[Cardiac resynchronization therapy in patients with heart failure: a 10-year experience].

Background: Multiple randomized trials support the clinical benefits of cardiac resynchronization therapy (CRT) in patients with heart failure (HF) and ventricular dyssynchrony. Since the year 2000 this therapy has been increasingly used in Chile.

Aim: To describe the clinical characteristics and follow-up of HF patients undergoing CRT in a single Chilean university hospital during the last 10 years.

[Placement of a biventricular resynchronization device in a patient with a persistent left superior vena cava: report of one case].

Persistent left superior vena cava is the most common venous congenital malformation and is usually asymptomatic. Its presence could increase the difficulty for transvenous lead implantation. We report a 71-year-old woman with an idiopathic dilated cardiomyopathy, atrial fibrillation and heart failure that required biventricular resynchronization therapy.

[Twiddler syndrome: report of one case].

We report a 26 year old patient who had a single chamber pacemaker implantation one year before. During a routine pre-operative evaluation, pacemaker dysfunction was demonstrated due to sensing and pacing failure, associated to left pectoral muscle rhythmic contraction. Chest X-ray confirmed Twiddler syndrome, in which twisting or rotation of the device inside the pocket results in lead dislodgement and device malfunction.