ECG of<unk>  The cause is poorly understood. However several risk factors are associated with<unk> . Risk factors * In the preimplantation period, two variables are predicted to predispose to the syndrome. First is low sinus rate, and second is a higher programmed lower rate limit. In postimplantation, an increased percentage of ventricular paced beats is the only variable that significantly predicts development of<unk> . * Patients with intact VA conduction are at greater risk for developing<unk> . Around 90% of patients with preserved AV conduction have intact VA conduction, and about 30-40% of patients with complete AV block have preserved VA conduction. Intact VA conduction may not be apparent at the time of<unk>  implantation or even may develop at any time after implantation. * Patients with noncompliant ventricles and diastolic dysfunction are particularly sensitive to loss of atrial contribution to ventricular filling and have a greater chance of developing the syndrome. This includes patients with cardiomyopathy (hypertensive, hypertrophic, restrictive) and elderly individuals. * Other factors correlated with development of<unk>  include decreased stroke volume, decreased cardiac output, and decreased left atrial total emptying fraction associated with ventricular pacing.
Pacemaker syndrome
Pre-excitation syndrome
Takotsubo cardiomyopathy
Torsades de pointes
Primary ventricular fibrillation
Aicardi syndrome
Unstable angina
Sudden arrhythmic death syndrome