Abstract
Objectives. The purpose of this study was to assess the prevalence of cardiac and psychiatric diagnoses in patients with chest pain and palpitations. Design. Consecutive patients (n=198), aged between 18 and 65, referred to a cardiac outpatient unit for evaluation for chest pain or palpitations, were asked to participate. Patients with a previous history of heart disease, confirmed by a cardiologist, were excluded. The final sample comprised 160 patients. The cardiac evaluation comprised a bicycle stress test, myocardial scintigraphy, coronary angiography, or Holter monitoring. The psychiatric evaluation consisted of a diagnostic interview. Results. The prevalence of coronary heart disease was 4%. No cases of arrhythmia in need of treatment were detected. The prevalence of psychiatric disorders, among those without coronary heart disease, was 39%: 14% panic disorder, 14% somatoform disorders, and 5% major depression. Conclusion. Cardiac conditions were rare, and the prevalence of panic and somatoform disorders was about three times higher than that of cardiac disease. The study illustrates the importance of having a strategy to identify psychiatric disorders in patients referred for chest pain or palpitations.
Chest pain and palpitations are the two most frequent reasons for seeking cardiac investigation Citation[1]. Most patients referred to cardiac outpatient clinics for examination of these complaints do not have heart disease Citation[2], Citation[3]. Patients with non-cardiac chest pain or benign palpitations often have a poor prognosis in terms of symptom persistence, emotional distress, limitations in everyday activities, and concerns about having heart disease Citation[2], Citation[4], Citation[5].
During the past decade, there has been a change in hospitalization policy for patients with acute coronary syndrome. Most patients with new onset angina are now urgently hospitalized and not referred for outpatient evaluation. This change may have influenced the prevalence of coronary heart disease (CHD) and psychiatric disorders at cardiac outpatient clinics.
Chest pain and palpitations are core symptoms of panic disorder. Studies conducted in cardiac settings have shown that 10–19% of patients with palpitations Citation[6], Citation[7], and at least 25% of those with non-cardiac chest pain, suffer from panic disorder Citation[3], Citation[8]. The prevalence of somatoform disorders has been reported to 15–20% in patients with non-cardiac chest pain and 2–3% in palpitations Citation[3], Citation[6], Citation[7].
The aims of the present study were to assess the prevalence of cardiac diagnoses and psychiatric disorders in patients with palpitations or chest pain referred for cardiac investigation.
Material and methods
Ethics
The research protocol was accepted by the Regional Committee for Medical Research Ethics in Trondheim in May 2006 and by the Norwegian Social Science Data Service in Bergen in June 2006.
Patients
Consecutive patients aged between 18 and 65, who were referred to the cardiac outpatient unit at Molde Hospital, Norway, for evaluation of chest pain or palpitations between May 2006 and May 2007 were asked to participate. The outpatient clinic receives all referrals in a catchment area of about 75 000 inhabitants.
The head of the cardiac unit screened all referrals. The inclusion criteria were: Citation[1] referral for chest pain or arrhythmias, Citation[2] age 18–65 years, and Citation[3] the ability to understand and write Norwegian. The exclusion criteria were: Citation[1] mental retardation, Citation[2] psychosis, and Citation[3] previous organic heart disease confirmed by a cardiologist. All participating patients signed an informed consent form.
Of 219 consecutive patients, 21 cancelled both the cardiological and the psychiatric evaluation, 36 did not want to participate in the study, and two were excluded (one did not speak Norwegian properly, and one was mentally retarded). A total of 160/198 patients (81%) completed the study. Of these, 112 were referred for chest pain and 48 for palpitations. The 36 who did not want to participate in the study did not differ significantly from the participants regarding age, sex, prevalence of CHD (result of the cardiac evaluation), or chest pain/palpitations ratio.
Demographic and clinical data
Sex, age, marital status, education, main source of income during the previous six months, number of days on sick leave in the previous three months, previous psychiatric treatment, and duration of actual symptoms were assessed by reading the referrals and questioning the patients.
Cardiac evaluation
In addition to routine cardiac evaluation, the cardiologist completed a form consisting of risk factors for CHD and clinical descriptors for chest pain (duration, character, site and radiation of chest pain, and precipitating factors) or palpitations (duration of symptoms, character of arrhythmias or complaints, and syncope). All patients underwent a 12-lead resting electrocardiogram (ECG).
The interpretation of the standard bicycle stress test was based on ST-segment deviation, arrhythmias, blood pressure response, and the presence of chest pain. The evaluation was based on the patient's history, ECG, and the results of the stress test. If the cardiologist found the results consistent with CHD, or if there was doubt about the diagnosis, the patients were referred for myocardial scintigraphy, or coronary angiography.
If there was doubt about the conclusion from the Holter monitoring, the patients also underwent seven days of ECG monitoring (R-test) or a bicycle stress test.
Blood samples were taken to analyse fasting blood sugar, CRP, total cholesterol, fT4, and TSH.
The cardiac evaluations were performed and administered at the cardiology unit at Molde Hospital, except for the coronary angiography, which was performed at St. Olav University Hospital, Trondheim.
Psychiatric diagnostic interview
In this study, we focused on three main groups of psychiatric disorders: anxiety disorders including panic disorder, mood disorders including major depression, and somatoform disorders. The main criterion for panic disorder is the presence of attacks of fear or discomfort including at least four specified somatic symptoms. Among these symptoms are chest pain, palpitations, sweating, sensation of shortness of breath, nausea, feeling dizzy, and fear of dying. Somatoform disorders constitute a group of psychiatric disorders with predominantly physical symptoms that are not fully explained by a general medical condition.
All psychiatric disorders were obtained by using the Structured Clinical Interview for DSM-IV axis I disorders, SCID-I Citation[9]. The interviews were performed before the cardiac evaluation and administered by a psychiatrist (the first author EJ), trained in the use of this method. The interviewer was blind to the results of the cardiac evaluation. The first 15 interviews were discussed in detail with the last author (EWM), and consensus was obtained. For all psychiatric diagnoses, the criteria had to be met within one month prior to the interview.
Statistics
The comparisons between groups were performed by using chi-square test for categorical data, Mann–Whitney U test for ordinal variables, and independent-samples t-tests for continuous variables. All tests were two tailed. The alpha level was p < 0.05. Statistical Package for Social Sciences (SPSS) version 15 was used for all analyses.
Results
Socio-demographic characteristics
The ratio of women to men was 34/14 for palpitations and 52/60 for chest pain (p = 0.005). The median age for patients with palpitations and chest pain was 45 and 54, respectively. The groups did not differ significantly in marital status, level of education, main source of income during the previous six months, days on sick leave prior to evaluation, or duration of present symptoms.
Prevalence of heart disease
A flow chart of psychiatric and cardiac evaluation is given in . Five patients with chest pain (4%) and one with palpitations had CHD verified by coronary angiography, giving a total of 6/160 (4%) in the whole sample. Four of the six patients with verified CHD had abnormal findings on the exercise ECG. No arrhythmias in need of treatment were discovered.
Figure 1. Flow chart for psychiatric and cardiac evaluation.
Prevalence of psychiatric disorders among those without cardiac disease
A total of 22/154 patients (14%) had panic disorder (at least one panic attack in the month prior to investigation), 21/154 (14%) had any somatoform disorder, and the prevalence of major depression was 7/154 (5%) (). The prevalence of any psychiatric disorder was 39%, and when specific phobias were excluded, the prevalence was 29%. Among those who had a cardiac condition confirmed, one had an anxiety disorder (social phobia), none had panic disorder. When comparing those with chest pain and those with palpitations, no significant differences in prevalence of psychiatric disorders were found.
Table I. Prevalence of psychiatric disorders in patients referred for chest pain or palpitations where no cardiac disease was confirmed by the cardiac evaluation.
Discussion
Among patients below age 65 referred to cardiac evaluation for angina or palpitations in an outpatient setting, the prevalence of CHD and arrhythmia was 4%, whereas in 39% the symptoms were most likely caused by psychiatric disorders.
Prevalence of heart disease
Only in 6 of 160 patients (4%) was a cardiac condition in need of treatment verified. The low frequency of verified CHD and no arrhythmias in need of treatment indicate that the threshold for being referred for a cardiac evaluation was low. The prevalence of CHD among the patients with chest pain in this study was lower than in a comparable study conducted about 10 years earlier (16%). In both studies, those above 65 years of age were excluded Citation[3]. This might reflect the change in hospitalization policy for patients with acute coronary syndrome seen during the last decade.
Prevalence of psychiatric disorders
Most previous studies have found that panic disorder is frequent among patients referred for cardiac evaluation for chest pain or palpitations Citation[3], Citation6–8. Our results confirm these findings, even though our prevalence rate of panic disorder among patients with chest pain was somewhat lower than previously reported Citation[3], Citation[8].
Dammen et al. found a high prevalence of somatoform disorders (19%) among patients with chest pain at another cardiology outpatient clinic in 1994–1995 Citation[3], and this was confirmed in a nine-year follow-up (14%) Citation[4]. In our sample, the prevalence was somewhat lower (14%), and we found similar prevalence among patients referred for chest pain and palpitations.
Study limitations
The cardiac evaluations were carried out by different cardiologists and some trained doctors in specialist training, under the supervision of a cardiologist. The methods used for non-invasive testing (exercise ECG, myocardial scintigraphy, and ECG monitoring) all have false negatives. For more advanced testing, the patients had to be referred to another city, and more patients with CHD might have been detected with easier access to specialized tests. The waiting time for a bicycle stress test was 2–3 months in this period. Some cases with psychiatric disorders and symptomatic heart disease might have remitted during this delay, and this might have influenced the prevalence rates.
Patients aged above 65 were excluded from the study, because we wanted to compare our results to those of previous studies Citation[3]. However, patients >65 years comprise a rather large proportion of patients referred for cardiac evaluation and the relatively low frequency of patients with CAD/arrhythmias in our study may at least partly be a result of the exclusion of these patients. This limits the generalizability of the results of the study.
This study was carried out in a rural area, and this might give a bias compared with previous studies carried out in big cities. One advantage was that the study was conducted in routine clinical practice, on all patients consecutively referred to a unit receiving all referrals in a catchment area, and with the use of clinical methods commonly used in practice.
Implications for clinical practice and future research
Psychiatric disorders are more frequent than cardiac disease among patients referred for chest pain and palpitations to cardiac units. There is a need for routines to identify these patients because effective treatment is available, and their prognosis without specific treatment is poor. Screening for mental disorders should be part of a comprehensive evaluation of patients with chest pain and palpitations, especially when no heart disease is verified. Whether this screening should be conducted in a cardiology unit or in the office of the general practitioner is a matter for further discussion.
Conclusion
A substantial proportion of patients referred to cardiac evaluation for chest pain or palpitations suffer from psychiatric disorders, and cardiac disorders are rare. It is important to have a strategy to identify mental disorders, especially panic disorder, so that patients can be provided with effective treatment. This might reduce unnecessary suffering and development of a chronic condition.
Acknowledgements
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
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