Age: 58
Gender: Female
Occupation: Professional gardener
Working diagnosis: Repaired partial atrioventricular septal defect
HISTORY
The patient was well until her mid-20s, when she noted progressive shortness of breath. Workup led to the diagnosis of a large primum ASD with left AV valve regurgitation (LAVVR).
She underwent surgery to close the defect and address the regurgitation. To repair the valve, the surgeon placed sutures between the mural and superior bridging leaflets that formed the left AV valve. When tested intraoperatively, this repair left a small residual leak, but it was felt that further suturing would create valvular stenosis.
The patient did well during the next 20 years, enjoying a full, active life including having and raising her three children.
Ten years ago she developed atrial fibrillation, which was converted to sinus rhythm with direct current (DC) cardioversion. Digoxin was started. She had several further episodes of atrial fibrillation in the next 4 years, each treated successfully with DC cardioversion. Multiple antiarrhythmic medications were tried, but each failed to prevent recurrent atrial fibrillation. Five years ago the patient had a few spells of lightheadedness. Sinus pauses up to 5 seconds long were noted on 24-hour ECG monitoring. Therefore a VVI pacemaker was inserted.
Apart from hypertension treated medically, she had no other medical problems. However, the patient noted gradual deterioration in her exertional tolerance and was seen again in clinic for review.
Comments: Not uncommonly the presence of a large primum ASD will not be found until adulthood. Partial AVSD implies that there are two discrete valvular orifices although there is a common AV “annular” ring (junction).
The left valve has three leaflets; therefore, technically, it is not a “mitral” valve, as the latter implies two leaflets. Instead, the proper terminology used is “left AV valve.”
The surgeon’s drawing of the intraoperative findings is shown ( Fig. 11-1 ), drawn from the perspective of an open right atrium, looking through the ASD toward the right and left AV valves. The surgeon may face the dilemma of relieving completely the regurgitation at the expense of inducing valve stenosis. Most surgeons would restore competence of the trileaflet AV valve by placing sutures between the superior and inferior bridging leaflets (and not between the mural and one of the bridging leaflets, as in this patient).
In today’s practice, left AV valve competence is assessed intraoperatively by TEE while weaning from cardiopulmonary bypass. This method assists optimal surgical repair and could potentially improve the long-term outcome following repair of the left AV valve.
Comments: In this patient, recurrent episodes of atrial fibrillation over 2 decades may suggest the development of significant LAVVR and LA enlargement. Recurrent atrial fibrillation per se may, in turn, worsen valvular regurgitation.
Even with optimal valvar repair, long-term LAVVR is not uncommon; reported reoperation rates for LAVVR vary from 6% to 18% between adult and pediatric series.
AVSD is associated with inherent abnormalities of the conduction system, relating to the abnormal common AV junction. Thus, AV block is not uncommon. Sinus node dysfunction is less common, but known to occur even before surgery ; it may relate to long-standing RA dilatation and stretch, as per any type of large ASD in the older patient. Furthermore, because of the surgical approach to repair through the RA, sinus node injury may also occur (less common in contemporary cohorts).
CURRENT MEDICATIONS
Digoxin 0.25 mg daily
Sotalol 80 mg twice daily
Losartan 50 mg twice daily
Amlodipine 5 mg daily
Warfarin adjusted for an INR of 2.0–3.0
Comments: The combination of digoxin and sotalol should provide optimal rate control for atrial fibrillation, and the doses could be increased if needed without the risk of bradycardia because of the indwelling pacemaker. Losartan and amlodipine were added for hypertension.
PHYSICAL EXAMINATION
BP 145/70, HR 70 bpm (paced), oxygen saturation 98%
Height 148 cm, weight 47 kg, BSA 1.39 m 2
Surgical scars: Median sternotomy
Neck veins: The JVP was mildly elevated, but a normal waveform was seen.
Lungs/chest: Clear to auscultation
Heart: The heart rhythm was regular. There was a widened and somewhat displaced apical impulse. The first and second heart sounds were normal, including a normal A2 and P2. There was a grade 3/6 holosystolic murmur at the apex, but no basal murmur or diastolic murmur.
Abdomen: Normal without organomegaly
Extremities: Mild lower extremity edema
Comments: BP control may not be optimal despite therapy.
The nature and location of the murmur clearly indicate LAVVR. The fact that neither a third heart sound nor a diastolic heart murmur was heard may indicate that the regurgitation is not severe. There is no evidence for concomitant AV valve stenosis.
ELECTROCARDIOGRAM
FINDINGS
Heart rate: 72 bpm
QRS axis: −60°
QRS duration: 100 msec
Atrial fibrillation with leftward axis, LV hypertrophy, and nonspecific ST segment depression with T-wave inversion. No pacemaker function seen.
Comments: LV hypertrophy is not a typical finding in AVSD patients but was present here prior to insertion of her pacemaker, indicating that systemic hypertension or outflow tract obstruction may have been long-standing.
Patients with AVSD typically have a leftward or extreme right QRS axis (superior axis) from inherent differences in their AV conduction. The ST changes could be related to digoxin or to LV hypertrophy.
CHEST X-RAY
FINDINGS
Cardiothoracic ratio: 71%
The cardiac silhouette was grossly enlarged. The prominent bulging at the right cardiac border indicates RA enlargement. The LA was also enlarged as indicated by the wide tracheal bifurcation angle and the relatively horizontal left main bronchus. The central pulmonary arteries were prominent. The patient had a transvenous pacing system with a single electrode placed in the RV apex.
Comments: The CXR suggests both RA and LA enlargement, in this case almost certainly reflecting long-standing atrial fibrillation and AV valve regurgitation (although a significant left-to-right shunt at the atrial level needs to be excluded).
EXERCISE TESTING
| Exercise protocol: | Modified Bruce |
|---|---|
| Duration (min : sec): | 6 : 23 |
| Reason for stopping: | Dyspnea |
| ECG changes: | None |
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