Differential hemodynamic adaptations to tilt test in patients with idiopathic atrial fibrillation.

The hemodynamic response during the transition from the supine to standing position in idiopathic atrial fibrillation (AF) patients is not completely understood. This study aimed to analyze the hemodynamic changes that occur during the head-up tilt test in idiopathic AF patients. We investigated the hemodynamic changes during the head-up tilt test with impedance cardiography in 40 AF patients (12 with AF rhythm-AFr and 28 with sinus rhythm-AFsr) and 38 non-AF controls. Patients with AFr had attenuated SVI decrease after standing when compared to AFsr and non-AF [ΔSVI in mL/m2: -1.3 (-3.4 to 1.7) vs. -6.4 (-17.3 to -0.1) vs. -11.8 (-18.7 to -8.0), respectively; p < 0.001]. PVRI decreased in AFr but increased in AFsr and non-AF [ΔPVRI in dyne.seg.m2/cm5: -477 (-1148 to 82.5) vs. 131 (-525 to 887) vs. 357 (-29 to 681), respectively; p < 0.01]. Similarly, compared with non-AF patients, AFr patients also had a greater HR and greater CI increase after standing. The haemodynamic response to orthostatic challenge suggests differential adaptations between patients with AF rhythm and those reverted to sinus rhythm or healthy controls. Characterizing the hemodynamic phenotype may be relevant for the individualized treatment of AF patients.

Investigating autonomic nervous system dysfunction among patients with post-COVID condition and prolonged cardiovascular symptoms.

Heart Rate Variability (HRV) and arterial pressure (AP) variability and their responses to head-up tilt test (HUTT) were investigated in Post-COVID-19 syndrome (PCS) patients reporting tachycardia and/or postural hypotension. Besides tachycardia, PCS patients also showed attenuation of the following HRV parameters: RMSSD [square root of the mean of the sum of the squares of differences between adjacent normal-to-normal (NN) intervals] from statistical measures; the power of RR (beat-to-beat interval) spectra at HF (high frequency) from the linear method spectral analysis; occurrence of 2UV (two unlike variation) pattern of RR from the nonlinear method symbolic analysis; and the new family of statistics named sample entropy, when compared to control subjects. Basal AP and LF (low frequency) power of systolic AP were similar between PCS patients and control subjects, while 0 V (zero variation) patterns of AP from the nonlinear method symbolic analysis were exacerbated in PCS patients. Despite tachycardia and a decrease in RMSSD, no parameter of HRV changed during HUTT in PCS patients compared to control subjects. PCS patients reassessed after 6 months showed higher HF power of RR spectra and a higher percentage of 2UV pattern of RR. Moreover, the reassessed PCS patients showed a lower occurrence of 0 V patterns of AP, while the HUTT elicited HR (heart rate) and AP responses identical to control subjects. The HRV and AP variability suggest an autonomic dysfunction with sympathetic predominance in PCS patients. In contrast, the lack of responses of HRV and AP variability indices during HUTT indicates a marked impairment of autonomic control. Of note, the reassessment of PCS patients showed that the noxious effect of COVID-19 on autonomic control tended to fade over time.

Vasoactive Biomarkers in Patients With Vasovagal Syncope During Head-Up Tilt Test: A Case-Control Study.

Background: Vasovagal syncope (VVS) is the most common cause of syncope. Some stages of its pathophysiological mechanisms remain unclear. Vasoactive substances such as nitric oxide metabolites (NOx) and endothelin (ET) may be involved during acute orthostatic stress. Objective: To analyze plasma changes in NOx and ET and heart rate variability (HRV) in the supine positions (T1) and during the head-up tilt test (HUTT) (T2), in patients with VVS (case group) and control group. Methods: Thirty-seven patients (17 in the case group and 20 in the control group), matched for age and sex (mean aged 31.8 years) underwent HUTT with simultaneous HRV recording and venipuncture. Blood samples were collected during phases T1 and T2 and the analysis was performed without knowledge of the HUTT result. Results: In the total sample, there was an increase in NOx values (P = .014), however there was no increase in ET values from phase T1 to phase T2. Patients with VVS tended to increase plasma NOx values (P = .057) and had significantly higher plasma values compared to ET (P = .033) between phases T1 to T2. In the control group, there was no significant change in the values of these vasoactive substances. Regarding HRV, there were a decrease in the component HF (high frequency) and increased of the LF (low frequency)/HF ratio during HUTT. Conclusions: There was an increase in ET during HUTT occurred only in the case group. These patients are more likely to have an imbalance between antagonistic vasoactive biomarkers during orthostatic stress.

Early Cerebral Hypoperfusion in Patients with Orthostatic Intolerance Without Tachycardia During Head-Up Tilt Test is Independent of Vasovagal Response.

BACKGROUND: Cerebral hypoperfusion before syncope has been shown in patients with chronic orthostatic intolerance (OI) without tachycardia, but it is unknown if an initial decrease of cerebral blood flow velocity (CBFv) could be related to the vasovagal response (VVR) to head-up tilt test (HUTT). OBJECTIVE: The objective of the study was to compare cardiovascular, cerebrovascular, and autonomic variables during HUTT in OI patients with or without a VVR. METHODS: We included 74 subjects (58% female, mean age 33 ± 12 years) who underwent a 30-min HUTT and were divided into three groups: OI with VVR positive (VVR+), OI without VVR negative (VVR-), and asymptomatic healthy subjects with negative HUTT (control group). Cardiovascular, cerebrovascular, and autonomic variables were assessed beat-to-beat during HUTT with a Task Force monitor and a trans-cranial Doppler. Mean values were evaluated at baseline and throughout the first 10 min of tilting. RESULTS: Cardiovascular variables were similar in the three groups. Systolic, diastolic, and mean CBFv were similar in VVR+ and VVR-, but both groups had lower CBFv than the control group. Systolic and diastolic CBFv decreased from baseline since min 1 in VVR+ and VVR- and since min 5 in the control group. The mean CBFv had a significant decrease since min 1 compared to baseline in all groups. Spectral indices of heart rate and blood pressure variability showed a similar autonomic response to HUTT in all groups. CONCLUSION: Patients with chronic OI without tachycardia have early postural cerebral hypoperfusion, regardless of the VVR during HUTT.

Pediatric patients' head-up-tilt-test with pharmacological challenge, it is safe?

Syncope in pediatrics represents an important cause of visits to the emergency units. For this reason, excluding a cardiac or malignant origin is essential at the time of the initial approach to determine what is the next step in management, or if they need to be referred to a pediatric cardiologist and/or electrophysiologist. Vasovagal syncope is the most frequent cause of syncope in pediatrics, in which a detailed clinical history is enough to make the diagnosis. If no diagnosis is concluded by the history, or if it is necessary to define the hemodynamic response of the patients, the head-up-tilt-test is indicated; this will trigger syncope due to an orthostatic stress caused by the angulated table (passive phase). If a negative response remains, it can be followed by a pharmacologic challenge to trigger the hemodynamic response, which is still controversial in pediatrics. The pharmacologic challenge increases the sensitivity with a slight reduction in test specificity. Although there is not a specific drug for the challenge in pediatric patients yet, the most commonly drugs used are nitrates and isoproterenol, the latter related to a great number of adverse effects. Sublingual administration of nitrates in the challenge has been proven to be ideal, effective, and safe in this specific age group. The aim of this article is to make a literature search to demonstrate the effectiveness and safety of the pharmacologic challenge during the head-up-tilt-test in pediatrics, emphasizing a study conducted at the National Institute of Cardiology with isosorbide dinitrate.

El síncope en edades pediátricas representa una causa importante en las visitas a unidades de urgencias, por lo que excluir un origen cardíaco o maligno es fundamental al momento del abordaje inicial para determinar la conducta a seguir o la necesidad de derivar al cardiólogo pediatra o electrofisiólogo. El síncope vasovagal (SVV) es la causa más frecuente de síncope en pediatría, para cuyo diagnóstico basta una historia clínica detallada. Cuando ésta no es suficiente para determinar el diagnóstico de síncope reflejo o es necesario definir el tipo de respuesta que lo origina, está indicada una prueba de mesa inclinada que produce un estrés ortostático por la angulación y ello desencadena un síncope (fase pasiva). En pruebas no concluyentes está indicado un reto farmacológico para precipitar la respuesta hemodinámica, pero aún es un tema de controversia en edades pediátricas. El reto farmacológico incrementa la sensibilidad de la prueba, con una ligera reducción de la especificidad. Si bien no existe todavía un medicamento específico para la población pediátrica, los más empleados son los nitratos y el isoproterenol, este último relacionado con un mayor número de efectos adversos. La administración sublingual de los nitratos utilizados ha demostrado ser ideal, efectiva y segura en los pacientes pediátricos. El objetivo del artículo es realizar una revisión de las publicaciones médicas que demuestran la efectividad y seguridad del reto farmacológico durante la prueba de mesa inclinada en pacientes pediátricos, con énfasis en un estudio conducido en el Instituto Nacional de Cardiología con dinitrato de isosorbida (DNIS).

Pediatric patients head-up-tilt-test with pharmacological challenge, it is safe? / Mesa inclinada en pacientes pediátricos con reto farmacológico, ¿es seguro?

Abstract Syncope in pediatrics represents an important cause of visits to the emergency units. For this reason, excluding a cardiac or malignant origin is essential at the time of the initial approach to determine what is the next step in management, or if they need to be referred to a pediatric cardiologist and/or electrophysiologist. Vasovagal syncope is the most frequent cause of syncope in pediatrics, in which a detailed clinical history is enough to make the diagnosis. If no diagnosis is concluded by the history, or if it is necessary to define the hemodynamic response of the patients, the head-up-tilt-test is indicated; this will trigger syncope due to an orthostatic stress caused by the angulated table (passive phase). If a negative response remains, it can be followed by a pharmacologic challenge to trigger the hemodynamic response, which is still controversial in pediatrics. The pharmacologic challenge increases the sensitivity with a slight reduction in test specificity. Although there is not a specific drug for the challenge in pediatric patients yet, the most commonly drugs used are nitrates and isoproterenol, the latter related to a great number of adverse effects. Sublingual administration of nitrates in the challenge has been proven to be ideal, effective, and safe in this specific age group. The aim of this article is to make a literature search to demonstrate the effectiveness and safety of the pharmacologic challenge during the head-up-tilt-test in pediatrics, emphasizing a study conducted at the National Institute of Cardiology with isosorbide dinitrate.

Resumen El síncope en edades pediátricas representa una causa importante en las visitas a unidades de urgencias, por lo que excluir un origen cardíaco o maligno es fundamental al momento del abordaje inicial para determinar la conducta a seguir o la necesidad de derivar al cardiólogo pediatra o electrofisiólogo. El síncope vasovagal (SVV) es la causa más frecuente de síncope en pediatría, para cuyo diagnóstico basta una historia clínica detallada. Cuando ésta no es suficiente para determinar el diagnóstico de síncope reflejo o es necesario definir el tipo de respuesta que lo origina, está indicada una prueba de mesa inclinada que produce un estrés ortostático por la angulación y ello desencadena un síncope (fase pasiva). En pruebas no concluyentes está indicado un reto farmacológico para precipitar la respuesta hemodinámica, pero aún es un tema de controversia en edades pediátricas. El reto farmacológico incrementa la sensibilidad de la prueba, con una ligera reducción de la especificidad. Si bien no existe todavía un medicamento específico para la población pediátrica, los más empleados son los nitratos y el isoproterenol, este último relacionado con un mayor número de efectos adversos. La administración sublingual de los nitratos utilizados ha demostrado ser ideal, efectiva y segura en los pacientes pediátricos. El objetivo del artículo es realizar una revisión de las publicaciones médicas que demuestran la efectividad y seguridad del reto farmacológico durante la prueba de mesa inclinada en pacientes pediátricos, con énfasis en un estudio conducido en el Instituto Nacional de Cardiología con dinitrato de isosorbida (DNIS).

Pediatrics patients head-up tilt test with pharmacological challenge, it is safe?

Syncope in pediatrics represents an important cause of visits to the emergency units. For this reason, excluding a cardiac or malignant origin is essential at the time of the initial approach in order to determine what is the next step in management, or if they need to be referred to a pediatric cardiologist and/or electrophysiologist. Vasovagal syncope is the most frequent cause of syncope in pediatrics, in which a detailed clinical history is enough to make the diagnosis. If no diagnosis is concluded by the history, or if it is necessary to define the hemodynamic response of the patients, the head-up tilt test is indicated; this will trigger syncope due to an orthostatic stress caused by the angulated table (passive phase). If a negative response remains, it can be followed by a pharmacologic challenge in order to trigger the hemodynamic response, which is still controversial in pediatrics. The pharmacologic challenge increases the sensitivity with a slight reduction in test specificity. Although there is not a specific drug for the challenge in pediatric patients yet, the most commonly drugs used are nitrates and isoproterenol, the latter related to a great number of adverse effects. Sublingual administration of nitrates in the challenge has been proven to be ideal, effective and safe in this specific age group. The aim of this article is to make a literature search in order to demonstrate the effectiveness and safety of the pharmacologic challenge during the head-up tilt test in pediatrics, emphasizing a study conducted at the National Institute of Cardiology with isosorbide dinitrate.

El síncope en edades pediátricas representa una causa importante en las visitas a unidades de urgencias, por lo que excluir un origen cardíaco o maligno es fundamental al momento del abordaje inicial para determinar la conducta a seguir o la necesidad de derivar al cardiólogo pediatra o electrofisiólogo. El síncope vasovagal (SVV) es la causa más frecuente de síncope en pediatría, para cuyo diagnóstico basta una historia clínica detallada. Cuando ésta no es suficiente para determinar el diagnóstico de síncope reflejo o es necesario definir el tipo de respuesta que lo origina, está indicada una prueba de mesa inclinada que produce un estrés ortostático por la angulación y ello desencadena un síncope (fase pasiva). En pruebas no concluyentes está indicado un reto farmacológico para precipitar la respuesta hemodinámica, pero aún es un tema de controversia en edades pediátricas. El reto farmacológico incrementa la sensibilidad de la prueba, con una ligera reducción de la especificidad. Si bien no existe todavía un medicamento específico para la población pediátrica, los más empleados son los nitratos y el isoproterenol, este último relacionado con un mayor número de efectos adversos. La administración sublingual de los nitratos utilizados ha demostrado ser ideal, efectiva y segura en los pacientes pediátricos. El objetivo del artículo es realizar una revisión de las publicaciones médicas que demuestran la efectividad y seguridad del reto farmacológico durante la prueba de mesa inclinada en pacientes pediátricos, con énfasis en un estudio conducido en el Instituto Nacional de Cardiología con dinitrato de isosorbida (DNIS).

ST elevation myocardial infarction during head-up tilt testing.

We report a case of ST elevation myocardial infarction (STEMI) during head-up tilt testing (HUTT). A 54-year-old man was admitted to our emergency department after four episodes of syncope. Treadmill test and electrophysiological study were normal. During passive HUTT, the patient had inferolateral ST elevation. Coronary angiography showed two severe lesions in the right coronary artery and circumflex artery.

POLYMORPHISMS IN ß-ADRENERGIC RECEPTORS ARE ASSOCIATED WITH INCREASED RISK TO HAVE A POSITIVE HEAD-UP TILT TABLE TEST IN PATIENTS WITH VASOVAGAL SYNCOPE.

BACKGROUND: Vasovagal syncope (VVS) is a frequent clinical condition in which a genetic background seems to be implicated. Considering that the adrenergic receptors (ARs) may play a role in VVS, the present study has as principal aim to determine if the α- and ß-AR (ADRA and ADRB) gene polymorphisms are associated with an increased risk to have a positive head-up tilt table (HUTT) test in patients with VVS. Methods: Nine polymorphisms in the ADRA1A (rs1048101, rs1383914, rs574584, and rs573542), ADRB1 (rs1801252 and rs1801253), ADRB2 (rs1042713 and rs1042714), and ADRB3 (rs4994) genes were analyzed using the 5' exonuclease TaqMan genotyping assay in a group of 134 patients with VVS. RESULTS: Under different models, the rs1801252 (OR = 8.63, 95% CI: 0.95-78.72, Precessive = 0.02), rs1042713 (OR = 1.94, 95% CI: 1.02-3.66, Padditive = 0.04), and rs4994 (OR = 2.46, 95% CI: 1.01-6.01, Pdominant = 0.042 and OR = 2.62, 95% CI: 1.04-6.63, Pover-dominant = 0.03) polymorphisms were associated with increased risk for a positive HUTT. All models were adjusted for statistically significant covariates. CONCLUSION: These results suggest that some polymorphisms of the ß-AR genes could contribute to a positive tilt test in patients with VVS.

Polymorphisms in ß-adrenergic receptors are associated with increased risk to have a positive head-up tilt table test in patients with vasovagal syncope

Abstract Background Vasovagal syncope (VVS) is a frequent clinical condition in which a genetic background seems to be implicated. Considering that the adrenergic receptors (ARs) may play a role in VVS, the present study has as principal aim to determine if the α- and β-AR (ADRA and ADRB) gene polymorphisms are associated with an increased risk to have a positive head-up tilt table (HUTT) test in patients with VVS. Methods: Nine polymorphisms in the ADRA1A (rs1048101, rs1383914, rs574584, and rs573542), ADRB1 (rs1801252 and rs1801253), ADRB2 (rs1042713 and rs1042714), and ADRB3 (rs4994) genes were analyzed using the 5’ exonuclease TaqMan genotyping assay in a group of 134 patients with VVS. Results Under different models, the rs1801252 (OR = 8.63, 95% CI: 0.95-78.72, Precessive = 0.02), rs1042713 (OR = 1.94, 95% CI: 1.02-3.66, Padditive = 0.04), and rs4994 (OR = 2.46, 95% CI: 1.01-6.01, Pdominant = 0.042 and OR = 2.62, 95% CI: 1.04-6.63, Pover-dominant = 0.03) polymorphisms were associated with increased risk for a positive HUTT. All models were adjusted for statistically significant covariates. Conclusion These results suggest that some polymorphisms of the β-AR genes could contribute to a positive tilt test in patients with VVS.

Cardiovascular coupling during graded postural challenge: comparison between linear tools and joint symbolic analysis

ABSTRACT Background A joint symbolic analysis (JSA) is applied to assess the strength of the cardiovascular coupling from spontaneous beat-to-beat variability of the heart period (HP) and the systolic arterial pressure (SAP) during an experimental protocol inducing a gradual baroreflex unloading evoked by postural change (i.e. graded head-up tilt). Method: The adopted JSA can quantify the degree of association between the HP and SAP variabilities as a function of the time scale of the HP and SAP patterns. Traditional linear tools assessing the HP-SAP coupling strength, such as squared correlation coefficient, squared coherence function, and percentage of baroreflex sequences, were computed as well for comparison. Results: We found that: i) JSA indicated that the strength of the cardiovascular coupling at slow temporal scales gradually increased with the magnitude of the orthostatic challenge, while that at fast temporal scales gradually decreased; ii) the squared correlation coefficient and percentage of baroreflex sequences did not detect this behavior; iii) even though squared coherence function could measure the magnitude of the HP-SAP coupling as a function of the time scale, it was less powerful than JSA owing to the larger dispersion of the frequency domain indexes. Conclusion: Due to its peculiar features and high statistical power, JSA deserves applications to pathological groups in which the link between HP and SAP variabilities is lost or decreased due to the overall depression or impairment of the cardiovascular control.

Cardiovascular and autonomic alterations in rats with Parkinsonism induced by 6-OHDA and treated with L-DOPA.

OBJECTIVE: Evaluate the effects caused by L-DOPA on cardiovascular and autonomic parameters in an animal model of Parkinsonism induced by 6-hydroxydopamine (6-OHDA). METHODS: Adult male Wistar rats were subjected to bilateral microinfusion of 6-OHDA or saline (sham group) in the substantia nigra, and treated by gavage with L-DOPA or water for 7 days after surgery. On the 6th day the rats were subjected to femoral artery catheterization for cardiovascular recording. Mean arterial pressure (MAP) and heart rate (HR) were evaluated at baseline and during head up tilt (HUT) protocol. Spectral analysis of cardiovascular variability was performed using the V2.4 CardioSeries software v2.4. The lesion was quantified by dopamine levels in the striatum. RESULTS: Dopamine levels in the striatum were decreased in 6-OHDA rats (sham: 4.79 ± 0.49 ng/mg; 6-OHDA: 1.99 ± 0.68 ng/mg) and were not recovered by Prolopa treatment. Baseline values of MAP and HR were not different between groups. HUT induced an increase in MAP and HR (ΔMAP: 17 ± 1 mm Hg, ΔHR: 39 ± 4 bpm) that were attenuated in 6-OHDA and in Prolopa treated animals. At baseline, the systolic arterial pressure (SAP) variance was lower in the 6-OHDA AND sham prolopa groups. Spontaneous baroreflex sensitivity was higher at baseline in the 6-OHDA group as compared to all studied groups. CONCLUSIONS: Our data suggest that treatment with Prolopa did not interfere with cardiovascular variables at baseline. However, during HUT, the 6-OHDA and Prolopa control animals presented a lower cardiovascular compensation, suggesting a possible autonomic impairment in Parkinsonism induced by 6-OHDA.