Biosensor Applications to Antitachycardia Devices

Current arrhythmia detection algorithms are unable to adequately distinguish stable from unstable tachycardias; therefore application of a biosensor to antitachycardia devices has been proposed to improve their performance, Right heart pressures and impedance have been investigated for incorporation into these systems. Integration of other parameters (oxygen saturation, preejection period, pH, cardiac output, flow, and temperature) into these devices might also prove useful. The status of these biosensor arrhythmia detection algorithms and their application to antitachycardia devices are described below.     

Advances in Catheter Ablation use of Unipolar Electrograms

Ventricular tachycardia in man can be eliminated by relatively small lesions in the reentrant circuit. This report includes a review of available energy sources, and methods for localizing arrhythmias. Methods to assure contact and prevent perforation using low frequency electrograms are presented including the new finding of reverse ST deflection with contact. Experience with laser energy in dogs showed discrete homogenous lesions. When compared with DC shock the animals showed far less arrhythmia and the lack of far field effect greatly reduced echo abnomalities in the post shock period. Studies with radiofrequency show ability to produce localized lesions similar to the laser but with a more flexible catheter. Localization requires a correlation of techniques including pacemapping, activation maps and pacing during tachycardia. Early activation (< −60 ms) at times 180–320 ms, with comparable pace to QRS during tachycardia with no change in morphology best localized the slow zone of the reentrant circuit. The low frequency unipolar electrogram from the tip and immediately proximal electrode revealed contact with ST deviation. The distal deviation was always greater than the proximal RV free wall and posterior basal produced depression rather than elevation of the electrogram. While the mechanism of ST reversal with contact is not understood and may relate to the type of indifferent reference used (Wilson central terminal), the ST depression reveals the same information about contact that elevation does in most other areas of the heart studied in our patients.     

COMPARISON OF METHOTREXATE WITH AZATHIOPRINE OR 6-MERCAPTOPURINE IN REFRACTORY RHEUMATOID ARTHRITIS: A LIFE-TABLE ANALYSIS

Methotrexate (MTX) appears to be useful in patients with rheumatoidarthritis (RA) refractory to othe drugs but its long-term toxicityand efficacy are uncertain. A retrospective study of MTX insuch patients i comparison with the purine analogues, azathioprineand 6-mercaptopurine was made using life-table analysis. Eighty-fourpatients took MTX in a median dose of 7.5 mg/week whilst 55received purin analogues, 100 mg/day (median). By 12 months,19.3% of patients had ceased MTX due to toxicit) compared with29.3% for purine analogues. Toxicity severe enough to warrantstopping therapy wa uncommon after 8 months with either drug.At 12 months 61.5% of the MTX patients had achieve defined criteriaof improvement compared with 25.6% for the purine analogues(p < 0.05). The number c patients improving on purine analoguesdid not increase substantially after 6 months, whereas the numbeimproving with MTX continued to 12 months. MTX in a low-doseregimen is useful in refractory RA an superior to low-dose purineanalogues.     

Our Postpandemic World: What Will It Take to Build a Better Future for People and Planet?

Policy Points

• Despite the pandemic''s ongoing devastating impacts, it also offers the opportunity and lessons for building a better, fairer, and sustainable world.
• Transformational change will require new ways of working, challenging powerful individuals and industries who worsened the crisis, will act to exploit it for personal gain, and will work to ensure that the future aligns with their interests.
• A flourishing world needs strong and equitable structures and systems, including strengthened democratic, research, and educational institutions, supported by ideas and discourses that are free of opaque and conflicted influence and that challenge the status quo and inequitable distribution of power.