A simplified differential pacing technique for the evaluation of bidirectional cavo-tricuspid isthmus block during ablation of typical atrial flutter.

PURPOSE: Bidirectional block of the cavo-tricuspid isthmus (CTI) is an established endpoint of CTI-dependent atrial flutter (AFl) ablation. Differential pacing has been used to evaluate the CTI block. The purpose of this study is to describe a modified differential pacing technique to evaluate the CTI block. METHODS: Sixty-two patients underwent radiofrequency (RF) ablation of CTI-dependent AFl. The acute endpoints were non-inducibility of the AFl, and verification of the bidirectional CTI block by our methodology. Pacing was performed in the CS with an ablation catheter positioned immediately lateral to the CTI ablation line, and then 1-2 cm more laterally. The stimulus-to-ablation catheter atrial electrogram intervals were measured at these sites (StimCS-Abl1 and StimCS-Abl2, respectively). Pacing with the ablation catheter also was performed at these 2 sites, and the stimulus-to-CS electrogram intervals (StimABL1-CS and StimABL2-CS) were measured. The criteria for the bidirectional block were StimCS-Abl1 > StimCS-Abl2, and StimABL1-CS > StimABL2-CS. Clinical efficacy was defined as freedom from recurrent AFl during follow-up. RESULTS: Following 12.2 ± 3.7 min of RF delivery across the CTI, intervals were StimCS-Abl1 = 181.2 ± 22.7 ms and StimABL1-CS = 181.0 ± 23.6 ms, and StimCS-Abl2 = 152.2 ± 26.5 ms and StimABL2-CS = 151.2 ± 22.7 (P < 0.001). Atrial flutter was rendered not inducible in all patients, and no procedural complications were encountered. During the next 15.9 ± 0.7 months, two patients were lost to follow-up, and among the 62 other patients, one (1.7%) had flutter recurrence. CONCLUSIONS: The bidirectional CTI block can be assessed quickly and easily using only the ablation and CS catheters for differential pacing.

Effects of omega-3 polyunsaturated fatty acids on fibrosis, endothelial function and myocardial performance, in ischemic heart failure patients.

BACKGROUND & AIMS: Polyunsaturated fatty acids (PUFAs) may affect the cardiovascular system with a multiplicity of mechanisms. We assessed the effects of omega-3 PUFAs supplements on inflammation, fibrosis, left ventricle performance and endothelial function of ischemic heart failure (HF) patients. METHODS: In this double-blind, placebo controlled, cross-over trial we enrolled 31 patients with ischemic HF, followed by a 6-week wash-out period. Omega-3 PUFAs (2 g daily, 8 weeks) were administered PO in the intervention arm. Left ventricle ejection fraction (EF), global longitudinal strain and the ratio E/e' (early ventricular filling to early mitral annulus velocities)were measured. Endothelial function was evaluated by flow mediated dilation and myocardial fibrosis by soluble ST2. High sensitive C Reactive protein (hsCRP) levels were measured as an inflammatory marker. RESULTS: Treatment with omega-3 PUFA, compared to placebo, improved: left ventricle EF (percent increased by 4.7% vs 1.7%); global longitudinal strain (decreased by -10.6% vs -2.3%); the E/e' ratio (decreased by -9.47% vs -2.1%); ST2 levels (decreased by -4.53% vs -2.37%); flow mediated dilation (percent increased by 44% vs. 11% and hsCRP levels (decreased by -6.13% vs 4.35%) (p < 0.05 for all). CONCLUSION: Short term treatment with omega-3 PUFAs in subjects with stable ischemic HF improved inflammatory and fibrotic status as well as endothelial function in parallel with systolic and diastolic performance of left ventricle. These findings provide further insights regarding the impact of omega-3 PUFAs administration on left ventricle performance indices, systemic inflammation and fibrosis biomarkers in patients with ischemic HF.

Electrophysiology testing for risk stratification of patients with ischaemic cardiomyopathy: a call for action.

Current guidelines recommendations, based on the results of primary sudden cardiac death prevention trials, use the left ventricular ejection fraction (LVEF) as a sole criterion for the indication of implantable cardioverter defibrillator therapy for primary prevention purposes. In this article, we review the sensitivity and specificity of LVEF for predicting arrhythmic vs. non-arrhythmic cardiac death and examine existing evidence on the use of electrophysiology testing for risk stratification of ischaemic patients with reduced left ventricular function.

Coexistent Types of Atrioventricular Nodal Re-Entrant Tachycardia: Implications for the Tachycardia Circuit.

BACKGROUND: There is evidence that atypical fast-slow and typical atrioventricular nodal re-entrant tachycardia (AVNRT) do not use the same limb for fast conduction, but no data exist on patients who have presented with both typical and atypical forms of this tachycardia. We compared conduction intervals during typical and atypical AVNRT that occurred in the same patient. METHODS AND RESULTS: In 20 of 1299 patients with AVNRT, both typical and atypical AVNRT were induced at electrophysiology study by pacing maneuvers and autonomic stimulation or occurred spontaneously. The mean age of the patients was 47.6±10.9 years (range, 32-75 years), and 11 patients (55%) were women. Tachycardia cycle lengths were 368.0±43.1 and 365.8±41.1 ms, and earliest retrograde activation was recorded at the coronary sinus ostium in 60% and 65% of patients with typical and atypical AVNRT, respectively. Thirteen patients (65%) displayed atypical AVNRT with fast-slow characteristics. By comparing conduction intervals during slow-fast and fast-slow AVNRT in the same patient, fast pathway conduction times during the 2 types of AVNRT were calculated. The mean difference between retrograde fast pathway conduction during slow-fast AVNRT and anterograde fast pathway conduction during fast-slow AVNRT was 41.8±39.7 ms and was significantly different when compared with the estimated between-measurement error (P=0.0055). CONCLUSIONS: Our data provide further evidence that typical slow-fast and atypical fast-slow AVNRT use different anatomic pathways for fast conduction.