The value of multidisciplinary team in syncope clinic for the effective diagnosis of complex syncope

Syncope is a perplexing challenge that often receives thorough evaluation, yet the diagnosis remains unclear. Usually, the emergency department is the first point at which patients present with syncope. However, diverse medical factors, including low diagnostic rates and inconsistent management by doctors, add to healthcare costs and delay diagnosis for syncope patients.


INTRODUCTION
Syncope is defined as a transient loss of consciousness (TLOC) due to cerebral hypoperfusion and characterized by rapid onset, short duration, and spontaneous complete recovery. 1 It is experienced by almost half of the population during a lifetime and accounts for significant morbidity. 2 The incidence of a first report of syncope was 6.2 per 1,000 person-years, 3,4 which accounts for approximately 3% of emergency department (ED) visits and 6% of hospital admissions. 5 Diagnosis of syncope is always challenging because most patients are asymp-1. Long history of recurrent syncope, in particular that occurring before the age of 40.
3. Occurring while in a crowded and/or hot place. 4. Autonomic activation before syncope: pallor, sweating, faint, and/or nausea/vomiting. 5. Occurring in association with prolonged standing. 6. Occurring during or immediately after eating, micturition, gastrointestinal stimulation (swallow, defecation), cough, sneeze, exercise, laughing, and/or brass instrument playing. 7. Occurring with head rotation or pressure on carotid sinus (as in tumors, shaving, tight collars). 8. Carotid sinus massage is positive or head-up tilt testing is positive if the patient is without prodromes and/or without apparent triggers and/or shows atypical presentation. Syncope due to OH: Syncope due to OH is highly probable if the patient's history of syncope fits the criteria below: 1. Occurring during exercise, after meals, and/or prolonged bed rest. and 47.77 ± 15.50 years old (OH). There were significant differences among all groups (F = 8.771, P < 0.001). Patients with reflex syncope and with OH were younger than patients with cardiac syncope (P < 0.001/P = 0.001) and patients with syncope of uncertain etiology (P = 0.011/P = 0.009) ( Table 3).
Across diagnostic categories, the ratio of men and women was significantly different ( 2 = 13.038, P = 0.004). Men are more likely to present with cardiac syncope (66.7%), while women are more likely to present with reflex syncope (67.3%) (P = 0.001) ( Table 4).

DISCUSSION
This study was carried out by a multidisciplinary team in the syncope clinic, who collected data on the diagnostic yield, specific diagnosis of TLOC, proportion of syncope type, hospitalization rate, recurrence rate of syncope, and age and gender distribution across diagnostic categories of syncope. The diagnostic rate was 91.6%, with an admission rate of 23.4%. Reflex syncope was shown to be the most common However, it is not recommended to take further investigations if diagnosis is nearly certain or highly likely based on medical history of patients after initial evaluation. 1 Since not every reflex syncope patient had head-up tilt test or carotid sinus massage, it is inevitable that there may be some misdiagnosis of reflex patients.

Syncope clinic and admission rate
Syncope represents a common and challenging symptom complex for practicing physicians, and it can be debilitating and associated with high healthcare costs. 19  through 2010, they found the admission rates for syncope patients ranged from 27% to 35%. 24 Other investigations showed that the hospitalization rates of syncopal patients ranged from 46.5% to 51.4%, if the patients did not receive specific medical care from syncope unit or some other similar departments. 9,10,23 In our study, the admission rate was 23.4%, which was lower than many prior studies.

The value of syncope clinic
As the guideline of 2018 ESC recommend, patients presenting with probable TLOC will be categorized into no TLOC, syncope, and TLOCnonsyncopal groups according to their rough medical history. Thereafter, syncope patients will go through initial syncope evaluation including detailed history and physical examination, ECG, and supine and standing blood pressure. Then some patients can get certain or highly likely diagnosis, and treatment can be started. The other patients with uncertain diagnosis will be grouped based on risk stratification. Those in the high-risk group are advised for early inpatient evaluation and treatment, while those in the low-risk group need no further evaluation. 1 The syncope clinic in our study is a little different from the guideline of 2018 ESC.
First, in our study, all patients have been to the ED before due to urgent loss of consciousness and have underwent a series of investigations but could not get stated diagnosis from the ED. That means a high proportion of these patients would get definite diagnosis after initial evaluation in the syncope clinic because of the sufficient medical information and they were not advised to be admitted if they were diagnosed as reflex syncope or OH, thus reducing admission rate. In that research, up to 78.5% patients with syncope did not require admission, which concluded that hospitals should develop outpatient syncope management units to reduce inappropriate hospitalization. 9 We believe that the syncope clinic composed of cardiologists and neurologists is an effective form to manage syncope patients.

LIMITATIONS
There are potential limitations to our findings. First, selection bias exists in the research. Patients who presented at the syncope clinic had already been to the ED, so the patients recruited into our study were those who had received unclear diagnoses from ED. These patients do not represent all those with syncope. Many patients with OH were easily diagnosed in the ED due to evident symptoms; thus, only patients with obscure presentations were included in our study. Second, as the idea of syncope clinic is novel to the public, our specific clinic was not widely known to patients with syncope during the period of our research, thereby limiting the sample size. We expect future research to employ larger samples. Third, the absence of a follow-up visit is a major limitation. Relevant clinical outcomes, such as mortality, major adverse events, and recurrence of syncope after treatment, were not included. The present study did not have sufficient power to assess these events due to the low event rates; larger sample size will be needed to evaluate these outcomes in the future.

CONCLUSION
Syncope clinic is a multidisciplinary unit with efficient and effective procedures that can elevate diagnostic rates, lower admission rates, reduce medical costs, and therefore reduce waste of medical resources. Although diagnostic rates improved in the syncope clinic, some cases remain undiagnosed. Specific efforts should be made to further decrease the number of patients discharged without an established diagnosis. Additionally, careful monitoring is warranted to maintain standards of care that have been thus far achieved.