PMC6465686_01
Case 1: EKG changes observed on day 32 after 1 dose of pembrolizumab 200 mg infusion showing left bundle branch block (a) and right bundle branch block (b).
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F1
Electrocardiogram (ECG) and telemetry findings showed that the patient had alternating right (RBBB) and left bundle branch block (LBBB), episodes of asystole, and third-degree block with a junctional escape rhythm (Fig. 1a, b).
PMC6465686_02
PMC6465686_03
Case 3: EKG changes observed on day 12 after 1 dose of pembrolizumab 2 mg/kg infusion showing right bundle branch block.
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F2
On presentation, his ECG demonstrated RBBB (Fig. 2) and a transthoracic echocardiogram showed right ventricular dilation with normal right systolic function and a hyperdynamic left ventricle with preserved regional wall motion.
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Case 4: Cardiac MRI showed T2 intramyocardial intensity consistent with edema and early gadolinium enhancement, consistent with the Lake Louise Criteria for myocarditis.
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F3
A cardiac MRI showed T2 intramyocardial intensity consistent with edema and early gadolinium enhancement (see Fig. 3) consistent with the Lake Louise Criteria for myocarditis.
Case 4: Autopsy specimen of the heart demonstrating multiple white tumor metastatic nodules in the right atrium.
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F4
On gross examination of the heart, multiple white tumor metastatic nodules were noted in the right atrium, septum, right and left ventricle, raising the possibility of an on-target cardiotoxicity of ICIs directed at the tumor nodules (Fig. 4).
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