Tissue Tracking Imaging for Identifying the Origin of Idiopathic Ventricular Arrhythmias: A New Role of Cardiac Ultrasound in Electrophysiology

Several strategies for mapping ventricular outflow tract tachycardia have been reported as useful indices for differentiating between those originating from the right and the left side. Recently, tissue tracking imaging (TTI) has been demonstrated as a novel non-invasive modality for identifying the origin of outflow tract tachycardias. Tissue tracking imaging is an ultrasonographic technique that measures the myocardial motion amplitude towards the transducer in each region during systole, identifying regional myocardial displacement on the basis of myocardial velocities using color Doppler myocardial imaging principles. In this technique, the origin of the arrhythmia could be recognized as the site where the earliest color-coded signal (ECCS) appeared on the myocardium at the onset of the systole. In preliminary studies this modality was found to be useful in differentiating out flow tract ventricular tachycardias. ECCS was always found below or at the level of the pulmonary valve in all arrhythmias which could be ablated from the right ventricular outflow tract, while in those where the origin was above the pulmonary valve could be ablated from the left sinus of valsalva. These results indicate that TTI can provide detailed and accurate information on the arrhythmia origin of OT-VT and may be useful for differentiating between an OT-VT originating from the LV epicardium remote from the LSV and that from the LSV. Newer advances in echocardiographic technologies like high resolution, high frame rate real time three dimensional echocardiography with speckle tracking may further improve the precise localization of arrhythmias in the future

U wave: an Important Noninvasive Electrocardiographic Diagnostic Marker

Study of U waves exemplifies important clinical role of noninvasive electrocardiography in modern cardiology. Present article highlights significance of U waves with a clinical case and also summarizes in brief the history of the same

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

D-Dimer assay as a non invasive test for the diagnosis of left atrial Thrombi in Indian patients with Rheumatic MS

BACKGROUND: Systemic embolism is a serious and sometime fatal complication of rheumatic MS. OBJECTIVE: We assessed the predictive power of D-Dimer level to predict occurrence of left atrial (LA) thrombi in patients with rheumatic mitral stenosis (MS). METHODS: D-dimer levels were analyzed for 24 patients with rheumatic MS with LA clot and 22 patients with rheumatic MS with no LA clot undergoing transeosophageal echocardiography. A level more than 4 µg/ml was taken as elevated to predict the presence of LA clot in the study groups. RESULTS: For a cut-off value of 4 µg/ml, sensitivity was 66.67 % and specificity 100 % for prediction of LA clot and AUC 0.710. A cut-off value of less than 1 µg/ml, sensitivity was 91.67 % and 87. 5 % negative predictive value for ruling out presence of LA clot and AUC 0.721. CONCLUSION: A higher value of D-dimer can predict the possible presence of a LA clot and very low value can predict absence of clot in patients with rheumatic MS

D-Dimer assay as a non invasive test for the diagnosis of left atrial Thrombi in Indian patients with Rheumatic MS

Background: Systemic embolism is a serious and sometime fatal complication of rheumatic MS. Objective: We assessed the predictive power of D-Dimer level to predict occurrence of left atrial (LA) thrombi in patients with rheumatic mitral stenosis (MS). Methods: D-dimer levels were analyzed for 24 patients with rheumatic MS with LA clot and 22 patients with rheumatic MS with no LA clot undergoing transeosophageal echocardiography. A level more than 4 μg/ml was taken as elevated to predict the presence of LA clot in the study groups. Results: For a cut-off value of 4 μg/ml, sensitivity was 66.67 % and specificity 100 % for prediction of LA clot and AUC 0.710. A cut-off value of less than 1 μg/ml, sensitivity was 91.67 % and 87. 5 % negative predictive value for ruling out presence of LA clot and AUC 0.721. Conclusions: A higher value of D-dimer can predict the possible presence of a LA clot and very low value can predict absence of clot in patients with rheumatic MS