Dataset Information

Paroxysmal supine hypoxaemia with hyperthyroidism and atrial fibrillation: a case report of a diagnostic challenge.

ABSTRACT:

Background

A patent foramen ovale (PFO) is a persistent embryonic defect in the interatrial septum. Platypnoea-orthodeoxia syndrome is characterized by positional hypoxaemia that is most commonly due to right-to-left shunting through a PFO. Dynamic right-to-left shunting through a PFO can also exacerbate positional hypoxaemia without platypnea-orthodeoxia syndrome.

Case summary

A 78-year-old woman with hyperthyroidism and paroxysmal atrial fibrillation (AF) presented with positional hypoxaemia exacerbated by supine positioning. Diagnostic testing revealed intermittent right-to-left shunting through a PFO triggered by worsening atrial functional tricuspid regurgitation and elevated right atrial pressures. Diuresis, rate control, and thyroidectomy initially led to resolution of positional hypoxaemia, but recurrent AF episodes triggered right-to-left shunting with recurrent desaturation. Left atrial and cavo-tricuspid isthmus ablation led to restoration of normal sinus rhythm and resolution of positional hypoxaemia without PFO closure.

Discussion

The clinical presentation of intermittent intracardiac right-to-left shunting can mimic decompensated heart failure with pulmonary oedema. Persistent hypoxaemia out of proportion to the degree of pulmonary oedema and minimally responsive to supplemental O₂ should raise suspicion for right-to-left shunt aetiology. Positional arterial blood gases can facilitate the diagnostic evaluation of refractory hypoxaemia in cases of suspected shunting. Diagnostic imaging for PFO detection includes both transthoracic and transesophageal echocardiography with Valsalva manoeuver and agitated saline injection. Closure of a PFO for management of arterial deoxygenation syndromes should not be performed before treating other causes of arterial deoxygenation and optimizing factors that may exacerbate shunting across the PFO.

SUBMITTER: Liu LY

PROVIDER: S-EPMC9204465 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:RationaleAtrial fibrillation (AF) is encountered rarely in pregnancy. Management of maternal AF is challenging as it poses a threat to both maternal and fetal well-being.Patient concernsWe report a case of a 35 weeks pregnant woman who presented in emergency with sudden-onset palpitations and mild shortness of breath with no personal/family history of cardiac diseases.DiagnosesPatient's pulse was irregularly irregular with an average rate of 179 beats per minute. The obstetric examination was normal.DiagnosisHigh-sensitive cardiac troponin T (hs-cTnT) was elevated. The 12 lead electrocardiogram (ECG) confirmed AF. The obstetric ultrasound, electronic fetal heart rate (EFHR) trace, and maternal echocardiography were normal.InterventionsThe patient was admitted under joint cardiology and obstetric care and monitored with continuous telemetry. She was commenced on a therapeutic dose of low-molecular weight heparin (LMWH) and intravenous fluid. She received a single 200 Joule synchronized direct current (DC) shock under general anesthesia in operation theater, which reverted the rhythm back to normal. EFHR monitoring was normal pre- and post-DC cardioversion. We acknowledge the unwise use of therapeutic dose of LMWH before DC cardioversion (DCCV) because of a potential need for emergency cesarean delivery for maternal and/or fetal compromise.OutcomeThe patient remained well and in sinus rhythm after cardioversion. She was discharged home the following day on Flecainide (anti-arrhythmic) and therapeutic dose of low molecular weight heparin (LMWH) and followed up in outpatient clinics frequently. She had a baby at term and received prophylactic LMWH for 10 days post-cesarean. She was discharged from cardiology clinic when she was 10 weeks postnatal, and Flecainide was discontinued.LessonsWe are reporting this case because of the rarity of the condition and successful use of DCCV for treating maternal AF. High-sensitive cardiac troponin T (hs-cTnT) level is a useful laboratory indicator to gauge the severity of AF in pregnancy. We emphasize to make the arrangements for EFHR monitoring and potential cesarean delivery and advocate cautious use of thromboprophylaxis while planning for electrical cardioversion (ECV) for maternal AF.