Evaluating cardioversion outcomes for atrial fibrillation on novel oral anticoagulants versus warfarin: experience at a tertiary referral centre.

BACKGROUND: Current guidelines recommend anticoagulation prior to cardioversion in patients with atrial fibrillation of >48 h or unknown duration to reduce thromboembolic risk. Therapeutic anticoagulation with warfarin, with INR between 2 and 3, is consistently achieved in approximately 60% of patients. AIMS: We evaluated outcomes and assessed differences in direct current cardioversion (DCCV) in patients treated with warfarin and novel oral anticoagulants (NOAC) at our institution. METHODS: A retrospective analysis of consecutive DCCV at a tertiary referral over 18 months was conducted. Analysis of cardioversion records allowed completion of a standardised dataset. Clinical variables recorded included (1) CHADSVASC score, (2) anticoagulant use, and (3) bleeding complications. RESULTS: During this period 187 DCCVs were scheduled; 119 on warfarin and 68 on NOAC. DCCV was deferred in 26% (n = 31) of the warfarin group and 4.4% (n = 3) of the NOAC group (p = 0.0002). The average time interval between referral and DCCV was 144.43 and 109.32 days for the warfarin and NOAC groups, respectively (p value = 0.023). 7.56% (n = 9) of the warfarin population had a bleeding event compared to a 2.94% total bleeding rate in NOAC group (p = 0.213). Deferral of elective DCCV and additional anticoagulant monitoring was estimated at €1160 per procedure. CONCLUSION: In elective cardioversions, the group anticoagulated with NOAC was less likely to have subtherapeutic anticoagulation and hence deferred procedures and had reduced health care consumption when compared to the group anticoagulated with warfarin.

Electrocardiographic features of septal location of right ventricular outflow tract tachycardia.

A consistent 12-lead electrocardiogram (ECG) morphology and characteristic frontal plane axis shift from sinus rhythm to ventricular tachycardia (VT) was demonstrated in 10 consecutive patients with idiopathic right ventricular outflow tract (RVOT) VT. All arrhythmias were successfully ablated on the septal side of the RVOT.

Long-term thresholds of nonsteroidal permanent pacing leads: a 5-year study.

The present commercial market supports many nonsteroidal endocardial pacing leads of differing construction. In order to compare the performance of these configurations, we studied the long-term pacing properties of three representative lead types by randomized clinical trial in 99 patients undergoing a first elective VVI implant. Thirty-one patients received sintered platinum leads, 36 activated pyrolytic carbon leads, and 32 vitreous carbon leads. All received generators capable of noninvasive threshold testing. Acute sensing parameters were R wave amplitude and ST segment elevation measured from the endocardial electrogram. Noninvasive voltage thresholds were measured at implantation, 2 days, 1, 3, and 6 months, and yearly thereafter for 5 years. There were no significant differences between leads in pacing or sensing capabilities at implantation. All three demonstrated similar increases in thresholds, peaking at 1 month, then falling to a plateau by 6 months and did not vary significantly thereafter. There were no significant differences in thresholds between leads during 5 years of follow-up. The lowest mean threshold at 5 years was 0.93 V at 0.5 ms. This study suggests that: (1) although these lead types all perform well, none offers any particular clinical advantage over another; (2) the degree of early threshold peaking precludes immediate postimplant output reduction, but later thresholds are sufficiently low to enable reductions in pacing output; (3) safe low energy pacing requires greater attention to the lead-generator combinations; (4) data obtained at subsequent annual follow-up provided no additional useful clinical information to that obtained at 1 year; and (5) in the absence of other differences, cost can be the deciding factor in lead selection.

Is ventricular ectopy a legitimate target for ablation?

Radiofrequency ablation has an established role in the treatment of non-ischaemic ventricular tachycardia. A few patients present with symptomatic but benign ventricular ectopy that can be mapped to the right ventricular outflow tract. The successful use of radiofrequency ablation in a patient with drug resistant, symptomatic ventricular ectopy is reported. Radiofrequency ablation may have a useful role in more benign arrhythmias.

Pharmacological therapy of arrhythmias complicating dilated cardiomyopathy--implications of the arrhythmogenic substrate.

Dilated cardiomyopathy is a global myocardial abnormality in which it is likely that there are relatively homogeneous electrical conditions. The pattern of arrhythmic complications, especially atrial ectopic beats, ventricular ectopic beats and the brief salvoes of polymorphic ventricular tachycardia which are characteristic of the condition, suggest that triggered automaticity is a more likely arrhythmia mechanism than reentry. Although treatment with 'conventional' antiarrhythmic agents has an important place, drugs which alter myocardial loading conditions (and thus, thereby, a possible mechanism of triggered automaticity) may be effective. Therapeutic strategies directed against the basic disease processes are in an early stage of clinical development but they hold great promise for the future.

Efficacy, safety and duration of nitrate-free interval to prevent tolerance to transdermal nitroglycerin in effort angina.

The magnitude of tolerance to the anti-anginal efficacy of transdermal nitroglycerin and the efficacy and safety of short (4 h) and long (10 h) nitrate-free intervals for its prevention, were investigated in a randomized, double-blind, placebo-controlled crossover trial of 4 week-long treatment regimens: placebo, continuous therapy with a 50 mg patch (10 mg.24 h-1), and 4 h and 10 h nitrate-free periods. Only patients showing greater than 1 min increase in time to 1 mm ST depression after acute patch administration were eligible. Twelve men completed the study. One other anti-anginal medication (a beta-blocker in nine and calcium antagonist in two) was permitted in a constant dose throughout the study. Patients underwent exercise testing on days 1 and 7 of each treatment period, and 24 h ambulatory ECG monitoring on day 6. Compared to placebo, transdermal nitroglycerin on day 1 significantly improved time to 1 mm ST depression by 35%, and time to angina, exercise duration and maximal workload by 21%, 13% and 9% respectively. These improvements were totally lost after 7 days' continuous therapy, but completely maintained by a 10 h nitrate-free period (improvements of 35%, 25%, 16% and 11% respectively) but not by a 4 h nitrate-free period (non-significant improvements of 15%, 2%, 4% and 1% respectively). The differences between 10 and 4 h nitrate-free were significant for each end-point. Neither duration of ambulatory ischaemia, nor the proportion of patients experiencing greater than or equal to 5 min ischaemia during the scheduled nitrate-free interval differed between treatments.(ABSTRACT TRUNCATED AT 250 WORDS)