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.
Oregon's climate is generally mild. West of the Cascade Mountains, winters are chilly with frequent rain, while light snowfall occurs a few days a year; temperatures can get very cold, but only occasionally, as the result of Arctic cold waves.