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Significance of ventricular arrhythmias in idiopathic dilated cardiomyopathy
Insights
Ventricular arrhythmias in idiopathic dilated cardiomyopathy predict sudden cardiac death. Frequent and complex ventricular arrhythmias, identified by Holter monitoring, are significant indicators of mortality risk in these patients.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Idiopathic dilated cardiomyopathy (IDC) is a significant cause of heart failure.
- Ventricular arrhythmias are common in IDC but their prognostic significance requires further elucidation.
Purpose of the Study:
- To prospectively assess the incidence and prognostic significance of ventricular arrhythmias in patients with IDC.
- To determine if specific arrhythmic parameters predict mortality, including sudden cardiac death.
Main Methods:
- Prospective study of 74 patients with IDC diagnosed via clinical and cardiac catheterization.
- 24-hour ambulatory electrocardiography (Holter monitoring) performed at baseline.
- Follow-up for 2-21 months to assess mortality outcomes (congestive heart failure vs. sudden death).
Main Results:
- High incidence of ventricular arrhythmias: 35% with frequent VPCs, 87% with complex VPCs (Lown grade III/IV), 49% with nonsustained VT.
- Patients who died suddenly had significantly more VT episodes, ventricular pairs, and total VPCs compared to survivors and those who died from CHF (p < 0.01).
- Discriminant analysis using hemodynamic and arrhythmic variables effectively separated survivors from non-survivors.
Conclusions:
- Ventricular arrhythmias, particularly frequent and complex ones, are highly prevalent in IDC.
- The burden of ventricular arrhythmias is a significant predictor of sudden cardiac death in IDC patients.
- Holter monitoring is crucial for risk stratification in IDC, identifying patients at higher risk for sudden cardiac death.
Abstract:
The incidence and prognostic significance of ventricular arrhythmias identified by 24-hour ambulatory electrocardiography (Holter) was prospectively assessed in 74 patients with idiopathic dilated cardiomyopathy (IDC). The criteria for diagnosis of IDC were based on clinical and cardiac catheterization findings. Holter monitoring was performed at the time of entry into the study. Patients were followed for 2 to 21 months (mean 11 +/- 3). Frequent ventricular premature complexes (VPCs) (greater than 1,000/24 hours) were seen in 35%, and complex VPCs (Lown grade III and IV) in 87% of the patients. Forty-nine percent of the patients had nonsustained ventricular tachycardia (VT) consisting of 3 to 32 beats with rates from 110 to 230 beats/min, and 20% had ventricular pairs. No correlation was found between clinical symptoms or the degree of left ventricular (LV) impairment and the number of ventricular pairs or episodes of VT. During follow-up, 19 patients died, 7 from congestive heart failure (CHF) and 12 suddenly. Patients who died suddenly had significantly more episodes of VT, ventricular pairs or total VPCs (p less than 0.01 each) compared with survivors and those who died from CHF. No significant differences were found between patients who died from CHF or suddenly with respect to LV end-diastolic pressure, LV end-diastolic volume index, LV ejection fraction (EF) and cardiac index. A linear stepwise discriminant function analysis using hemodynamic (LVEF and cardiac index) and arrhythmic (number of VT episodes and ventricular pairs) variables resulted in a meaningful separation between survivors and patients who died from CHF or suddenly.(ABSTRACT TRUNCATED AT 250 WORDS)