Amiodarone is a highly effective treatment for supraventricular and ventricular tachyarrhythmia; however, it could be associated with several serious adverse effects, including liver injury. We report the clinical and histological features of two contrasting Japanese patients with amiodarone-induced reversible and irreversible hepatotoxicity. One patient with amiodarone-induced irreversible hepatotoxicity showed liver cirrhosis during treatment with amiodarone and died of hepatic failure; the other patient, who had reversible hepatotoxicity, showed a reversible course of liver function and imaging after discontinuation of amiodarone. We emphasize the importance of close monitoring of liver enzymes and evaluation of liver computed tomographic imaging as well as liver biopsy during treatment with amiodarone, and discontinuation should be considered when amiodarone-induced hepatotoxicity is suspected.

Background: Some patients with COVID-19 experienced sudden death due to rapid symptom deterioration. Thus, it is important to predict COVID-19 symptom exacerbation at an early stage prior to increasing severity in patients. Patients with COVID-19 could experience a unique “silent hypoxia” at an early stage of the infection when they are apparently asymptomatic, but with rather low SpO2 (oxygen saturation) levels. In order to continuously monitor SpO2 in daily life, a high-performance wearable device, such as the Apple Watch or Fitbit, has become commercially available to monitor several biometric data including steps, resting heart rate (RHR), physical activity, sleep quality, and estimated oxygen variation (EOV). Objective: This study aimed to test whether EOV measured by the wearable device Fitbit can predict COVID-19 symptom exacerbation. Methods: We recruited patients with COVID-19 from August to November 2020. Patients were asked to wear the Fitbit for 30 days, and biometric data including EOV and RHR were extracted. EOV is a relative physiological measure that reflects users’ SpO2 levels during sleep. We defined a high EOV signal as a patient’s oxygen level exhibiting a significant dip and recovery within the index period, and a high RHR signal as daily RHR exceeding 5 beats per day compared with the minimum RHR of each patient in the study period. We defined successful prediction as the appearance of those signals within 2 days before the onset of the primary outcome. The primary outcome was the composite of deaths of all causes, use of extracorporeal membrane oxygenation, use of mechanical ventilation, oxygenation, and exacerbation of COVID-19 symptoms, irrespective of readmission. We also assessed each outcome individually as secondary outcomes. We made weekly phone calls to discharged patients to check on their symptoms. Results: We enrolled 23 patients with COVID-19 diagnosed by a positive SARS-CoV-2 polymerase chain reaction test. The patients had a mean age of 50.9 (SD 20) years, and 70% (n=16) were female. Each patient wore the Fitbit for 30 days. COVID-19 symptom exacerbation occurred in 6 (26%) patients. We were successful in predicting exacerbation using EOV signals in 4 out of 5 cases (sensitivity=80%, specificity=90%), whereas the sensitivity and specificity of high RHR signals were 50% and 80%, respectively, both lower than those of high EOV signals. Coincidental obstructive sleep apnea syndrome confirmed by polysomnography was detected in 1 patient via consistently high EOV signals. Conclusions: This pilot study successfully detected early COVID-19 symptom exacerbation by measuring EOV, which may help to identify the early signs of COVID-19 exacerbation. Trial Registration: University Hospital Medical Information Network Clinical Trials Registry UMIN000041421; https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000047290

We herein report a case of nonbacterial thrombotic endocarditis (NBTE) in a patient with previously undiagnosed lung cancer. A 62-year-old woman presented to our hospital with multiple cerebral infarctions. There was no evidence of valvular heart disease or vegetations. Whole-leg ultrasonography revealed deep vein thrombosis of the left peroneal vein. We administered direct oral anticoagulants (DOACs) for a presumed diagnosis of paradoxical embolisms caused by patent foramen ovale. Unfortunately, she experienced further embolization and died. At a postmortem examination, she was diagnosed with NBTE and metastatic adenocarcinoma of the lung. Our experience with this patient suggests that DOACs may be an insufficient treatment for NBTE.

Objectives: The aim of this study was to investigate left ventricular (LV) function reserve in hypertrophic cardiomyopathy (HCM) patients with and without cardiac troponin gene mutations before transition to the dilated phase. Methods: LV ejection fraction (EF) was continuously evaluated in 52 patients with non-obstructive HCM during supine ergometer exercise using radionuclide ventricular function monitoring with a cadmium telluride detector (VEST). On the basis of genetic analysis, patients were divided into two groups: 10 with cardiac troponin gene mutations (group A) and 42 without these gene mutations (group B). Results: Exercise duration, peak exercise load, and heart rate during exercise did not differ between the two groups. The differences from baseline to peak exercise of the LV end-diastolic volume decreased similarly in the two groups. In contrast, the difference of the LV end-systolic volume in group A increased significantly compared with group B (17.7% (SD 12.7%) vs 3.4% (SD 13.2%); p = 0.0031). Consequently, the difference of LVEF in group A decreased significantly in contrast with group B (–14.1% (SD 11.1%) vs –1.2% (SD 11.7%); p = 0.0025). Additionally, the changes in LVEF and stroke volume decreased significantly more in group A than in group B (–22.2% (SD 18.6%) vs –1.1% (SD 17.8%); p = 0.0017 and –12.9% (SD 21.7%) vs 12.3% (SD 24.4%); p = 0.0042, respectively). Conclusions: These results suggest that HCM patients with cardiac troponin gene mutations may display exercise-induced LV systolic dysfunction more frequently than HCM patients without this abnormality.