Background Systemic connective tissue diseases are still challenging for clinicians since they have a complex pathophysiology and diversified clinical presentations. Dermatomyositis and Polimyositis may often involve cardiovascular system resulting in arrhythmias and conduction disturbances . Publications about non-invasive heart diagnostics methods (ECG and 24h Holter ECG) designed to examine large groups of dermatomyositis and polimyositis patients for arrhythmia and conduction disturbances are scarce.
Objectives The aim of our study was to determine the ECG and Holter deviations among patients with documented dermatomyositis and polimyositis.
Methods The study group consisted of 30 patients (7 males and 23 females). 19 patients were diagnosed with polimyositis, 11 with dermatomyositis. Mean disease duration was 6.5 years (SD ±4.7). None of the patients included in the study demonstrated symptoms of rhabdomyolysis. The patients in the study group had the following concomitant diseases: arterial hypertension in 13 patients, hyperthyroidism in 3 patients (in euthyrosis), hypothyroidism in 2 patients (in euthyrosis). The control group consisted of 30 healthy subjects (8 males and 22 females) with no autoimmune, metabolic, or cardiovascular diseases documented. All patients signed the study participation consent. Subjects in both groups (study and control) underwent twelve-lead ECG. We measured QRS complex, PQ interval, P wave and conduction disturbances assuming the following norms: for QRS complex ≤100ms, PQ interval ≤200ms, P wave ≤110ms. Blood samples were taken and the following were assessed: creatine kinase level (CK), aldolase level (ALD) and lactate dehydrogenase level (LDH). All patients were applied a three-channel Holter ECG (Oxford DMS-3). Holter recordings (with the use of Cardioscan ver. 12 software) were analyzed: SDDN, SDDNi, SDANN, rMSSD, pNN50, VLF, LF, HF, maximum QT/QTc interval in the recording, and ventricular extrasystolic beats.
Results In the 12-lead resting ECG of the study group we did not observe any deviations from neither the range of PQ interval nor P wave. However bundle branches blocks were observed, i.e. right bundle branch block in three patients, left anterior fascicle block in one patient, and complete block of left bundle bunch in one patient. We did not observe any statistically significant differences in parameters assessing the autonomic system function (Table 1), the QT/QTc interval, ventricular rhythm disorders/extrasystolic beats (Table 2). We observed significant differences (p<0,0001) between the control and the study group when comparing enzymes activities (CPK, LDH, ALD) (Table 3).
Conclusions 1. Higher values of the activity of enzymes (CPK, LDH and CK) compared to the control group do not correlate with the durinal variability of cardiac rhythm, which implies a lack of disease affinity to involve the autonomic system.
2. Conduction disturbances in DM and PM affect mainly the His-Purkinje system.
3. No significant differences in QT/QTc interval and the frequency of occurrence of ventricular arrhythmia were observed.
Bienias, P., et al., Arrhythmias and conduction disturbances in patients with connective tissue diseases. Kardiol Pol, 2008. 66(2): p. 194-9.
Disclosure of Interest None declared