Alessandro Di Toro

Heart rate/blood pressure ratio as predictor of neuromediated syncope

BACKGROUND Predicting the occurrence of syncope in advance during tilt test could be useful to prepare the medical staff in preventing complications connected with this procedure, particularly in patients with no pre-syncopal symptoms. Our objective was to develop a simple algorithm able to predict the onset of neuromediated syncope during the tilt test. METHODS We analysed the trend in RR interval, blood pressures, the ratio of these two variables and their derivative, as possible predictors of neuromediated syncope during tilt test. We studied 145 patients: 72 tilt test positive (age 7-82 years, 23 male, 49 female) and 73 tilt test negative (age 8-82 years, 36 male, 37 female), coming at our attention for suspected syncope. We evaluated time of prediction, sensitivity, specificity and receiver-operating curves (ROC) of the trends in RR interval, blood pressure, their ratio and the derivative of their ratio, in predicting syncope. RESULTS The derivative of the ratio between RR interval and systolic blood pressure (dRR/SBP) was able to predict syncope 44.1 ± 6.6s in advance with a sensitivity of 86.2% and a specificity of 89.1%. Area under the curve of ROC was 0.877 (p<0.001). The method was able to predict syncope in all three forms of neuromediated syncope: cardioinhibitory, mixed and vasodepressor. Similar results were found using the pulse pressure (dRR/PP). CONCLUSIONS Using dRR/SBP or dRR/PP it is possible to predict the occurrence of syncope in advance during tilt test.

Parasympathetic Stimuli on Bronchial and Cardiovascular Systems in Humans

Background It is not known whether parasympathetic outflow simultaneously acts on bronchial tone and cardiovascular system waxing and waning both systems in parallel, or, alternatively, whether the regulation is more dependent on local factors and therefore independent on each system. The aim of this study was to evaluate the simultaneous effect of different kinds of stimulations, all associated with parasympathetic activation, on bronchomotor tone and cardiovascular autonomic regulation. Methods Respiratory system resistance (Rrs, forced oscillation technique) and cardio-vascular activity (heart rate, oxygen saturation, tissue oxygenation index, blood pressure) were assessed in 13 volunteers at baseline and during a series of parasympathetic stimuli: O2 inhalation, stimulation of the carotid sinus baroreceptors by neck suction, slow breathing, and inhalation of methacholine. Results Pure cholinergic stimuli, like O2 inhalation and baroreceptors stimulation, caused an increase in Rrs and a reduction in heart rate and blood pressure. Slow breathing led to bradycardia and hypotension, without significant changes in Rrs. However slow breathing was associated with deep inhalations, and Rrs evaluated at the baseline lung volumes was significantly increased, suggesting that the large tidal volumes reversed the airways narrowing effect of parasympathetic activation. Finally inhaled methacholine caused marked airway narrowing, while the cardiovascular variables were unaffected, presumably because of the sympathetic activity triggered in response to hypoxemia. Conclusions All parasympathetic stimuli affected bronchial tone and moderately affected also the cardiovascular system. However the response differed depending on the nature of the stimulus. Slow breathing was associated with large tidal volumes that reversed the airways narrowing effect of parasympathetic activation.

Diagnostic role of head-up tilt test in patients with cough syncope

AIMS The aim of this study was to describe the head-up tilt (HUT) test and carotid sinus massage (CSM) responses, and the occurrence of syncope with coughing during HUT in a large cohort of patients. METHODS AND RESULTS A total of 5133 HUT were retrospectively analysed to identify patients with cough syncope. Head-up tilt followed by CSM were performed. Patients were made to cough on two separate occasions in an attempt to reproduce typical clinical symptoms on HUT. Patients with cough syncope were compared with 29 age-matched control patients with syncope unrelated to coughing. A total of 29 patients (26 male, age 49 ± 14 years) with cough syncope were identified. Coughing during HUT reproduced typical prodromal symptoms of syncope in 16 (55%) patients and complete loss of consciousness in 2 (7%) patients, with a mean systolic blood pressure reduction of 45 ± 26 mmHg, and a mean increase in heart rate of 13 ± 8 b.p.m. No syncope or symptoms after coughing were observed in the control group. The HUT result was positive in 13 (48%) patients with the majority of positive HUT responses being vasodepressor (70% of positive HUT). Carotid sinus massage was performed in 18 patients being positive with a vasodepressor response causing mild pre-syncopal symptoms in only 1 patient. CONCLUSION Syncope during coughing is a result of hypotension, rather than bradycardia. Coughing during HUT is a useful test in patients suspected to have cough syncope but in whom the history is not conclusive.

The effects of parasympathetic activity on bronchial tone

Current opinion is that a vagal stimulation is beneficial for the cardiovascular apparatus but also causes airflow obstruction. The aim of this study was to examine this paradox. By using the within-breath Forced Oscillation Technique, inspiratory resistance and reactance at 5 Hz (R5 and X5, respectively) and cardio-vascular activity can be simultaneously measured humans at baseline and during baroreceptors stimulation by neck suction, allowing the study of the correlation between the parasympathetic activation and airway caliber. Correlation between changes in lung function and neck suction at 0.1Hz was tested in 15 volunteers using the cross-spectrum between either R5 or X5 and the stimulating waveform. Baroreceptors stimulation induced cardiovascular changes compatible with parasympathetic activation. The magnitude of the cross-spectrum between the pressure swings applied to the neck and both R5 and X5 presented a peak at 0.1 Hz with a higher coherence for R5 than X5. On average, R5 slightly but significantly increased compared to baseline, while changes in X5 were negligible. The response to the stimulation was highly variable among subjects.

Slatentizzazione multifattoriale di deficit di G6PD

Glucose-6-phosfate dehydrogenase (G6PD) deficiency is the most common human enzyme defect, being present in more than 400 million people worldwide. The G6PD enzyme catalyzes the first step in the pentose phosphate pathway, leading to antioxidants that protect cells against oxidative damage. This genetic disease is characterized by a wide spectrum of clinical manifestations, both in different people and in the same patient. It seems to be due to the large number of genetic errors that can determine the defect and to the multiplicity of triggers able to inducing the hemolytic anemia tipical of this disease. This is what we present in the following case report, subject normally eating fava beans, who had never associated the ingestion with discomfort.

Il Tilt Table Test nella sincope da tosse

Coughing is a rare cause of syncope and the role of Tilt Table Test is not clear yet. The aim of this study was to describe the head-up tilt-test (TTT) and the occurrence of syncope with coughing during TTT in a small cohort of patients. A total of 5133 TTT were retrospectively analyzed to identify patients with cough syncope. A total of 9 patients (Male, age 51±14 years) with cough syncope were identified. Patients with cough syncope were compared to 12 age-matched control patients with syncope unrelated to coughing. Patients were made to cough on 3 separate occasions in an attempt to reproduce typical clinical symptoms on TTT. We present here the preliminary results of this ongoing study, as a confirm of dates described in literature.

Un caso di eosinofilia sospetta

Strongyloidiasis is a human parasitic disease caused by the nematode Strongyloides stercoralis. It is endemic in the tropical and subtropical regions and infects up to one hundred million people in the world. It is widespread also in Europe and ipoendemic areas in Italy exist. The health consequences of S. stercoralis infections range from asymptomatic light infections to chronic symptomatic strongyloidiasis. We report the case of an elderly woman who had never been in tropical regions and presented with weight loss and asthenia.

Manifestazione internistica di patologia psichiatrica

Psychogenic polydipsia is the act of compulsive water drinking. It is a well-recognized phenomenon that occurs in patients with psychiatric diseases, which, when severe enough, can lead to hyponatremia and characterize Self-Induced Water Intoxication (SIWI). SIWI patients present with various neurological findings such as brain edema, coma, convulsion and death due to secondary severe hyponatremia. Non-neurological symptoms, such as rhabdomyolysis, have been rarely described. In this case we will present a patient who presented with severe hyponatremia secondary to psychogenic polydipsia and rhabdomyolysis.

Utilità dell’ecografia toracica nella pratica clinica

L’ecografia del torace non e ancora diffusa quanto quella addominale, nonostante una notevole quantita di studi ne attesti l’importanza. Riportiamo un caso nel quale l’ecografia toracica e stata utile complemento diagnostico alle classiche tecniche di imaging.

Una sincope “scolastica”

La sincope neuromediata rappresenta la causa piu comune di perdita di coscienza nella popolazione generale ed in particolare fra i giovani. Proponiamo il caso di un bambino di otto anni che presentava sincopi recidivanti nel corso delle ore scolastiche e, attraverso l’analisi dei dati ottenuti durante il tilt table test al quale lo abbiamo sottoposto, la descrizione dei meccanismi con cui il sistema nervoso autonomo interviene nella genesi di questo tipo di sincope.