BACKGROUND: A 65-year-old man, Filipino, with comorbidities consulted because of shortness of breath. Chest computed tomography scan showed ground-glass opacities and crazy paving patterns (computed tomography severity score = 29). He required oxygen at 4 L/min, with bradycardia. Cardiac enzymes and transthoracic echocardiogram did not show abnormalities. Serial electrocardiogram and electrolytes showed arrhythmia and electrolyte imbalance. Accumulated evidence showed that cardiac involvement is common in patients with COVID-19.1,2 Atrial and ventricular arrhythmia is common even if there is no history of arrhythmia, normal cardiac biomarkers, and transthoracic echocardiogram. Different mechanisms have been proposed for the cause of electrolyte imbalance (see Discussion) that may lead to arrhythmia. Both potassium and calcium were used as a marker of clinical severity and worse prognosis in patients with COVID-19.3,4

CONCLUSION: Arrhythmia in COVID-19 patients are more frequent in elderly with comorbidities. Close monitoring and correction of electrolyte imbalance are important to prevent arrhythmia, which can sometimes be fatal.

INTRODUCTION: Functional capacity is a strong predictor of mortality and nonfatal cardiovascular outcomes in both men and women with and without coronary artery disease. This study aimed to compare the distance traveled of the 6-minute walk test (6MWT) to the metabolic equivalent (MET) of the treadmill exercise test (TET) as a measure of functional capacity among healthy ManilaMed (Medical Center Manila) employees and to determine and compare the distance traveled in 6MWT and the MET of TET according to general characteristics such as age, sex, height, weight, and body mass index (BMI) as determinants of maximal walking distance and the cause of the early termination of the TET. METHODS: This was a single-center prospective cross-sectional study done at a private tertiary hospital. All participants underwent TET and 6MWT. Metabolic equivalent of TET, distance traveled in 6MWT, and the computed MET of the distance traveled were recorded and analyzed. RESULTS: Fifty healthy employees performed both the 6MWT and the TET to measure their functional capacity. Twenty-two were males, and 28 were females. The mean age was 31.80 ± 7.17 years, and the mean ± SD for BMI was 25.05 ± 4.32 kg/m2. Using 400 m as predictor of good functional capacity, the farther the distance traveled (>400 m), the higher the MET they achieved in the TET, and the lower the distance traveled (<400 m), the lower the MET achieved in the TET (t test P = 0.0125). This study also showed that more than or equal to 400-m distance traveled in the 6MWT can be used as a measure of good functional capacity in this population. However, there was a significant difference (t test P = 0.006) in the computed MET in the 6MWT in relation to the MET achieved in TET. In this study age, sex, and BMI were the predictors of the distance traveled in the 6MWT (P = 0.0049) and in the TET. CONCLUSION The distance traveled in meters in the 6MWT can be used as an objective measure of functional capacity in healthy population, and >400-m distance can be used as a parameter of good functional capacity. The formula used to compute MET in the 6MWT is not comparable with the MET achieved in TET. Age, sex, and BMI significantly influenced the performance in the 6MWT and TET.