Cerebral Oxygenation Responses to Standing in Young Patients with Vasovagal Syncope.

Vasovagal syncope (VVS) is common in young adults and is attributed to cerebral hypoperfusion. However, during active stand (AS) testing, only peripheral and not cerebral hemodynamic responses are measured. We sought to determine whether cerebral oxygenation responses to an AS test were altered in young VVS patients when compared to the young healthy controls. A sample of young healthy adults and consecutive VVS patients attending a Falls and Syncope unit was recruited. Continuous beat-to-beat blood pressure (BP), heart rate, near-infrared spectroscopy (NIRS)-derived tissue saturation index (TSI), and changes in concentration of oxygenated/deoxygenated Δ[O2Hb]/Δ[HHb] hemoglobin were measured. BP and NIRS-derived features included nadir, peak, overshoot, trough, recovery rate, normalized recovery rate, and steady-state. Multivariate linear regression was used to adjust for confounders and BP. In total, 13 controls and 27 VVS patients were recruited. While no significant differences were observed in the TSI and Δ[O2Hb], there was a significantly smaller Δ[HHb] peak-to-trough and faster Δ[HHb] recovery rate in VVS patients, independent of BP. A higher BP steady-state was observed in patients but did not remain significant after multiple comparison correction. Young VVS patients demonstrated a similar cerebral circulatory response with signs of altered peripheral circulation with respect to the controls, potentially due to a hyper-reactive autonomic nervous system. This study sets the grounds for future investigations to understand the role of cerebral regulation during standing in VVS.

Association between hypotension during 24†h ambulatory blood pressure monitoring and reflex syncope: the SynABPM 1 study.

AIMS: Diagnostic criteria for ambulatory blood pressure monitoring (ABPM) in patients with suspected reflex syncope are lacking. The study hypothesis was that patients with reflex syncope have a higher prevalence of systolic blood pressure (SBP) drops on ABPM. METHODS AND RESULTS: ABPM data from reflex syncope patients and controls, matched by average 24 h SBP, age, sex, and hypertension were compared. Patients with constitutional hypotension, orthostatic hypotension, and predominant cardioinhibition during carotid sinus massage or prolonged electrocardiogram monitoring or competing causes of syncope were excluded. Daytime and nighttime SBP drops (<110, 100, 90, 80 mmHg) were assessed. Findings were validated in an independent sample. In the derivation sample, daytime SBP drops were significantly more common in 158 syncope patients than 329 controls. One or more daytime drops <90 mmHg achieved 91% specificity and 32% sensitivity [odds ratio (OR) 4.6, P < 0.001]. Two or more daytime drops <100 mmHg achieved 84% specificity and 40% sensitivity (OR 3.5, P = 0.001). Results were confirmed in the validation sample of 164 syncope patients and 164 controls: one or more daytime SBP drops <90 mmHg achieved 94% specificity and 29% sensitivity (OR 6.2, P < 0.001), while two or more daytime SBP drops <100 mmHg achieved 83% specificity and 35% sensitivity (OR 2.6, P < 0.001). CONCLUSION: SBP drops during ABPM are more common in reflex syncope patients than in controls. Cut-off values that may be applied in clinical practice are defined. This study expands the current indications for ABPM to patients with reflex syncope.

Increased multimorbidity is associated with impaired cerebral and peripheral hemodynamic stabilization during active standing.

BACKGROUND: Age-related morbidities and frailty are associated with impaired blood pressure (BP) and heart rate (HR) recovery after standing. Here we investigate how multimorbidity affects cerebral and peripheral hemodynamics during standing in a large sample of older patients. METHODS: Patients were recruited from a national Falls and Syncope Unit. They underwent an active stand test (5-10 min lying +3 min standing) with monitoring of continuous BP, HR, total peripheral resistance (TPR), stroke volume (SV), and a near-infrared spectroscopy (NIRS) derived cerebral tissue saturation index (TSI). A multimorbidity count was derived from a 26-item list of conditions. Features derived from the signals included: nadir, overshoot, value at 30 s, steady-state and recovery rate. Robust linear regression was used to assess the association between multimorbidity, TSI and peripheral hemodynamics while correcting for covariates. A p-value <0.05 was considered statistically significant. RESULTS: Multimorbidity was associated with poorer recovery of TSI at 30 s after standing (ß: -0.15, CI:[-0.25-0.06], p = 0.009) independent of all peripheral hemodynamics. Impaired diastolic BP (DBP) recovery at 30s (ß:-1.34, CI:[-2.29-0.40], p = 0.032), DBP steady-state (ß:-1.18, CI:[-2.04-0.32], p = 0.032), TPR overshoot-to-nadir difference (ß:-0.041, CI:[-0.070-0.013], p = 0.045), and SV at 30s (ß:1.30, CI:[0.45 2.15], p = 0.027) were also associated with increasing multimorbidity. After sex stratification, only females demonstrated impaired TSI with multimorbidity at overshoot (ß: -0.19, CI: [-0.32 -0.07], p = 0.009), 30 s (ß: -0.22 [-0.35-0.10], p = 0.005) and steady-state (ß: -0.20, CI:[-0.35-0.04], p = 0.023), independent of peripheral hemodynamics. CONCLUSIONS: Transient cerebral oxygenation and peripheral hemodynamic responses are impaired with multimorbidity (frailty) in older patients, particularly in females. This study demonstrates the feasibility of using NIRS in this clinical context and may inform the development of clinical management strategies targeting both cerebral oxygenation and blood pressure impairments in patients with faints and falls.

Association between gait speed and the SHARE Frailty Instrument in a Falls and Syncope Clinic.

PURPOSE: Identifying physical frailty is useful in the context of falls and syncope assessment. The phenotype-based SHARE Frailty Instrument for Primary Care (SHARE-FI) does not measure gait speed. We evaluated the association between SHARE-FI and gait speed in a Falls' and Syncope Unit (FASU). METHODS: We recruited a pilot sample of patients aged 50 and over attending FASU between November 2019 and March 2020. The association between gait speed and SHARE-FI was assessed with the Spearman's co-efficient (rs). Logistic regression was conducted to investigate the association controlling for age, sex, body mass index, comorbidities and polypharmacy. RESULTS: 104 participants were included (34 frail) median (IQR) age 74 (68-79) years. 68 were female. There was a significant negative correlation between frailty and gait speed (rs - 0.54, P < 0.001). In the multivariable model, gait speed remained independently associated with frailty (OR 0.09, 95% CI 0.02-0.52, P = 0.007). CONCLUSIONS: SHARE-FI significantly captured gait speed in this clinical sample, adding to its validity.

Long-term cardiac monitoring in older adults with unexplained falls and syncope.

AIMS: Unexplained falls account for 20% of falls in older cohorts. The role of the implantable loop recorder (ILR) in the detection of arrhythmias in patients with unexplained falls is unknown. We aimed to examine the diagnostic utility of the ILR in detection of arrhythmogenic causes of unexplained falls in older patients. METHODS: A single centre, prospective, observational cohort study of recurrent fallers over the age of 50 years with two or more unexplained falls presenting to an emergency department. Insertion of an ILR (Reveal, Medtronic, Minnesota, USA) was used to detect arrhythmia. The primary outcome was detection of cardiac arrhythmia associated with a fall or syncope. The secondary outcome was detection of cardiac arrhythmia independent of falls or syncope, and falls or syncope without associated arrhythmia. RESULTS: Seventy patients, mean age 70 years (51-85 years) received an ILR. In 70% of patients cardiac arrhythmias were detected at a mean time of 47.3 days (SD 48.25). In 20%, falls were attributable to a modifiable cardiac arrhythmia; 10 (14%) received a cardiac pacemaker, 4 (6%) had treatment for supraventricular tachycardia. Patients who had a cardiac arrhythmia detected were more likely to experience a further fall. CONCLUSIONS: 14 (20%) patients demonstrated an arrhythmia which was attributable as the cause of their fall. Patients who have cardiac arrhythmia are significantly more likely to experience future falls. Further research is important to investigate if early detection of arrhythmogenic causes of falls using the ILR prevents future falls in older patients.

The Role of the Syncope Management Unit.

Syncope is a common symptom, experienced by 15% of persons less than 18 years old and up to 23% of elderly nursing home residents, so it is important to consider optimizing strategies for the management of these patients. The strategy selected will inevitably differ from place to place. However, an organized structure offers more cost-effective care. This article discusses possible health care delivery models for syncope management and reviews the current status of the organization of syncope care, to show the value of a multidisciplinary approach to the organized management of patients with syncope.