Only case reports and case series that recorded cardiac involvement, injury, or myocardial inflammation in patients who acquired COVID-19 confirmed by RT-PCR were chosen for this study. The articles were in English, Portuguese, and Spanish, and only studies that presented information on clinical manifestations, with or without changes in the ECG and echocardiogram were included. Alterations considered abnormal in the ECG were based on the Recommendations for the Standardization and Interpretation of the Electrocardiogram Guidelines from the American Heart Association/American College of Cardiology/Heart Rhythm Society, consisting of atrial or ventricular arrhythmias, conduction disorders, or other electrophysiological information indicated in the exam as suggestive of pathology. Abnormalities in echocardiogram followed recommendations from the American Society of Echocardiography and included reduced ejection fraction, motility disorders, wall or ventricle thickening, presence of blood clots, or other morphological and non-morphological changes that imply abnormal heart functioning. ^{16 - 22}

In this study, articles that were not case reports, series of cases, or observational studies were excluded. Articles from literature reviews, encyclopedias, editorials, book chapters, conference summaries, correspondence, reviews, news, and small communications were also excluded. Studies that did not present data regarding age, sex, ECG, echocardiogram, RT-PCR result, and myocarditis related to SARS-CoV-2 infection were excluded.

In the respective studies, the age group ranged from 15 to 81 years, with the mean age of 51 years. In addition, the male sex (63.6%) was the most prevalent.

Most patients had fever at hospital admission, accounting for 54.5% of the articles that reported myocarditis in COVID-19. ^{25 - 27 , 31 , 34 , 36 - 38 , 40 - 43} Subsequently, symptoms such as dyspnea (54.5%), ^{2627 , 30 - 33 , 35 - 37 , 39 , 40 , 43} cough (45.4%), ^{26 , 27 , 29 , 32 - 34 , 38 - 41} and chest pain (22.7%), ^{24 , 25 , 28 , 29 , 35} respectively, affected patients ( Table 2 ).

Table 2

Authors	Age	Sex	Symptoms/ Clinical manifestations	Comorbidities
Al-Assaf et al. 23	58-year-old	Male	Asymptomatic	SAH
Nikoo et al. 24	38-year-old	Female	Malaise, chest pain, nausea, vomiting	Not informed
Fischer et al. 25	15-year-old	Male	Chest pain, fever	Not informed
Malekrah et al. 26	71-year-old	Male	Weakness, fever, cough, dyspnea	Not informed
Purdy et al. 27	53-year-old	Male	Fever, cough, weak breath, tachycardia, tachypnea	Not informed
	30-year-old	Female	Fatigue, weak breathing, tachycardia, tachypnea, hypotension	Obesity
Tiwary et al. 28	30-year-old	Male	Abdominal pain, chest pain, fatigue, vertigo	DM1, obesity, SAH, glaucoma, diabetic nephropathy, and CKD
Abdelazeem et al. 29	41-year-old	Female	Chest pain, cough	Not informed
Mathews et al. 30	67-year-old	Male	Diarrhea and dyspnea	DM1, history of acute myocardial infarction, coronary artery disease, and CKD
Veronese et al. 31	51-year-old	Female	Dyspnea, palpitations, fever	Thalassemia minor
Venkata et al. 32	67-year-old	Male	Malaise, anorexia, dry cough, dyspnea, severe respiratory distress	Chronic obstructive pulmonary disease, CKD, DM2; history of hepatocellular carcinoma, rectal adenocarcinoma, and non-small cell lung cancer
Dabbagh et al. 33	67-year-old	Female	Cough, pain in the left shoulder, severe dyspnea, and orthopnea	Non-ischemic heart disease with LVEF of 15% in 2018, but improved to 40% after treatment
Mangiameli et al. 34	57-year-old	Female	Fever, cough and severe fatigue	Not informed
Faraj et al. 35	36-year-old	Male	Chest pain and dyspnea	Not informed
Cárdenes et al. 36	74-year-old	Male	General malaise, fever, dyspnea, and severe hypoxemia	SAH, DM2, and history of hemorrhagic stroke
Bascuñana et al. 37	40-year-old	Male	Fever, dyspnea, diarrhea, and abdominal pain	CKD
Minhas et al. 38	58-year-old	Female	Productive cough, fatigue, fever, and diarrhea	DM2, SAH, and dyslipidemia
Haddadin et al. 39	71-year-old	Female	Nonproductive cough, dyspnea at minimal efforts, orthopnea, and loss of smell and taste	Parkinson’s disease, bipolar disorder, and DM2
Loghin et al. 40	29-year-old	Male	Nonproductive cough, fever, myalgia, sore throat, malaise, and dyspnea	No comorbidities
Rey et al. 41	59-year-old	Male	Nonproductive cough, low fever, asthenia, and headache	SAH, DM2, and history of hemorrhagic stroke
Nicol et al. 42	40-year-old	Male	Fever, fatigue, anosmia, and myalgia	Obesity
Yokoo et al. 43	81-year-old	Male	Fever and dyspnea	SAH
Bernal-Torres et al . 44	38-year-old	Female	Palpitations	No comorbidities

CKD: chronic kidney disease; DM1: type 1 diabetes mellitus; DM2: type 2 diabetes mellitus; SAH: systemic arterial hypertension.

Regarding the comorbidities associated with the clinical status of the patients, the most prevalent were systemic arterial hypertension (27.3%) ^{23 , 28 , 36 , 38 , 41 , 43} and type 2 diabetes mellitus (22.7%). ^{32 , 36 , 38 , 39 , 41} However, it is worth noting that 31.8% of the patients did not present comorbidities, ^{23 , 26 , 27 , 34 , 35 , 40 , 44} as shown in Table 2 .

The ECG showed that most patients presented elevation of the ST segment (31.8%). ^{25 , 34 , 36 , 38 , 40 , 41 , 44} In addition, six studies (27.3%) reported normality in their patients, ^{24 , 30 , 32 , 35 , 37 , 42} as shown in Table 3 .

Table 3

Authors	ECG changes	Echocardiogram changes	RT-PCR	CMRI Description	Hemodynamic Aspects	Treatment	Clinical Outcome
Al-Assaf et al. 23	Bradycardia, sinus rhythm, and 2:1 atrioventricular block	Slightly dilated aorta	Positive	Edema of the interventricular septum and myocarditis	No changes were recorded.	Definitive cardiac pacemaker	Hospital discharge
Nikoo et al. 24	Sinus rhythm	Diffuse hypokinesis with reduced LVEF of 20% to 25%	Positive	Diffuse myocardial inflammation of the left ventricular myocardium	Hypotension; SaO 2 92%; hypercoagulability; increased troponin I, prothrombin time, and INR; and hydroelectrolytic disorders	Amiodarone; dexamethasone; temporary cardiac pacemaker	Hospital discharge
Fischer et al. 25	Diffuse elevation of the ST segment without reciprocal changes	Mild diffuse hypokinesis with preserved LVEF (50%)	Positive	Moderate left ventricle dysfunction, involvement of posterolateral wall of the left ventricle related to acute myocardial edema, LGE, and myocarditis	The hemodynamics of the patient remained stable. Increased high-sensivity troponin I was related.	Bisoprolol; ramipril	Hospital discharge
Malekrah et al. 26	Intermittent block of the left branch; episodes of atrial fibrillation with bradycardia	Normal	Positive	Not performed	SaO 2 85% and normal blood pressure	Hydroxychloroquine; combination of lopinavir and ritonavir; permanent cardiac pacemaker	Persistence of left branch block
Purdy et al. 27	Sinus taquicardia with J-spot elevation in inferolateral leads	Reduced LVEF (25%) with diffuse hypokinesis and moderately dilated right ventricle with reduced right ventricular function	Positive	Not performed	Low cardiac output and cardiac index with progression to cardiogenic shock; SaO 2 95%	Methylprednisolone; hydroxychloroquine + empirical antibiotic; aspirin, atorvastatin, isosorbide, dinitrate, hydralazine, carvedilol, and eplerenone	Hospital discharge
	Sinus tachycardia	Reduced LVEF (45%), hypokinesis, and moderate pericardial effusion	Positive	Not performed	Lactic acidosis, elevated NT-proBNP and D-dimer, and diagnosis with cardiogenic shock, which was treated	Hydroxychloroquine, vitamin C, zinc, and atorvastatin	Hospital discharge
Tiwary et al. 28	Left bundle branch block	Pericardial effusion, early right ventricular ventricle prolapse, and ventricular wall thickening	Positive	Not performed	Increased troponin I, progressive hypotension, and progressive increase of fraction of inspired oxygen	Norepinephrine and vasopressin, remdesivir, convalescent plasma, dexamethasone and cefepima + doxycycline	Hospital discharge
Abdelazeem et al. 29	Atrial fibrillation	Left ventricular hypertrophy and infiltrative cardiomyopathy	Positive	Extensive myocarditis involving sub-epicardial and mid-wall of the left ventricular and interventricular septum	Increased troponin I, increased BNP, and increased D-dimer	Diltiazem, steroids, antibiotics, remdesivir, and convalescent plasma	Hospital discharge
Mathews et al. 30	Sinus rhythm	Reduced LVEF (24%)	Positive	Not performed	Increased troponin, increased NT-proBNP, and increased erythrocyte sedimentation rate	Metimazole + prednisone	Not informed
Veronese et al. 31	Ventricular tachycardia	Hypocontratile left ventricle, reduced LVEF (30%), and wall thickening	Positive	Biventricular functional recovery, diffuse edema recovery, LGE involving LV basal-lateral and basal-inferior walls, and myocarditis	Cardiogenic shock with severe metabolic acidosis, increased troponin I, hypotension, signs of peripheral hypoperfusion, and SaO 2 93%	Mechanical circulatory support with intra-aortic balloon counterpulsation + veno-arterial extracorporeal membrane oxygenator + methylprednisolone pulse therapy	Not informed
Venkata et al. 32	Sinus rhythm	Preserved LVEF, severely dilated right ventricle, and severe tricuspid regurgitation	Positive	Not performed	Elevated high-sensitivity troponin I and D-dimer	Ventilatory support in prone position, norepinephrine, and vasopressin	Death
Dabbagh et al . 33	Low voltage in member derivations	Slightly reduced LVEF and pericardial effusion	Positive	Not performed	Normal troponin I and midly elevated BNP	Intubation, cardiac catheterization, hydroxychloroquine, colchicin, and glucocorticoids	Hospital discharge
Mangiameli et al. 34	ST-segment elevation in anteroseptal leads and ST-segment depression with T-wave inversion in DIII and aVF	Anteroapical wall hypokinesis and reduced LVEF (20%)	Positive	Not performed	Normal blood pressure, SaO 2 81%, elevated high-sensitivity troponin T	Emergency coronary angiography, nitroglycerin, and verapamil	Death
Faraj et al. 35	Sinus rhythm	Pericardial effusion	Positive	Not performed	Normal blood pressure, SaO 2 85% to 88%, elevated platelet counts, and elevated ferritin	Colchicin, vitamin C, vitamin D, zinc, and azithromycin	Hospital discharge
Cárdenes et al. 36	Isolated elevation in D3 and ST unevenness in V2-V4	Left ventricular dysfunction with inferolateral hypokinesis	Positive	Not performed	Increased troponin T, D-dimer, BNP, and lactate dehydrogenase; septic shock and cardiogenic shock associated; hypercoagubility; and DIC	Norepinephrine, emergency cardiac catheterization, percutaneous coronary intervention, and placement of 2 drug-eluting stents; hydroxychloroquine and tocilizumab	Death
Bascuñana et al. 37	Sinus rhythm	No changes	Positive	Not performed	Normal blood pressure, SaO 2 93%, lymphopenia, thrombocytopenia, high serum C-reactive protein and D-dimer levels, high-sensitivity cardiac troponin I level, metabolic acidosis, anemia, and elevated lactate dehydrogenase	Oxygen therapy, volume replacement, hydroxychloroquine, azithromycin, and methylprednisolone	Hospital discharge
Minhas et al. 38	Sinus tachycardia and ST segment elevation in I and aVL leads	Reduced LVEF (20%)	Positive	Not performed	High blood presure, SaO 2 82%, increased troponin I level, and evolution to cardiogenic shock	Dual antiplatelet therapy, heparin, hydroxychloroquine, and azithromycin	Death
Haddadin et al. 39	Complete heart block with junctional ventricular escape rhythm	Thickened mitral valve leaflets and dilated left atrium	Positive	Not performed	High blood pressure, SaO 2 97%, leukocytosis, anemia, hyponatremia, elevated C-reactive protein, and elevated fibrinogen	Introduction of dual camera cardiac pacemaker	Death
Loghin et al. 40	Sinus taquicardia and ST elevation in leads II, III, aVF, and V6	No changes	Positive	Myocardial edema and myocarditis	Hemodynamic stability	Orotracheal intubation	Hospital discharge
Rey et al. 41	ST-segment elevation in the lower leads and v4 to V6, Q wave, and first degree atrioventricular block	No changes	Positive	Not performed	Thrombocytosis, atherosclerotic plaque rupture, high blood pressure, SaO 2 92%, elevated C-reactive protein, elevated D-dimer, and DIC	Tirofiban, aspirin, plasugrel, enoxaparin, hydroxychloroquine, ceftriaxone, and azithromycin	Death
Nicol et al. 42	Sinus tachycardia	Reduced LVEF (45%), low cardiac output, and small pericardial effusion	Positive	Systolic dysfunction with global hypokinesia, myocardial inflammation, pericardial effusion, myocarditis, and LGE	High blood pressure; elevated BNP, C-reactive protein, fibrinogen, procalcitonin, D-dimer, and cardiac troponin (high-sensitivity troponin I)	Angiotensin-converting enzyme inhibitors, beta blockers, and antibiotic	Hospital discharge
Yokoo et al. 43	Showed no signs of ischemia	Reduced LVEF (35%)	Positive	Ischemic pattern on the left ventricle base septum wall, diffuse hypokinesia, global systolic function involvement, myocarditis, and LGE areas with an ischemic pattern on the left ventricle base septum wall	SaO 2 91% and high troponin T	Antibiotics, steroids, and hemodynamic monitoring	Hospital discharge
Bernal-Torres et al. 44	Diffuse elevation of the ST segment, with depression of the PR segment and Spodick sign	Reduced LVEF (30%), global hypokinesis, and mild pericardial effusion	Positive	Transmural extent of myocardial edema to both ventricles, myocarditis, and left ventricular LGE	Elevated jugular venous pressure, hypontesion, cardiogenic shock, SaO 2 95%, metabolic acidosis, and increased troponin I and BNP	Oxygen therapy, methylprednisolone, human immunoglobulin, hydroxychloroquine, azithromycin, norepinephrine, dobutamine, levosimendan, and furosemide	Hospital discharge

BNP: type B natriuretic peptide; DIC: disseminated intravascular coagulation; LGE: late gadolinium enhancement; LVEF: left ventricular ejection fraction; RT-PCR: reverse-transcriptase chain reaction; PR Segment: the period of the electrocardiogram from the beginning of the P wave to the beginning of the Q wave; SaO2: oxygen saturation; ECG: electrocardiogram; CMRI: cardiac magnetic resonance imaging.

When observing the results of the echocardiograms presented in the studies, the presence of hypokinesis (31.8%), ^{24 , 25 , 27 , 31 , 34 , 36 , 44} left ventricular ejection fraction below 50% (45.5%), ^{24 , 27 , 30 , 31 , 33 , 34 , 38 , 42 - 44} and pericardial effusion (27.3%) were significant. ^{27 , 28 , 33 , 35 , 42 , 44}

CMRI was performed in 40.9% of the studies. ^{23 - 25 , 29 , 31 , 40 , 42 - 44} The presence of myocarditis (88.8%), ^{23 , 25 , 29 , 31 , 40 , 42 - 44} edema (66.6%), ^{23 , 25 , 31 , 40 , 44} myocardial inflammation (66.6%), ^{23 , 24 , 29 , 42 , 43} and late gadolinium enhancement (LGE) (55.5%) ^{25 , 31 , 42 - 44} were the most frequent characteristics among the studies that reported CMRI.

The increased levels of troponin I or troponin T (63.6%) ^{24 , 25 , 28 - 34 , 36 - 38 , 42 - 44} were the most recurrent hemodynamic alterations in patients who developed cardiac involvement due to COVID-19. There were frequent reports of oxygen saturation (SaO ₂ ) below 95% (40.9%), ^{24 , 26 , 31 , 34 , 35 , 37 , 38 , 41 , 43} increased D-dimer (31.8%), ^{27 , 29 , 32 , 36 , 37 , 41 , 42} evolution of patients to cardiogenic shock (22.7%), ^{27 , 31 , 36 , 38 , 44} and occurrence of metabolic acidosis (18.1%). ^{27 , 31 , 37 , 44}

It is possible to observe that the treatment varied, from more conservative to more invasive treatments. For the most part, treatment was based on the use of drugs (72.4%), such as antibiotics, ^{27 - 29 , 35 , 37 , 38 , 41 - 44} antimalarials, ^{26 , 27 , 33 , 36 - 38 , 41 , 44} antihypertensive, ^{25 , 27 , 34 , 42 , 44} antiarrhythmic, ^{24 , 25 , 27 , 29 , 34 , 42 , 44} antiretroviral, ^{26 , 28 , 29} corticosteroids, ^{24 , 27 - 31 , 33 , 37 , 43 , 44} and others. Others were managed with procedures, associated or not with medical therapy, such as pacemaker implantation (18.1%) ^{23 , 24 , 26 , 39} and orotracheal intubation (13.6%). ^{32 , 33 , 40}

Hospital discharge was prevalent in 59.1% of cases. ^{23 - 25 , 27 - 29 , 33 , 35 , 37 , 42 - 44} However, in 27.3% of the studies, the patients died, and these clinical outcomes were the most representative. ^{32 , 34 , 36 , 38 , 39 , 41}Table 3 summarizes the data.

Due to the nature of the descriptive studies, the results presented are liable to investigator bias, selection procedure bias, and selection bias.