Age: 37 years
Gender: Female
Working diagnosis: Childhood cyanosis
HISTORY
The patient had been investigated as a child for episodes of possible cyanosis. She had been referred to a teaching hospital and followed until her teenage years. The patient remained well throughout this time and believed her previous cyanotic episodes settled. Neither she nor her family could recall the details of the problem or any investigations, though she was certain she never had surgery.
Over the next 20 years the patient remained asymptomatic and did regular aerobic exercise without limitation. After initiating discussions regarding pregnancy with her family doctor and relating this uncertain history of cyanosis, she was referred to an ACHD clinic. Despite several attempts, it was not possible to retrieve any clinical notes from either her original family doctor or the tertiary referral center.
Comments: In the past it was often routine policy for many units to destroy old case records after an interval of nonattendance. In patients with ACHD this often meant the unfortunate loss of old operation notes and results of previous investigations. Detailed discussions, including written documentation, with patients and their families will hopefully prevent similar shortcomings in the future.
Very few cardiac lesions cause intermittent cyanosis and then improve or are apparently cured. This history would tend to suggest a small right-to-left shunt rather than a progressive disorder with pulmonary vascular disease or impaired pulmonary blood flow.
Although being asymptomatic with a congenital cardiac disorder is reassuring, the absence of reported symptoms does not exclude important cardiac conditions that may impact on long-term outcome or the ability, for example, to carry a pregnancy safely.
PHYSICAL EXAMINATION
BP 104/68 mm Hg, HR 72 bpm, oxygen saturation on room air 100%
Height 162 cm, weight 65 kg, BSA 1.71 m 2
Surgical scars: None
Neck veins: A normal, nonelevated waveform was seen.
Lungs/chest: Clear to auscultation
Heart: Rhythm was regular. There was a widely split first heart sound. No murmurs were heard. Normal peripheral pulses were present.
Extremities: Nonedematous. There was no visible cyanosis. The nail beds were not clubbed in the hands or feet.
Comments: This patient was fully saturated at rest, but it is possible that desaturation/cyanosis might occur only during exercise. Right-to-left shunting at the atrial level may occur either through a PFO or an ASD, and occurs when RA pressure rises above LA pressure in the presence of a septal defect.
The normal neck veins are reassuring, but neck veins may be normal even when significant pathology is present, such as tricuspid regurgitation into a large RA with increased compliance.
The first heart sound is persistently split because of delayed closure of the tricuspid valve. This can be due to the presence of congenital abnormalities of the tricuspid valve itself or conduction abnormalities such as LBBB, or an ASD.
All professionals caring for congenital heart patients would be advised to check specifically for clubbing in the feet (see Case 17 ).
LABORATORY DATA
| Hemoglobin | 14.6 g/dL (11.5–15.0) |
| Hematocrit/PCV | 42% (36–46) |
| MCV | 88 fL (83–99) |
| Platelet count | 237 × 10 9 /L (150–400) |
| Sodium | 142 mmol/L (134–145) |
| Potassium | 4.2 mmol/L (3.5–5.2) |
| Creatinine | 0.8 mg/dL (0.6–1.2) |
| Blood urea nitrogen | 3.9 mmol/L (2.5–6.5) |
Comments: The laboratory results showed no evidence of erythrocytosis, which indicates that even transient cyanosis is not likely.
ELECTROCARDIOGRAM
FINDINGS
Heart rate: 73 bpm
PR interval: 195 msec
QRS axis: +127°
QRS duration: 135 msec
Sinus arrhythmia. Borderline first-degree AV block. Right-axis deviation. Atypical, complete RBBB. Generally low voltage.
Comments: The findings here suggest abnormalities of the RV and perhaps the RA. This could be consistent with volume overload conditions such as an ASD or Ebstein anomaly of the tricuspid valve. P-waves that are tall and peaked may be due to RA enlargement. AV block is common in many conditions, as are accessory pathways (25% of Ebstein anomaly patients). Low-voltage QRS complexes can be due to large body habitus, fluid retention states, and pulmonary disease and are commonly seen in Ebstein anomaly.
CHEST X-RAY
FINDINGS
Cardiothoracic ratio: 63%
Cardiomegaly with enlargement of the RA. Prominent main pulmonary artery. Normal lung parenchyma and mediastinum.
Comments: The CXR in this setting confirms gross right atrial enlargement, more so than might be expected from an ASD alone. Furthermore, and in contrast to ASDs, the pedicle of the heart is small, in keeping with the reduced pulmonary and systemic forward flow and cardiac output. This combination is much more suggestive of Ebstein anomaly. The CXR may vary greatly depending on the lesion severity. The heart may adopt a globular appearance due to the dilated RA. The cardiothoracic ratio is a good indicator of severity and may be useful as a serial measurement to assess disease progression.
EXERCISE TESTING
| Exercise protocol: | Modified Bruce |
|---|---|
| Duration (min : sec): | 13 : 38 |
| Reason for stopping: | Stopped by technician |
| ECG changes: | None |
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