Background: Mitral valve prolapse (MVP) is rarely associated with sudden cardiac arrest. The "Pickelhaube sign" (tissue Doppler at the lateral mitral annulus ≥16cm/s) is a novel echocardiographic marker for Malignant MVP, which has not been previously described in children.

Case: 13 year-old female with Marfan syndrome and MVP with moderate mitral regurgitation (MR) presented with resuscitated cardiac arrest. An implantable defibrillator (ICD) was placed. Over the ensuing 15 months, she had 3 more appropriate ICD discharges for ventricular fibrillation despite escalation from beta blocker, to Sotalol, to amiodarone. Holter monitoring and ICD data did not show significant ventricular ectopy.

Decision‐making: Though her MR was only moderate and did not meet criteria for surgery on that basis, she was presented to our adult Mitral Valve Reference Center. Echocardiography showed the "Pickelhaube sign" with a velocity of 20cm/s (fig). She underwent mitral valve repair. Her MR was reduced to trivial with elimination of prolapse. On follow up, the lateral annular velocity was reduced to 9cm/s (fig). On only beta blocker, she has not experienced any ICD discharges in the 19 months since surgery.

Conclusion: Mitral valve-associated arrhythmias are not usually encountered in children. Multidisciplinary consideration of a pediatric patient with an adult Mitral Valve Reference Center led to the key finding of the "Pickelhaube sign" as an indication for repair which successfully addressed her arrhythmia.

Background: Proton beam therapy causing radiation-induced pericarditis is not a well-known cause of pericarditis. We present a case of a patient with Li-Fraumeni Syndrome who developed acute onset radiation-induced pericarditis.

Case: 46-year old female with history of breast cancer and Li-Fraumeni Syndrome presented with acute chest pain 10 days after initiation of proton beam therapy. Her electrocardiogram did not show any diffuse ST-elevations. She had elevated inflammatory markers with ESR 38 mm/hr, CRP 145 mg/L with D-Dimer 0.77 ug/ml. CT scan of chest showed no evidence of pulmonary embolism (PE) with trace pericardial fluid (Fig.1).

Decision‐making: Due to her history of breast cancer, elevated D-Dimer and acute onset chest pain, PE was ruled out. The etiology of her chest pain was diagnosed as pericarditis, likely induced by proton beam therapy, and she was started on ibuprofen followed by Colchicine. She had symptom resolution in 1 month. While there have been several documented cases of radiation-induced pericarditis, pericarditis caused by proton beam therapy is rare.

Conclusion: Our goal is to educate clinicians about this rare case due to the lack of documented cases of pericarditis secondary to proton beam therapy. Clinical suspicion in patients receiving this form of radiation and early management can lead to rapid symptomatic improvement in these patients.

Background: Ibrutinib is an irreversible Bruton's tyrosine kinase (BTK) inhibitor that is used to treat B-cell malignancies. Specifically, it has been shown to be extremely efficacious against chronic lymphocytic leukemia (CLL). Ibrutinib has numerous side effects and is noted to be especially cardiotoxic. Here, we present a case of ibrutinib induced new onset atrial fibrillation (AF).

Case: A 64-year-old male with a history of hypertension and CLL Rai stage IV presented to the emergency department for palpitations. His medications included ibrutinib 420 mg once daily and valsartan 80 mg once daily. Physical examination revealed irregularly irregular rhythm and electrocardiogram showed AF with rapid ventricular response.

Decision‐making: Deciding to stop or continue ibrutinib and AF management were the biggest challenges. After ruling out reversible causes of AF and consulting oncology, it was decided to discontinue ibrutinib due to this side effect being witnessed in 3%-16% of patients. Rate control was achieved with metoprolol succinate 25 mg once daily. Cardioversion should be considered only in those patients who can tolerate anticoagulation for a short time given the heightened risk of acute stroke in post cardioversion period. Therefore, our patient was started on apixaban 5 mg twice a day and scheduled for transesophageal cardioversion for restoration of the normal rhythm.

Conclusion: Ibrutinib induced AF is a serious therapy-limiting side effect. The anticoagulation for stroke prophylaxis needs to be considered on case-to-case basis.

Background: A massive hiatal hernia causing left atrial (LA) compression is an uncommon etiology of syncope that has clinical significance with regard to focused history, sequential diagnostic evaluation, and a multidisciplinary interventional approach.

Case: A 64-year-old male presented with a four-month history of recurrent syncopal and near-syncopal episodes associated with heavy meals and large volume intake of carbonated beverages. Evaluation for cardiac causes of syncope was unrevealing, however TTE did demonstrate near complete echogenic obliteration of the LA cavity with a decreased velocity time integral. A TEE and contrasted CT chest were performed, which revealed a large hiatal hernia with posterior LA mass effect.

Decision‐making: Given the diagnostic findings, the hiatal hernia was deemed to be the culprit pathology resulting in LA compression, transiently decreased LA stroke volume and cardiac output, and subsequent syncope. Surgical repair of the hiatal hernia was recommended through multidisciplinary discussion. The patient opted for outpatient management and was discharged home with precautionary measures. This case highlights the utility of maintaining a broad differential for cardiac syncope, including extracardiac causes which may result in hemodynamic compromise.

Conclusion: Extrinsic LA compression is a rare cause of syncope that highlights the interplay between clinical findings, multimodal cardiac diagnostic imaging, and cardiac hemodynamics.