title: Cardiovascular sequel of neck irradiation in head and neck cancer patients.
abstract: The baroreflex is an important afferent mechanism controlling autonomic functions. As afferent nerves course through the neck, they are susceptible to damage by neck irradiation in head and neck cancer patients. With increased survival of head and neck cancer patients because of improved therapy, the cardiovascular morbidity and mortality in them have become apparent and this is of clinical concern. There are few case reports of baroreflex failure as a chronic sequel to neck irradiation.
  
  
  
  The present study evaluated the changes in cardio-autonomic tone and postural cardiovascular reflex in neck-irradiated patients.
  
  
  
  Head and neck cancer patients who had received neck irradiation (n = 15) and healthy controls (n = 15) were evaluated for heart rate variability with time domain analysis of 5 min ECG recording. Postural cardiovascular reflexes were studied with changes in blood pressure and heart rate in the lying to standing test.
  
  
  
  Our results suggest that there is a reduction in overall time domain measures of heart rate variability and weakened postural reflexes in neck-irradiated patients.
  
  
  
  Decreased heart rate variability in neck-irradiated patients reflects an independent risk of cardiovascular morbidity. The early detection of cardiovascular impairment in such patients may help healthcare professionals in providing better care. Furthermore, the dose delivered to the carotid sinus should be monitored and restricted.
authors.affiliation: a Department of Physiology , All India Institute of Medical Sciences Bhubaneswar , Bhubaneswar , Odisha , India.
authors.forename: Manish
authors.initials: M
authors.lastname: Goyal
authors.affiliation: b Department of Clinical Oncology , Delhi State Cancer Institute , New Delhi , India.
authors.forename: Pragya
authors.initials: P
authors.lastname: Shukla
authors.affiliation: c Department of Radiation Oncology , Medanta The Medicity , Gurugram , Haryana , India.
authors.forename: Deepak
authors.initials: D
authors.lastname: Gupta
authors.affiliation: c Department of Radiation Oncology , Medanta The Medicity , Gurugram , Haryana , India.
authors.forename: Shyam
authors.initials: S
authors.lastname: Bisht
authors.affiliation: d Department of Physiology , King George's Medical University , Lucknow , Uttar Pradesh , India.
authors.forename: Nar Singh
authors.initials: NS
authors.lastname: Verma
authors.affiliation: d Department of Physiology , King George's Medical University , Lucknow , Uttar Pradesh , India.
authors.forename: Sunita
authors.initials: S
authors.lastname: Tiwari
authors.affiliation: e Department of Radiotherapy , King George's Medical University , Lucknow , Uttar Pradesh , India.
authors.forename: Madan Lal
authors.initials: ML
authors.lastname: Bhatt
mesh_terms: D000328:Adult; D017704:Baroreflex / Q000528:radiation effects*; D001794:Blood Pressure / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006258:Head and Neck Neoplasms / Q000503:physiopathology* / Q000532:radiotherapy*; D006339:Heart Rate / Q000528:radiation effects*; D006801:Humans; D007194:India; D008297:Male; D011878:Radiotherapy / Q000009:adverse effects; D011879:Radiotherapy Dosage
keywords: Baroreflex; autonomic tone; heart rate variability; postural hypotension