Sustained ventricular arrhythmias in NSTE ACS rare but high-risk

Jun 19 2012

By Lauretta Ihonor

Sustained ventricular fibrillation (VF) or tachycardia (VT) in patients admitted with non-ST-segment elevation acute coronary syndrome (NSTE ACS) are uncommon but worsen patients' prognosis markedly if they do develop, researchers report.

Their findings show that such arrhythmias are more likely to happen at least 48 hours after admission than earlier, say Jonathan Piccini (Duke University Medical Center, Durham, North Carolina, USA) and colleagues.

Moreover, the occurrence of VF or VT at least 48 hours after NSTE ACS admission raises the 1-year mortality risk of NSTE ACS patients 20-fold.

As reported in the journal Circulation, Piccini and team assessed the rates of sustained VF and VT among 9211 NSTE ACS patients.

The arrhythmias were defined as sustained if each episode lasted more than 30 seconds and/or was accompanied by hemodynamic compromise requiring electrical defibrillation or intravenous antiarrhythmic medications.

VF or VT occurred in 141 (1.5%) patients. Of these, 55 (39.0%) experienced the arrhythmia within 48 hours of admission, and 86 (61.0%) had the arrhythmia more than 48 hours after admission for NSTE ACS.

Logistic regression modeling was used to assess the relationship between sustained VF or VT within 48 hours and 30-day mortality.

Piccini and team found that patients who experienced either arrhythmia within 48 hours of admission had higher 30-day mortality rates than those who did not have a VF or VT event, at respective rates of 13.0% versus 2.2%.

The same trend was observed for 1-year mortality.

When compared with patients with no VF or VT, those who had either arrhythmia more than 48 hours after admission had an almost three-fold higher risk for 1-year death than those who had their arrhythmia within 48 hours of admission.

Predictors for sustained VF or VT, such as elevated baseline troponin levels and a history of angina, were similar among all patients who experienced either ventricular arrhythmia, regardless of the timing of the arrhythmia.

The researchers conclude: "These data suggest that patients with NSTE ACS require monitoring beyond 48 hours and highlight the importance of investigating the efficacy of interventions, such as the wearable defibrillator or an ICD, in preventing arrhythmic death in patients with early sustained VT/VF."

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