title: Summer syncope syndrome redux.
abstract: BACKGROUND
  While antihypertensive therapy is known to reduce the risk for heart failure, myocardial infarction, and stroke, it can often cause orthostatic hypotension and syncope, especially in the setting of polypharmacy and possibly, a hot and dry climate. The objective of the present study was to investigate whether the results of our prior study involving continued use of antihypertensive drugs at the same dosage in the summer as in the winter months for patients living in the Sonoran desert resulted in an increase in syncopal episodes during the hot summer months.
  
  
  METHODS
  All hypertensive patients who were treated with medications and admitted with International Classification of Diseases, 9th Revision code diagnosis of syncope were included. This is a 3-year retrospective chart review study. They were defined as "cases" if they presented during the summer months (May to September) and "controls" if they presented during the winter months (November to March). The primary outcome measure was the presence of clinical dehydration. The statistical significance was determined using the 2-sided Fisher's exact test.
  
  
  RESULTS
  A total of 834 patients with an International Classification of Diseases, 9th Revision code diagnosis of syncope were screened: 477 in the summer months and 357 in the winter months. In patients taking antihypertensive medications, there was a significantly higher number of cases of syncope secondary to dehydration during the summer months (40.5%) compared with the winter months (29%) (P = .04). No difference was observed in the type of antihypertensive medication used and syncope rate. The number of antihypertensives used did not increase the cases of syncope in either summer or winter.
  
  
  CONCLUSIONS
  An increased number of syncope events was observed in the summer months among people who reside in a dry desert climate and who are taking antihypertensive medications. The data confirm our earlier observations that demonstrated a greater number of cases of syncope among people who reside in a dry desert climate who were taking antihypertensive medications during summer months. We recommend judicious reduction of antihypertensive therapy in patients residing in a hot and dry climate, particularly during the summer months.
authors.affiliation: University of Arizona at South Campus, Tucson. Electronic address: jenniferhuang@mail.arizona.edu.
authors.forename: Jennifer Juxiang
authors.initials: JJ
authors.lastname: Huang
authors.affiliation: University of Arizona at South Campus, Tucson.
authors.forename: Chirag
authors.initials: C
authors.lastname: Desai
authors.affiliation: University of Arizona at South Campus, Tucson.
authors.forename: Nirmal
authors.initials: N
authors.lastname: Singh
authors.affiliation: University of Arizona at South Campus, Tucson.
authors.forename: Natasha
authors.initials: N
authors.lastname: Sharda
authors.affiliation: University of Arizona at South Campus, Tucson.
authors.forename: Aaron
authors.initials: A
authors.lastname: Fernandes
authors.affiliation: University of Arizona at South Campus, Tucson.
authors.forename: Irbaz Bin
authors.initials: IB
authors.lastname: Riaz
authors.affiliation: University of Arizona, Sarver Heart Center, Tucson.
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Alpert
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001130:Arizona; D003681:Dehydration / Q000150:complications; D003889:Desert Climate; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007024:Hypotension, Orthostatic / Q000139:chemically induced* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012621:Seasons; D013575:Syncope / Q000139:chemically induced* / Q000209:etiology
chemical_list: D000959:Antihypertensive Agents
keywords: Heat syncope; Hypertension; Summer; Summer syncope