Second-degree type 1 AV block is usually not serious and does not require special management. Rarely, it may progress to a high degree of AV block, which is a serious condition. Second-degree type 1 AV block is usually not clinically significant, but a few patients may experience symptoms such as palpitations and a feeling of pauses in the heartbeat. It can be seen in some healthy adults, children and athletes, and may be associated with increased vagal tone at rest. Other possible causes include coronary myocardial infarction and coronary artery spasm. For those with second-degree type 1 atrioventricular block ventricular rate is not too slow, no special treatment is needed. A very small number of patients may progress to a high degree of atrioventricular block due to a variety of factors, and this is a serious condition that requires prompt medical attention and pacing therapy under the direction of a physician.