Intramyocardial Hematoma

Corresponding Author

Intramyocardial hematoma (IMH) is a rare and often fatal complication, described as an incomplete cardiac rupture or hemorrhagic dissociation between the myocardial fibers.1, 2, 3 It most commonly occurs spontaneously after acute myocardial infarction,3, 4, 5 but it has also been reported following percutaneous coronary intervention (PCI), particularly during chronic total occlusion PCI, catheter ablation of scar-mediated ventricular tachycardia or premature ventricular complexes, cardiac surgery, and chest trauma.1, 2, 3, 4, 5, 6 IMH may involve the interventricular septum, left ventricular (LV) free wall, right ventricular (RV) wall, or left atrial wall.^3,4,7

In their case report in this issue of JACC: Case Reports, Van Cauteren et al⁸ describe a large septal intramyocardial dissecting hematoma following PCI, highlighting this life-threatening complication. A 56-year-old patient presented with sudden-onset exertional chest pain, and echocardiography revealed wall motion abnormality in the right coronary artery (RCA) territory. Coronary angiography demonstrated a 90% mid-RCA stenosis, and the patient underwent PCI with placement of 2 stents. Final angiography revealed a small Ellis type 2 perforation in the distal RCA, thought to be secondary to wire perforation of a small distal branch. Immediate postprocedure echocardiography showed no pericardial effusion, and the patient remained hemodynamically stable; therefore, conservative management was initially pursued.⁸

Three hours later, the patient developed recurrent chest pain. Repeat echocardiography revealed no pericardial effusion but demonstrated a large intracardiac mass within the basal-to-mid interventricular septum extending toward the RV.⁸ A follow-up study 30 minutes later showed rapid expansion with cavitation and flow on color Doppler imaging.⁸ Urgent coronary angiography confirmed ongoing bleeding into the septum, evidenced by contrast staining in segments of the distal RCA, right posterior descending artery, and right posterolateral branches. Balloon tamponade was unsuccessful, but placement of a covered stent sealed the distal vessel perforation, with sacrifice of the right posterolateral branch.⁸

The patient subsequently stabilized, and serial multimodality imaging, including echocardiography, computed tomography angiography (CTA), and cardiovascular magnetic resonance (CMR), confirmed an intramyocardial hematoma within the interventricular septum extending toward the RV without further expansion.⁸ This case underscores the importance of heightened clinical awareness of IMH and close post-PCI surveillance, particularly when contrast extravasation is observed. Serial imaging and a multidisciplinary approach were critical in guiding management and achieving a favorable outcome.⁸

The clinical presentation, management, and prognosis of IMH depend on multiple factors, including patient age, comorbidities, ventricular function, hematoma size and location, and hemodynamic stability.1, 2, 3, 4, 5, 6 IMH may result in myocardial rupture, tamponade, pseudoaneurysm formation, outflow tract obstruction, ventricular arrhythmias, and death.1, 2, 3, 4, 5, 6^,9 Intramyocardial blood tracking can lead to further myocardial separation and avulsion of perforating vessels, exacerbating hemorrhage and ischemia.^1,2,4,6,9

Currently, there are no standardized guidelines for the diagnosis or management of IMH. Its heterogeneous clinical presentation necessitates a high index of suspicion.^3,4 Published case reports and retrospective series emphasize that early recognition, vigilant monitoring, timely imaging, and prompt multidisciplinary decision-making may be lifesaving, even when angiographically minor coronary perforation is initially observed.^1,2,4,5

Diagnosis relies heavily on multimodality imaging.^2,4,7,9 Transthoracic echocardiography is typically the first-line modality owing to its accessibility and bedside availability.^4,7,9 Serial imaging with multiple views, color Doppler, and myocardial contrast echocardiography can help differentiate IMH from myocardial tissue and identify communicating channels.^7,9 However, limited image quality may complicate differentiation from LV thrombus, pseudoaneurysm, or trabeculations.^2,4,7,9 In such cases, comparison with prior studies and serial imaging are invaluable.^4,9 CTA offers high spatial resolution and delineates communication with adjacent structures, while CMR provides superior tissue characterization and diagnostic confidence.^4,7 Limitations of CMR include cost, prolonged scan times, and contraindications in patients with certain implanted devices.^2,4,7

Management strategies range from conservative monitoring to surgical evacuation of the hematoma and myocardial repair.^2,4,6,9 Small, stable hematomas are often managed conservatively with spontaneous resolution.^4,6,9 Surgery is typically reserved for expanding IMH with hemodynamic compromise, myocardial rupture, or tamponade unresponsive to percutaneous intervention.^1,2,4,7 When IMH results from coronary perforation during PCI, balloon tamponade, covered stents, or coil or fat embolization may be employed to halt bleeding and prevent progression.^1,9 Despite intervention, prognosis remains variable and often poor, underscoring the need for consistency in diagnostic and management strategies for this uncommon but high-risk complication.^1,2,4,5

The case presented by Van Cauteren et al⁸ serves as a critical reminder that although IMH is rare, it should remain high on the differential diagnosis after myocardial infarction or PCI complicated by coronary perforation of any severity. Knowledge of IMH, coupled with prompt diagnosis and a coordinated multidisciplinary approach, is essential to optimizing patient outcomes.

Funding Support and Author Disclosures

The author has reported there are no relationships relevant to the contents of this paper to disclose.