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2289Background-Ablation of ventricular tachycardia (VT) is sometimes unsuccessful when ablation lesions are of insufficient depth to reach arrhythmogenic substrate. We report the initial experience with the use of a catheter with an extendable/ retractable irrigated needle at the tip capable of intramyocardial mapping and ablation. Methods and Results-Sequential consenting patients with recurrent VT underwent ablation with the use of a needletipped catheter. At target sites, the needle was advanced 7 to 9 mm into the myocardium, permitting pacing and recording. Infusion of saline/iodinated contrast mixture excluded perforation and ensured intramyocardial deployment. Further infusion was delivered before and during temperature-controlled radiofrequency energy delivery through the needle. All 8 patients included (6 male; mean age, 54) with a mean left ventricular ejection fraction of 29% were refractory to multiple antiarrhythmic drugs, and 1 to 4 previous catheter ablation attempts (epicardial in 4) had failed.Patients had 1 to 7 (median, 2) VTs present or inducible; 2 were incessant. Some intramyocardial VT mapping was possible in 7 patients. A mean of 22 (limits, 3-48) needle ablation lesions were applied in 8 patients. All patients had at least 1 VT terminated or rendered noninducible. During a median of 12 months follow-up, 4 patients were free of recurrent VT, and 3 patients were improved, but had new VTs occur at some point during follow-up. Two died of the progression of preexisting heart failure without recurrent VT. Complications included tamponade in 1 patient and heart block in 2 patients. Conclusions-Intramyocardial infusion-needle catheter ablation is feasible and permits control of some VTs that have been refractory to conventional catheter ablation therapy, warranting further study. (Circulation. 2013;128:2289-2295.)

t This survey was conducted under the auspices of the Laboratory Section of the American Public Health Association, and the Division of Research Grants and Fellowships of the National Institutes of Health. * The majority of these cases (1,275) occurred since 1930.and 3.2 per cent in bacterial, rickettsial, parasitic, and fungus infections, respectively. Complications occurred in 59 or 4.7 per cent of the non-fatal in-

This report summarizes the laboratory infections which have come to the attention of the authors since 1950. As a result they are able to picture the current extent of this continuing problem. The findings are related to trends in research and to interest in certain agents.