Faculty Bibliography

A 52-year-old lady presented to the emergency department with recurrent episodes of dizziness and near-syncope on awakening up or swinging her left arm. Initial rhythm strips demonstrated intermittently non-conducted p waves corresponding to inappropriate pacemaker inhibition and oversensing malfunction. Pacemaker was interrogated in the ED showing ventricular lead noise and decreased lead impedance over a one year period. The patient was diagnosed with pacemaker lead failure supported by correlating pacemaker lead variation with homolateral arm movement. The patient was referred to an electrophysiologist and underwent new right ventricular lead placement with the resolution of symptoms.

Cardiac perforation by a pacemaker lead is a rare complication of pacemaker implantation. Presentation can vary from chest pain and shortness of breath to the patient being completely asymptomatic. Diagnosis is usually made by high-resolution computed tomography (HRCT) scan of the chest. Electrocardiograph (EKG) usually shows the absence of a paced rhythm, but it doesn't provide a definitive diagnosis. We describe a case of late cardiac perforation by an atrial pacemaker lead with no signs or symptoms of pericardial tamponade.

Arrhythmias are commonly mapped using a timing reference signal. There are a number of situations where mapping may be difficult or even impossible using conventional reference-based mapping. Wobbling arrhythmias or those who do not maintain a 1:1 relationship with the reference signal are problematic. Local vector mapping may be performed in these situations to map arrhythmias without the use of a reference signal.

OBJECTIVE:To evaluate warfarin prescription, quality of international normalised ratio (INR) monitoring and of INR control in patients with atrial fibrillation (AF) and chronic kidney disease (CKD). METHODS:We performed a retrospective cohort study of patients with newly diagnosed AF in the Veterans Administration (VA) healthcare system. We evaluated anticoagulation prescription, INR monitoring intensity and time in and outside INR therapeutic range (TTR) stratified by CKD. RESULTS:Of 123 188 patients with newly diagnosed AF, use of warfarin decreased with increasing severity of CKD (57.2%-46.4%), although it was higher among patients on dialysis (62.3%). Although INR monitoring intensity was similar across CKD strata, the proportion with TTR≥60% decreased with CKD severity, with only 21% of patients on dialysis achieving TTR≥60%. After multivariate adjustment, the magnitude of TTR reduction increased with CKD severity. Patients on dialysis had the highest time markedly out of range with INR <1.5 or >3.5 (30%); 12% of INR time was >3.5, and low TTR persisted for up to 3 years. CONCLUSIONS:There is a wide variation in anticoagulation prescription based on CKD severity. Patients with moderate-to-severe CKD, including dialysis, have substantially reduced TTR, despite comparable INR monitoring intensity. These findings have implications for more intensive warfarin management strategies in CKD or alternative therapies such as direct oral anticoagulants.