A case report of severe cardioinhibitory reflex syncope associated with COVID-19

Background Coronavirus disease 2019 (COVID-19) has been recognised as a disease with a broad spectrum of clinical manifestations. In this report we illustrate an extraordinary case of severe cardioinhibitory reflex syncope with prolonged asystole associated with COVID-19. Case summary A 35-year-old male patient presented to the emergency department with a ten-day history of postural syncope and fever. ECG monitoring during positional change revealed reflex syncope with cardioinhibitory response, exhibiting sinus bradycardia, subsequent asystole and transient loss of consciousness (TLOC). The patient tested positive for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and was admitted to the ICU where temporary transvenous pacing was necessary because of prolonged episodes of asystole. Work-up included extensive cardiac and neurological diagnostic testing, but did not yield any structural abnormalities. Although temporary pacing was able to abort syncope, a decision was made to hold off on permanent pacing as the most likely aetiology was felt to be temporary cardioinhibitory reflex syncope associated with COVID-19. The patient was discharged with mild symptoms of orthostatic intolerance and responded well to education and lifestyle modification. Outpatient follow-up with repeat tilt testing after three and six months initially showed residual inducible syncope but was eventually normal and the patient remained asymptomatic. Discussion We believe that autonomic imbalance with a strong vagal activation due to acute SARS-CoV-2 infection played a pivotal role in the occurrence of transient syncope in this patient’s condition. Although pacemaker implantation would have been a reasonable alternative, a watch-and-wait approach should be considered in similar instances.

Cardiac Pacing in Cardioinhibitory Reflex Syncope: Clinical Use of Closed-loop Stimulation

Cardiac pacing has been studied extensively in patients with reflex syncope over the past two decades. The heterogeneity of the forms and clinical manifestations of reflex syncope explain the controversial results of older randomised clinical trials. New evidence from recent trials has changed medical practice, now leading to clear indications for pacing in patients with asystolic syncope documented during carotid sinus massage, implantable cardiac monitoring or tilt testing. Given that recent trials in reflex syncope have been performed using the closed-loop stimulation algorithm, the authors will briefly discuss this pacing mode, review hypotheses about the mechanisms underlying its activation during syncope and provide practical instructions for programming and troubleshooting.

Reflex syncope in the UK Armed Forces

IntroductionReflex syncope is the most common subtype of syncope and, despite not being associated with increased mortality, often results in significant morbidity and costly diagnostics. Reflex syncope can be of concern for certain occupational groups and may be exacerbated by some occupations. Reflex syncope in the military is anecdotally common but the extent in the UK Armed Forces (UKAF) is unknown. The aim of this study was to assess the incidence and prevalence of reflex syncope in the UKAF.MethodsA retrospective search of the Defence Medical Information Capability Programme using prespecified read-codes was performed at defence primary healthcare centres over the period of 1 January 2019 to 1 January 2020. Data were obtained on 76 103 service personnel (SP) (53% of the UKAF).ResultsThe overall syncope case rate for the UKAF was 10.5 per 1000 person-years (p-yrs). In comparing services there was a significantly increased risk of syncope in the British Army (10.7 per 1000 p-yrs) compared with the Royal Air Force (8.6 per 1000 p-yrs) (p=0.0365), SP who served overseas (16.7 per 1000 p-yrs) in comparison with UK medical centres (10.3 per 1000 p-yrs) (p<0.0001), and British Army units that regularly took part in State Ceremonial and Public Duties (15.8 per 1000 p-yrs vs 10.2 per 1000 p-yrs) (p=0.0035). Army training units conferred a significantly reduced risk of syncope (p<0.0001).ConclusionsThese data are the first to define the incidence and prevalence of syncope in the UKAF. Orthostasis and heat are probable triggers, although recruits are potentially protected. These data offer opportunities to improve the health and well-being of SP, with economic, logistical and reputational benefits for the UKAF. Further research to identify personnel at risk of future syncopal events may allow for targeted use of countermeasures.

Patients with reflex syncope have a higher prevalence of atrial fibrillation than general population which is predicted by the type of the tilt table test response

Introduction Reflex syncope is the result of an imbalance between the sympathetic and parasympathetic nervous system. The autonomic nervous system has been associated to some forms of atrial fibrillation (AF). Objective The aim of this study was to assess the prevalence of AF in patients with reflex syncope and a positive tilt table test and to identify the type of tilt test response in patients with AF in comparison to patients without AF. Methods We retrospectively studied consecutive patients that underwent a tilt table test at our institution between 2016 and 2019. We selected those patients with a positive test. Patients with an implanted pacemaker at the time of the tilt test and patients followed in a different institution were excluded. Previous diagnoses of AF episodes were assessed. We analysed the clinical characteristics and the tilt table test results according to previous history of AF. Results We studied 49 patients with a positive tilt test. Seven (14.3%) patients had previously diagnosed paroxysmal AF at the time of the tilt table test. Patients with AF were older, had more frequently hypertension, and the tilt test response was more frequently a vasodepressor than mixed or cardioinhibitory response (71.4% vs. 28.6%) (Table). In univariate analysis, age and hypertension were associated with AF, respectively, OR 1.08 (95% CI 1.01–1.17), p=0.034 and OR 10.80 (95% CI 1.19–98.36), p=0.035. A vasodepressor response was also associated with AF (OR 6.25, 95% CI 1.06–36.74, p=0.043). Conclusions Patients with reflex syncope and a positive tilt table test had a higher prevalence of AF than the general population. A vasodepressor response was associated with AF as were age and hypertension, demonstrating the possible impact of the autonomic nervous system and the multifactorial nature of AF. FUNDunding Acknowledgement Type of funding sources: None.

Effect of aging on cerebral tissue oxygenation in relation to reflex syncope

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Swedish Heart and Lung Foundation, The Swedish Heart and Lung Association, ALF funds, Skåne University Hospital Funds, The Crafoord Foundation. Background There is an increased susceptibility to syncope with aging attributed to age-related physiological impairments. Cerebral oximetry non-invasively measures cerebral tissue oxygenation (SctO2) and has been shown to be valuable in syncope evaluation. SctO2 has been found to decrease with aging but it is unknown whether the decrease in SctO2 is related to increased susceptibility to syncope during orthostatic provocation. By measuring SctO2 during head up tilt test (HUT) we can study age-related differences in SctO2 and their impact on developing reflex syncope. Purpose To investigate the effect of age on the cerebral tissue oxygenation threshold for syncope and presyncope among patients with vasovagal syncope. Methods Non-invasive haemodynamic monitoring and near-infrared spectroscopy (NIRS) were applied during head-up tilt (HUT) in 139 vasovagal syncope patients (mean [SD] 45[17] years, 60% female), and 82 control patients with a normal response to HUT (45[18] years, 61% female). Group differences in SctO2 and systolic blood pressure (SBP) during HUT in supine position, after 3 and 10 min of HUT, 30 seconds prior to syncope ("presyncopal phase") and during syncope in different age groups (&lt;30, 30-60 and &gt;60 years) were compared using one-way ANOVA and Tukey"s multiple comparison test. Associations between age and SctO2 were studied using linear regression models adjusted for sex and concurrent SBP. Results Lower SctO2 in supine position was associated with increasing age among controls (B=-0.085, p = 0.010) but not among VVS patients (B=-0.036, p = 0.114). No age-related differences in SctO2 were found after 3 and 10 minutes of HUT and during syncope. Mean SctO2 (%) during the presyncopal phase decreased over the advancing age groups (&lt;30: 66.9 ± 6.2, 30-60: 64.5 ± 6.1, &gt;60: 62.2 ± 5.8; p = 0.009 for inter-group comparison). In contrast, mean SBP during the presyncopal phase did not differ by age groups (&lt;30: 85.6 ± 21.8, 30-60: 77.6 ± 19.7, &gt;60: 77.6 ± 20.8 mmHg, p = 0.133). Age was associated with lower SctO2 during the presyncopal phase after adjusting for sex and SBP (B = 0.096, p = 0.001). Conclusion Older VVS patients have lower cerebral tissue oxygenation in the presyncopal phase compared with younger patients independently of systolic blood pressure. These results suggest either that with imminent reflex syncope cerebral tissue oxygenation diminishes more with advancing age or that cerebral deoxygenation is better tolerated by older reflex syncope patients. Abstract Figure.

S-reflex score: a predictor score of vaso-vagal reflex syncope

Funding Acknowledgements Type of funding sources: None. Introduction Reflex syncope is one of the most common causes of syncope, usually associated with unspecified triggers and prodromes. The probability of occurrence is higher when concomitant factors coexist whether inherent to individual or related to environment, and changes in conventional tests may prove useful in their diagnosis. Objective Identify predictive factors in the initial investigation in order to establish a predictor score of vasovagal reflex syncope (VVS). Methods Observational and retrospective study, with descriptive analysis and correlation of patients followed in syncope appointment at a Cardiology Center from 1 January 2015 to 31 Novembe 2019. Descriptive analysis on patient characteristics and complementary exams were carried out. The correlation test used between categorical variables was Chi-square and among continuous variables the T-Student test with a significance level of 95%. Independent predictors of VVS were identified through binary logistic regression considering a p = 0.05, with subsequent application of a discriminatory function using the lambda Wilks test to determine the discriminant score of variables under analysis. SPSS 24.0 was used for statistical analysis. Results Identified N694 patients, 52% male, mean age of 63 years. 15.7% of patients with suspected VVS in a first impression. At the end, 22.9% diagnosed with VVS and of these 66% had syncope recurrence. 42% had long prodromes (p = 0.013), 17% with heat prodromes (p = 0.012), in 11.3% the trigger was the meal (p = 0.031), 12.2% suffered trauma (p = 0.07) and 59.7% had ECG with pathological q wave (p = 0.00), thus showing to be independet predictors of VVS. A predictor score of VVS was determined using the formula = -0.761 + (0.529.Long_Prodromes) + (0.721.Heat_Prodromes) + (0.313.Trigger_Meal) + (2,431.ECG_q) - (0.542.Trauma), with a cutoff value of 0.258, specificity of 90.5% with discriminative power of 87%. Conclusion The final diagnosis of VVS was higher than suspicions during initial clinical investigation and 66% of these patients had recurrence. The independent predictors factors of VVS are long prodromes, heat prodromes, meal as a trigger, ECG with q waves and trauma. The S-Reflex score was determined with a good discriminative power with high specificity. Considering clinical variables and conventional exams, this score could be useful to guide the strategy for syncope patients after the first evaluation to a more cost-effective strategy.

Recommendations for tilt table testing and other provocative cardiovascular autonomic tests in conditions that may cause transient loss of consciousness

An expert committee was formed to reach consensus on the use of tilt table testing (TTT) in the diagnosis of disorders that may cause transient loss of consciousness (TLOC) and to outline when other provocative cardiovascular autonomic tests are needed. While TTT adds to history taking, it cannot be a substitute for it. An abnormal TTT result is most meaningful if the provoked event is recognised by patients or eyewitnesses as similar to spontaneous events. The minimum requirements to perform TTT are a tilt table, a continuous beat-to-beat blood pressure monitor, at least one ECG lead, protocols for the indications stated below and trained staff. This basic equipment lends itself to the performance of (1) additional provocation tests, such as the active standing test, carotid sinus massage and autonomic function tests; (2) additional measurements, such as video, EEG, transcranial Doppler, NIRS, end-tidal CO2 or neuro-endocrine tests; and (3) tailor-made provocation procedures in those with a specific and consistent trigger of TLOC. TTT and other provocative cardiovascular autonomic tests are indicated if the initial evaluation does not yield a definite or highly likely diagnosis, but raises a suspicion of (1) reflex syncope, (2) the three forms of orthostatic hypotension (OH), i.e. initial, classic and delayed OH, as well as delayed orthostatic blood pressure recovery, (3) postural orthostatic tachycardia syndrome or (4) psychogenic pseudosyncope. A therapeutic indication for TTT is to teach patients with reflex syncope and OH to recognise hypotensive symptoms and to perform physical counter manoeuvres.