Age: 31 years
Gender: Female
Occupation: Nurse
Working diagnosis: Repaired atrioventricular septal defect
HISTORY
The patient had an AVSD diagnosed in infancy and repaired in childhood. By age 6, however, she needed left AV valve repair. However, AV valve regurgitation persisted. One year later she underwent left AV valve replacement with a Bjork Shiley (single disc mechanical) valve.
She developed paroxysmal, then chronic atrial fibrillation at 21 years. This required medical management with amiodarone initially, followed by bisoprolol. She was also on warfarin. In addition she was started on losartan for elevated blood pressure.
At 23 years she experienced sudden chest pain and shortness of breath and suffered a large anterior myocardial infarction. She was found to have an occlusion of the left anterior descending coronary artery, felt to be embolic in origin. Eventually, a large LV aneurysm formed.
Three years later she had worsening ventricular dilatation and dysfunction, and symptoms of severe heart failure. It was decided that she should undergo LV aneurysmectomy with further left AV valve replacement using a bileaflet Carbomedics 27-mm valve. The procedure went well, and she made an excellent recovery, though remained in permanent atrial fibrillation.
At age 30 she and her partner were considering having their first child. She was referred for prepregnancy counseling to a multidisciplinary pregnancy cardiac clinic.
The patient had no family history of congenital heart disease and had no chromosomal anomaly.
Comments: AVSD denotes a deficiency of AV muscular and membranous septa. A prevalence of 0.19 per 100 live births, accounting for 2.9% of congenital cardiac malformations, has been quoted.
Primary repair of AVSD in the first 3 to 6 months of age has been the preferred surgical management since the early 1980s. This patient had her surgical repair in an earlier era. Because the left AV valve is not a normal mitral valve, postoperative AV valve function is as important to assess as the septal closure itself. Failure of adequate left AV valve repair occurs in up to one fifth of procedures. The need for valve replacement occurs in about 5%.
Chronic atrial fibrillation occurs in 18% of patients long term after repair of incomplete AVSD and in up to 50% of adult patients who undergo valve surgery. The combination of these factors in this case makes atrial fibrillation seem unsurprising even at this young age.
The cause of the embolus was not clear, but felt most likely related to the presence of a prothrombotic valve. There was no residual ASDs, and she has always been compliant with warfarin. The LA was not huge.
Aneurysmectomy can at times restore some LV geometry and more favorable LV mechanics. The Bjork Shiley valve was functioning normally at the time of surgery, but was replaced both to offer a more appropriately sized valve now that the patient was an adult, and because it had been implicated in the coronary embolus.
CURRENT SYMPTOMS
The patient was asymptomatic. She felt able to carry on all her typical activities of daily living, including shopping, walking, and climbing stairs. She denied palpitations, orthopnea, or chest pain.
NYHA class: I
Comments: Despite her remarkable history of LV dysfunction, she has no self-reported symptoms.
PHYSICAL EXAMINATION
BP 110/70 mm Hg, HR 82 bpm, oxygen saturation 99%
Height 161 cm, weight 63 kg, BSA 1.68 m 2
Surgical scars: There was a midline sternotomy scar.
Neck veins: Seen 2 cm above the sternal angle with a normal waveform
Lungs/chest: Clear to auscultation
Heart: The pulse was regular. There was a prosthetic first heart sound. No murmurs were audible. The apical impulse was not palpable.
Abdomen: No abnormalities were seen.
Extremities: Peripheral pulses were normal, there was no edema.
Comments: The findings are fairly nondescript and as expected for a patient with a prior valve replacement. She was not in atrial fibrillation at the time of the exam.
LABORATORY DATA
| Hemoglobin | 13.2 g/dL (11.5–15.0) |
| Hematocrit/PCV | 41% (36–46) |
| MCV | 85 fL (83–99) |
| Platelet count | 260 × 10 9 /L (150–400) |
| Sodium | 136 mmol/L (134–145) |
| Potassium | 4.2 mmol/L (3.5–5.2) |
| Creatinine | 0.88 mg/dL (0.6–1.2) |
| Blood urea nitrogen | 6 mmol/L (2.5–6.5) |
Comments: All within normal/desirable limits.
ELECTROCARDIOGRAM
FINDINGS
Heart rate: 105 bpm
QRS axis: −160°
QRS duration: 100 msec
Sinus tachycardia
Extreme axis deviation
There are precordial Q-waves and mild ST elevation from the prior anterior infarction.
Comments: The axis deviation reflects her prior LV aneurysmectomy surgery and her AVSD.
Because of the intermittent atrial fibrillation, a 24-hour ECG was performed, which showed several episodes of atrial fibrillation, all with appropriate ventricular rate control.
EXERCISE TESTING
| Exercise protocol: | Modified Bruce |
|---|---|
| Duration (min : sec): | 10 : 28 |
| Reason for stopping: | Dyspnea |
| ECG changes: | Atrial fibrillation |
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