Bradycardia can be caused by: 1  Changes in the heart that are the result of aging.  Diseases that damage the heart's electrical system. These include coronary artery disease, heart attack, and infections such as endocarditis and myocarditis.
Portland Weather In May. The highest recorded temperature in May for Portland for the past 70 years was 100 degrees Fahrenheit, most recently measured on May 28, 1983, and the normal high is 67.
June average seven days of temperatures to reach or exceed 80 degrees, July usually sees 15 days, and August averages 15. Portland also sees an average of 12 days of 90 degrees or above. The first frost is in early November, and the last frost in early April.