Syncope and conduction problems: when is pacing the solution?

SSS is characterized by sinus bradycardia and asystole. Syncope from SSS carries a better prognosis than syncope from heart block. AV node heart block is signaled by P-R prolongation and Wenckebach periodicity. Symptoms vary in severity, with or without syncope. TF heart block is preceded by left-bundle branch block or by right-bundle branch block plus fascicular block. Prognosis for the unpaced patient subject to TF block is grave. The fact that ECGs suggesting sinus bradycardia, P-R prolongation, and bifascicular block (all causes of syncope) are very common among the elderly and usually have an innocent course, increases the difficulty of deciding which patient will benefit from pacing. Certainly a pacemaker should not be inserted because of abnormal ECG alone.