Detection of cardiac arrhythmia patterns in ECG through H × C plane.

The aim of this study is to formulate a new methodology based upon informational tools to detect patients with cardiac arrhythmias. As it is known, sudden death is the consequence of a final arrhythmia, and here lies the relevance of the efforts aimed at the early detection of arrhythmias. The information content in the time series from an electrocardiogram (ECG) signal is conveyed in the form of a probability distribution function, to compute the permutation entropy proposed by Bandt and Pompe. This selection was made seeking its remarkable conceptual simplicity, computational speed, and robustness to noise. In this work, two well-known databases were used, one containing normal sinus rhythms and another one containing arrhythmias, both from the MIT medical databank. For different values of embedding time delay τ, normalized permutation entropy and statistical complexity measure are computed to finally represent them on the horizontal and vertical axes, respectively, which define the causal plane H×C. To improve the results obtained in previous works, a feature set composed by these two magnitudes is built to train the following supervised machine learning algorithms: random forest (RF), support vector machine (SVM), and k nearest neighbors (kNN). To evaluate the performance of each classification technique, a 10-fold cross-validation scheme repeated 10 times was implemented. Finally, to select the best model, three quality parameters were computed, namely, accuracy, the area under the receiver operative characteristic (ROC) curve (AUC), and the F1-score. The results obtained show that the best classification model to detect the ECG coming from arrhythmic patients is RF. The values of the quality parameters were at the same levels reported in the available literature using a larger data set, thus supporting this proposal that uses a very small-sized feature space to train the model later used to classify. Summarizing, the attained results show the possibility to discriminate both groups of patients, with normal sinus rhythm or arrhythmic ECG, showing a promising efficiency in the definition of new markers for the detection of cardiovascular pathologies.

A Soliton-Based Model Mimics the Arterial Pulse Propagation as Much as a Widely Used 1D Model.

INTRODUCTION: A comparison among two blood pressure pulse propagation models has made in this work. One of them is a traditional model based upon the Navier Stockes equations in one spatial dimension, the one along the direction of the arteries (from here NS1D), the other is based the concept of soliton propagation using the Korteweg De Vries equation (named KdV). METHODS: The arterial three is assumed a long successive connection of serial segments of arteries, at the inlet of the network (close up to the aorta), an acquired pulse, in vivo, wave is imposed. The computed of the peripheral blood pressure at the outlet of the final segment constitutes the output of the model (near the radial artery). RESULTS: Both models reproduced main characteristics of the measured radial wave pressure for the same input. CONCLUSION: The results show that the model KdV have many conceptual and computer benefits than the usual model NS1D that constitutes an interesting pathway for the scientific research.

Fractal dimension as an index of left ventricular ischaemia: a pilot study.

Myocardial perfusion is performed by the left and the right coronary arteries, which deliver blood to the left and right ventricles, respectively. The impairment of arterial flow supply to the cardiac muscle by disease denotes a phenomenon known as ischaemia. Previous studies have demonstrated the ability of fractal dimension (FD) value of a physiological parameter in differentiating healthy/pathological behaviours. The aim of this study consisted in quantifying the loss of ventricular thickness fractal complexity in order to determine if FD is an intrinsic marker of acute coronary ischaemia. Five mongrel dogs weighing 18.8-26.5 kg (24.4 ± 3.3, mean ± SD) were submitted to this studio. A left ventricular pressure transducer and a fluid-filled catheter for later calibration of the pressure transducer were introduced through a stab wound near the apex. Two pairs of ultrasonic microcrystals (5 MHz) for continuous wall thickness measurements were implanted at the anterior and posterior walls of the left ventricle following a previously described technique. During coronary occlusion, the ischemic wall started to thin at the very onset of relaxation (showing abnormal motility), while the normoperfused wall displayed postejective thickening. Concomitantly, posterior ventricular wall thickness and anterior wall ventricular thickness showed a significant decrease in its FD value (P <0.05). In conclusion, loss of time series fractal complexity (waveform fine structure diminution or 'unwrinkling') constitutes a marker of the presence of an ischemic process. As a result, a single scalar value is sufficient to characterize the entire behaviour of the time series. This value manifested a similar trend compared to the most well-known clinical indices of myocardial ischaemia.

Flow behavior and applicability of models for different hemodynamic states.

Arterial behavior analysis requires an accurate and dynamic knowledge of the stimuli and reactions involved. Belonging parameters quantification is performed by a data acquisition process and the application of existing models. However, it turns essentially to analyze the adjustment degree of the aforementioned models in terms of the arterial tree. Blood flow behavior as well as wall shear rate and the arterial compliance are anatomic location dependent. The main objective of the present work is to analyze the existing functional relationships between arterial wall and blood flow, in a particular place (brachial artery), in order to asses the specific model applicability, in cases such Poiseuille or Womersley models. In addition, due to the characteristic of the study, gender differential dynamic responses will be evaluated.

Cisplatin-vinorelbine combination chemotherapy in locally advanced non-small cell lung cancer.

AIM: The North Milan Group presents the results of a phase II study on a cisplatin-vinorelbine combination schedule in the treatment of locally advanced non-small cell lung cancer to evaluate its activity and tolerability. METHODS: Seventy-six consecutive patients entered the study. Patients' characteristics were the following: males/females 69/7; median age, 61.4 years (range, 40-73); ECOG performance status, 0-1; 17 stage IIIa and 59 stage IIIb. There were 49 squamous cell carcinomas, 20 adenocarcinomas, and 7 large cell carcinomas. All patients had not been previously treated and showed measureable disease. Treatment consisted of vinorelbine, 25 mg/m2 on days 1 and 8, plus cisplatin, 80 mg/m2 on day 1, administered intravenously every 21 days for three standard courses. RESULTS: Seventy-four patients were evaluable for response. Objective responses were documented in 42/74 patients with an overall response rate (CR+PR) of 56.7%; 18/74 patients (24.3%) showed stable disease and the remaining 14/74 (18.9%) went into progression. Twelve patients (16.2%) were suitable for a subsequent surgery. The median duration of response was 13.3 months. Survival time ranged from 4 to 36 months; it was 14.6 months for PR patients, 8.6 months for NC and 5 months for PD. Mean survival time is presently 12.85 months (SE, 1.2 months). Toxicity evaluated on 222 cycles administered was acceptable, and it was necessary to use G-CSF or delay the treatment because of severe leukopenia in only a few cases. CONCLUSIONS: The regimen is active and safe: the slight survival increase is likely due to the small amenability to surgery achieved (16.2%). However, our results are fully comparable to others obtained with vinorelbine in two/three drug combination chemotherapy regimens.

Epirubicin, cisplatin, and continuous infusion 5-fluorouracil is an active and safe regimen for patients with advanced gastric cancer. An Italian Group for the Study of Digestive Tract Cancer (GISCAD) report.

BACKGROUND: A Phase II confirmatory multicenter trial was performed to evaluate a combination of epirubicin, cisplatin, and continuous infusion 5-fluorouracil (ECF) in treating patients with advanced gastric cancer. METHODS: Fifty-three patients with locally advanced (n = 7) or metastatic (n = 46) gastric cancer received a dose of epirubicin (50 mg/m2) and cisplatin (60 mg/m2) intravenously every 21 days for eight cycles with 5-fluorouracil (200 mg/m2/day) by intravenous continuous infusion for 21 consecutive weeks, administered through a central line using an external pump. RESULTS: Eight complete responses and 22 partial responses (response rate = 56%, 95% confidence interval +/- 13) were achieved. Twelve patients had stable disease. The median duration of response was 10 months (range, 3-21 months), and the median survival for all the patients was 9+ months (range, 2-28 months). Overall toxicity, which was primarily hematologic, was mild with only three patients requiring hospitalization for neutropenic fever. No death due to toxicity occurred. CONCLUSIONS: This study found that the ECF regimen is substantially active in treating patients with advanced gastric cancer and has a favorable pattern of toxicity. This schedule clearly deserves randomized comparative trials for palliation of metastatic disease and for adjuvant purposes.

Cisplatin plus epirubicin and etoposide followed by irradiation plus lonidamine in stage III nonsmall cell lung cancer.

Forty-seven patients with stage III nonsmall cell lung cancer (NSCLC) were treated with the sequential administration of combination chemotherapy consisting of cisplatin, epirubicin and etoposide and of irradiation plus lonidamine. The response rate was 49% after chemotherapy with an improvement of 14% after radiation therapy and lonidamine. The median survival was around 15 months for responders and 9 months for nonresponders. Toxicity was moderate and acceptable. It is concluded that this schedule is active in the treatment of NSCLC.