Background:
Cardiac MIBG imaging provides prognostic information in patients with chronic heart failure (CHF). Recent studies showed that the highest occurrence of severe arrhythmic events (SAE) was seen in CHF patients with an intermediate decrease in MIBG uptake rather than the lowest values. On the other hand, non-sustained ventricular tachycardia (NSVT) has been shown to be associated with SAE in CHF patients. However, there is little information available on long-term prognostic value of intermediate decrease in MIBG up take and NSVT for the prediction of severe ventricular tachyarrhythmias in implantable cardioverter defibrillator (ICD) patients.
Methods and Results:
We prospectively enrolled 201 consecutive outpatients with ICD (age: 64±14 years, male: 81%, NYHA class:1.7±0.7, LVEF: 49±17%). At entry, all patients underwent cardiac MIBG imaging and 24-hour Holter electrocardiogram monitoring. An intermediate decrease in heart-to-mediastinum ratio on delayed planar image (H/M) was defined as 1.40-1.89. NSVT was defined as consecutive 3 or more beats and more than 100 bpm. During a follow-up period of 4.0±2.5 years, 59 patients had appropriate ICD discharge for severe ventricular tachyarrhythmias. At multivariate Cox regression analysis, intermediate decrease in H/M and NSVT were significantly and independently associated with appropriate ICD discharge after adjustment with age, sex and low left ventricular ejection fraction (≤35%). Appropriate ICD discharge was significantly more frequently observed in patients with both intermediate decrease in H/M and NSVT and with either intermediate decrease in H/M or NSVT than with none of them (47% vs 36% vs 14%, p<0.0001).
Conclusions:
Combination of cardiac MIBG imaging and NSVT would be more strongly associated with an increased risk for severe ventricular tachyarrhythmias in ICD patients.
Anger and long-term mortality and ventricular arrhythmias in patients with a first-time implantable cardioverter-defibrillator: data from the MIDAS study