A catheter includes a shaft for insertion into an organ of a patient, and an extendable distal-end assembly. The distal-end assembly is coupled to the shaft and includes multiple splines. At least one spline includes one or more electrodes and at least one strain-relief element that is configured, when the distal-end assembly is extended in the organ, to allow the spline to conform to a surface of the organ so as to make contact between the electrodes and the surface.