(248) Paradoxical Bradycardia: A Retroperitoneal Hematoma Following Percutaneous Coronary Intervention

Introduction: Paradoxical bradycardia is an aberrant physiologic response to hemorrhage, defined as a heart rate less than 60 beats per minute. We present a case of paradoxical bradycardia secondary to a retroperitoneal hematoma following percutaneous coronary intervention (PCI).

Description: A 69-year-old woman with atrial fibrillation and triple-negative breast cancer presented from cardio-oncology clinic after an echocardiogram revealed a reduced ejection fraction (40%) and a left ventricular thrombus. Left heart catheterization via right femoral access revealed multivessel coronary artery disease. PCI with drug-eluting stents were placed at the proximal left anterior descending artery and bifurcation with the diagonal branch. Triple antithrombotic therapy with aspirin, ticagrelor, and heparin was started.

She subsequently experienced two episodes of hypotension with junctional bradycardia, reporting vasovagal-like symptoms. Her symptoms improved with fluid boluses, however she then fluctuated between sinus bradycardia and tachycardia. There was concern for sinus node dysfunction given long-term metoprolol use, right coronary artery disease, and history of chemoradiation and she was considered for pacemaker implantation. However, a computed tomography scan revealed a large right-sided retroperitoneal hematoma. Anticoagulation was held, and she received two units of packed red blood cells. She stabilized and remained in normal sinus rhythm.

Discussion: Bradycardia is an atypical presentation for a retroperitoneal hematoma following PCI. The pathophysiology is multiphasic. When blood first fills the retroperitoneum it augments vagal tone. Then, hemorrhage activates a cardioprotective bradycardic (Bezold-Jarisch) reflex by increasing vagal efferent activity in mechanoreceptors inside the left ventricle.

Risk factors for retroperitoneal bleeds include glycoprotein IIb/IIIA inhibitors and female anatomical variance. Although the incidence of retroperitoneal hematomas have declined, triple antithrombotic regimens are associated with higher bleeding risks.

In summary, clinicians should be mindful of paradoxical bradycardia following PCI as an early clinical manifestation of retroperitoneal hematoma, which is associated with increased short-term mortality.