A recent PLOS One study of acute coronary syndrome (ACS) (1) reports on factors that impact sleep disturbance. Even though it may seem obvious that people who have a heart attack may suffer from a lack of sleep later, this study finds that some factors may have a greater impact than others, and some of these may even be actionable. By taking a few steps, could it be possible to help decrease the lack of sleep after a heart attack? While it may not revolutionize cardiac (or sleep) medicine, this study does gives us a baseline to start a discussion.
Acute Coronary Syndrome (ACS)
According to the CDC and Mayo Clinic, acute coronary syndrome is a generic term describing conditions causing a sudden reduction in blood flow to the heart. This can include myocardial infarction (“heart attack”) and unstable angina (chest pain that occurs even at rest without an apparent reason)(refs 2,3).
This was a longitudinal study, meaning that the researchers followed the participants over a given length of time. The study started with 180 patients, and the researchers assessed sleep disturbance (using the 4-item Jenkins Sleep Scale, or JSS-4) at the time of hospital admission (time zero), 3 months, and 12 months. 101 patients completed the entire 12-month study. Also, the investigators did an extensive search of other factors or variables (covariates) that may have an effect. The covariates included within the study were:
- Demographic factors, such as
- Employment status (full-time, part-time, retired, or unemployed)
- Living arrangement (living alone or with at least one other person)
- Level of education
- Clinical variables
- Cardiac clinical variables, of course, such as the index event (STEMI vs. non-STEMI), severity of acute coronary syndrome
- Fear of dying
- Feeling of helplessness
- Sleep apnea
- Use of sleeping pills and antidepressants
- Other comorbidities (meaning other diseases or conditions also present within a single patient)
- Health behaviors
- Body-mass index (BMI)
- Smoking status (Never smoked, previous smokers, or current smokers)
- Alcohol consumption
- Weekly physical activity
What were the results?
Interestingly, the study did not find a statistically relevant general connection between sleep disturbance after having an ACS, such as a heart attack, and socioeconomic factors or most clinical factors. So, did they find any factors that may be tied to an in increase in sleep disturbances after cardiac events? Yes. The researchers note a statistically significant increase in sleep disturbance for three general categories:
- Individuals with a history of depression
- Patients who experienced “distress during ACS”
The authors define “distress during ACS” as patients who reported a greater fear of dying or a sense of helplessness during the actual cardiac event.
Why does sleep (and this study) matter?
Anecdotally, we have been told that a good nights’ sleep is ‘good for you’. Studies have shown that many people who have had a heart attack or other sudden cardiac event (ACS) experience sleep disturbance of some degree afterward (4-6). Some studies have indicated that impaired sleep after cardiac events are associated with a worse prognosis (7-9). This current study helps define what factors may be associated with increased sleep impairment. Some of these factors are not preventable or cannot be modified, such as gender. However, other factors are “potentially modifiable” (as the authors state it) and easier to assess at time of admission during the heart attack. For example, trying to remain as calm as possible and decrease anxiety (decrease fear of dying and feelings of helplessness) may have have a greater, long-term impact on decreasing sleep disturbance in the patient’s future.
- von Känel R, Meister-Langraf RE, Zuccarella-Hackl C, et al. Sleep disturbance after acute coronary syndrome: A longitudinal study over 12 months. Pizzi C, ed. PLoS ONE. 2022;17(6):e0269545. doi:10.1371/journal.pone.0269545
- CDC. Other conditions related to heart disease | CDC. Gov. Centers for Disease Control and Prevention. Published January 20, 2022. Accessed July 14, 2022. https://www.cdc.gov/heartdisease/other_conditions.htm
- Acute coronary syndrome – Symptoms and causes. Mayo Clinic. Accessed July 14, 2022. https://www.mayoclinic.org/diseases-conditions/acute-coronary-syndrome/symptoms-causes/syc-20352136
- Madsen MT, Huang C, Zangger G, Zwisler ADO, Gögenur I. Sleep disturbances in patients with coronary heart disease: a systematic review. J Clin Sleep Med. 2019;15(3):489-504. doi:10.5664/jcsm.7684
- Shaffer JA, Kronish IM, Burg M, Clemow L, Edmondson D. Association of acute coronary syndrome-induced posttraumatic stress disorder symptoms with self-reported sleep. Ann Behav Med. 2013;46(3):349-357. doi:10.1007/s12160-013-9512-8
- Coryell VT, Ziegelstein RC, Hirt K, Quain A, Marine JE, Smith MT. Clinical correlates of insomnia in patients with acute coronary syndrome. Int Heart J. 2013;54(5):258-265. doi:10.1536/ihj.54.258
- Clark A, Lange T, Hallqvist J, Jennum P, Rod NH. Sleep impairment and prognosis of acute myocardial infarction: a prospective cohort study. Sleep. 2014;37(5):851-858. doi:10.5665/sleep.3646
- Zhu CY, Hu HL, Tang GM, et al. Sleep quality, sleep duration, and the risk of adverse clinical outcomes in patients with myocardial infarction with non-obstructive coronary arteries. Front Cardiovasc Med. 2022;9:834169. doi:10.3389/fcvm.2022.834169
- Kim JW, Stewart R, Lee HJ, et al. Sleep problems associated with long-term mortality in acute coronary syndrome: Effects of depression comorbidity and treatment. Gen Hosp Psychiatry. 2020;66:125-132. doi:10.1016/j.genhosppsych.2020.08.004