CLINICAL STATEMENTS AND GUIDELINES ers, and some antiarrhythmic medications may relieve symptoms of palpitations.S2.2.2-18 PVCs that occur during an exercise test are associ- ated with a higher risk of death.S2.2.2-19 In 1 study, PVCs that occur during recovery are a stronger predictor of death than PVCs occurring only during exercise.S2.2.2-20 However, PVCs are common in trained athletes who have palpitations, in whom there does not appear to be increased risk of death based on studies of small num- bers of athletes, at least in those without other cardio- Complex PVCs may not represent a benign finding in endurance athletes. An electrophysiological study may be needed to as- sess patients arrhythmogenic risk.S2.2.2-22 Very frequent PVCs, >10000 to 20000 a day, can be associated with depressed LV function in some patients that is revers- ible with control of the PVCs, and has been referred to as PVC-induced cardiomyopathy.S2.2.2-23,S2.2.2-24 (See also Section 8.5. PVC-Induced Cardiomyopathy.) Very rarely, idiopathic PVCs from the outflow tract may trig- ger malignant VA in patients without structural heart 2.1.2. VT and VF During ACS Approximately half of patients with out-of-hospital cardiac arrest with the first rhythm identified as VF and who survive to hospital admission have evidence of acute MI (AMI).S2.2.2-27 Of all out-of-hospital cardiac arrests, >50% will have significant coronary artery le- sions on acute coronary angiography.S2.2.2-27 Of patients hospitalized with AMI, 5% to 10% have VF or sus- tained VT prior to hospital presentation, and another 5% will have VF or sustained VT after hospital arrival, most within 48 hours of admission. 