Intracardiac Ultrasound and Mapping Integration-Guided Endomyocardial Biopsy for the Diagnosis of Myocardial Melanoma Metastasis

Central Illustration

hyperintensity indicating the presence of edema.There was no significant gadolinium uptake on firstpass perfusion.There was late gadolinium enhancement (LGE) of the mass with a central core of hypoenhancement of an eccentric T2 hyperintense and T1 isointense left lateral ventricular tumor of 2.2 Â 3.3 cm (Figure 1).To confirm the suspected diagnosis of myocardial metastatic melanoma and establish an appropriate treatment plan, a multidisciplinary cardiology team decided to perform a left ventricular endomyocardial biopsy guided by real-time imaging.
After consent from the patient and his family and consultation with oncology, the patient was taken to the electrophysiology laboratory for the biopsy.Electrodes for the Carto 3 (Biosense Webster) electroanatomic 3-dimensional mapping system were applied to the patient's back, and the Sentinel Cerebral Protection System (Boston Scientific) was deployed in the right innominate and left carotid arteries after access was obtained to the right radial artery.Intravenous heparin was administered to anticoagulate the patient.
The right femoral vein was accessed to advance an 8-F sensor-enabled intracardiac ultrasound catheter (Soundstar, Biosense Webster) into the right cardiac chambers where the absence of intracardiac thrombus was confirmed.The Cartosound software (Biosense Webster) was used to register and reconstruct the left ventricular anatomy, and the tumor and anterolateral papillary muscle were tagged (Figure 2).
Transseptal access was obtained with a Baylis VersaCross sheath and electrified wire under intracardiac ultrasound guidance.The sheath was replaced with a Vizigo deflectable sheath (Biosense Webster), which was advanced into the left ventricle.A matrix was created with a PentaRay NAV multielectrode catheter (Biosense Webster) to visualize other electrified tools in the spatial registration of the left ventricular cardiac anatomy.Intracardiac bipolar voltage recorded from the endocardium overlying the tumor was normal (>1.5 mV).
A biopsy forceps was connected to a bipolar cable and advanced through the Vizigo deflectable sheath.The forceps was directed to the tumor with the aid of the deflectable sheath and intracardiac ultrasound visualization, and multiple samples were obtained and sent to pathology for evaluation (Figure 2).The patient tolerated the procedure well, and all catheters were removed.Heparin was reversed with intravenous protamine, and the patient returned to recovery.A follow-up echocardiogram showed no evidence of pericardial effusion, and the patient had no evidence of neurologic deficit.Aspirin 81 mg daily was prescribed for 1 month.
Because the tumor did not invade into the left ventricle, long-term anticoagulation was not considered indicated.

FIGURE 1 Cardiac Magnetic Resonance Imaging
The figure illustrates the cardiac tumor and its characteristics.The arrow is pointing to the tumor that corresponds to an 18 F-fluorodeoxyglucose avid mass previously identified by positron emission tomography/computed tomography.

Intracardiac Echocardiography Mapping Integration for EMB
A P R I L 2 0 2 4 : 3 2 5 -3 2 8 Pathology confirmed cardiac melanoma metastasis, and the patient was counseled and scheduled for immunotherapy with an intravenous nivolumab and relatlimab combination.Follow-up imaging demonstrated a reduction in size from 3.3 Â 2.2 cm to 2.6 Â 1.4 cm after 6 months of treatment.

CASE DISCUSSION
][7][8][9] Imaging modalities such as echocardiography and electroanatomic mapping systems have been used to guide the procedure, especially in cases of uncommon diseases such as sarcoidosis, eosinophilic myocarditis, or arrhythmogenic cardiomyopathy. 3,4,6,7,9Transthoracic echocardiography and positron emission tomography/computed tomography can identify morphologic and 18 F-fluorodeoxyglucose avidity, respectively. 3,4,9Cardiac magnetic resonance provides myocardial tissue characterization and in our case provided insights into the lesion characteristics (Figure 1).Cine steadystate free precession frequency assesses morphologic and dynamic motion with high spatial and temporal resolution.T1-and T2-weighted sequences discriminate the neoplastic lesion from a normal myocardium and are influenced by different tissue composition such as fat, edema, proteinaceous content, or hemorrhage.
Unexpectedly, there was a lack of first-pass perfusion.We suspect this was caused by an abundance of tissue necrosis and edema and paucity of vascularity.There was intense LGE indicating the presence of inflammation and tissue necrosis/fibrosis.We suspect the well-circumscribed core of hypoenhancement on LGE imaging represented a focus of fluid.

Intracardiac Echocardiography Mapping Integration for EMB
In some cases, surgical or fluoroscopically guided EMB may have prohibitive risks. 3,4,8,97][8]10 For example, in a case in which a cardiac tumor affecting the lateral wall of the left ventricle required sampling, a transseptal access of the left ventricle was obtained using intracardiac ultrasound guidance. 3,4,9,10The tumor and anatomy were then identified and registered with intracardiac ultrasound in a 3-dimensional mapping system. 3,4,9,106][7] This technique may be particularly useful in patients with suspected cardiac metastases from melanoma in whom blind biopsy may miss the affected areas. 66][7] Further studies are needed to evaluate the long-term clinical outcomes of EAVM-guided biopsy and its cost-effectiveness compared to traditional blind biopsy.

CONCLUSIONS
EMB guided by intracardiac ultrasound integrated to a 3-dimensional electroanatomic mapping system is feasible and may result in higher yield and enhanced safety.In the case we present, the challenge represented by the location of a single lesion of a limited size could be effectively overcome with a percutaneous procedure, resulting in a definitive diagnosis.

FUNDING SUPPORT AND AUTHOR DISCLOSURES
Dr Widmer is an advisor to Abbott, Medtronic, and Philips.All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

FIGURE 2
FIGURE 2 Carto Mapping System Screen During Endomyocardial Biopsy

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A C C : C A R D I O O N C O L O G Y , V O L .6 , N O . 2 , 2 0 2 Fan et al A P R I L 2 0 2 4 : 3 2 5 -3 2 8