Implantable event recorder, a new aid in the diagnosis of arrhythmogenic syncopes

History and clinical findings: A 52-year-old woman had for 31 years been ex periencing occasional episodes of dizziness and syncope, as well as sudden attacks of "shaking" in the chest associated with cramp-like pain. nausea a nd weak spells, each lasting for up to 45 min. She had since childhood been suffering from atopy, with bronchial asthma and polyvalent allergies. On e xamination, which was otherwise unremarkable, her blood pressure was 140/10 0 mm Hg with a sinus tachycardia of 110/min. She was admitted for implantat ion of an event recorder to establish the etiology of the described symptom s. Investigations: The results of routine laboratory tests, including those of thyroid function, were within normal limits. The ECG showed sinus rhythm a nd minor left precordinal abnormalities of repolarization. The echocardiogr am was normal and coronary angiography excluded coronary heart disease. Treatment and course: 3 weeks after ambulatory implantation of an event rec order (Reveal(R), Medtronic) she again had an attack. The recorded ECC indi cated a supraventricular tachycardia (190/min), preceded by an atrial extra systole, lasting 3 min 14s. She was treated with digitalis and verapamil, h er asthma contraindicating solatol. She had refused further invasive diagno stic measures. The appearance of an allergic rash required a change of drug s to propafenon. But as this, too, was poorly tolerated, electrophysiologic al testing was undertaken. It revealed an AV nodal reentry tachycardia whic h was treated with local ablation: supraventricular extrasystoles continued to occur frequently, but there were no further episodes of reentry tachyca rdia. Conclusion: In patients with recurrent syncopes, but otherwise unremarkable clinical findings, an implantable event recorder may provide important dia gnostic information, especially relating to a possible arrhythmogenic cause .