Background <p>Emergency medical technicians (EMTs) are crucial for early diagnosis and treatment of cardiac arrhythmias. Continuous training is needed, and innovative methods such as microlearning and webinars may offer advantages over traditional approaches.</p> Methods <p>In this quasi-experimental study, 75 EMTs in Zabol, Iran (2024) were randomly assigned to microlearning, webinar, or control groups. The microlearning group received 22 short online sessions; the webinar group attended two 55-minute virtual lectures. Knowledge and self-efficacy were measured before, immediately after, and one month after the interventions using validated questionnaires.</p> Results <p>Microlearning was more effective and sustainable than both webinar and control methods in improving participants’ knowledge and self-efficacy, especially at the one-month follow-up. Compared with the baseline, the microlearning group maintained nearly 95% of their immediate post-test improvement after one month, while the webinar group’s scores dropped by about 25%, and the control group showed no meaningful change. The differences between microlearning and the other groups at one month were statistically significant (<i>P</i> &lt; 0.001).</p> Conclusions <p>Microlearning is more effective and durable than webinars for enhancing EMTs’ knowledge and self-efficacy in managing cardiac arrhythmias. It is recommended as a practical approach for continuous clinical education.</p>