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Prevalence of arrhythmias in patients with idiopathic dilated cardiomyopathy
1Department of Cardiology, First Affiliated Hospital, Nanjing, Medical College.
Insights
Idiopathic dilated cardiomyopathy (IDCM) patients frequently experience ventricular arrhythmias (VA) and heart block. Elevated catecholamine levels and increased isoproterenol sensitivity were observed, correlating with adverse outcomes including sudden cardiac death.
Area of Science:
- Cardiology
- Electrophysiology
- Internal Medicine
Background:
- Idiopathic dilated cardiomyopathy (IDCM) is a significant cause of heart failure.
- Arrhythmias are common in IDCM, but their specific prevalence and impact require further elucidation.
- Autonomic nervous system dysfunction may play a role in IDCM progression and outcomes.
Purpose of the Study:
- To investigate the prevalence and types of arrhythmias in patients with IDCM.
- To explore the relationship between arrhythmias, cardiac dysfunction severity, and autonomic markers.
- To assess the association between arrhythmias and mortality, including sudden cardiac death.
Main Methods:
- Holter monitoring was performed on 105 patients diagnosed with IDCM.
- Arrhythmia types, including ventricular premature beats (VPB), ventricular tachycardia (VT), and heart block, were recorded.
- Serum catecholamine levels (norepinephrine, epinephrine) and isoproterenol sensitivity were measured. Electrophysiological studies (HBE) were conducted.
Main Results:
- 100% of patients exhibited ventricular premature beats (VPB), with 58.1% having complex VPB and 25.7% experiencing short runs of ventricular tachycardia (VT).
- Atrioventricular block (A-VB) or bundle branch block (BBB) occurred in 46.7%, and atrial arrhythmias in 38.1%.
- Elevated serum norepinephrine and epinephrine levels, along with increased isoproterenol sensitivity, were significantly higher than in controls (P < 0.01). Ventricular arrhythmias were not correlated with NYHA class, illness duration, or sex. Eight patients died, six from sudden cardiac death due to VT/VF.
Conclusions:
- Ventricular arrhythmias and conduction abnormalities are highly prevalent in IDCM.
- Autonomic dysfunction, indicated by elevated catecholamines and heightened isoproterenol sensitivity, is characteristic of IDCM.
- These arrhythmias and autonomic imbalances are associated with increased risk of mortality, particularly sudden cardiac death.
Abstract:
A total of 105 patients with idiopathic dilated cardiomyopathy (IDCM) underwent Holter monitoring. The prevalence of arrhythmias was as follows: ventricular premature beats (VPB) 100%, including complex VPB 58.1%, short runs of ventricular tachycardia (VT) 25.7%, A-VB or BBB 46.7%, atrial arrhythmias 38.1%, sinus node dysfunction 6.6%, ST-T change 38.1%. The incidence of ventricular arrhythmia (VA) was not related to severity of cardiac dysfunction (NYHA), duration of illness and sex. The most common arrhythmia was VA, the second one was heart block and atrial arrhythmia. Serum norepinephrine and epinephrine levels were 743.4 +/- 252.5 and 688.0 +/- 452.4 pg/ml, respectively, which were higher than those in control group (P < 0.01). Isoproterenol sensitivity test (ICD25) 8.43 +/- 11.21 micrograms, was also much higher than that in control group (P < 0.01). Average H-V interval was 69.4 +/- 13.3 msec in HBE. Eight patients died. Two died of congestive heart failure (class II-IV), and six cases were diagnosed as sudden cardiac death resulting from VT and VF.