Summer Syncope Syndrome Redux



      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.


      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.


      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.


      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.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to The American Journal of Medicine
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Sun B.C.
        Quality-of-life, health service use, and costs associated with syncope.
        Prog Cardiovasc Dis. 2013; 55: 370-375
        • Sarasin F.P.
        • Louis-Simonet M.
        • Carballo D.
        • Slama S.
        • Junod A.F.
        • Unger P.F.
        Prevalence of orthostatic hypotension among patients presenting with syncope in the ED.
        Am J Emerg Med. 2002; 20: 497-501
        • Staessen J.A.
        • Fagard R.
        • Thijs L.
        • et al.
        Randomised double-blind comparison of placebo and active treatment for older patients with isolated systolic hypertension. The Systolic Hypertension in Europe (Syst-Eur) Trial Investigators.
        Lancet. 1997; 350: 757-764
        • Bień B.
        • Wilmańska J.
        • Jańczak W.
        • et al.
        Syncope and near-syncope as a multifactorial problem in geriatric inpatients: systemic hypotension is an underrated predictor for syncope exclusively.
        Adv Med Sci. 2011; 56: 352-360
        • Huang J.J.
        • Sharda N.
        • Riaz I.B.
        • Alpert J.S.
        Summer syncope syndrome.
        Am J Med. 2014; 127: 787-790
        • Risher J.F.
        • Todd G.D.
        • Meyer D.
        • Zunker C.L.
        The elderly as a sensitive population in environmental exposures: making the case.
        Rev Environ Contam Toxicol. 2010; 207: 95-157
        • Fedorowski A.
        • Burri P.
        • Juul-Möller S.
        • Melander O.
        A dedicated investigation unit improves management of syncopal attacks (Syncope Study of Unselected Population in Malmo—SYSTEMA I).
        Europace. 2010; 12: 1322-1328
        • Mussi C.
        • Ungar A.
        • Salvioli G.
        • et al.
        Orthostatic hypotension as cause of syncope in patients older than 65 years admitted to emergency departments for transient loss of consciousness.
        J Gerontol A Biol Sci Med Sci. 2009; 64: 801-806
        • Galli A.
        • Barbic F.
        • Borella M.
        • et al.
        Influence of climate on emergency department visits for syncope: role of air temperature variability.
        PLoS One. 2011; 6: e22719