autonomic nervous system dysfunction. There have also been reports of congestive heart failure , electrocardiographic abnormalities (i.e., sinus node arrest, junctional bradycardia , high degree AV block , and arrhythmias ), palpitations, Raynaud's phenomenon , syncope, and tachycardia. Cases of sinus bradycardia and atrioventricular block have been reported, both with and without