Monitoring for serious arrhythmias and high risk of sudden death.

Ventricular premature beats (VPBs) are present in 85% of patients with coronary heart disease (CHD). A classification of VPBs based on frequency, multiformity, repetitive pattern, and degree of prematurity promises to aid in identifying patients at high risk of sudden death. Advanced grade or repetitive forms of VPBs are observed in 41% of patients with CHD who are monitored for 24 hours while ambulatory. Exercise stress is less effective than monitoring, but when advanced grades are exposed by exercise, they are likely to be persistent for two or more hours during monitoring. Such persistent and advanced grades characterize patients with multivessel coronary artery disease. Diurnal variations occur in VPB frequency and pattern with significant reduction during sleep. This as well as other facts suggest a primary role for neural activity in the genesis of ventricular ectopy. The relevance of these observations to sudden death is considered.