Abstract 16019: Right Hemidiaphragm Paralysis Leading to Right Heart Failure

Background Diaphragmatic paralysis occurs due to direct or indirect damage to the phrenic nerve and can cause unilateral elevation. Diaphragmatic paralysis is usually asymptomatic; however, we present a case of syncope caused by right hemidiaphragm paralysis leading to extrinsic compression of the right heart causing hemodynamic compromise.

Case A 78-year-old female with a history of advanced dementia, and hypertension presented following a syncopal episode and was found altered and hypotensive. A chest X ray showed an elevated right hemidiaphragm. A Transthoracic echocardiogram demonstrated hyperdynamic systolic function of the left ventricle with an ejection fraction of 70 to 75% and a left ventricular outflow tract (LVOT) gradient of 64 mmHg. It was suspected that extrinsic compression of the right atrium and ventricle lead to underfilling of the left ventricle causing LVOT obstruction resulting in hypotension and syncope.

Discussion . Due to the patient’s underlying severe dementia her family wished for a conservative approach and additional cardiac investigation was deferred. She was treated conservatively with beta blockers to increase her diastolic filling time and intravenous fluids to promote LV filling in order to reduce her LVOT obstruction. Treatment of diaphragm paralysis depends on the severity of symptoms such as dyspnea on exertion, fatigue and syncope. An option that was discussed was diaphragmatic plication to decrease the intrathoracic pressure and the extrinsic compression on the right heart. More commonly, unilateral diaphragmatic paralysis is asymptomatic and is managed conservatively with observation.

Conclusion: Cardiac complications of hemidiaphragm paralysis are rare but this case illustrates how extrinsic compression of the right heart can lead to dynamic LVOT obstruction and highlights the importance of integrating imaging findings when evaluating patients for syncope.