Background: Adenosine is currently used in the treatment and differential diagnosis of regular tachycardia. However, the efficacy of its employment has not been studied in elderly people.
Methods: We evaluated the safety, and the diagnostic and therapeutic utility of adenosine in elderly people aged over 70 years with regular sustained tachycardia, compared with a group of patients aged under 70 years affected by the same arrhythmia. Adenosine was given to 107 patients in increasing bolus doses up to 18 mg during regular broad and narrow complex tachycardia; 49 patients were aged 70 and over, and 58 patients were aged less than 70 years. In the former group, surface ECG showed 38 narrow complex tachycardias and 11 broad complex ones; in the second group there were 48 narrow complex tachycardias and 10 broad complex ones.
Results: Adenosine was effective in 94% of the elderly patients and in 93% of the younger patients. In the group aged over 70 years, adenosine restored sinus rhythm in 37% of patients and revealed the mechanism of arrhythmia in 57%. Adenosine restored sinus rhythm in 50% of patients under 70 years and revealed atrial or sinus tachycardia in 43%. The incidence of symptomatic side effects and peri-conversion ventricular arrhythmias was similar in the two groups. There were ventricular pauses over 3 s long in four (8%) of the older patients (maximum pause 7 s) and in two patients (3%) of the group under 70 years (maximum pause 6 s). No adverse haemodynamic effects were observed.
Conclusion: These data demonstrate the safety and the value of adenosine in the diagnosis and treatment of regular tachycardia in elderly patients.