, infection, or anxiety.
- For symptomatic tachyarrhythmias requiring medication, beta-blockers like metoprolol (25-50 mg twice daily) or labetalol (100-200 mg twice daily) are generally considered safe after the first trimester 1.
- Calcium channel blockers such as verapamil (120-240 mg daily in divided doses) may be used if beta-blockers are contraindicated.
- Adenosine (6-12 mg IV rapid push) can be used for acute termination of supraventricular tachycardia.
- Severe or refractory cases may require cardiology consultation and consideration of cardioversion, which is generally safe during pregnancy with appropriate fetal monitoring 1.
Specialized Care
- Underlying cardiac conditions like structural heart disease or cardiomyopathy require specialized multidisciplinary care.
- Regular monitoring of both maternal and fetal well-being is essential throughout treatment, with adjustments to medication dosing as pregnancy progresses 1.
From the Research
Tachycardia in Pregnancy: Causes and Risks
- Tachycardia in pregnancy is a common complication due to hormonal changes that can enhance pre-existing arrhythmias or induce new arrhythmias in the presence of congenital heart defects in pregnant females 2.
- The presence of tachyarrhythmia during pregnancy poses a risk to both the mother and the fetus, necessitating proper treatment with medications 2.
- Tachycardia can be physiological or pathological, and distinguishing between the two can be a challenge, requiring an understanding of the cardiovascular changes that occur during pregnancy 3.
Diagnosis and Treatment
- The finding of a persistent tachycardia, regardless of symptoms, should prompt clinical review and consideration of investigations such as blood tests, electrocardiography, and echocardiography 3.
- Treatment of tachyarrhythmias in pregnancy differs little from that in non-pregnant adults, and unstable arrhythmias should follow Resuscitation Council UK guidelines 3.
- Vagal maneuvers and adenosine are first-line treatments for atrioventricular-nodal-reentry tachycardia (AVNRT), which is the most common tachydysrhythmia in pregnancy 4.
- Calcium channel blockers, such as verapamil and diltiazem, may be as effective as adenosine in converting AVNRT to sinus rhythm, without the negative short-term side effects 4.
Management and Care
- Pregnant women with pathological arrhythmias require care from a multidisciplinary team, including obstetricians, obstetric anesthetists, specialist midwives, cardiologists, and obstetric physicians 3.
- The management of tachyarrhythmias in pregnancy involves considering the potential teratogenic side effects of antiarrhythmic drugs and utilizing new techniques such as cardiac ablation with minimal or no radiation exposure to the fetus or mother 2.
- Most patients with AVNRT may be discharged with appropriate follow-up, and several studies demonstrate that nondihydropyridine calcium channels (verapamil and diltiazem) are equally as efficacious as adenosine in converting AVNRT to sinus rhythm, without the negative side effects 4.