Abstract 2154: Paroxysmal Atrial Tachyarrhythmia (AT) as a Trigger for Heart Failure Exacerbations: Assessment by Implanted Trans-pulmonary Impedance Sensor
Introduction: From clinical experience, it is known that worsening of heart failure (HF) is often associated with a seemingly greater susceptibility to atrial tachyarrhythmias (AT), particularly atrial fibrillation. However, it is not clear whether it is the HF or the AT that is the sentinel event, and triggers the other. recently, certain contemporary implantable pulse generators (IPGs) are able to estimate intra-thoracic fluid status by means of detecting alterations of trans-pulmonary electrical impedance (OptiVol® [OV], Medtronic Inc). This capability permits long-term assessment of HF in pts. Employing this tool (i.e., OV) this study examined the temporal relationship between HF as assessed by OV method and AT events.
Methods: Fourteen patients (pts: males, 71%, mean age 70±6.7 years) with OV-capable IPGs were enrolled. At each patient visit, OV index values since last follow-up, and AT duration (hours) were collected. OV Index >60 based on Medtronic Impedance Diagnostics in Heart Failure Trial (MID-HeFT) data was used as a cutoff to signify HF. Devices were interrogated to ascertain the temporal relationship of OV Index >60 and incidence of AT. Results are presented as mean ± SD.
Results: Eighty-five pt visits were analyzed (mean=6.1 visits per pt, average follow-up, 21.7±5.7 months). Left-ventricular ejection fraction was 40±10%, with ischemic cardiomyopathy accounting for 57% pts. In 23 of 85 visits the OV index exceeded threshold and episodes of AT were detected by the device. Of these 23 instances in which there was AT-HF concordance, AT onset preceded the increase of OV index above threshold in 21/23 cases (91% of the time), comprising 9 of 14 pts (64%).
Conclusions: In patients with both systolic HF and paroxysmal AT, our findings suggest that AT tends to precede worsening of heart failure and may act as the trigger event.