RESUMEN
BACKGROUND: Imbalance in autonomic nervous system and impaired myocardial repolarization have been shown to increase the risk for arrhythmias in patients with arterial hypertension. This study evaluated the effects of masked hypertension on QT interval dynamicity. METHODS: The study group consisted of 108 consecutive patients with masked hypertension and 102 control subjects. Twenty-four-hour Holter monitoring was performed before anti-hypertensive treatment. CONTEC holter software was used to calculate HRV and QT dynamicity parameters. All subjects had a complete history, laboratory examination, and transthoracic echocardiography. RESULTS: There was no significant difference in age-gender distribution between patients and controls. Non-sustained VT was present in four patients (2.9%). SDNN, RMSSD, PNN50, LFnu, HFnu were significantly decreased in masked hypertension, whereas LF/HF ratio was significantly increased. QT/RR slopes over 24 hours were significantly increased in masked hypertension for QT end and QT apex (QTapex/RR: 0,15 ± 0,12 vs 0,27 ± 0,18 p < .001; QTend/RR: 0.19 ± 0.12 vs 0.35 ± 0.22, p < .001). CONCLUSIONS: This study showed for the first time that masked hypertension was associated with a significant worsening of HRV and QT dynamicity parameters.
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Arritmias Cardíacas/fisiopatología , Sistema Nervioso Autónomo/fisiopatología , Frecuencia Cardíaca/fisiología , Hipertensión Enmascarada/fisiopatología , Miocardio , Adulto , Estudios de Casos y Controles , Ecocardiografía , Electrocardiografía Ambulatoria , Femenino , Humanos , Hipertensión/fisiopatología , Masculino , Persona de Mediana Edad , Taquicardia Ventricular/fisiopatologíaRESUMEN
BACKGROUND AND OBJECTIVE: Currently Coronary Artery Disease (CAD) is one of the most prevalent diseases, and also can lead to death, disability and economic loss in patients who suffer from cardiovascular disease. Diagnostic procedures of this disease by medical teams are typically invasive, although they do not satisfy the required accuracy. METHODS: In this study, we have proposed a methodology for the automatic diagnosis of normal and Coronary Artery Disease conditions using Heart Rate Variability (HRV) signal extracted from electrocardiogram (ECG). The features are extracted from HRV signal in time, frequency and nonlinear domains. The Principal Component Analysis (PCA) is applied to reduce the dimension of the extracted features in order to reduce computational complexity and to reveal the hidden information underlaid in the data. Finally, Support Vector Machine (SVM) classifier has been utilized to classify two classes of data using the extracted distinguishing features. In this paper, parameters of the SVM have been optimized in order to improve the accuracy. RESULTS: Provided reports in this paper indicate that the detection of CAD class from normal class using the proposed algorithm was performed with accuracy of 99.2%, sensitivity of 98.43%, and specificity of 100%. CONCLUSIONS: This study has shown that methods which are based on the feature extraction of the biomedical signals are an appropriate approach to predict the health situation of the patients.
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Enfermedad de la Arteria Coronaria/diagnóstico , Máquina de Vectores de Soporte , Adulto , Anciano , Anciano de 80 o más Años , Algoritmos , Enfermedad de la Arteria Coronaria/fisiopatología , Electrocardiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis de Componente Principal , Adulto JovenRESUMEN
AIMS: To determine whether cardiac autonomic dysfunction represents a risk factor for diabetic retinopathy (DR) development and progression in persons with type 1 diabetes mellitus (T1DM). METHODS: The study comprised 154 normoalbuminuric persons with T1DM divided into two groups according to the DR presence: with and without DR. Cardiovascular autonomic functioning was measured at baseline using conventional and spectral analysis. Participants were re-examined for the DR presence 18months after. RESULTS: The group with DR had longer disease duration compared to the group without DR (20 vrs 11.5years, p<0.001), heart rate coefficient of variation (HRV-CV) at rest and during deep breathing were lower in participants with DR (p=0.001 and 0.004), as well did spectral indices of HRV: low frequency (LF) band, high frequency (HF) band (p=0.003 and 0.022) while LF/HF ratio indicating sympathovagal balance was higher (p=0.037). No difference in glycaemic control or blood pressure value were observed. Twenty-one (13.36%) participants developed non proliferative DR or progressed to proliferative DR. Cox proportional regression showed that the 18months risk from retinal deterioration was reduced by 33.4% by each increase in the HRV-CV of 1%, 12.7% for the same HRV-CV increase during deep breathing while LF band of 1ms(2) results in 8.6% risk reduction. CONCLUSIONS: This study provides evidence that DR should not be considered merely a metabolic control manifestation and that HRV-CV as well as spectral indices of HRV might serve as a practical tool to identify a subgroup of T1DM patients with higher risk of retinal deterioration.
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Enfermedades del Sistema Nervioso Autónomo/fisiopatología , Sistema Nervioso Autónomo/fisiopatología , Diabetes Mellitus Tipo 1/fisiopatología , Retinopatía Diabética/fisiopatología , Frecuencia Cardíaca/fisiología , Adulto , Presión Sanguínea/fisiología , Diabetes Mellitus Tipo 1/complicaciones , Femenino , Humanos , Masculino , Análisis de Regresión , Factores de RiesgoRESUMEN
Although patients with chronic disorders of consciousness (DOC), including unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS), show a limited repertoire of awareness signs, owing to a large-scale cortico-thalamo-cortical functional disconnectivity, an activation of some cortical areas in response to relevant stimuli has been described by means of electrophysiological and functional neuroimaging approaches. In addition, cognitive processes associated with autonomic nervous system (ANS) responses elicited by nociceptive stimuli have been identified in some DOC patients. In an attempt to identify ANS functionality markers that could be useful in differentiating UWS and MCS individuals, we measured the amplitude, latency and γ-band power (γPOW) of ultra-late laser-evoked potentials (CLEPs) and skin reflex (SR), which both express some aspects of cognitive processes related to ANS functionality, besides other ANS parameters either during a 24(hh)-polygraphy or following a solid-state laser repetitive nociceptive stimulation. MCS showed physiological modification of vital signs (O2 saturation, hearth rate, hearth rate variability) throughout the night and a preservation of SR-γPOW, whereas UWS did not show significant variations. Following repetitive nociceptive stimulation, MCS patients had a significant increase in CLEP-γPOW, O2 saturation, hearth rate, and hearth rate variability, whereas UWS individuals did not show any significant change (but two patients, who reached high Coma Recovery Scale-Revised scores). Hence, our work suggests that a wide-spectrum electrophysiological evaluation of ANS functionality may support DOC differential diagnosis. Interestingly, the two above-mentioned UWS patients showed MCS-like vital sign modifications and electrophysiological pain responsiveness. It is therefore hypothesizable that our approach could be helpful in identifying residual aware autonomic system-related cognitive processes even in some UWS patients. Such issue draws the attention to either DOC clinical diagnosis or adequate pain treatment in DOC patients.