Key result
Multimodal monitoring detects ~21 mmHg lower SBP during physical activity in syncope patients versus controls.
Why the study?
The authors sought to propose a new test, Multimodal Monitoring for Diagnosis of Dysautonomia (MMDD), to evaluate autonomic nervous system function in patients with syncope.
Does the Multimodal Monitoring for Diagnosis of Dysautonomia (MMDD) test differentiate autonomic nervous system function between patients with syncope and healthy controls?
Case-Control (n=42)
No
Does the Multimodal Monitoring for Diagnosis of Dysautonomia (MMDD) test differentiate autonomic nervous system function between patients with syncope and healthy controls?
Absolute Event Rate: 111% vs 132%
p-value: p=0.033
The novel Multimodal Monitoring for Diagnosis of Dysautonomia (MMDD) protocol is feasible and can detect subtle autonomic nervous system differences to identify patients with syncope.
Caution against routine MMDD use in syncope; hypothesis-generating for diagnostic validation in prospective cohorts.
To propose a new test to evaluate the autonomic nervous system in patients with syncope: Multimodal Monitoring for Diagnosis of Dysautonomia (MMDD). We included 21 patients with syncope (16 female, 6 male, mean age 43.5 years) and 21 with no-syncope subjects (15 female, 7 male, mean age 45.1 years) to perform a test of nine 2-min stages: four while resting and four during active testing of autonomic response. Transcranial-Doppler, electrocardiogram, and photoplethysmography blood pressure pulse-to-pulse monitoring, allow registering six variables from the Middle Cerebral Artery and four from the Cardiovascular System. We analyze each variable's mean differences in each stage and its change when they pass from one stage to another with the T and Z tests. To understand the significance of the change, we use a logistic regression model for a certain subgroup of variables. Since we have a small dataset, we use the bootstrap technique to infer the general behavior that characterizes a syncope. Our data confirm differences between syncope and non-syncope patients during MMDD stress stages 2, 4, 6 and 8. Bootstrap and multivariate logistic regression allow us to identify which sets of variables in each of these stages of the MMDD are sufficiently sensitive to recognizing syncope. MMDD protocol can recognize a syncope patient with some confidence by detecting subtle changes in the autonomic nervous system. This protocol encourages us to continue to study the effectiveness of MMDD protocol allowing a new approach to future research.
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Nader et al. (2020) conducted a case-control in Syncope (n=42). Multimodal Monitoring for Diagnosis of Dysautonomia (MMDD) vs. Healthy controls was evaluated on Systolic blood pressure during stage 8 (physical activity) (p=0.033). The Multimodal Monitoring for Diagnosis of Dysautonomia protocol detected significant differences in autonomic responses, including lower systolic blood pressure during physical activity (111 vs 132 mmHg, p=0.033), in patients with syncope compared to controls.
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