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In interventional cardiologists and radiologists, the left side of the head is known to be more exposed to radiation than the right. A connection to occupational radiation exposure is biologically plausible, but risk assessment is difficult due to the small population of interventional cardiologists and the low incidence of these tumours. This may be a chance occurrence, but the cause may also be radiation exposure. Scientific study further delineating occupational risks is essential. Since interventional cardiologists have the highest radiation exposure among health professionals, major awareness of radiation safety and training in radiological protection are essential and imperative, and should be used in every procedure.

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BACKGROUND Pharmacologic and ablative therapies for atrial fibrillation (AF) have suboptimal efficacy. Newer gene-based approaches that target specific mechanisms underlying AF are likely to be more efficacious in treating AF. Parasympathetic signaling appears to be an important contributor to AF substrate. OBJECTIVE The purpose of this study was to develop a nonviral gene-based strategy to selectively inhibit vagal signaling in the left atrium and thereby suppress vagal-induced AF. METHODS In eight dogs, plasmid DNA vectors (minigenes) expressing Gαi C-terminal peptide (Gαictp) was injected in the posterior left atrium either alone or in combination with minigene expressing Gαoctp, followed by electroporation. In five control dogs, minigene expressing scrambled peptide (GαRctp) was injected. Vagal- and carbachol-induced left atrial effective refractory periods (ERPs), AF inducibility, and Gαi/octp expression were assessed 3 days following minigene delivery. RESULTS Vagal stimulation- and carbachol-induced effective refractory period shortening and AF inducibility were significantly attenuated in atria receiving a Gαi2ctp-expressing minigene and were nearly eliminated in atria receiving both Gαi2ctp- and Gαo1ctp-expressing minigenes. CONCLUSION Inhibition of both Gi and Go proteins is necessary to abrogate vagal-induced AF in the left atrium and can be achieved via constitutive expression of Gαi/octps expressed by nonviral plasmid vectors delivered to the posterior left atrium.