Background: Social media sites like Twitter are growing in popularity and offer new avenues to share and seek health information. Twitter may also serve as an important public health tool for experts to widely disseminate accurate information about cardiovascular health. The manner and extent of the public's information-seeking behavior however is unknown. To better understand public inquiries about resuscitation, we sought to characterize tweets with questions about cardiac arrest, CPR, and AEDs. Methods: A database of 53,971 tweets relating to resuscitation was created using a Twitter search engine for daily tweet downloads from April 19-May 22, 2011. Search terms were: AED, cardiac arrest, CPR, defibrillation, heart arrest, and resuscitation. Tweets containing nonsensical, non-English, non-sequitur, or irrelevant information were excluded (n=39,990). Remaining tweets were individually evaluated for information seeking questions. Results: Of 13,981 tweets with resuscitation-relevant content, 1% (162) had questions related to cardiac arrest/CPR/AED. Inquires were distributed across the study time period with a mean 4.8 questions daily. Several tweets, 21% (34/162) were cardiac arrest-related queries related to: symptoms, risk factors, prognosis, distinction from heart attack, treatment options, utility of abdominal compressions, and therapeutic hypothermia indications. Several tweets, 39% (63/162) were CPR-specific queries related to: definitions, guidelines, technique, certification classes (location, duration, and professional requirements), neonatal resuscitation, hyperventilation treatment, and accuracy of media portrayal of resuscitation. Additionally, 40% (65/162) of tweets were AED-specific queries related to: device safety, cost, purchasing advice, availability, proper use, effectiveness, and batteries. Conclusion: Twitter offers a novel venue for the public to ask questions regarding cardiovascular health. While few tweets were true information-seeking messages, they represent unique opportunities for expert intervention, education, and awareness. Future work in this field may aim to uncover how receptive users are to professional answers and healthcare education delivered via tweets.