Emotional stress is well known as a risk factor for cardiovascular events^[1-3]. However, the risk of cardiovascular events caused by watching soccer games remains controversial. Until now, there has been no multicenter study that has investigated the relationship between watching soccer games and cardiac arrhythmia evaluated by 24-hours Holter Electrocardiography (Holter ECG). World Cup Soccer (WCS) was held in Brazil from June to July 2014. In this study, we investigated the frequency of arrhythmia and ischemic changes using Holter ECG in patients with cardiovascular diseases and those suspected of having cardiac disease during the Japan National Team’s matches in WCS 2014.

Materials and Methods

Study population: We enrolled 25 patients (mean age 63 ± 19 years, 10 males) who underwent Holter ECG in the outpatient clinic of four cardiology divisions on June 19 and June 24, 2014. During the WCS qualifying rounds, Japan versus Greece and Japan versus Columbia were broadcast on live television at 7 AM on June 20 and 5 AM on June 25, 2014 (Japan time). The patients were not informed about the study protocol before Holter ECG but were notified about the study when they returned the Holter ECG recorders during which they were asked if they had watched any soccer matches on live television. Then, the patients were divided into two groups: the watching (W) group consisted of 7 patients who had watched WCS on live television and the non-watching (NW) group consisted of 18 subjects who had not watched WCS. All protocols were approved by the ethics committee of Juntendo University (14-032), and all participants provided an informed consent before their participation in this study according to the guidelines established in the Declaration of Helsinki.

Measurements: We measured the total number of heart beats, frequency of premature atrial contractions (PACs) and Premature Ventricular Contractions (PVCs), and ischemic changes using a 24-hours Holter ECG system (SCM-8000; FUKUDA DENSHI, Tokyo, Japan). These events were measured each hour. Ischemic changes were also diagnosed using ST-segment depression in the CM5 lead.

Statistical analysis
Continuous variables were compared using the unpaired t-test or Mann–Whitney U-test, and categorical variables were compared using the chi-squared test. A value of P < 0.05 was considered to indicate statistical significance. All data were analyzed using JMP® 11 for Windows (SAS Institute Inc., Cary, NC, USA).

Results

  Patient characteristics: The clinical characteristics of the study subjects are shown in Table 1. Seventeen patients (61%) had cardiovascular diseases (ten patients with a trial fibrillation, three with coronary artery disease, four with valvular heart disease, three with cerebrovascular disease, and one with hypertrophic cardiomyopathy). The clinical characteristics, including age, sex, body mass index, coronary risk factors, and underlying disease, did not differ between the groups. The concomitant use of medications in each group is shown in Table 2. There were no significant differences in medical treatment between the groups.

Table 1: Patient Characteristics

Table 2: Concomitant use of medications.

Arrhythmic and ischemic events: A comparison of Holter ECG data between the groups is shown in Table 3. There was no significant difference in the mean heart rate for 24 hours between the groups. There was also no significant difference in total PVCs over 24 hours. However, the frequency of PVCs during the 2 h of each match was significantly higher in the W group than that in the NW group (61 ± 101 vs. 7 ± 8, P = 0.03) (Figure). The frequency of PVCs 1 h before matches was also significantly higher in the W group than that in the NW group (15 ± 17 vs. 3 ± 5, P = 0.01). There was no significant difference in the frequency of PVCs 1 hour after matches. There was no significant difference in total PACs during the matches between the groups. There were also no significant differences in the levels of maximum ST depression over the 24 hours and during the 2 hours of matches between the groups. No ventricular tachycardia, ventricular fibrillation, or other cardiovascular events occurred during the study period.

Table 3: Comparison of Holter ECG data between the two groups

Figure 1: PVCs relative to the start of the match. h; hours. Data are represented as the mean ± standard error. *p < 0.05.

Discussion

  This study demonstrated a significant association between watching WCS and frequency of PVCs in patients with cardiovascular diseases and patients suspected of having cardiovascular disease. To the best of our knowledge, this is the first multicenter study to investigate the prevalence of arrhythmia evaluated by Holter ECG in patients with/or suspected of having cardiovascular diseases who watched WCS.

  Previous studies have shown that at least 20% of episodes of life-threatening ventricular arrhythmia and unexpected death occurred under the influence of acute emotional stress^[3-7]. Acute and chronic emotional stress has been shown to induce autonomic nervous system activation and provoke physical disabilities^[8]. These strong mental stressors influence the sympathetic tone, increase blood pressure and vasoconstriction, produce inflammatory mediators, cause endothelial dysfunction, and lead to a hypercoagulable state, which can trigger cardiovascular events. It has been suggested that increases in heart rate, blood pressure, myocardial contractility, coronary flow, and coronary tone may promote vulnerable plaque rupture^[9]. Studies have shown that disasters such as earthquakes increase the occurrences of acute coronary syndromes, and ventricular tachyarrhythmia and hospitalization in patients with implantable cardiac defibrillators^[10]. Also the prevalence of post-traumatic stress disorder after earthquakes, increased the frequency of death, acute myocardial infarction, stroke, and heart failure^[11].

  Watching a soccer match is often associated with emotional stress. Fédération Internationale de Football Association (FIFA) WCS involving national teams is one of the most popular sporting events in the world. In the WCS in 1998, England and Argentina played each other in the first round of the finals, and Argentina won in a penalty shootout. The Hospital Episode Statistics in England showed an increase in hospital admission for acute myocardial infarctions during the following 3 days relative to those on other days without matches. The increase in myocardial infarctions could have been triggered by emotional distress, such as a favorite football team losing in an important match^[12]. When France, as the host country, won a game in the WCS, cardiovascular mortality in men decreased on the game day, which suggested that the immense fervor and collective euphoria observed at the time of a victory could decrease mortality^[13]. In the WCS 2006, Germany lost in overtime in the semi-finals. The prevalence of cardiac emergencies was 2.66 times higher on the days of matches than during the control period. In patients with coronary artery disease, the prevalence of emergencies was 4.03 times higher than that during the control period. The highest number of events was observed within the 2 hours of the match. The next highest risk periods was each 2 hours before and after the match^[14]. These data suggested that watching a stressful soccer match was a risk for acute cardiovascular events. In addition, a significant increase in PVCs during a match and 1 hour before a match is consistent with the results of the present study. As discussed above, several studies have reported the increase in cardiovascular emergencies during the events^[15-19]. However, a recent study has reported that watching soccer was not necessarily associated with an increased incidence of cardiovascular events^[20]. These data suggest that further studies are needed to clarify our findings.

  The Japan National Football Team had a scoreless draw and lost in the next match. In this study, the matches were in the early morning on June 20 (7 AM kickoff, Japan time) and June 25 (5 AM kickoff, Japan time). The wake-up time may have affected the study results because these factors may be associated with sympathetic tone, less sleep, and more drinking of alcohol and caffeine, in early morning matches^[21] However, only four patients slept during the two matches in the NW group. No significant differences in the total PVCs, PVCs during matches, or PVCs in other hours were shown between the awaking subjects and sleeping subjects in the NW group (data not shown).

  In this study, nonsustained ventricular tachycardia or fatal arrhythmia was not observed. It has been reported that prediction of cardiac and arrhythmogenic death was strongly associated with the prevalence of PVCs and nonsustained ventricular tachycardia that was a trigger of sustained ventricular tachycardia and ventricular fibrillation^[22]. The prevalence of high risk patients, such as those with ischemic heart disease, was relatively low, and patients with ongoing chronic heart failure were not included in this study. Most of the patients underwent Holter ECG to evaluate the cause of palpitation and chest pain and/or were examined to determine the number of extra heart beats. For these reasons, ventricular tachycardia and fatal arrhythmia were not observed in this study

  This study had several limitations. First, this was a retrospective multicenter study with a small sample size. Prospective studies with a large number of subjects are needed to confirm our findings. Second, as mentioned above, the reason for performing Holter ECG was mainly to evaluate palpitation, chest pain, and extra systole. Therefore, the present results might not be representative of other subjects. Third, heart rate variability and heart rate turbulence were not evaluated. Fourth, alcohol and caffeine intake were not quantified, which might be confounding factors. Finally, all subjects were Japanese. Racial differences in enthusiasm during soccer matches may have been a major limitation.

Conclusion

  In conclusion, a significant association between watching WCS and frequency of PVCs was observed in patients with cardiovascular diseases and patients who were suspected of having cardiac diseases.

Funding: This work was supported by the Ministry of Education, Culture, Sports, Science, and Technology-supported Program for the Strategic Research Foundation at Private Universities, Japan.

Conflict of Interest:
  There were no conflicts of interest.

References