TACHYCARDIA-BRADYCARDIA SYNDROME - A disorder consisting of abnormalities of supraventricular impulse generation and conduction which produce a wide variety of intermittent rapid and slow supraventricular arrhythmias. Common symptoms include palpitations, faintness, and fainting. Diagnosis is generally by 24 hour cardiac monitoring. A permanent pacemaker is indicated for those who are unresponsive to drug therapy.