Age: 88 years
Gender: Female
Personal information: Grandmother
Working diagnosis: Secundum atrial septal defect
HISTORY
The patient was healthy throughout her childhood and adult years. She had two uneventful pregnancies, and has two healthy sons and numerous grandchildren.
Mild hypertension was diagnosed 15 years ago, and the patient was treated with medication. Around that same time she developed atrial fibrillation, which was treated with digoxin and aspirin and has been permanent for the last decade.
After the death of her husband several years ago, she managed to live independently. However, over the last few years she noted decreasing effort tolerance and frequent chest infections. She found it difficult to manage housework, shopping, and gardening while living on her own, and therefore moved to a larger city to be nearer her children. On arrival she established medical care with a new general practitioner.
She does not smoke or drink alcohol. There was no family history of congenital or ischemic heart disease.
Comments: Although she is now 88 years old the patient has until recently led an active and independent life. Obviously, elderly patients with exertional breathlessness will have ischemic heart disease much more commonly than an ASD, but it is not uncommon for a secundum ASD to present for the first time in an elderly patient.
Although the particular details are unknown, it is surprising that atrial fibrillation did not prompt a more thorough workup including echocardiography, which should have demonstrated her large ASD.
Worsening symptoms in this patient with an ASD are probably due to substantial left-to-right shunting and RV volume overloading (both tend to increase with age because of an increase in left ventricular end-diastolic pressures), and the development of PAH or LV diastolic dysfunction from systolic hypertension.
ASDs can be familial (autosomal dominant); at least three genes have been recently identified in families with ASD.
CURRENT MEDICATIONS
Digoxin 125 µg daily
Bendrofluazide 2.5 mg daily (a diuretic used for blood pressure control)
Perindopril 2 mg daily (for blood pressure control)
Aspirin 75 mg daily (presumably for her permanent atrial fibrillation)
Comments: Given her atrial fibrillation, hypertension, and age, the role of anticoagulation should be discussed with the patient. She is at risk of stroke (even after ASD repair) and should be advised to take warfarin unless there is a contraindication.
PHYSICAL EXAMINATION
BP 155/86 mm Hg, HR 70 bpm, oxygen saturation 92% on room air, near sea level
Height 158 cm, weight 53 kg, BSA 1.53 m 2
Surgical scars: None
Neck veins: 5 cm above sternal angle, normal waveform
Lungs/chest: Clear
Heart: There was an irregular rhythm, with a right parasternal heave. There was a normal first heart sound and wide splitting of the second sound with a loud pulmonary component (P2). There was also a 3/6 ejection systolic murmur in the third left intercostal space.
Abdomen: The abdominal examination was unremarkable.
Extremities: Extremities were well perfused without edema.
Comments: Hypertension may need better control. Her resting ventricular rate response to atrial fibrillation was well controlled. Oxygen saturation was mildly reduced, prompting one to consider why she might have a right-to-left shunt.
The right parasternal heave is indicative of significant RV volume and/or pressure overloading.
The loud P2 indicates elevated pulmonary artery (PA) pressures. The ejection systolic murmur is secondary to increased flow through the RVOT and pulmonary valve. Fixed splitting of the second heart sound would be expected in a patient with a secundum ASD but can be difficult to hear in some patients.
There were no clinical signs of right or left heart failure.
LABORATORY DATA
| Hemoglobin | 13.5 g/dL (11.5–15.0) |
| Hematocrit/PCV | 39% (36–46) |
| MCV | 93 fL (83–99) |
| Platelet count | 137 × 10 9 /L (150–400) |
| Sodium | 141 mmol/L (134–145) |
| Potassium | 4.4 mmol/L (3.5–5.2) |
| Creatinine | 1.0 mg/dL (0.6–1.2) |
| Blood urea nitrogen | 7.3 mmol/L (2.5–6.5) |
Comments: It is important to know whether the renal function is normal (systemic hypertension, on diuretics and an ACE inhibitor), especially if percutaneous intervention is to be considered.
ELECTROCARDIOGRAM
FINDINGS
Heart rate: 66 bpm
QRS axis: +123°
QRS duration: 133 msec
Atrial fibrillation
Right axis deviation
Right bundle branch block
Nonspecific ST segment depression
Comments: RBBB with right axis deviation should immediately prompt consideration of right heart disease. Right axis deviation is commonly associated with a secundum ASD, while RBBB with a leftward axis would be more typical for a primum ASD (see Case 15).
The ST segments in the inferior and anterior chest leads, especially V3–5, are downward sloping, and due to some combination of digoxin effect, RBBB, and RV hypertrophy.
CHEST X-RAY
FINDINGS
| Cardiothoracic ratio: | 76% |
There is gross cardiomegaly, with prominent central pulmonary arteries and a generally plethoric pulmonary vasculature. There is RA and presumably RV dilation (which would have been better seen on the lateral view, yet is not available).
Comments: Most likely, the large cardiac silhouette is mainly due to RA and RV enlargement. Prominent central pulmonary arteries may indicate volume or pressure overload, although the latter is unlikely given the numerous peripheral pulmonary vessels (no “pruning”).
EXERCISE TESTING
Pretest HR: 52, oxygen saturation 94%
Posttest HR: 66, oxygen saturation 87%
Distance walked: 221 m
Comments: In elderly patients who are not able to reliably perform maximal exercise testing, the 6MWT is a useful submaximal alternative for functional assessment. It is safe in the older population. The mean walk distance in patients older than 68 years of age is 344 m.
Other information from the test includes the peak heart rate and the oxygen saturation after exercise, which are particularly valuable in congenital heart disease. This test can be easily repeated in the future to monitor for clinical deterioration or improvement after an intervention.
In this patient, the minimal increase in heart rate is not surprising given her medically controlled atrial fibrillation. More important, there was mildly progressive oxygen desaturation after 6 minutes (94% to 87%) suggesting right-to-left shunt during exercise, intrinsic lung disease, or congestive heart failure.
ECHOCARDIOGRAM
OVERALL FINDINGS
The RV was severely dilated. The LV was small, with a left ventricular end-diastolic dimension of 42 mm and an end-systolic dimension of 25 mm. The LA was dilated. There was moderate tricuspid regurgitation; otherwise, valve function was normal. The RV size relative to the LV can be seen, as well as LA enlargement.
Comments: The RV enlargement is secondary to the chronic left-to-right shunt. The LA enlargement was probably due to the volume overload, hypertension, and chronic atrial fibrillation itself.
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