The electrocardiographic interpretation of ventricular pacing suppression algorithms in the pacemaker.

Algorithms designed to reduce the right ventricular (RV) pacing burden are widely available in modern dual-chamber implantable pacing devices. These algorithms allow the atrioventricular delay for sensed ventricular events to be longer than for ventricular paced events. However, since these features are unique to pacemaker manufacturers, they often produce unfamiliar electrocardiographic (ECG) appearances that suggest pacemaker dysfunction. We describe a Vp suppression algorithm used in Biotronik dual-chamber pacemakers and implantable cardioverter-defibrillator devices.

Thoracic impedance measurement in heart stimulation and cardiac arrhythmias.

The electrocardiogram (ECG) interpretation in patients with implantable cardioverter defibrillator (ICD) is often a puzzling problem. The difficulty of the device function evaluation further increases in the presence of unfamiliar timing cycles and additional functions. We present an interesting ECG with a special function of a Biotronik ICD devices called the thoracic impedance monitoring, and demonstrate its behavior in a patient with atrial fibrillation, pacing beats, ventricular ectopic beats, and couple of ventricular beats. This report shows unexceptional occurrence of tricky ECG finding in patient with Biotronik ICDs.

Pacing spikes following QRS complexes: What is the mechanism?

The electrocardiogram (ECG) interpretation in patients with implantable cardioverter defibrillator (ICD) is often a puzzling problem. The difficulty of the device function evaluation further increases in the presence of unfamiliar timing cycles and additional functions. Authors present a special function of a Biotronik ICD devices called the thoracic impedance monitoring, and demonstrate its behavior in a patient with sinus rhythm, ventricular ectopic beats, and ventricular tachycardia episode. This report shows unexceptional occurrence of tricky ECG finding in patient with Biotronik ICD.

Switch between AAI and DDD mode pacing-What is the mechanism?

The electrocardiogram (ECG) interpretation in patients with implantable pacemaker is often a perplexing problem. The difficulty in the device evaluation increases in the presence of novel timing cycles and additional functions. Authors describe a special function frequently encountered in Medtronic dual-chamber pacemakers and implantable cardioverter-defibrillator devices called managed ventricular pacing (MVP) and demonstrate its performance in the patient with undersensing episodes in ventricular channel. Intermittent ventricular undersensing in the device with MVP feature turned on caused repetitive mode switches between AAI and DDD mode. This report shows unexceptional occurrence of tricky ECG findings in patient with Medtronic dual-chamber device.

Venous Stenosis and Occlusion in the Presence of Endocardial Leads.

BACKGROUND: Venous stenosis and occlusion in the presence of endocardial leads constitute one of the complications of permanent cardiac pacing either by pacemaker, implantable cardioverter-defibrillator or cardiac resynchronization therapy. OBJECTIVES: The aim of this study was to assess the incidence of stenosis and occlusions and determine the risk factors in patients with endocardial leads in a prospective single-center study. MATERIAL AND METHODS: Two hundred eighty consecutive patients aged 25-95 years (male 68.8%) were included. A contrast venography examination of the ipsilateral access vein was performed. The whole study population was divided into 2 groups, based on the presence (group I) or absence (group II) of endocardial leads. RESULTS: Venous stenosis/occlusion was identified in 51 patients (37.5%) in group I and in 3 patients (3.6%) in group II; p < 0.0001. The lead presence most highly correlated with venous complications (OR = 4.172; p < 0.001). In patients with endocardial leads divided into I A and I B according to venous patency diabetes mellitus was proved in multivariate analysis to be the only protective factor against the development of venous stenosis/occlusion (OR = 0.473; p = 0.010). CONCLUSIONS: The presence of endocardial leads is a predisposing factor for venous stenosis/occlusion and increases the risk 4-fold. The venous lesions in the presence of endocardial leads are less frequent among patients with diabetes mellitus.