PMC9411010_01
Progressive alterations on ECG. (a) Sinus rhythm and normal cardiac conduction before immune checkpoint inhibitor use. (b) New-onset left anterior fascicular branch block on admission. (c) New-onset complete right branch block plus left anterior fascicular branch block, namely bifascicular branch block. (d) Intermittent second degree atrioventricular block, with frequent premature atrial contractions, ST segment elevation, and poor R-wave progression in precordial leads. (e) Third degree atrioventricular block. Blue arrows indicating regular P waves. (f) Ventricular tachycardia (VT) with heart rate of 230 beats/min.
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Indicators including blood cell count, transaminase, creatinine, troponin I (TnI), creatine kinase (CK), creatine kinase MB (CK-MB), thyroid function, electrocardiography (ECG, Figure 1(a)), and echocardiography were unremarkable before initiation of camrelizumab treatment. ECG on admission showed a new-onset left anterior fascicular branch block (Figure 1(b)), followed by bifascicular branch block on the next day (Figure 1(c)). On day 3 of hospitalization, ECG revealed an intermittent second-degree atrioventricular block, with frequent premature atrial contractions, ST segment elevation, and poor R-wave progression in precordial leads (Figure 1(d)). Third-degree atrioventricular block occurred abruptly within the same day (Figure 1(e)) even with stable gas exchange and serum electrolyte levels, and then, an urgent temporary pacemaker was inserted. Although multiple therapeutic measures were administered, clinical status deteriorated after the occurrence of ventricular tachycardia (VT) with heart rate of 230 beats/min (Figure 1(f)).
Coronary angiography showing a normal coronary artery anatomy.
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Considering the elevated biomarkers of myocardial damage and dynamic ECG alterations, coronary angiography was performed to exclude myocardial infarction even without typical clinical presentations, which revealed normal coronary artery anatomy (Figure 2).