T wave oversensing and low percentage of biventricular pacing in cardiac resynchronization therapy

The success of cardiac resynchronization therapy (CRT) depends on a high percentage of ventricular pacing. We present the electrocardiography and electrograms of a patient who underwent an implantable cardioverter-defibrillator (ICD) with CRT implantation showing a low percentage of ventricular pacing as a result of T wave oversensing of paced QRS. The patient showed no clinical improvement. We suggest finding a good sensitivity of F waves in induced ventricular fibrillation during ICD implantation in order to overcome the harm of possible oversensing

MAMI registration report 1996–2010

Background: To summarize the results of MAMI registration and compare them to other national and foreign records published. Methods: Observational, prospective and multicenter study based on a wide source of data incoming from 50 Intensive Care Units in Spain during 15 years, from April 1996 to December 2010. Demographic, clinical, etiological and electrocardiographic (ECG) variables were collected before pacemaker implantation. Type of intervention, electrical measurement at implantation, model and serial number of devices and electrodes as well as early complications (before hospital discharge) were also recorded. Results: During this period 31766 interventions have been reported: 24643 first implants (77.6%) and 7123 replacements (22.4). The total number of patients is lower than interventions because some of them were included as first implants and as replacements after years. In first implant the average age, clinical signs, ECG disorders and pacing modes were described. Data collected in device replacement interventions were average age, pacing modes and cause for replacement. 45% of implanted devices were endowed with rate control algorithm. In last 3 years increased to 82.4%. From 1996 to 2010 we have seen a decline in VVI(R) pacing mode in favor to DDD(R) mode. AAI(R) and VDD(R) modes have remained invariable. Finally, we show data on early complications and mortality. Conclusions: MAMI registration is a valid tool for recording the activity of pacemaker implantation. It showed variations and trends of pacing modes and algorithms along the years. Data is recorded separately for men and women so they can be compared

Cardiac ‘resynchronization’ by a left lateral accessory pathway

We present the case of a 21 year-old woman with unremarkable medical history except for tachycardia episodes. The ECG showed a delta wave pre-excitation by a left lateral pathway. One radiofrequency pulse temporarily terminated the accessory pathway conduction, revealing a nodal conduction with complete left bundle branch block. (Cardiol J 2012; 19, 5: 536-538