The frequency of atrioventricular block during adenosine stress testing in young, middle-aged, young-old, and old-old adults.

The frequency of atrioventricular (AV) block was evaluated in 600 consecutive patients of different age groups referred for pharmacologic stress testing. Adenosine was infused at 140 mg/kg/min for a total of 6 minutes in conjunction with radionuclide myocardial perfusion imaging. Seventy-five patients (12.5%) were young adults (< 49 years old), 214 (35.6%) were middle-aged (50-65 years), 195 (32.6%) were young-old (66-75 years), and 116 patients (19.3%) were old-old (over 75 years). The frequencies of first-degree AV block in young adults, middle-aged, young-old, old-old, and all ages were 14.6%, 9.3%, 14.3%, 17.24%, and 13.16%, respectively. The frequencies of second-degree AV block were 14.65%, 7.0%, 8.7%, 15.5%, and 10.1%, respectively. The frequencies of third-degree AV block were 2.66%, 2.33%, 1.0%, 2.58%, and 2.0%, respectively. Comparison of the incidence of the three types of AV block for each age group vs. all patients showed no statistically significant difference (p > 0.08). All types of AV block were of short duration, were well tolerated, and did not require discontinuation of the adenosine infusion or specific treatment. This study confirms the safety of adenosine stress testing in all age groups for evaluation of coronary artery disease and risk assessment.