Investigation Into Resuscitated Sudden Death; How Are We Doing?

Background: Although cornerstone treatment for survivors of cardiac arrest remains ICD, there are compelling reasons to find a cause. These include adjunctive treatments, medications to avoid and implications for family. Extensive investigation with imaging, ECGs and provocative tests are recommended. Methods:We aimed to audit the degree of investigation of patients with no known cause for their cardiac arrest, to determine the proportion of patients who received a diagnosis, and to ascertain whether those patients who remain idiopathic had adequate testing. Results: Two-hundred-and-thirty-six patients received an ICD at Waikato Hospital in 2014 and 2015; of these 66 were for secondary prevention. Forty-eight had known cardiac disease sufficient to explain their event, leaving 18 with no known cause. Of these ‘idiopathic’ patients, a diagnosis was obtained after testing in 6 patients; one sarcoidosis, two Brugada Syndrome, two DCM of unknown aetiology and one J wave syndrome. Twelve remained undiagnosed despite investigation including ECG, exercise test, echocardiogram, (CT) coronary angiography, MRI and ajmaline challenge. However, 8 patients did not have ajmaline and 4 had no exercise test and may have had important conditions overlooked. Adenosine and adrenaline testing was uncommon. Conclusion: Audit of the investigation of cardiac arrest survivors has highlighted important omissions in the search for a cause. Currently, only one third of unexplained cardiac arrests receive a diagnosis. Education of cardiologists and other health professionals in the importance of investigation may improve diagnostic yield.