Short Term Effects of Mild Severity COVID-19 on Left Ventricular Functions

Purpose: We aimed to evaluate long term effects of COVID-19 disease on left ventricular function using speckle tracking echocardiography. Methods: In our study, 96 non-hospitalized patients who were diagnosed with COVID-19 disease in our center between 15 August 2020 and 01 September 2020 and 96 age and gender matched control subjects were included. Results:The mean follow up duration was 137 ± 7 days. White blood cell, neutrophile and lymphocyte were signicantly lower and C-reactive protein (CRP) and neutrophil to lymphocyte ratio (NLR) were signicantly higher in the COVID-19 group. (6.6 ± 2.8 vs. 24.4 ± 21.8, p <0.001 and 4.1 ± 2.5 vs. 7.1 ± 4, p <0.001, respectively). LV-GLS and LV-GCS were signicantly lower in the COVID-19 group. (-20.1 ± 3.1 vs -15.9 ± 2, p <0.001 and -29.3 ± 2.1 vs -26.3 ± 2.1, p <0.001, respectively). LV-GLS and LV-GCS were found to be negatively correlated with CRP (rs = -0.515, p <0.001 and rs = 0.-466, p <0.001, respectively) and NLR (rs = -0.494, p <0.001 and rs = -434, p <0.001, respectively). Conclusion: Deteriorating effects of COVID-19 disease on both LV-GCS and LV-GLS can be seen even in the short term. These detrimental effects seem to be associated with CRP levels and NLR measured in the course of active infection.


Introduction
COVID-19 disease, which was rstly identi ed in Wuhan, China in December 2019, is an infectious respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [1] Currently, the world is still under the in uence of the disease, which later on turned into a pandemic. [2] In addition to lung involvement in the form of interstitial pneumonia, multiorgan failure can develop in more severe cases. Along with respiratory system involvement, it has been found that cardiovascular and mental disorders are also seen during the course of COVID-19 infection [3]. Previous reports have revealed myocardial damage in 20-40% of COVID-19 cases hospitalized due to cardiac chest pain, fulminant heart failure, cardiac arrhythmias and cardiac arrest [3] Conventional echocardiographic assessment may sometimes be insu cient for evaluation of global ventricular systolic function. Studies showed that left ventricular systolic function which appears to be normal with traditional echocardiographic methods, can be found to be deteriorated in speckle tracking echocardiographic (STE) imaging [4]. Echocardiographic imaging techniques enable more quantitative evaluation of complex ventricular movements [5]. Among these imaging techniques, speckle tracking is an operator and angle independent method for evaluating regional and global wall movements and is more sensitive in detecting subclinical right and left ventricular dysfunction [6]. In a very recent study, left ventricular global longutinal strain (LV-GLS) was found to be affected by COVID-19 infection.
Furthermore, it was found to be an independent predictor of mortality in COVID-19 patients [7].
In this study we aimed to investigate possible subtle changes in left ventricular systolic function in patients with COVID 19 disease using STE and determine whether the improvement in clinical and laboratory ndings is accompanied by cardiac improvement in the long term.

Material And Method
This cross-sectional, single-centre study was performed in University of Ordu Training and Research Hospital, which was determined to treat COVID-19 patients by Turkish Republic Ministry of Health, between November 15 August 2020 and 01 September 2020. The mild severity COVID-19 patients; was de ned as patients who were followed outpatient, non-hospitalized, and who had constituional symptoms including fever, muscle and / or joint pain, cough, sore throat, without respiratory distress (respiratory rate <24/minutes, peripheral capillary oxigen saturation (SpO2) > 93% at room) according to the World Health Organization and the Republic of Turkey Ministry of Health COVID-19 Treatment Guidelines . 120 patients with mild severity COVID-19 disease who were older than 18 years old and treated with only hydroxychloroquine and/or favipiravir were respectively enrolled in the study. Patients with systolic heart failure (LVEF ≤ 50%), coronary artery disease, chronic in ammatory disease, hypertension, severe chronic renal and liver failure, right or left ventricular failure, atrial brillation, complete or incomplete branch block, moderate-severe valve pathology, pacemaker, anemia, chronic renal failure, thyroid dysfunction, pulmonary embolism, cancer, chronic lung disease, body mass index (BMI) > 30 kg/m 2 were excluded. In addition, patients who were given steroids and/or heparin treatments along with hydroxychloroquine and/or favipiravir due to COVID-19 and those who had any other active infection disease and used antibiotics and poor echocardiographic images were excluded. After the exclusion criterias were applied, the study continued with 96 mild severity COVID-19 patients. Age and sex matched 96 healthy individuals forming the control group were selected consecutively from the outpatient clinic.
Demographic data, baseline characteristics, medical history, drugs and medications used for COVID-19, smoking habits and laboratory values were obtained using the hospital's medical database. Laboratory parameters including; complete blood count (CBC), C -reactive protein (CRP), D-dimer, ferritin, cardiac troponin I (cTnI) and other biochemical parameters were measured at the rst admission to the hospital before COVID-19 treatment started. The entire study population were evaluated via two-dimensional

Diagnosis of COVID-19
According to the World Health Organization and the Republic of Turkey Ministry of Health according to the COVID-19 Treatment Guidelines, patients who were matching the de nition of probable SARS-CoV-2 infection case underwent testing with molecular methods to scan for viruses. Throat and nasopharynx swab samples were collected from all patients in our study to extract SARS-CoV-2 RNA. Real-time reverse transcription polymerase chain reaction assay (RT-PCR) molecular method was applied for RNA analysis of SARS-CoV-2 virus. Cases with SARS-CoV-2 RNA in RT-PCR method were accepted as COVID-19.

Two-dimensional echocardiography (2DE)
Conventional 2D echocardiographic examination was performed using a commercially available echocardiography device (EPIQ 7C; Philips Medical Systems, Andover, Massachusetts) in line with the recommendations of the American Echocardiography Association[8] . All these echocardiographic examinations were performed by experienced two operators. Echocardiographic examinations were performed in left lateral decubitus position after resting for at least 15 min. Blood pressures of the study population were measured prior to echocardiographic examination; right arm average systolic blood pressure was measured 118.5 mmHg / diastolic blood pressure was measured 78.5 mmHg, left arm average systolic blood pressure was measured 120.5 mmHg / diastolic blood pressure was measured 80.5 mmHg. All measurements were taken in three consecutive cycles, and average values were calculated. Patients with optimal views of left ventricul for STE analysis were included in the study. 12 patients were excluded due to poor echocardiographic images. The patients were monitored by electrocardiogram throughout the procedure. Left ventricle (LV) and left atrium (LA) diameters and LV wall thicknesses were measured from parasternal long axis views by M-mode echocardiography. Left ventricular ejection fraction (LVEF) was calculated from the apical 4-chamber and 2-chamber images using the Modi ed Simpson method [9]. Pulsed vawe Doppler velocity recordings were obtained in apical four-chamber images via placing the sample volume at the tips of the mitral valve. E/A ratio was calculated following assessment of mitral early peak velocity (E) and mitral late peak velocity (A). Stroke volume (EDV-ESV, ml) and cardiac output (stroke volume x heart rate, l/m) were driven after calculation of LV end-diastolic volume (LV EDV, ml) and end-systolic volume (LV ESV, ml).
Tricuspid regurgitation peak velocity was used for measurement of systolic pulmonary artery pressure (sPAP). Devereux formula was used to calculate the LV mass [10]. Finally, all measurements were reanalysed considering the body mass index (BMI).

Speckle Tracking Echocardiography
The myocardial deformation quantitative analysis function of 2D-STE was used to evaluate myocardial function. The end of systole was de ned as the time at which the aortic valve is closed and the end of diastole was de ned as the peak R wave in the electrocardiogram. Endocardial borders were monitored within the frame of 2D images at the end of systole. A wide myocardial width was adjusted to determine the epicardial border. Automatic function was used to determine the midpoints between the endocardial and epicardial borders and the middle myocardial border. In order to ensure correct tracking and to involve all LV wall thickness for 2D speckle viewing width, manual adjustment was performed when necessary. Apical four-, three-, and two-chamber views were used for evaluation of LV-GLS.
All images used for speckle-tracking echocardiographic analysis were obtained using the QLAB-CMQ software program Philips Epiq 7C at a frame rate of 50 to 70 fps. Peak systolic strain measurements of each segment were automatically taken by a software (analysis) program. Following assessment of longitudinal strain values of a total of 18 segments, the mean value was determined as the global strain [11] (Figure 1). The circumferential strain used to evaluate myocardial shortening/ lengthening along the LV curvature was measured from the LV mid-ventricular short-axis view. The global circumferential strain was calculated from the average peak systolic strain value of six segments.
Negative values were used to determine global longitudinal and circumferential strains, and less negative values indicated lower strains. (Figure 2).

Statistical analyses
In all statistical analysis SPSS 22.0 Statistical Package Program for Windows (SPSS Inc., Chicago, IL, USA)was used. In order to test normality of distribution Kolmogorov-Smirnov test was used. Quantitative variables were speci ed as the mean ± standard deviation. Categorical variableswere shown as number and percentage values. Differences between groups were evaluated by using Student's t-test andMann Whitney U test. Categorical variables were compared with Chi-square test. Spearman correlation analysis was performed to examine the relationship between LV GCS, LV GLS and NLR, CRP. A p value of <0.05 was accepted as statistically signi cant.

Results
A total of 96 patients who had recovered from COVID-19 disease and 96 healthy controls were included in the study. The mean follow-up duration in the patient group was 137 ± 7 days. The mean age was similar in the COVID-19 and control groups. (43.4 ± 12.8 vs. 44.3 ± 13.1, p = 0.590, respectively). There was no statistically signi cant difference between the groups in terms of gender, BMI, heart rate, diabetes, hypertension and smoking status. White blood cell, neutrophil and lymphocyte were signi cantly lower in the COVID-19 group. On the other hand, C-reactive protein levels and NLR were signi cantly higher in the COVID-19 group. (2.6 ± 1.8 vs. 24.4 ± 20.1, p < 0.001 and 4.1 ± 2.5 vs. 7.1 ± 4, p < 0.001, respectively).
Average levels of C -reactive protein (CRP), ferritin and D-dimer were higher than normal values in only patients with COVID-19. cTnI level was higher than normal values in only three patients with COVID-19.
The baseline characteristics and laboratory ndings of the study population are summarized in Table 1.    (Table 2). Spearman correlation analysis showed that there was a statistically signi cant negative correlation between LV-GLS and LV-GCS values and CRP levels (rs = -0.515, p < 0.001 and rs = 0.-466, p < 0.001, respectively) (Fig. 3A, 3B) as well as NLR (rs = -0.494, p < 0.001and rs = -434, p < 0.001, respectively). (Fig. 4A, 4B) .Left ventricular systolic function was found to be similarly affected in both men and women. LV GLS − 15. The novel coronavirus COVID-19 outbreak, rst reported on December 8 2019 in Hubei province of China, was recognized as a pandemic by the World Health Organization (WHO) on March 11, 2020. Now available data in public databases, signi es that the infection and mortality risk increases in men and elderly individuals [3]. However, in our study, left ventricular systolic function was found to be similarly affected in both men and women.
Systematic in ammation, pro-in ammatory cytokine storm and sepsis resulting in multiorgan failure and death can be seen in severe COVID-19 disease [12]. Cardiac arrhythmia is also an expected nding in COVID-19 disease and the possible pathophysiologic mechanisms are metabolic dysfunction, myocardial in ammation, and activation of the sympathetic nervous system [13]. Following Acute Respiratory Distress Syndrome (ARDS), arrhythmia is the second most common clinical nding in severe COVID-19 disease and was detected in 16.7% of the patients. The frequency of arryhthmia was 7% in patients who did not require ICU treatment and 44% in those who were admitted to the ICU [14]. Atrial brillation, conduction block, ventricular tachycardia, and ventricular brillation were the most common arrhythmia types.
Fulminant myocarditis is one of the catastrophic cardiac complications of COVID-19 disease. Heart failure was reported in 23% of COVID-19 patients in a recent report in China. Reports, heart Heart failure was evident in 12% of the survivors and in approximately 52% of those who lost their lives [15]. In a another study, LV-GLS was found to be impaired even in patients who did not have a severe COVID-19 disease and had relatively low troponin levels [7]. Subtle myocardial deterioration was de ned as a predictor of death in COVID-19 disease. Therefore, LV longitudinal strain was adopted to be a precise predicion tool for COVID-19 disease considering its early and more robust detection capacity compared to conventional echocardiography [7].
The Neutrophile-Lymphocyte ratio (NLR) can be calculated simply by dividing the absolute neutrophile count by the lymphocyte count. The increase in NLR is valuable in terms of re ecting the general in ammatory status of the patient [16]. It has been reported that neutrophils are the rst in ammatory cells to migrate to ischemic myocardial tissue, and they in ict damage via proteolytic enzymes, reactive oxygen radicals and by stimulating secretion of the other neutrophils [17]. In ammation is known to be the starting point for all cardiovascular disorders. NLR has been reported to be in a strong relationship with cardiovascular diseases in many epidemiological studies [18]. The main reason for this is that NLR consists of two separate in ammation markers. It is well known that especially severe cases of COVID 19 have a higher rate of NLR [19]. In a study including 245 hospitalized patients, NLR was identi ed as an independent predictor of in-hospital mortality for COVID-19 disease [20]. In our study, the relationship between LV-GLS and LV-GCS values and CRP levels as well as NLR supports the hypothesis that active in ammation is an indicator of long term cardiac outcomes. Based on these ndings, it can also be speculated that evaluation of NLR during the active course of the disease may be helpful in identifying the individuals with high cardiac risk.
High levels of lactate dehydrogenase (LDH), serum creatine kinase (CK), and CRP were detected in patients with COVID-19 disease [21]. Moreover high CRP level was positively correlated with lung lesions in the early stage and re ected severity of COVID-19 disease [22]. Another study revealed that CRP levels increase signi cantly and predict severe COVID-19 disease even before ndings are detected in lung computerized tomography (CT) imaging [23]. These studies emphasize the prognostic value of CRP levels in COVID-19 disease.
We speculate that, the reasons for subclinical deterioration in LV systolic function even after an average of 4.5 months following active disease may be the delay in healing of COVID-19 myocarditis and/or the damage caused by the in ammation itself in the acute period. The negative correlation between increasing levels of CRP levels and NLR and decreasing LV-GLS and LV-CS values seem to support this hypothesis. However, longer-term follow-up is needed to monitor how long the cardiac effect will continue or whether it will be permanent.

Limitations
Single center design, small sample size and short follow up can be considered as the limitations of our study. Other in ammatory markers such as interleukin-6 and erythrocyte sedimentation rate could also be evaluated. Lack of data about myocardial function before COVID-19 disease can hinder interpretation of our outcomes. Comorbidities and medications used are possible confounders for strain measurements. Finally addition of a con rmation method for evaluation of myocardial impairment such as magnetic resonance imaging would strengthen the scienti c power of our study.
Consequently, both LV-GCS and LV-GLS were found to be decreased in patients with COVID-19 disease in the long term. This decrease is associated with the increase in CRP levels and NLR. Since subclinical LV systolic dysfunction can not be detected by conventional echocardiographic assessment, we believe in the necessity of STE to evaluate left ventricular systolic function in COVID-19 patients in the long term. Close follow-up of the patients with subclinical LV systolic dysfunction may be reasonable in terms of preventing more severe cardiac complications.