TLX2 and chronic obstructive pulmonary disease: Finally, KB‐R7954 (an NCX inhibitor, 10 μM) suppressed the nonsustained or sustained VTs induced by the combination of 20‐Hz tachypacing with isoproterenol treatment in 6 of 8 COPD RVOTs (p = 0.002) and 5 of 8 nicotine‐treated COPD RVOTs (p = 0.007).