Heart rate node, where the faster pacemaker cells driving the self-generated rhythmic firing and responsible for the heart's autorhythmicity are located. For endurance athletes at the elite level, it is not unusual to have a resting heart rate between 33 and 50 bpm. The "maximum heart rate" (HR) is the highest heart rate an individual can achieve without severe problems through exercise stress, and generally decreases with age. Since HR varies by individual, the most accurate way of measuring any single person's HR is via a cardiac stress test. In this test, a person is subjected to controlled physiologic stress (generally by
Cardiac neural crest cells of heart attacks include cardiac arrhythmias and heart failure. Although CNCCs are important in embryos, some CNCCs are retained in a dormant state to adulthood where they are called "neural crest stem cells". In 2005, Tomita transplanted neural crest stem cells from mammal hearts to the neural crest of chick embryos. These CNCCs were shown to migrate into the developing heart of the chick using the same dorsolateral pathway as the CNCCs, and differentiate into neural and glial cells. Tamura's study of 2011 examined the fate of CNCCs after a heart attack (myocardial infarction) in young mice. The CNCCs in