Coronary microvascular dysfunction, arrythmias, and sudden cardiac death: A literature review.

The coronary vascular system has a unique structure and function that is adaptive to myocardial demand. It is composed of a continuous network of vessels receding in size from epicardial arteries to the microvascular circulation. Failure to meet myocardial demand results in ischemia, angina, and adverse myocardial outcomes. It is evident that 50 % of patients with angina have a non-obstructive coronary disease and 66 % of these patients have coronary microvascular dysfunction (CMD). The impact of CMD on the atria and ventricles is exhibited through its association with atrial fibrillation and distortion of ventricular repolarization. Ultimately, this influence increases the risk of mortality, morbidity, and sudden cardiac arrest. CMD serves as an independent risk for atrial fibrillation, increases ventricular electrical inhomogeneity, and contributes to the progression of cardiac disease. The underlying pathogenesis may be attributed to oxidative stress evident through reactive oxygen species, impaired vasoactive function, and structural disorders such as fibrotic changes. Myocardial ischemia, brought about by a demand-supply mismatch in CMD, may create a milieu for ventricular arrythmia and sudden cardiac arrest through distortion of ventricular repolarization parameters such as QT dispersion and corrected QT dispersion.

Current landscape of clinical trials for HPV-positive head and neck squamous cell carcinoma (HNSCC).

This study aims to determine the current state of clinical trials regarding HPV-positive head and neck squamous cell carcinoma (HNSCC). Clinical trials were filtered to fit the study's aim using Clinicaltrials.gov: trials concerning HNSCC specifically those related to HPV done between January 2005 and December 2020 were extracted and information regarding location, duration, phases, patient recruitment, trial status, results, primary outcome, type of intervention and publication status were collected and analysed. As a result, 123 trials were included. North American countries (USA and Canada) conducted more than two-thirds of the trials (72.4%) compared to European countries and the rest of the world. Trials in phase II constituted more than half of those included in this study (53.7%). From the 123 trials included in this study, only 30 had their NCT identification number linked to publications, but less than half (46.7%) of the publications stemmed from trials with results. Drug combination was the most widely studied treatment modality. Despite falling in the middle of the spectrum with respect to the number of trials when compared to other diseases, our research highlights the need for even more trials tackling multiple aspects of HPV-positive HNSCC.