A post submitted by CGI member BolenReport.
Video Explanation with Dr. Levy
"A new condition known as multisystem inflammatory syndrome in children (MIS-C) has emerged since the onset of the COVID pandemic, appearing primarily in advanced COVID infections. [52,53] MIS-C, and MIS in adults, simply means the COVID infection has resulted in a widespread amount of inflammation in the body, often involving the heart and the lungs. Minimal to advanced heartbeat conduction problems have occurred secondary to MIS-C, ranging from the often-innocuous prolonged PR interval (see below) on the ECG to advanced and potentially life-threatening degrees of AV block. [54,55] When heart function is normal, the AV node allows a rapid conduction of the heartbeat throughout all of the heart muscle cells so that heart muscle contraction is synchronized and optimally efficient. AV block results in an abnormal slowing of the heart rate and sometimes fatal secondary arrhythmias, including complete stoppage of the heartbeat (asystole). It appears likely that the spike protein can damage the heart at any age, and that the spike protein can be present because of the infection itself and/or the vaccination targeted at the infection.
"The PR interval is the amount of time that the heartbeat takes to traverse the atrial chambers in the heart before reaching the conduction-accelerating AV node. The normal PR interval ranges from 0.12 to 0.2 seconds. In younger individuals, especially well-trained athletes, a PR interval greater than 0.2 is usually completely normal. However, when PR interval measurements have always been 0.2 or less and then start to lengthen as an older adult, there should be significant concern that the aging conduction system might manifest more significant conduction abnormalities in the future.
"In the setting of the pandemic, it is of particular concern when PR interval prolongation is seen for the first time following a bout of COVID and/or following a vaccination. This is a clear indicator of new inflammation in at least some of the heart cells, however minimal it may be. Regardless, it should not just be assumed to be of no importance. All disease has a spectrum of pathology, and the earliest stages of pathology should never be trivialized.  In a Harvard study that extended over a 30- to 40-year period, it was found that individuals with PR intervals greater than 0.2 seconds had twice the risk of atrial fibrillation, three times the risk of needing a pacemaker (meaning the presence of advanced degrees of heart block), and nearly a one and a half times increase in all-cause mortality. Furthermore, greater degrees of PR interval prolongation led to an even greater risk. 
"However, ignoring the inherent pathology in a pandemic-induced prolonged PR interval is exactly what the Federal Aviation Administration (FAA) appears to have done. Facing a shortage of pilots due to both the vaccine requirement it initiated during the pandemic for the pilots to fly, along with many early retirements that resulted, the FAA decided to change the rules, disregarding long-standing parameters of normalcy based on medical science and not convenience. The FAA has now declared a PR interval of 0.3 seconds to be the "new normal" in the FAA Guide for Aviation Medical Examiners as of October, 2022. The October, 2021 standards asserted the PR interval was normal only at 0.2 seconds or less. When the pilot has "no symptoms" he or she can now obtain clearance to fly with a PR interval of 0.3 or less. And when that interval is greater than 0.3, a "current Holter and cardiac evaluation" are then required. Considering that the normal PR interval ranges between 0.12 and 0.20 seconds, an interval of 0.3 seconds represents a "permissible" increase in this interval by over 100% relative to the low normal interval of 0.12 seconds. This is not a nominal increase in PR interval, but a very large one.
"Even now, a treadmill exercise stress test is not required to receive medical clearance to fly, even for commercial pilots. This is simply not a safe policy by the FAA and arguably a shocking one, as many pilots are in the age range when heart attacks occur without any early symptoms but with a normal ECG, the ECG being the only mandatory heart-related test. Roughly a third of all deaths around the world are due to cardiovascular disease. And in western countries sudden cardiac death occurs in about half of all coronary artery disease patients. [58,59] Much more vigorous cardiac evaluations should be performed in prospective pilots, and repeated at appropriate intervals. A normal ECG means a heart attack has not occurred, nothing more. A fatal heart attack from very advanced coronary artery disease could occur 10 minutes after the normal ECG was recorded. No pilot should ever fly when there is a persistent elevation of troponin levels and/or D-dimer levels (see below). It is irrelevant that the pilot might feel well, have a normal ECG, and have no clinical evidence of myocarditis.