Tree or ICD?

79-year old man known with ischemic heart disease, NYHA I, LVEF 30%, single-chamber Medtronic ICD for primary intervention programmed according to the 2019 HRS/EHRA recommendations.

He was cutting trees in his garden when he suddenly felt a "thump" on his chest. He was fully concious but not sure whether he was hit by a tree branch, or whether he had received an ICD shock.

This is why he performed a transmission to our hospital with the following extract. We decided to admit the patient an on arrival we discovered an asymptomatisch patient with the same rhythm and he received yet another shock. He received substrate modification through ablation and has remained free of symptoms.

What is happening? What could we change in programming so he won't get shocks during full conciousness when this rhythm reccurs?