AIMS: To determine waiting period-related morbidity, mortality, and adverse events in acute patients waiting for a permanent pacemaker (PPM).METHODS AND RESULTS: A retrospective chart review of all PPM implantations in Region Zealand, Denmark, in 2009 was conducted. Patients were excluded if they were discharged from the hospital during the waiting period or referred from the outpatient department. Adverse events were tracked. Four hundred and eighty-seven PPM implantations were identified. Of these, 259 patients (53.2%) required acute PPM implantation and waited a mean of 5.1 days from PPM indication to implantation. A lack of implantation capacity was responsible for 4.5 of the waiting days. Twenty-nine patients (11.2%) developed infection while waiting, primarily urinary tract infections. Thirteen patients (5.0%) suffered non-sustained ventricular tachycardia, and eight patients (3.1%) suffered clinical cardiac arrest followed by successful resuscitation. Three patients (1.2%) died during the waiting period before successful implantation. Forty-eight patients (18.5%) received the sympathomimetic beta-adrenergic agent, isoprenaline, and seven patients (13.7%) had malignant arrhythmias or cardiac arrest, reaching statistical significance (P <0.05). Twenty-eight patients (10.8%) had a temporary transvenous-pacing catheter applied acutely.CONCLUSIONS: The patients awaited acute PPM implantations for a mean of 4.5 days because of capacity problems. Overall, 83 patients (32.0%) experienced at least one adverse event during the waiting period. The present study indicates that a waiting period is dangerous as it is associated with an increased risk of adverse events. Acute PPMs should be implanted with a 24-h pacemaker implantation service capacity.