ProBNP kinetics in acute onset atrial fibrillation

When a patient presents in atrial fibrillation, the time of onset impacts treatment decisions. In patients who lack tachycardia awareness estimation of the time of onset is difficult. This study suggests we can take advantage of proBNP kinetics to estimate time of onset. Not something to change practice yet, but interesting:

Results Mean plasma NT-proBNP levels and 95% CIs (pg/ml) during the 48-h period following onset of AF were: 0–6 h: 636 (395 to 928), 6–12 h: 1364 (951 to 1778), 12–18 h: 1747 (1412 to 2083), 18–24 h: 1901 (1549 to 2253), 24–36 h: 1744 (1423 to 2066) and 36–48 h: 1101 (829 to 1373). Mean time to peak NT-proBNP levels was 16.7 (0.7) h; 29 patients reached their peak levels within 24 h. The mean peak NT-proBNP level was significantly higher than those obtained at 0–6 h and at 36–48 h after onset of AF (p less than 0.001 for both). There was no correlation between ventricular rate and plasma NT-proBNP levels during any time period after onset of AF.

Conclusion In patients with new-onset AF but no clinical or radiographic evidence of heart failure, plasma NT-proBNP levels rise progressively to a peak during the first 24 h and then rapidly fall. This pattern may serve as an aid to assess the time from AF onset.