Rapid Review·Cardiovascular
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Congenital Heart Disease
T1Must knowPatent Foramen Ovale
Focus on
A flap that never sealed — present in one adult in four, silent in almost all, and the culprit when a young patient with a DVT has a stroke. Bubble echo with Valsalva shows the right-to-left shunt. Nothing for the incidental PFO; device closure for the young patient with a cryptogenic stroke and no other cause.
Key takeaways
What it is
Patent foramen ovale
a normal variant in which the foramen ovale stays patent beyond 1 year of age.- The septum primum fails to fuse with the septum secundum after birth, leaving a flap-valve tunnel, not a hole (Atrial Septal Defect).
When it opens
it stays closed while left atrial pressure exceeds right, and opens transiently with coughing, straining or Valsalva, permitting brief right-to-left shunting.How common
present in about 25 percent of adults.Clinical features and diagnosis
Asymptomatic in nearly everyone
no murmur, normal examination and electrocardiogram, until a complication of right-to-left shunting.Paradoxical embolism
a venous thrombus (after deep vein thrombosis) crosses to the arterial side and causes an ischemic stroke in a young patient without another cause (cryptogenic stroke); also decompression illness in divers.Platypnea-orthodeoxia
dyspnea and desaturation on sitting up that resolve lying down (positional shunting); hypoxemia when right atrial pressure is high.A bubble study is the best initial test
transthoracic echocardiography with agitated saline; the defect is often found incidentally.- A right-to-left shunt that opens with coughing or Valsalva is diagnostic (bubbles in the left atrium within a few beats).
Transesophageal echo
defines the anatomy before closure.In cryptogenic stroke, exclude the other causes first
prolonged rhythm monitoring for atrial fibrillation, vessel imaging, hypercoagulability testing in the young, a search for deep vein thrombosis.| Patent foramen ovale | Atrial Septal Defect | |
|---|---|---|
| Anatomy | Flap-valve tunnel from failed fusion | True tissue deficiency |
| Shunt | Intermittent right-to-left with straining | Continuous left-to-right |
| Murmur and S2 | None; normal S2 | Pulmonic flow murmur, fixed split S2 |
| Right heart | Normal | Volume overload; late pulmonary hypertension |
| Closure | Only after an embolic event | For right-ventricular enlargement, symptoms, a significant shunt |
Management and complications
Asymptomatic
no treatment and no follow-up.After an embolic event (ischemic stroke) attributed to the foramen
in a patient aged 18 to 60 with no other cause, percutaneous device closure plus antiplatelet therapy reduces recurrence.- The benefit is largest with a large shunt or a septal aneurysm; antiplatelet therapy alone if closure is declined.
Anticoagulation instead
when there is a concurrent deep vein thrombosis, pulmonary embolism or hypercoagulable state (treat the venous thromboembolism itself).Complications
paradoxical embolic stroke and systemic embolism, decompression illness, hypoxemia with raised right-sided pressures.- After closure: transient atrial fibrillation and device thrombus.
A 38-year-old has an ischemic stroke with no atrial fibrillation, no vessel disease and no hypercoagulable state; a bubble study shows bubbles crossing to the left atrium on Valsalva. What is the diagnosis and the treatment?
A patent foramen ovale with paradoxical embolism (cryptogenic stroke, age 18 to 60). Treat with percutaneous device closure plus antiplatelet therapy; anticoagulate instead if there is a deep vein thrombosis or a hypercoagulable state.
How it's tested
A 34-year-old woman on oral contraceptives develops sudden aphasia and right arm weakness after a long flight; bubble echo shows bubbles in the left atrium with Valsalva and leg duplex shows a DVT: paradoxical embolism through a PFO — anticoagulate the DVT; consider closure after the venous thrombosis is treated and no other stroke cause is found.
A 28-year-old with a cryptogenic stroke, a PFO with an atrial septal aneurysm, negative 30-day monitoring and a normal hypercoagulable screen: percutaneous PFO closure plus antiplatelet therapy — fewer recurrent strokes than antiplatelets alone.
A 45-year-old's routine echo shows a small PFO with bubbles only on Valsalva; no symptoms ever: normal variant — reassure, no treatment.
Bubbles appear in the left atrium after 8 beats rather than 3, in a patient with nosebleeds and telangiectasias: pulmonary AVM (HHT), not a PFO — the delay is the clue.
Dyspnea and hypoxemia that appear when the patient sits up and vanish when lying flat: platypnea–orthodeoxia from a positional right-to-left shunt through a PFO — closure.
Go deeper
Guidelines: 2021 AHA/ASA Secondary Stroke Prevention Guideline
Related Step 2 pages: Atrial Septal Defect, Fetal Circulation & Transition at Birth, Cardiac Embryology Essentials, Hereditary Hemorrhagic Telangiectasia, Approach to Congenital Heart Disease
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