Evaluation with Heart Rate Variability for the Treatment Effect of Aminophylline in Patients with Bradycardia after Cervical Spinal Cord Injury: A Preliminary Study

Noriyuki Ishikawa, Naohisa Miyakoshi, Tetsuya Suzuki, Akiko a Misaw, Yuichi Takano, Yoichi Shimada

Department of Orthopedic Surgery, Akita Prefectural Center on Development and Disa- bility, Akita, Japan.
Department of Orthopedic Surgery, Akita Red Cross Hospital, Akita, Japan.
Department of Orthopedic Surgery, Akita University Graduate School of Medicine, Akita, Japan.
Iwai Orthopaedic Medical Hospital, Tokyo, Japan.

DOI: 10.4236/ojo.2013.31003                

Abstract

After cervical spinal cord injury (SCI), the autonomic nervous system (ANS) becomes impaired and then, bradycardia can develop. In view of this, we performed to prescribe aminophylline as pharmacotherapy for bradycardia. The study population consisted of 36 patients with cervical SCI. Bradycardia developed in 20 patients (55.6%), of these patients, 8 showed spontaneous recovery. Twelve patients had persistent bradycardia, therefore, aminophylline was administered at 0.5 mg/kg/hr by intravenous infusion. Their average heart rate increased within 24 hours after the start of infusion. In heart rate variability analysis for 7 preliminarily selected patients, the spectral waveforms of “oligowave type” indicating ANS impairment tended to appear in relatively early phase after injury (i.e., 2 days to 2 weeks after injury), whereas “normal type” was observed in the late phase (i.e., at 4 weeks). “Sympathetic block type” was observed throughout the follow-up period (2 days to 4 weeks). “Sympathetic block type” was also observed in a non-bradycardic patient on day 2. These results underscore the importance of treating ANS impairment with aminophylline while keeping in mind that bradycardia can occur even in post-SCI patients without clinical manifestations.

Keywords

Spinal Cord Injury; Aminophylline; Heart Rate Variability; Autonomic Nervous System; Bradycardia

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	N. Ishikawa and T. Takano, “Aminophylline for the Treatment of Bradycardia after Cervical Spinal Cord Injury,” Journal of Spine Research, Vol. 1, No. 3, 2010, p.598.
[2]	S. Fukui, K. Miura, H. Kurokawa, M. Sano, K. Sato, M. Sasaki and H. Ito, “Evalution of the Autonomic Nervous Function in Patients with Chronic Obstructive Pulmonary Disease Based on the Heart Rate Variability: Particularly Regarding the Presence or Absence of Parasympathetic Tone,” Akita Journal of Medicine, Vol. 34, No. 1, 2007, pp. 35-41.
[3]	S. Akselrod, D. Gordon, F. A. Ubel, D. C. Shannon, A. C. Berger and R. J. Cohen, “Power Spectrum Analysis of Heart Rate Fluctuation: A Quantitative Probe of Beat-to-Beat Cardiovascular Control,” Science, Vol. 213, No. 4504, 1981, pp. 220-222. doi:10.1126/science.6166045
[4]	Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology, “Heart Rate Variability: Standards of Measurement, Physiological Interpretation and Clinical Use,” Circulation, Vol. 93, No. 5, 1996, pp. 1043-1065. doi:10.1161/01.CIR.93.5.1043
[5]	R. D. Berger, J. P. Saul and R. J. Cohen, “Transfer Function Analysis of Autonomic Regulation. I. Canine Atrial Rate Response,” American Journal of Physiology, Vol. 256, No. 1, 1989, pp. H142-H152.
[6]	V. K. Yeragani, K. Srinivasan, S. Vempati, R. Pohl and R. Balon, “Fractal Dimension of Heart Rate Time Series: An Effective Measure of Autonomic Function,” Journal of Applied Physiology, Vol. 75, No. 6, 1993, pp. 2429-2438.
[7]	B. Pomeranz, R. J. Macaulay, M. A. Caudill, I. Kutz, D. Adam, D. Gordon, K. M. Kilborn, A. C. Barger, D. C. Shannon, R. J. Cohen, et al., “Assessment of Autonomic Function in Humans by Heart Rate Spectral Analysis,” American Journal of Physiology, Vol. 248, No. 1, 1985, pp. H151-H153.
[8]	T. Sakamoto, T. Sadanaga and T. Okazaki, “Sequential Use of Aminophylline and Theophylline for the Treatment of Atropine-Resistant Bradycardia after Spinal Cord Injury: A Case Report,” Journal of Cardiology, Vol. 49, No. 2, 2007, pp. 91-96.