Table 1.
Tachycardia in pregnancy
| Differential diagnosis | Investigations | Management |
|---|---|---|
| Asymptomatic tachycardia | All other vital signs should be within normal limits Blood tests: normal ECG: sinus tachycardia Asymptomatic |
Usually an incidental finding, monitor for symptoms Provide open follow-up in the event that symptoms develop (Box 1) |
| Secondary sinus tachycardia | Blood tests: Hb, CRP, WCC, creatinine and TSH ECG: sinus tachycardia Chest X-ray |
Look for and treat the underlying cause: anaemia, infection, dehydration or pulmonary embolism |
| Inappropriate sinus tachycardia | 24-hour tape No underlying cause can be found |
Benefit of beta blockers is not certain14 Reassurance |
| Supraventricular tachycardia | Most common arrhythmia seen in pregnancy. There may be a history of SVT prior to pregnancy. ECG: Narrow complex tachycardia typically over 150 bpm and regular. Often normal between episodes but check for pre-excitation. |
Vagal manoeuvres Adenosine 6–24 mg Beta blockers (metoprolol, bisoprolol) Verapamil or diltiazem administered slowly (verapamil is drug of choice in women with severe asthma where adenosine or beta blockers are contraindicated) |
| Atrial tachycardia | ECG: abnormal P waves Echo: check for structural heart disease 24-hour tape: periods of acceleration or deceleration during onset or termination of a tachycardia |
Discuss with cardiologist Rate control with beta blockers, verapamil or digoxin (see SVT management for women with severe asthma) Rhythm control (either chemical cardioversion such as flecainide or DCCV) where rate control insufficient |
| Atrial fibrillation | ECG: absent P waves, irregular QRS complexes ECHO: check for structural heart disease Blood tests: Hb, TSH and electrolytes Underlying causes need investigation |
Rate control with beta blockers, verapamil or digoxin Discuss with cardiologist (see SVT management for women with severe asthma) Rhythm control: pharmacological or electrical cardioversion Anticoagulation (treatment dose or prophylaxis depending on VTE risk score) Regular follow-up and cardiology review (Box 3) |
| Ventricular tachycardia | ECG: broad complex tachycardia (idiopathic VT may have a normal ECG between episodes) | Discuss with cardiology Rhythm control with DCCV or pharmacological management (lidocaine or amiodarone) Ablation if medical therapy not sufficient Prophylactic beta blocker especially if underlying structural heart disease |
bpm = beats per minute; CRP = C-reactive protein; DCCV = direct current cardioversion; ECG = electrocardiography; ECHO = echocardiography; Hb = haemoglobin; SVT = supraventricular tachycardia; TSH = thyroid stimulating hormone; VT = ventricular tachycardia; VTE = venous thromboembolism; WCC = white cell count.