Age: 32 years
Gender: Female
Occupation: Nurse’s assistant
Working diagnosis: Atrial septal defect with pulmonary arterial hypertension
HISTORY
The patient was well until 10 years ago (22 years old) when she had a successful pregnancy but developed a deep vein thrombosis 1 week postpartum. She was treated with warfarin for 6 months.
She was then well until 2 years ago (30 years old) when she developed pneumonia and was admitted to her local hospital. CXR showed a large heart, and an echocardiogram showed a large ASD.
Three months later, she presented with a swollen leg and sudden shortness of breath. For the first time, a bluish discoloration of her lips and fingertips was noted. An echocardiogram demonstrated elevated right ventricular systolic pressure. She was felt to have had a pulmonary embolus and was again started on warfarin. She was also started on nocturnal oxygen with continuous positive airway pressure therapy.
She is a nonsmoker.
Comments: Patients with an isolated ASD are usually asymptomatic even well into adult life. Early symptoms may include exertional dyspnea or fatigue, atrial flutter, or occasionally thromboembolic events.
The patient has developed cyanosis. In a patient with an ASD, cyanosis is worrisome as it implies new right-to-left shunting through the defect. This suggests the presence of elevated RV filling pressures and PAH, which was confirmed by echo.
Causes to consider here include recurrent deep venous thrombosis; primary PAH, which can sometimes affect young women; and pulmonary vascular disease from chronic volume overload (i.e., Eisenmenger syndrome). However, only very large ASDs, especially in patients living at high altitude, can easily explain the development of Eisenmenger syndrome. Otherwise, other causes should be sought.
CURRENT SYMPTOMS
Currently she can walk slowly about 200 m on level ground. Sometimes she is pushed in a wheelchair while shopping. She has experienced lightheadedness on exertion. She denies chest pain, palpitations, or syncope but at the end of each day notes ankle swelling. She sleeps well but apparently snored until her continuous positive airway pressure therapy was started.
NYHA class: III
Comments: Snoring should not be ignored, since sleep apnea can be a cause of or contribute to PAH, heart failure, and stroke risk.
CURRENT MEDICATIONS
Warfarin 4 mg orally at bedtime (target INR 2–3)
Digoxin 250 µg daily by mouth
Nifedipine 60 mg twice daily by mouth (as pulmonary hypotensive therapy)
Comments: Anticoagulation is indicated because of the history of presumed deep venous thrombosis as well as suspected pulmonary embolism. In general, anticoagulation is recommended in patients with primary PAH. In patients with Eisenmenger syndrome, the use of anticoagulants is controversial and can be dangerous if the INR is not carefully controlled.
PHYSICAL EXAMINATION
BP 110/70 mm Hg, HR 90 bpm, oxygen saturation 78% on room air measured in the right hand and 76% in the left foot
Height 162 cm, weight 91 kg, BSA 2.02 m 2
Surgical scars: None
Neck veins: JVP was elevated to 8 cm above the sternal angle with a prominent CV-wave.
Lungs/chest: Chest was clear.
Heart: There was a RV lift. There was wide fixed splitting of the second heart sound with a loud pulmonary component. A third heart sound was heard at the left lower sternal border. There was a grade 2 pansystolic murmur medial to the apex.
Abdomen: There was mild hepatomegaly.
Extremities: There was moderate symmetric pitting edema of both ankles. Clubbing was seen in both fingers and toes.
PERTINENT NEGATIVES
There were no findings of scleroderma or rheumatoid arthritis.
Comments: Cyanosis is clearly present as the history suggested, and the workup must try to clarify the etiology.
A CV-wave is indicative of tricuspid regurgitation.
A wide and fixed split second heart sound is a cardinal clinical sign in patients with a significant ASD. It reflects delayed pulmonary valve closure and a relatively fixed and increased right ventricular stroke volume. In fact, fixed splitting is not always seen in typical ASDs, especially in a case like this in which the left-to-right shunt has lessened in the face of pulmonary hypertension, which is suggested by the loud pulmonary component of the second heart sound.
The pansystolic murmur indicates mitral or tricuspid regurgitation or a VSD. There are various clinical ways of making the distinction. If this were felt to be of mitral origin, one should consider whether this is a primum ASD with a regurgitant left AV valve.
The presence of clubbing suggests that right-to-left shunting has been more chronic than the history indicates.
LABORATORY DATA
| Hemoglobin | 16.9 g/dL (11.5–15.0) |
| Hematocrit | 50% (36–46) |
| MCV | 81 fL (83–99) |
| MCH | 26 pg (27–32.5) |
| Sodium | 135 mmol/L (134–145) |
| Potassium | 4.3 mmol/L (3.5–5.2) |
| Creatinine | 0.8 mg/dL (0.6–1.2) |
| Blood urea nitrogen | 4.2 mmol/L (2.5–6.5) |
| Iron | 5.7 µg/L (12.6–26.0) |
| Ferritin | 8 ng/mL (20–186) |
| TIBC | 88 µmol/L (50–80) |
| Transferrin saturation | 7% (20–45) |
Comments: The elevated hemoglobin concentration in this patient represents secondary erythrocytosis. Secondary erythrocytosis is seen in chronically cyanotic patients and should be proportional to the severity of the hypoxemia. The term “secondary erythrocytosis” refers to an isolated increase in red blood cells (as opposed to polycythemia in which all cell lines proliferate) and is a physiologic adaptation to chronic hypoxemia.
If the oxygen saturation is 78%, one should expect the hemoglobin to be as high as 20 to 23 g/dL. Thus, this patient is relatively anemic despite her raised hemoglobin. This is because she is iron deficient. There are several potential etiologies for this (see Case 72 ). Iron deficiency is associated with an increased risk for stroke in cyanotic heart disease. This should be treated with oral iron supplementation or intravenous iron if the oral form is not tolerated. Her exercise capacity may improve with a higher hemoglobin.
The expected pattern of microcytosis and hypochromia seen here may be found in as few as 16% of cyanotic patients with iron deficiency. Instead, patients often present with hyperchromia and/or macrocytosis.
ELECTROCARDIOGRAM
FINDINGS
Heart rate: 89 bpm
PR int: 220 msec
QRS axis: +246°
QRS duration: 109 msec
Sinus rhythm with borderline first-degree block
P-wave forces compatible with dextrocardia
Some peaking of P-waves in V1–3, indicating RA overload
Marked deviation of the QRS axis
Inferior Q-waves unlikely to reflect prior infarction. Poor R-wave progression in the left chest leads. T-wave inversion in leads V1–4.
Comments: In a patient with dextrocardia, one needs to know where the limb and precordial leads were placed. This tracing suggests reversed limb lead placement. Inverted T-waves in V1–4, together with a prominent S-wave in V6 may indicate right ventricular hypertrophy.
Extreme axis deviation is strongly suggestive of pulmonary hypertension in this context.
First-degree AV block is also common in adults with ostium primum ASD, but may be seen in “older” patients with a large secundum ASD.
Thus the ECG suggests that the patient may indeed have an ostium primum ASD, that is, an AVSD, rather than a secundum ASD.
CHEST X-RAY
FINDINGS
Cardiothoracic ratio: 67%
The cardiac silhouette was grossly enlarged. Dilatation of the central pulmonary arteries was suspected, although this was not well seen. The SVC was dilated. The prominent bulging at the right cardiac border indicated RA enlargement.
Comments: Abnormal findings in patients with PAH usually include prominent central pulmonary arteries and attenuation of peripheral vascular markings (pruning). Signs of RA and RV enlargement may also be present. Enlargement of the RA is expected, given the findings on the physical examination and ECG. If LA enlargement were also present (not seen here in Fig. 15-2 ), one should consider left AV valve regurgitation as a cause.
EXERCISE TESTING
A cardiopulmonary test was not performed.
Distance walked: 185 m
Pretest O 2 saturation: 78% (room air)
Posttest O 2 saturation: 65% (room air)
Posttest heart rate: 119 bpm
Comments: The 6-minute walk test (6MWT) is commonly used as an “objective” measure of exercise capacity in patients with PAH. It has been demonstrated that, in patients with idiopathic PAH, the distance walked in 6 minutes is related to functional class and is predictive of mortality. For example, 185 m is a very low distance for this test, even in cyanotic patients.
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