Can we trigger an acute coronary syndrome?

Worrying decrease in hospital admissions for myocardial infarction during the COVID-19 pandemic

Background

How coronavirus 2019 (COVID-19) is affecting management of myocardial infarction is a matter of concern, as medical resources have been massively reorientated and the population has been in lockdown since 17 March 2020 in France.

Aims

To describe how lockdown has affected the evolution of the weekly rate of myocardial infarctions (non-ST-segment and ST-segment elevation) hospital admissions in Lyon, the second largest city in France. To verify the trend observed, the same analysis was conducted for an identical time window during 2018–2019 and for an unavoidable emergency, i.e. birth.

Methods

Based on the national hospitalisation database [Programme de médicalisation des systèmes d’information (PMSI)], all patients admitted to the main public hospitals for a principal diagnosis of myocardial infarction or birth during the 2nd to the 14th week of 2020 were included. These were compared with the average number of patients admitted for the same diagnosis during the same time window in 2018 and 2019.

Results

Before lockdown, the number of admissions for myocardial infarction in 2020 differed from that in 2018–2019 by less than 10%; after the start of lockdown, it decreased by 31% compared to the corresponding time window in 2018–2019. Conversely, the numbers of births remained stable across years and before and after the start of lockdown.

Conclusion

This study strongly suggests a decrease in the number of admissions for myocardial infarction during lockdown. Although we do not have a long follow-up to determine whether this trend will endure, this is an important warning for the medical community and health authorities.

Obstructive sleep apnoea increases the incidence of morning peak of onset in acute myocardial infarction

AIMS

There exists a discrepancy regarding the relationship between obstructive sleep apnoea (OSA) and circadian variation during the onset of acute myocardial infarction (MI). We hypothesized that OSA patients show a characteristic circadian variation and that the severity of OSA significantly affects this variation.

METHODS AND RESULTS

The present study included 288 patients with first acute MI who underwent percutaneous coronary intervention within 12 h of symptom onset. The diagnosis of OSA required an apnoea-hypopnoea index (AHI) of ≥5 events/h. A total of 216 patients fulfilled the OSA criteria. The incidence of MI onset between 06:00 and 11:59 hours was significantly higher in OSA patients than in control patients (38 vs. 25%, p=0.039). Circadian variation in the morning peak of MI onset was attenuated in mild OSA (as defined by AHI, 5.0-14.9 events/h; 33 vs. 25%, p=0.240). Moderate-to-severe OSA (as defined by AHI ≥15.0 events/h) clearly increased the incidence of MI onset between 06:00 and 11:59 hours (43 vs. 25%, p=0.014). Multiple logistic regression adjusting for AHI (≥15.0 events/h), age, body mass index, hypertension, and current smoking showed that moderate-to-severe OSA significantly contributed to MI onset between 06:00 and 11:59 hours (odds ratio 2.00, p=0.010).

CONCLUSIONS

OSA showed a morning peak with regard to MI onset, and moderate-to-severe OSA significantly enhanced this circadian variation.

Triggers of acute cardiovascular events and potential preventive strategies: prophylactic role of regular exercise

There is now considerable evidence to suggest that acute myocardial infarction, sudden cardiac death, and stroke can be triggered by physical, chemical, and psychological stressors, including heavy physical exertion and situations that create heightened emotional stress. The increased risk appears to be largely limited to a susceptible subset of the population, that is, individuals with known or occult cardiovascular (CV) disease. In this article, we summarize the evidence supporting the impact of selected triggers in the pathogenesis of acute CV events, as well as the potential role of various preventive strategies, especially regular exercise training and improvements in cardiorespiratory fitness to reduce the CV risk imposed by various triggers.

Major adverse cardiac events during endurance sports

Major adverse cardiac events in endurance exercise are usually due to underlying and unsuspected heart disease. The investigators present an analysis of major adverse cardiac events that occurred during 2 consecutive annual long distance races (a 36-km beach cycling race and a 21-km half marathon) over the past 5 years. All patients with events were transported to the hospital. Most of the 62,862 participants were men (77%; mean age 40 years). Of these, 4 men (3 runners, 1 cyclist; mean age 48 years) collapsed during (n = 2) or shortly after the races, rendering a prevalence of 0.006%. Two patients collapsed after developing chest pain, 1 of whom needed resuscitation at the event site, which was successful. These patients had acute myocardial infarctions and underwent primary angioplasty. The third patient was resuscitated at the site but did not have coronary disease or inducible ventricular tachycardia or ventricular fibrillation and collapsed presumably because of catecholamine-induced ventricular fibrillation. The fourth patient experienced heat stroke and had elevated creatine kinase-MB and troponins in the absence of electrocardiographic changes. In conclusion, the risk for major adverse cardiac events during endurance sports in well-trained athletes is very low.