Polymorphic Ventricular Tachycardia Storm After Coronary Artery Bypass Graft Surgery: A Form of 'Angry Purkinje Syndrome'.

BACKGROUND: Polymorphic ventricular tachycardia (PMVT) is a highly lethal arrhythmia which is commonly caused by acute myocardial ischaemia. PMVT mediated by short-coupled ventricular ectopy patients with ischaemic heart disease but in the absence of acute ischaemia may relate to transient peri-infarct Purkinje fibre irritability and has been termed 'Angry Purkinje Syndrome'. METHODS: We present a case series of three patients with PMVT storm 3-5 days following coronary artery bypass graft surgery (CABG). In all three cases, recurrent episodes of PMVT were initiated by monomorphic ventricular ectopy with a short coupling interval. Acute coronary ischaemia was excluded in all three patients with a coronary angiogram and graft study. Two out of three of the patients commenced oral quinidine sulphate with subsequent rapid suppression of arrhythmia. Implantable cardiac defibrillators were implanted in all three patients and revealed no recurrence of PMVT following hospital discharge. CONCLUSION: The Angry Purkinje Syndrome is a rare but important cause of ventricular tachycardia storm after CABG surgery and is mediated by short-coupled ventricular ectopy in the absence of acute myocardial ischaemia. This arrhythmia may be highly responsive to quinidine.

Incidence of Premature Lead Failure in 2088 TendrilTM Pacing Leads: A Single Centre Experience.

BACKGROUND: Recent reports describe a high rate of premature lead failure in the St Jude/Abbott TendrilTM 2088 (St. Jude Medical Inc., St. Paul, MN, USA) pacing lead principally manifested by electrical noise. This finding awaits confirmation. METHODS: We performed a retrospective analysis of 2088 TendrilTM leads among 362 patients implanted from 2010 to 2018. Eligible leads were those with device interrogations beyond one month from lead implantation. Review of serial device interrogations was conducted for each lead, particularly focussing on electrical noise as a marker of premature lead dysfunction. RESULTS: Four hundred and eight (408) leads among 337 patients were included in this study, with an average patient age of 81±11 years at the time of lead implantation. Mean follow-up was 2.5±1.8 years. There were eight leads with electrical noise indicating premature lead failure. This reflects an overall 1.7% rate of lead dysfunction; the failure rate was 6.2% at 4 years. The majority of cases were detected during routine checks without adverse clinical consequences. Four (4) cases required device reprogramming to avoid interference or inhibition due to noise. CONCLUSION: The rate of Tendril TM 2088 premature lead failure appears to be similar to recent local and international studies. This study reports a significantly higher rate of lead dysfunction at 4 years (6.2%) than the published Abbott product performance reports.

An Update on Anticoagulation in Atrial Fibrillation.

Cerebrovascular accidents related to atrial fibrillation (AF) are potentially preventable with anticoagulation. Until recently, warfarin was the only proven anticoagulant to be effective in stroke prevention, however the novel, direct acting oral anticoagulants (DOACs) are now available, triggering a paradigm shift in treatment philosophy. Today, physicians need to consider in which patients anticoagulation should not be used rather than, as in the past, deciding in which patients it should be used. Although warfarin will continue to have a place in managing some patients with AF, in the future, the DOACs should be the predominant therapy for stroke prevention in patients with non-valvular AF.

Atrial response to ventricular antitachycardia pacing discriminates mechanism of 1:1 atrioventricular tachycardia.

BACKGROUND: Inappropriate shocks from implantable cardioverter defibrillators (ICD) remain a significant clinical problem despite device discrimination algorithms. The atrial response to antitachycardia pacing (ATP) may determine the mechanism of 1:1 A:V tachycardia. METHODS: For this study we refer to sinus tachycardia, atrial tachycardia (AT), atrial fibrillation, and flutter as atrial tachycardia (AT), and all other tachycardia as "non-AT." Three atrial response patterns during the burst of ATP were determined. The atrial cycle length (ACL) may be unchanged (type 1) indicating AT. The ACL may show variation during ATP (type 2) indicating variable VA block and does not discriminate between an AT and a non-AT mechanism, in which case a default diagnosis of non-AT is made. The ACL may accelerate to the ATP cycle length (type 3) indicating entrainment. A VAAV response at the end of ATP was considered diagnostic of AT (type 3A) whereas a VAV or VVA response was considered a non-AT mechanism (type 3B). This algorithm was applied to ICD tracings from 68 episodes of spontaneous 1:1 A:V tachycardia that had 136 sequences of ATP administered. The rhythm "truth" was determined by consensus of two experienced clinicians. RESULTS: The algorithm correctly identified AT with a sensitivity of 71.9% (95% CI: 67.1-73.6), and specificity of 95% (83.5-99.1). The PPV was 97.2% (90.9-99.5), and NPV 58.5% (51.4-61.0). Kappa was 0.57 (0.43-0.62). If used clinically the algorithm would have aborted 53.3% (8/15) of inappropriate shocks delivered into an AT-mechanism tachycardia and would not have withheld a shock for any episode of VT. CONCLUSION: Analysis of atrial response patterns during and after ventricular ATP can successfully discriminate tachycardia mechanism and may reduce inappropriate ICD shocks.