[Significance of pharmacodynamics tests in the study of sinus node function]

The evaluation of sinus function in man rests upon atrial stimulation techniques (rapid atrial stimulation, premature atrial stimulation); in a certain number of cases the results are inconclusive. There are various pharmaco-dynamic tests which can be used in such cases, the aim being to stimulate or depress the function of the sinus, or alternatively to modify the action of the extrinsic nerve supply. A study was carried out of sinus function in a series of 120 patients; pharmaco-dynamic tests were carried out using atropine in 43 cases, glucagon in 9 cases, isoproterinol in 9 cases, ajmaline in 9 cases, and piprofurol in 10 cases. The authors conclude from this study that it is worth adding the atropine test (which suppresses vagal tone), the glucagon test (which causes direct and limited stimulation of the sinus) and a test with an agent with a depressant action on the sinus coupled with a sympathetic-blocking action (such as piprofurol) to the conventional atrial stimulation tests.