Bacterial myocarditis is an inflammatory condition of the heart, caused by a bacterial infection. It is an uncommon occurrence in the western world and is mostly diagnosed as a complication of sepsis or a specific syndrome involving a bacterial infection.
Bacterial myocarditis, as every other type of myocarditis, features extremely variable clinical manifestations, with the symptoms ranging from none to an acute cardiac shock and heart failure . Due to the fact that it is caused by a bacterial infection, known or unknown to the patient, the symptoms that predominate in the clinical picture at first are those pertaining to the preceding infection. Depending on the type of infection, a patient may experience fever, sweating, chills, tachycardia, weakness, abdominal pain and other symptoms; at this time, although a bacterial inflammation of the myocardium may exist, the cardiac condition is considered still asymptomatic.
At the onset of substantial myocardial inflammation, symptoms originating from the cardiovascular system include angina pectoris, mild or profound arrhythmia, thoracic pain, dyspnea upon exertion, palpitations or an acute decompensation of heart failure, with no preceding risk . Bacterial myocarditis that is caused by a group A streptococcal infection (rheumatic fever), will lead to the patient experiencing additional symptoms, such as polyarthralgia, and subcutaneous nodules, chorea and/or erythema marginatum will be observed.
The extremely variable clinical presentation of bacterial myocarditis, further complicated by the symptoms associated with the initial infection, renders the diagnosis a challenging task. Even though a set of diagnostic criteria has been established, the final diagnosis is set after a biopsy result, consistent with a bacterial infiltration of the myocardium  .
Bacterial myocarditis is suspected when a priorly confirmed or suspected bacterial infection is followed by an arrhythmia or acute heart failure. The complete workup encompasses a plethora of tests, such as an electrocardiogram (ECG), cardiac enzyme laboratory tests, echocardiography, cardiac magnetic resonance imaging scans (MRI) and, eventually, a biopsy.
May reveal an atrioventricular or bundle branch block, arrhythmias of a ventricular or supraventricular origin, ST or T wave abnormalities and irregular Q waves. The electrocardiographic evaluation may mislead the physician to diagnose an ischemic phenomenon.
Enzymes associated with myocardial ischemia may be elevated, such as troponins or CK-MB.
May illustrate pericardial effusion, LV (left ventricular) or RV (right ventricular) dysfunction, dilatation and thrombi, located intracardially. The findings are non-pathognomonic of bacterial myocarditis and echocardiography is primarily employed in order to eliminate other conditions, such as valvular disease, from the differential diagnosis 
It's wider availability has greatly contributed to the diagnosis, as it can help to evaluate the heart both from a functional and morphological aspect while retaining the advantage of a non-invasive technique   . It can aid in the assessment of necrotic or fibrotic changes, pericardial effusion, edema or functional irregularities.
In symptomatic patients, myocarditis is suspected in the clinical setting when 1 clinical indication and 1 diagnostic indication is present. Thoracic pain, acute or chronic heart failure and arrhythmia, including syncope, palpitations and sudden cardiac death, constitute the clinical indications. The diagnostic indications encompass abnormal ECG findings, elevated cardiac enzymes or echocardiographic abnormalities. The final and assertive diagnosis of bacterial myocarditis is established after a biopsy histological examination reveals inflammation of the myocardium, with a culture that is positive for a specific pathogen.