Effects of Left and Right Pneumonectomy on Time‐ and Frequency‐Domain Parameters of Heart Rate Variability

Abstract

Background:Morbid cardiac events after pneumonectomy have been attributed to autonornic mechanisms. Analysis of heart rate variability (HRV) offers a noninvasive technique to assess modulation of sympathetic and parasympathetic activity. There is little data available on the systematic changes in time‐ and frequency‐domain parameters of HRV in response to pneumonectomy and cardiac plexus neural trauma. Methods:We measured HRV parameters in 54 patients undergoing left (n = 28) and right (n = 26) pneumonectomy (age 55 ± 11 years) who were without congestive heart failure, active ischemic heart disease, or dysrhythmias, and were not taking β‐blocker or calcium channel blocker therapy. Time‐ and frequency‐domain indices of HRV were measured before surgery (1 hour) and continuously after surgery (Holter) for 3 days. HRV indices measured were: mean R‐R interval (ms), mean of all 5‐minute standard deviation of R‐Rs (SDSD; ms); root mean square of difference of successive R‐Rs (rMSSD; ms); proportion of adjacent R‐Rs > 50 ms different (pNN50;%); total (TF; 0.01–1.00 Hz), low (LF; 0.04 ‐ 0.15 Hz) and high frequency (HF; 0.15–0.40 Hz) power (ms2). Results:Time (R‐R, SDSD, rMSSD, pNN50 and frequency (TF, LF, HF, LF/HF) indices of HRV decreased significantly in response to left or right pneumonectomy. The maximal decrease in HRV occurred during the first 24 to 48 hours. There were no differences between the groups in any measured HRV parameter. Mean heart rate ranged between 80 to 110 beats/min postoperatively for all patients. Conclusions:Decrements in time‐ and frequency‐domain indices of HRV occurred after pneumonectomy independently of the operative side. Global reductions in HRV after surgery support the presence of parasympathetic withdrawal. Although global changes in HRV may reflect an individual's response to surgical stress, the usefulness of HRV to study fine changes in physiological control mechanisms in the postoperative state appears limited. A.N.E. 1999;4(3):325–332