The current report represents detailed analysis of patients with acute inflammatory peri-myocardial diseases evaluated by echocardiography. The majority of our patients were young, predominantly males. Older age of the patients judged to have pericarditis versus those with predominant pericarditis may be related to exaggerated immune response in younger patients.
Our data show, that most of the patients presented with the clinical picture of acute inflammatory peri-myocardial syndrome have mixed pericardial and myocardial involvement with progressive decrease of ejection fraction from normal in those with pericarditis to severe LV dysfunction in pure myocarditis.
Most of the patients had ST segment elevation on the ECG. The 5 patients with pericarditis and less typical ECG changes, had symptoms of recent rather than acute onset. Prevalence of pericardial effusion decreased from pure pericarditis to predominant myocarditis. Inflammatory markers, CRP or ESR, were elevated in most patients. Our results highlight the predominance of infero-postero-lateral segmental involvement in patients with pericardial inflammatory syndromes, and underscore the important role of careful analysis by conventional echo. Even in patients with apparently pure pericarditis and normal or near normal EF, we found involvement of the infero-postero-lateral segments in 38%.
Several mechanisms have been proposed: In a recent study by Mahrholdt et al. [7], the type of myocardial involvement, initial presentation and clinical course of 87 patients with biopsy proven myocarditis could be linked to the infective agent. Parvovirus PVB19-infected patients sought medical attention early because of severe chest pain, the EF was only mildly impaired (mean 55%), and late gadolinium enhancement on MRI was localized predominantly in the lateral wall of the LV. In herpes virus HHV6 myocarditis, clinical symptoms at initial presentation were more variable as well as LVEF (mean 42%). Symptoms of heart failure were present in half of HHV6 infected patients, late enhancement of gadolinium was most frequently found in the the anteroseptal region. The majority of patients with combined PVB19/HHV6 myocarditis presented with subacute onset of heart failure, severe LV dysfunction (mean LVEF 25%), and late enhancement in the entire septum. Subepicardial location of late contrast enhancement foci in acute myocarditis can be related to the close proximity of this region to the inflamed pericardium. Cardiotropic viruses including PVB19 may cause polyserositis and pericarditis after the initial viremia [7]. In spite of these fascinating data, the yield of viral serology is still uncertain, and it is not commonly recommended for the diagnosis of perimyocarditis [8]. In our series etiologic agent was not identified.
Myocarditis often mimics myocardial infarction, and in these patients coronary imaging is necessary to rule out significant coronary artery disease. In our series 21 of the 100 patients underwent coronary angiography or cardiac CT, all had normal or non-significant coronary artery disease. Coronary spasm in myocarditis has been previously proposed [9–11], but cases of true coronary spasm proven on coronary angiography in patients with acute myocarditis/pericarditis are rare [12, 13]. In a recent study [14] biopsy proven PVB19 myocarditis was strongly associated with coronary spasm induced by acetylcholine testing during coronary angiography. The possible mechanism, proposed by the authors, is endothelial dysfunction induced by the myocardial inflammation or persistence of virus.
Speckle tracking imaging in acute inflammatory pericardial disorders
Speckle tracking imaging – advanced echocardiographic technique, was developed recently for quantitative evaluation of left ventricular function in patients with ischemic heart disease, valvular heart disease and other myocardial disorders.
Recently, we have reported on a group of 38 patients with acute inflammatory pericardial syndromes, a sub-group of the current 100 patients, who were also assessed with speckle tracking imaging [6]. The results of that study strongly support the current data.
Cardiac MRI in perimyocarditis
Although these observations highlight the importance of echocardiographic techniques in perimyocarditis, no doubt MRI should be considered the "gold standard" (15–18) : Mahrholdt et al. [15] in 2004, found delayed enhancement on MRI in patients with acute myocarditis (mean LVEF=47%) presented as a patchy distribution predominantly in the subepicardial region on the lateral free wall of the LV. In 21 of 28 patients biopsy was obtained from the area of late enhancement and in 19 active myocarditis was found.
In the study of Yelgec et al. [16], among 20 patients with acute myocarditis (mean LVEF=57%), delayed enhancement was present in 15 (75%) predominantly in the lateral LV wall (61%). In 15 of these 16 patients, there was a match between regional functional abnormalities and delayed enhancement.
Stensaeth et al. [17] found delayed enhancement in 27 of 42 patients with myocarditis (64%). In this series pericardial effusion occurred in 7 patients (17%). Late gadolinium enhancement occurred predominantly, in 86%, in the infero-lateral segments in mid or subepicardial segments.
Goitein et al. [18] published a series of 23 patients with acute myocarditis (mean LVEF=57%). Delayed enhancement was found in 21 of 23 patients (91%) in the infero-lateral region of the LV mostly in mid-ventricular segments. In this study echo detected wall motion abnormalities in 8 of 23 patients (35%). The distribution of wall motion abnormalities on echo matched the distribution of myocardial delayed enhancement on MRI in 6 of the 8 patients in whom wall motion abnormalities were seen on echo. In this study wall motion abnormalities seen on echo most often involved the inferior and infero-lateral segments at the mid LV.
Left ventricular dysfunction in myocarditis had been described previously in old echocardiographic studies. Of 41 patients with biopsy proven myocarditis 24 [58%] had ejection fraction less than 50%; 25 [64%] had regional LV dysfunction more often localized at the interventricular septum and at the apex; clinical presentation in most of the patients were congestive heart failure or arrhythmias [19]. This patient population was different from our patients. Today we know, that significant LV dysfunction and septo-apical wall motion abnormalities may be consistent with HHV-6 infection [7].
In another study published in 1984 [20], regional LV dysfunction was found in all 68 patients with myocarditis with predominant involvement of infero-apical segments. In this study M-mode echo technique was used.
In our study, wall motion abnormalities involved predominantly the infero-postero-lateral segments, and these observations are in concordance with results of MRI studies, dercribed above. These findings are also strongly supported by the postmortem study of Shirani et al. [21] in 1993, who found predominant location of gross myocardial lesions in acute mononuclear-cell myocarditis in the subepicardial region of the left ventricular free wall.
Long-term follow-up (mean 37 months) demonstrated that the outcome of patients with acute inflammatory peri-myocardial diseases is benign, however recurrent hospitalization due to recurrent inflammation is rather frequent.
Limitations
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1.
MRI was not a routine practice in our hospital in perimyocarditis during the study period.
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2.
This is a retrospective study, based on hospital records, however echocardiographic images, electrocardiograms and medical histories were all reviewed thoroughly.
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3.
An 18-segments model of the left ventricle was used instead of the traditional 16 –segments model. This was based on our previous experience published earlier.
