Age: 32 years
Gender: Female
Occupation: Part-time secretary
Working diagnosis: Ebstein anomaly of the tricuspid valve, 32 weeks pregnant
HISTORY
The patient was diagnosed with Ebstein anomaly of the tricuspid valve at the age of 2 years. She has remained well throughout her life, with a good exercise capacity and only occasional palpitations. She was told she may have Wolff-Parkinson-White (WPW) syndrome and had been started on digoxin and a beta-blocker.
Recently she became pregnant. She had been followed regularly by her local obstetrician and local cardiologist. The pregnancy had been uncomplicated, but the patient was more recently found to have high blood pressure and proteinuria. She was referred again for tertiary cardiology and obstetric advice at 32 weeks of pregnancy.
Comments: Ebstein anomaly of the tricuspid valve is characterized by apical displacement of the septal leaflet of the tricuspid valve. The subvalvar apparatus is often affected as well, with abnormal tethering of the chordae to the ventricular wall. The tricuspid valve is usually regurgitant, and less frequently stenotic.
Patients with mild to moderate Ebstein anomaly may remain asymptomatic for decades. However, symptoms occur earlier in life when the lesion is more severe. The diagnosis may be established in infancy because of a heart murmur. Alternatively, children or young adults may present with arrhythmia. When the anomaly is severe it may manifest itself with cyanosis at birth, or even with fetal hydrops or intrauterine death (“wall-to-wall heart”).
Preeclampsia is defined as new-onset hypertension and proteinuria (>300 mg over 24 or ++ in two urine samples). High blood pressure during pregnancy is one of the leading causes of both maternal and perinatal morbidity and mortality.
CURRENT SYMPTOMS
The patient had no specific complaints. Her exercise tolerance was good and without obvious limitation. She described occasional palpitations, lasting a few seconds only and never associated with other symptoms such as shortness of breath or fainting.
NYHA class: I
Comments: Pregnancy is generally well tolerated in patients with Ebstein anomaly. In a report of 44 mothers undergoing 111 pregnancies, there were no maternal deaths or major cardiovascular complications. However, if an ASD is present and the patient is cyanotic, cardiovascular complications are more likely.
Palpitations may be due to ectopic beats, atrial fibrillation, or flutter or reentrant tachycardia. Accessory pathways (WPW syndrome) are a common association with Ebstein anomaly (∼25%) and may lead to supraventricular tachycardia.
CURRENT MEDICATIONS
Atenolol 50 mg daily
Digoxin 250 µg daily
Comments: Beta-blockers have a relatively good safety profile during pregnancy, although there is a perceived risk of growth retardation for the fetus. This may also relate to the underlying condition for which the beta-blockers are prescribed, as many patients with native or operated congenital heart disease have a low systemic cardiac output. Digoxin is safe to use during pregnancy. However, it is not certain whether these drugs are either needed or effective in this particular patient.
PHYSICAL EXAMINATION
BP 142/72 mm Hg, HR 70 bpm, oxygen saturation on room air 96%
Height 158 cm, weight 63 kg, BSA 1.66 m 2
Surgical scars: None
Neck veins: The JVP was elevated to 6 cm above the sternal angle with a large V-wave visible.
Lungs/chest: Lungs were clear.
Heart: The heart rhythm was regular. There was an RV lift. There was a normal first sound and a normally split second sound. A 2–3/6 holosystolic murmur was audible at the lower left sternal border.
Abdomen: Gravid uterus, appropriate for dates
Extremities: There was trace pedal edema.
Comments: There is mild systolic hypertension.
The elevated JVP with presence of V-waves in the neck pulse is indicative of substantial tricuspid regurgitation. It should be noted that the jugular veins of most patients with Ebstein anomaly are normal in both height and waveform, the tricuspid regurgitation not being transmitted to the jugular veins by the very compliant and large RA (and liver).
The right ventricular lift reflects RV dilatation, and the holosystolic murmur is indicative of tricuspid regurgitation.
LABORATORY DATA
| Hemoglobin | 15.8 g/dL (11.5–15.0) |
| Hematocrit/PCV | 46% (36–46) |
| MCV | 91 fL (83–99) |
| Platelet count | 269 × 10 9 /L (150–400) |
| Sodium | 136 mmol/L (134–145) |
| Potassium | 4.4 mmol/L (3.5–5.2) |
| Creatinine | 0.64 mg/dL (0.6–1.2) |
| Blood urea nitrogen | 3.2 mmol/L (2.5–6.5) |
OTHER RELEVANT LAB RESULTS
| Protein | 2.2 μmol/dL (0.3–2.4) |
| Albumin | 4.2 g/dL (3.7–5.3) |
| Urinalysis | 2+ protein |
Comments: Usually hemoglobin/hematocrit will fall during pregnancy as blood volume expands. The slightly elevated hemoglobin here is unusual; it may reflect mild secondary erythrocytosis, due to a small right-to-left shunt during exercise through an interatrial communication or a PFO.
Serum protein levels remained normal despite preeclampsia.
ELECTROCARDIOGRAM
FINDINGS
Heart rate: 64 bpm
PR interval: 218 msec
QRS duration: 167 msec
Sinus rhythm with first-degree heart block
Left-axis deviation of initial forces and RBBB. Nonspecific repolarization changes related to RBBB. Reduced overall ECG voltages.
Comments: First-degree heart block is found in up to 50% of patients with Ebstein anomaly and may relate to right atrial dilatation and stretch. The RBBB and low ECG voltages are typical in this condition.
Up to 25% of patients with Ebstein anomaly have an accessory AV pathway (WPW) due to discontinuity of the central fibrous body. The accessory pathway might be the substrate for supraventricular tachycardia.
There was no pre-excitation (delta wave) to suggest WPW in this patient. A 24-hour ECG showed no evidence of sustained arrhythmia.
CHEST X-RAY
FINDINGS
Cardiothoracic ratio: 62%
Cardiomegaly is present with RA enlargement. A small pulmonary trunk and a small aortic knuckle are noted.
Comments: This CXR had been taken prior to conception. The cardiomegaly is due to dilatation of the RA and atrialized portion of the RV, and is anticipated in patients with Ebstein anomaly; it can be dramatic in extreme cases (wall-to-wall hearts).
A small aortic knuckle is also a common finding in Ebstein anomaly, because of the chronically low cardiac output in many patients.
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