An unusual ECG deflection: Fact or artifact?

Peculiar electrocardiographic findings are not unusual and upon careful review can often be clarified. We present a case of an 85year-old woman with no previous cardiac history, incidentally discovered high grade atrioventricular block, and a puzzling electrocardiographic complex of unclear etiology which defies reasonable physiological explanations. The finding resembled a tiny QRS in a perfectly regular R-R interval following only non-conducted P-waves. The patient declined further work-up, so a definite cause could not be determined, but based on history, complex morphology, and inability to reproduce or explain the findings, we were compelled to accept the finding as an artifact.

Association between left-handedness and cardiac autonomic function in healthy young men.

BACKGROUND: Effects of nonright-handedness on risk for sudden death associated with coronary artery disease via sympathetic imbalance contributed to ventricular arrhythmogenesis previously have been demonstrated. This study hypothesized that left-handedness might be associated with cardiac autonomic functions in healthy young men. The aim of this study was to examine the association between left-handedness and cardiac autonomic functions in healthy young men. METHODS: A total of 992 asymptomatic young male subjects underwent routine health checkup between May 2012 and July 2013, and were included in this study. All were submitted to a standard protocol that included a complete clinical examination, laboratory evaluation, 12-lead electrocardiogram, and 2D-echocardiogram. Fifty-two subjects were left-handed; 32 subjects had abnormal QRS-T angle. Statistical analyses were performed using statistical package SPSS 15.0 (IBM Corp., Armonk, NY, USA) and statistical significance was assessed at the two-tailed 0.05 threshold. RESULTS: A total of 52 (5%) subjects were left-handed; 32 (3%) subjects had an abnormal frontal QRS-T angle. The mean age, body mass index, systolic blood pressure, diastolic blood pressure, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, fasting glucose, current smoking, estimated glomerular filtration rate, hemoglobin, leukocyte count, platelet count, and echocardiographic parameters were not different between two groups. But subjects with left-handedness had greater prevalence of abnormal QRS-T angle. The left-handedness group had 18 subjects with abnormal QRS-T angle (34%) and the right-handedness group had 14 subjects with abnormal QRS-T angle (1.4%). The difference between two groups was significant (P < 0.001). CONCLUSION: In this study, there was a significant association between left-handedness and abnormal QRS-T angle in healthy young subjects.

Visual saliency detection approach for long-term ECG analysis.

BACKGROUND AND OBJECTIVE: Detection and analysis of QRS-complex as well as the processing of electrocardiogram (ECG) signal using computers are being practiced for over the last fifty-eight years, approximately, and yet the thirst of designing superior ECG processing and recognition algorithms still captures researchers' attention around the globe. A saliency detection-based technique for the processing of one-dimensional biomedical signals such as ECG is proposed here for the first time, to the best or our knowledge. METHODS AND RESULTS: In this proposed research work, first, a trigonometric threshold-based technique is used to identify the QRS-complexes from the ECG signal. Motion-artifact (MA) and sudden-change-in-baseline (SCB) types of noises are considered to be the toughest among others to filter out from the ECG signals as the bandwidths of these two types of noises overlap with that of the ECG. Only one feature is extracted from each of the QRS-complex-intervals, and the normalised values of this feature are arranged in the form of a gray-scale image. Then, a saliency detection-based technique is applied iteratively on the gray-scale image to detect those regions of the ECG signals, which are highly corrupted with MA and (or) SCB noises. Next, three unique geometric-features are extracted from the rest of the QRS-complexes, which are not corrupted with MA or SCB noises, and the normalised values of these three features are arranged in the form of an Red-Green-Blue (RGB) image. Again, the saliency detection-based technique is applied to identify the abnormal QRS-complexes from the RGB image. CONCLUSIONS: The technique is tested on long-term ECG signals; totaling a duration of 17.54 days, and its performance is evaluated through both quantitative and qualitative measures. The applicability, scope of implement in real-time scenarios, advantage of the proposed technique over the existing ones are discussed with a group of clinicians and cardiologists, and very affirmative and encouraging responses are received from them.