The present invention concerns an elongated medical device (1, 11) suitable for intravascular insertion. Said device comprising a flexible elongated body (2) having a distal portion (3) with a distal end (4) and a proximal portion (5), and an electrode assembly (80) located at the distal portion (3). The electrode assembly (80) comprises a plurality of at least x=4 support arms (81), wherein x is evenly divisible by the number 2, each support arm (81) having a proximal end part (81 a), a distal end part (81 b) and a main part (81 c) between the proximal end part (81 a) and the distal end part (81 b), the plurality of at least x=4 support arms (81) comprising first and second neighboring support arms (81.1, 81.2) forming pairs of neighboring support arms (81). The electrode assembly (80) further comprises a plurality of electrodes (82) arranged on the support arms (81) for collecting electrophysiological data. The plurality of at least x=4 support arms (81) is configured to have a first condition (UC), where the plurality of at least x=4 support arms (81) is arranged in a bundle, and a second condition (EC), where the plurality of at least x=4 support arms (81) is expanded, forming a basket type structure (83). All first and second neighboring support arms (81.1, 81.2) are combined at their proximal end parts (81 a) to form united end parts (88a), such that all pairs of neighboring support arms (81) are united at their proximal end parts (81 a). Further, each second and first neighboring support arms (81.2, 81.1) are combined at their distal end parts (81 b), to form united end parts (88b), such that all pairs of neighboring support arms (81) are united at their distal end parts (81 b), wherein each support arm (81) is combined at its distal end part (81 b) with a different neighboring support arm (81) than at its proximal end part (81 a).
