**3. Medical imaging in diagnosis and assessment of myocarditis and pericarditis**

#### **3.1 Electrocardiography**

Echocardiography is beneficial for assessing cardiac tissue dimensions, wall width, systolic and diastolic, and intracavitary thrombi. This technique can assess cardiac failure. Myocarditis has no special radiographic features in this technique. Nevertheless, myocarditis is characterized by widened, enlarged, and ischemic cardiomyopathies. This technique is commonly used as a diagnostic tool. The accuracy of electrocardiography for pericarditis and myocarditis is about 47% because ECG findings are basic T-wave deviations (**Figure 3**) [45].

The classical ECG examination is comprised of four stages of changes and it is described in about 50% of cases.

*Inflammatory Heart Diseases*

**Figure 1.**

**Figure 2.** *Shows dilated heart.*

*Shows the pericardium layers.*

**126**

are rub, abnormal ECG findings and possible pericardial effusion, chest discomfort, and breathing difficulties. The pericardial rub is best heard at the end of the expiration phase with patient sloping frontward [22–24]. About 30% of patients with myocarditis might be accompanied with pericarditis. Pericarditis is difficult to detect. Some postmortem studies suggest that pericarditis is a subclinical type. Pericarditis accounts for 5% of patients who are attending to emergency rooms due to myocardial infraction and chest discomfort [25–29]. On laboratory results, pericarditis can be detected in a troponin I test. Nevertheless, the elevation of troponin (I) is not used as the adverse prognosis of the disease [30, 31]. Serology may approve the cause as infectious or autoimmune pericarditis. Acute pericarditis onsets with mild signs and symptoms and its treatment lasts for 6 weeks. The infection symptoms might reoccur within 4–6 weeks [32, 33]. The prevalence of pericarditis may include idiopathic, tuberculosis, viral (HIV infection) or systemic infection, cancer (breast, leukemia, lymphoma, and lung), radiation therapy (about 4% of mediastinal Hodgkin's disease), cardiac surgery (20% of the cases

#### **Figure 3.**

*Shows the ECG scan of myocarditis and pericarditis.*

Those stages are:

**Stage 1**: (hours to a few days): the ST elevation and depression of the PR segment.

**Stage 2**: (first week): control of the ST and PR segments.

**Stage 3:** T-wave inversions.

**Stage 4:** standardization of ECG [46, 47].
