795 Electrocardiogram after successful primary angioplasty: does it still matter?

Abstract

@Background: elevated heart rate preceding the onset of ventricular tachycardia (VT), suggesting an increased sympathetic tone, has been reported to reduce the success of antitachycardia pacing (ATP) therapy in patients with implantable cardioverter defibrillators (ICD). Based on the data of the Variability Learned from Implantable Defibrillators (VALID) study, we aimed to assess the impact of autonomic tone on ATP effectiveness in ICD recipiens. Methods and results: a total of 36 out of 226 VALID-study patients implanted with a Biotronik ICD(Phylax XM or Microphylax+) were considred for the present sub-study. These devices have extended memory capacities (18000 RR intervals) that offerred the ability of analyzing heart rate variability (HRV) before the begening of the arrythmia. All the patients had ischemic heart disease. ATP programming was standardized within VT zones. During follow-up, 106 VTs recurred in these patients, 95 were terminated by ATP (ATP+) and ATP was unseccessful in 11 VTs (ATP-). HRV parameters were analyzed during the 30 minutes preceding VT onset. Two time- and three frequency-domain indices were derived semi-automatically: the standard deviation of normal RR intervals (SDNN), the proportion of adjacent normal RR intervals differing by > 50 ms (pNN50), the low-frequency (LF) power reflecting sympathetic tone, the high-frequency (HF) power reflecting parasympathetic activity, and the LF/HF power ratio. The following table summarizes the main