TRPV4 and ischemia: Little inducibility was found in all groups at baseline, but the number of total ventricular tachyarrhythmias (VTA) after regional ischemia were significantly higher in TRPV4+/+ animals of the HF(iso) group compared to TRPV4+/+ sham and TRPV4−/− receiving isoproterenol (Figure 3F).