Age: 35
Gender: Female
Occupation: Hairdresser
Working diagnosis: Repaired atrioventricular septal defect
HISTORY
The patient was diagnosed at birth with an intermediate AVSD. At age 3 she underwent repair of the defect with a large Dacron patch and suture repair of the “cleft” in the left AV valve. The surgery was successful, and her follow-up was unremarkable.
At age 17 she was readmitted for cardiac catheterization due to repeated episodes of syncope and left arm pain. The results revealed a gooseneck deformity of the LVOT, mild left AV valve regurgitation (LAVVR), and a 38 mm Hg gradient across her LVOT. No abnormality of the aortic arch vessels was demonstrated. The gradient was not felt to be hemodynamically significant, and the episodes were attributed to vasovagal attacks.
The patient had thereafter remained completely asymptomatic for an additional 18 years. Recent outpatient review revealed a long ejection systolic murmur over the left sternal edge, and further arrangements were made for investigation.
Comments: The term “intermediate AVSD” describes a variant of AVSD in which there is a large atrial communication with a common AV junction (which is a unifying feature of all AVSDs), yet there are two separate AV valves. In addition, there is a small, restrictive interventricular communication between the chordal attachments of the bridging leaflets.
In patients with partial or intermediate AVSDs, elective repair of the left AV valve at the time of ASD closure has been recommended to improve outcome, although reoperation may be needed in a certain percentage of patients. Obviously, repair of AVSD before pulmonary vascular disease develops is essential, although the latter is unlikely to develop early in life unless there is additional pathology (such as upper airway obstruction in a patient with Down syndrome). Early repair improves long-term survival prospects and functional class and reduces the risk of subsequent AV valve degeneration.
The development of subaortic stenosis is usually progressive, and patients may be asymptomatic (symptoms may be absent or mild). The reported interval from repair to the development of subaortic obstruction in partial or intermediate AVSDs ranges from months to many years after repair, hence the need for indefinite follow-up.
PHYSICAL EXAMINATION
BP 135/90, HR 90 bpm, oxygen saturation on room air 98%
Height 168 cm, weight 105 kg, BSA 2.21 m 2
Surgical scars: Median sternotomy scar
Neck veins: A normal JVP was seen.
Lungs/chest: The chest was clear.
Heart: There was a regular heart rhythm with occasional ectopic beats. No thrills or heaves were palpable. The heart sounds were normal with a 3/6 ejection systolic murmur heard best at the left sternal edge.
Abdomen: No abnormality detected
Extremities: No abnormality detected. Peripheral pulses were all present. There was no edema.
Comments: In this setting of an intermediate AVSD, an ejection systolic heart murmur over the left sternal edge suggests LVOT obstruction. A pansystolic murmur near the apex would, in turn, suggest LAVVR.
LABORATORY DATA
| Hemoglobin | 15.0 g/dL (11.5–15.0) |
| Hematocrit/PCV | 46% (36–46) |
| MCV | 91 fL (83–99) |
| Platelet count | 250 × 10 9 /L (150–400) |
| Sodium | 139 mmol/L (134–145) |
| Potassium | 4.3 mmol/L (3.5–5.2) |
| Creatinine | 0.76 mg/dL (0.6–1.2) |
| Blood urea nitrogen | 3.5 mmol/L (2.5–6.5) |
Liver function tests: Normal
Thyroid function tests: Normal
ELECTROCARDIOGRAM
FINDINGS
Heart rate: 96 bpm
QRS axis: −30°
QRS duration: 120 msec
PR duration: 220 msec
Sinus rhythm, frequent PVCs. Left axis deviation, and a very atypical RBBB. LA overload is likely.
Comments: The hallmark finding of AVSDs on ECG is a superior (leftward or extreme right) QRS axis, seen in 95% of patients. This is a result of the abnormal AV junction and inferior displacement of the conduction system. RV volume overload, when present, is reflected by an rsR pattern in the right precordial leads or, less commonly, by a qR pattern. The PR interval may be prolonged. This finding is thought to be due to increased intra-atrial conduction time, and, in general, these patients are at risk of complete heart block.
CHEST X-RAY
FINDINGS
Cardiothoracic ratio: 57%
Situs solitus, levocardia with a left aortic arch. Increased cardiothoracic ratio with a relatively small pedicle of the heart and a small aortic knuckle. Mild dilatation of the pulmonary trunk.
Comments: Apart from cardiomegaly, the CXR is normal. A small aortic knuckle is common in patients with congenital heart disease, in keeping with long-standing low systemic cardiac output.
EXERCISE TESTING
| Exercise protocol: | Modified Bruce |
|---|---|
| Duration (min : sec): | 9 : 31 |
| Reason for stopping: | Fatigue |
| ECG changes: | LAD, RBBB |
| Rest | Peak | |
|---|---|---|
| Heart rate (bpm): | 90 | 171 |
| Percent of age-predicted max HR: | 92 | |
| O 2 saturation (%): | 98 | 99 |
| Blood pressure (mm Hg): | 135/90 | 184/80 |
| Peak V o 2 (mL/kg/min): | 24.1 | |
| Percent predicted (%): | 53 | |
| Ve/V co 2 : | 37 | |
| Metabolic equivalents: | 7.2 | |
Comments: The patient’s peak V o 2 is below normal for her age and gender, but is fairly representative of many asymptomatic adult congenital heart disease patients.
Exercise intolerance is prevalent in adult congenital heart diseases, even among asymptomatic patients, and is as severe as in patients with noncongenital heart failure. Lack of heart rate response to exercise, pulmonary arterial hypertension, and impaired pulmonary function can all be important covariates for impaired exercise performance, as are underlying cardiac anatomy and physiology. Poor exercise capacity carries prognostic information in these patients and is associated with an increased risk of hospitalization or death independent of symptom status.
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