I want to find out if autonomic nervous system can be assessed in patients with ongoing atrial fibrillation and can that be correlated when the same patients are in Sinus rhythm?
What methods can be used to assess ANS function?
What parameters can be measured when patients are in AF?
Dear Habib Khan,
I think, one can try to record and process His-Purkinje System (HPS) electrograms. HPS is activated directly by the sinus node, which is modulated by ANS. Supposingly HPS is not affected by the AF. Probably it could be possible to record HPS electrograms non-invasively and extract "genuine" R-R intervals by subsequent signal processing. See, for example, article of the Flowers et al., Surface Recording of His-Purkinje Activity on an Every-beat Basis Without Digital Averaging, http://circ.ahajournals.org/content/63/4/948.full.pdf
Best regards,
ANS function is measured differently depending on which branch of the ANS you are interested in. If you want to assess parasympathetic function than HRV and RSA are good. Sympathetic function can be assessed using skin conductance.
Dear Khan,
You may have to try some modifications of the traditional heart rate variability (HRV) analysis that some researchers have used such as ;
1) Khand et al developed an index based on the circadian rhythm of atrioventricular nodal functional refractory periods. See their article : The assessment of autonomic function in chronic atrial fibrillation: description of a non-invasive technique based on circadian rhythm of atrioventricular nodal functional refractory periods.Europace 2006;8( 11):927-34. DOI: 10.1093/europace/eul111.
2) Suketu H Nanavati et al also used the P(parasympathetic) and S(sympathetic) method which is derived from combination of HRV analysis in conjunction with respiratory activity analysis in assessing ANS alteration in patients with AF. See their article:Altered Autonomic Activity with Atrial Fibrillation as Demonstrated by Non-invasive Autonomic Monitoring. US Cardiology - Volume 7 Issue 1;2010:7(1):47-50.
The bottom line is that no consensus method for ANS assessment in AF patients have been developed,leaving researchers with the option of modifying the traditional HRV analysis method to assess ANS dysfunction in AF.
Best regards
Dear Habib,
you might want to look at some studies published by Mainardi LT.
Best regards
Dear Habib,
one of the easiest ways to test sympathetic integrity is to measure blood pressure several times in the supine (5-10 min) and in the upright position (5-10 min). Assuming the arrhythmia does not change too much, a stable blood pressure indicates intact sympathetic vasoconstrictor regulation.
Best, Karsten
Dear Habib,
Yes, this is possible, you can monitor sympathetic and parasympathetic activities simultaneously and dynamically.
We are conducting a study (with Faculty of Medicine in Nice, France) on more than 100 subjects and some of them have various arrhythmias. We observed that practically, all subjects having arrhythmias have also a strong parasympathetic dominant activity. And this is valid even for those not taking beta-blocker medication.
Here attached a plot comparing a healthy subject and one exhibiting an arrhythmia. The protocol used here is paced respiration at 6 cycles/min. We haven't seen specific AF cases but the tool just delivers ANS activity, whatever protocol put in place.
A good quality ECG and QRS detector is assumed, as the tool (CODESNA_HRV) take in input the RR interval file (HRV).
If you're interested in, just check it out here: http://www.codesna.com/en/products/codesna_hrv/
Hope this can help.
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