Patterns of pulmonary vein potential disappearance during encircling ipsilateral pulmonary vein isolation can predict recurrence of atrial fibrillation.

BACKGROUND: The relationship between pulmonary vein (PV) potential (PVP) disappearance patterns during encircling ipsilateral pulmonary vein isolation (EIPVI) of atrial fibrillation (AF), and outcome was examined. METHODS AND RESULTS: A total of 352 consecutive AF patients (age, 61±12 years; 269 men, 76.4%; paroxysmal AF, n=239; persistent AF, n=73; and long-standing persistent AF, n=40) who underwent initial AF ablation were studied. After EIPVI with a double Lasso technique, pacing was performed from the PV carina to confirm isolation of the carina. PVP disappearance patterns were classified into 3 types: A, both superior and inferior PVP disappeared simultaneously; B, superior and inferior PVP disappeared separately; and C, additional RF applications were required inside the encircling lesions to eliminate the PVP after creating anatomical encircling lesions. The relationship between these patterns and outcome was examined. Six groups were defined according to the combination of right and left ipsilateral PVP disappearance patterns. The incidence of A-A, A-B, B-B, A-C, B-C, and C-C was 7.1%, 14.2%, 16.2%, 15.3%, 27.3%, and 19.9%, respectively. AF recurrence-free rate at 2 years for these 6 groups was 96%, 81%, 78%, 64%, 64%, and 59%, respectively (P<0.02). The incidence of a carina isolation was 153/154 (99.4%) for type A, 221/259 (85.3%) for type B, and 145/290 (50.0%) for type C. CONCLUSIONS: PVP disappearance pattern during EIPVI was significantly associated with the incidence of residual PV carina conduction and AF recurrence.

The incidence and clinical significance of non-isolation of the pulmonary vein carina after encircling ipsilateral pulmonary veins isolation for paroxysmal atrial fibrillation: a pitfall of the double-Lasso technique.

AIMS: Encircling ipsilateral pulmonary veins (PVs) isolation (EIPVsI) with the double-Lasso technique has proven to be effective to cure atrial fibrillation (AF). However, in this technique, PV mapping with circular catheters may miss a non-isolation of the PV carina. The purpose of this study was to reveal the incidence and clinical significance of a non-isolation of the PV carina after EIPVsI. METHODS AND RESULTS: We studied 81 consecutive paroxysmal AF patients (age 61 ± 12 years, 56 men), in whom EIPVsI was successfully performed in one encircling line with the endpoint of the demonstration of bidirectional conduction block between the PVs and left atrium (LA) with the double-Lasso technique. After a successful EIPVsI, pacing from the PV carina was performed and it captured the LA in 17 (21.0%) patients. During a mean follow-up period of 19 ± 13 months, AF recurred in 13 (16.0%) patients. A multivariate Cox proportional analysis revealed that a non-isolation of the PV carina after the EIPVsI was a significant predictor (hazard ratio = 3.91, 95% confidence interval = 1.13-14.16, P = 0.03) of AF recurrence. CONCLUSIONS: Pulmonary vein mapping with the double-Lasso technique did miss the non-isolation of the PV carina after a successful EIPVsI, which was an independent predictor of AF recurrence after the EIPVsI. Pacing from the PV carina may be required to confirm the electrical isolation of the PV carina after EIPVsI with the double-Lasso technique.

A randomized controlled trial of dabigatran versus warfarin for periablation anticoagulation in patients undergoing ablation of atrial fibrillation.

BACKGROUND: We aimed to evaluate the feasibility of an oral direct thrombin inhibitor, dabigatran, as a periprocedural anticoagulant for use with ablation of atrial fibrillation (AF). METHODS: Consecutive patients scheduled to undergo an AF ablation were randomly assigned to receive dabigatran (n = 45) or warfarin (n = 45) to compare their clinical feasibility. Both of those oral anticoagulants were discontinued the day before the ablation and were resumed after confirming hemostasis of the venipuncture site. A bridging therapy with heparin was not used in either of the patient groups. RESULTS: Dabigatran was switched to warfarin before the ablation because of dyspepsia in three patients. An occurrence of rebleeding from the venipuncture site was less common in dabigatran-allocated patients than in warfarin-allocated patients (20% vs 44%; P = 0.013). The reduction in the D-dimer level after the initiation of oral anticoagulants was greater in the dabigatran-allocated patients than in the warfarin-allocated patients. The time from the initiation of the anticoagulants to the ablation was significantly shorter in the dabigatran-allocated patients than in the warfarin-allocated patients (43 ± 7 vs 63 ± 13 days; P < 0.0001). There was only one fatal periprocedural complication in a patient receiving warfarin, who had a mesenteric arterial thrombosis after the ablation. CONCLUSIONS: An anticoagulation strategy with dabigatran may surpass that with warfarin in reducing both the periprocedural risk of minor bleeding and a hypercoagulable state, and the time to ablation in patients undergoing ablation of AF.

Outcomes of ablation of paroxysmal atrial fibrillation in patients on chronic hemodialysis.

INTRODUCTION: It is not common for patients on chronic hemodialysis (HD) to undergo catheter ablation of atrial fibrillation (AF). We aimed to show the outcomes of AF ablation in the HD patients. METHODS AND RESULTS: Thirty HD patients who underwent pulmonary vein (PV) isolation for drug refractory paroxysmal AF were retrospectively studied, and their AF recurrence free rate and frequency of periprocedural complications were compared to 60 age- and gender-matched control patients not requiring HD. A nonirrigated ablation catheter was used in both patient groups. During a mean follow-up period of 821 ± 218 days, 16 (54%) of the HD patients remained free from AF recurrence without any antiarrhythmic agents versus 47 (78%) of the control patients with an initial ablation (P = 0.013). A second ablation procedure was performed in 12 patients with an AF recurrence, and consequently 20 (67%) of the HD patients were in sinus rhythm compared to 53 (88%) of the controls during a follow-up duration of 747 ± 221 after the last ablation (P = 0.012). Bleeding from the venipuncture site requiring a prolonged hospital stay was identified in 2 HD patients and 1 control subject, while no life-threatening complications were observed in either patient group. CONCLUSION: Although the success rate of the PV isolation in HD patients was far from satisfactory, it may be considered as one of the therapeutic options for them.

High-frequency stimulation of the atria increases early recurrence following pulmonary vein isolation in patients with persistent atrial fibrillation.

BACKGROUND: High-frequency stimulation (HFS) of the atria induces atrial fibrillation (AF) when applied during sinus rhythm and elicits a parasympathetic response when delivered at sites where ganglionated plexi (GPs) are located. However, little is known about its impact after an electrophysiological study. OBJECTIVE: To evaluate the impact of HFS on the short-term and long-term outcomes after the ablation of persistent AF. METHODS: Thirty consecutive patients with persistent or long-standing persistent AF were randomly assigned to either receive HFS of the left atrium (n = 15) or not (n = 15) during their electrophysiological studies. Patients receiving HFS were examined to determine whether or not a vagal response was elicited by the HFS at sites where GPs were located before and after conventional pulmonary vein isolation without any ablation targeting the GPs. Patients not receiving the HFS underwent the ablation procedure alone. The rate of recurrence of AF within 3 months of the procedure (early recurrence [ER]) and the frequency of that occurring after that period (late recurrence) were compared between the patient groups. RESULTS: The incidence of ER occurred more frequently in patients with HFS than in those without (80% vs 40%; P = .015), whereas the occurrence of late recurrence was similar between the 2 groups (27% vs 33%; P = .73). In the HFS group, the number of GPs decreased from 3.4 ± 1.1 to 1.5 ± 0.8 after the pulmonary vein isolation (P < .0001), and the decrease was smaller in the patients experiencing ER than in those without. CONCLUSION: HFS increases the incidence of ER in patients with persistent AF despite a partial GP modification resulting from the pulmonary vein isolation.

Renin-angiotensin system inhibitors can suppress atrial fibrillation recurrence after encircling ipsilateral pulmonary vein isolation in patients with a non-dilated left atrium.

INTRODUCTION: The purpose of this study was to investigate whether the effects of renin-angiotensin system inhibitors (RASIs) after encircling ipsilateral pulmonary veins isolation (EIPVsI) for atrial fibrillation (AF) differed between patients with non-dilated and dilated left atria. MATERIALS AND METHODS: We retrospectively studied 292 consecutive patients (mean age=61±11 years, 75% males) who underwent successful EIPVsI for paroxysmal or persistent AF. RASIs' effects were compared between the patients with a non-dilated left atrium of <40 mm (n=178) and dilated left atrium of ≥40 mm (n=114). RESULTS: During a mean follow-up period of 18.9±12.7 months, AF recurred in 38 (21.4%) and 45 (39.5%) patients with non-dilated and dilated left atria, respectively. A multivariate Cox proportional analysis revealed that treatment with RASIs (hazard ratio (HR) 0.30, 95% confidence interval (CI) =0.13-0.66, p=0.003), the duration of AF (HR 1.08/year, 95% CI=1.01-1.16, p=0.03), a history of hypertension (HR 2.86, 95% CI=1.21-6.85, p=0.02) and the left ventricular ejection fraction (HR 0.54/10%↑, 95% CI=0.34-0.87, p=0.01) were associated with AF recurrences in patients with a non-dilated left atrium. On the other hand, only the duration of AF (HR 1.11/year, 95% CI=1.01-1.21, p=0.03) was associated with AF recurrences in those with a dilated LA, and RASIs had no effect on AF recurrences (p=0.65). CONCLUSIONS: RASIs suppressed AF recurrences after EIPVsI only in patients with a non-dilated left atrium.

Demonstration of reversible complete left bundle branch block following tachycardia-induced cardiomyopathy.

A 56-year-old man with atrial fibrillation and complete left bundle branch block (CLBBB) developed heart failure refractory to the initial medical treatment. Both the CLBBB and cardiac dysfunction completely recovered only with an advanced medical regimen for rate control and heart failure. This report describes a case with reversible CLBBB following tachycardia-induced cardiomyopathy, who was not a candidate for cardiac resynchronization therapy.

Imipramine inhibition of TRPM-like plasmalemmal Mg2+ transport in vascular smooth muscle cells.

Depression is associated with vascular disease, such as myocardial infarction and stroke. Pharmacological treatments may contribute to this association. On the other hand, Mg(2+) deficiency is also known to be a risk factor for the same category of diseases. In the present study, we examined the effect of imipramine on Mg(2+) homeostasis in vascular smooth muscle, especially via melastatin-type transient receptor potential (TRPM)-like Mg(2+) -permeable channels. The intracellular free Mg(2+) concentration ([Mg(2+) ](i) ) was measured using (31) P-nuclear magnetic resonance (NMR) in porcine carotid arteries that express both TRPM6 and TRPM7, the latter being predominant. pH(i) and intracellular phosphorus compounds were simultaneously monitored. To rule out Na(+) -dependent Mg(2+) transport, and to facilitate the activity of Mg(2+) -permeable channels, experiments were carried out in the absence of Na(+) and Ca(2+) . Changing the extracellular Mg(2+) concentration to 0 and 6 mM significantly decreased and increased [Mg(2+) ](i) , respectively, in a time-dependent manner. Imipramine statistically significantly attenuated both of the bi-directional [Mg(2+) ](i) changes under the Na(+) - and Ca(2+) -free conditions. This inhibitory effect was comparable in influx, and much more potent in efflux to that of 2-aminoethoxydiphenyl borate, a well-known blocker of TRPM7, a channel that plays a major role in cellular Mg(2+) homeostasis. Neither [ATP](i) nor pH(i) correlated with changes in [Mg(2+) ](i) . The results indicate that imipramine suppresses Mg(2+) -permeable channels presumably through a direct effect on the channel domain. This inhibitory effect appears to contribute, at least partially, to the link between antidepressants and the risk of vascular diseases.

Renin-angiotensin system blocker use may be associated with suppression of atrial fibrillation recurrence after pulmonary vein isolation.

INTRODUCTION: An additional approach may be essential to reduce recurrences of atrial fibrillation (AF) after pulmonary vein isolation (PVI). We examined the efficacy of renin-angiotensin system blockers (RAS-B) in suppressing AF recurrences after PVI. METHODS AND RESULTS: We retrospectively studied 264 consecutive patients (195 male, median age: 63 years) who underwent successful PVI of paroxysmal (n = 94) or persistent AF (n = 170). RAS-B treatment was performed in 145 patients (angiotensin-converting enzyme inhibitors; n = 13, angiotensin receptor blockers; n = 129, both; n = 3). Echocardiography was performed before and 3 months after the ablation to examine the occurrence of left atrial structural reverse remodeling (LA-RR). After a median follow-up of 195 (interquartile range: 95-316) days, AF recurred in 51 (19.3%) patients. A Cox regression analysis revealed that AF recurrence was significantly lower in the patients with RAS-B than in those without (hazard ratio [HR] = 0.41 [95% confidence interval (CI): 0.23-0.71], P = 0.002). After a multivariate adjustment for potential confounders, the use of RAS-B (HR = 0.39 [95% CI: 0.19-0.77], P = 0.007) and type of AF (HR = 0.30 [95% CI: 0.13-0.66], P = 0.003) were the independent predictors for AF recurrence during the entire follow-up. Although effect of RAS-B was not significant during the early follow-up (<3 month), it was the only independent predictor during the late follow-up (>3 months) (HR = 0.21 [95% CI: 0.08-0.53], P = 0.001). There were no significant differences in LA-RR occurrence regarding RAS-B medication. The use of RAS-B was an independent predictor of late AF recurrences irrespective of an early LA-RR occurrence. CONCLUSIONS: Treatment with RAS-B significantly reduced the AF recurrence after PVI. This benefit became more prominent 3 months after the PVI.

Heart slice NMR.

Nuclear magnetic resonance (NMR) spectroscopy of the heart is normally carried out using whole heart preparations under coronary perfusion. In such preparations, either radical changes in ionic composition of the perfusate or applications of numerous drugs would affect coronary microcirculation. This report communicates the first (31)P NMR spectroscopy study using a heart slice preparation (left ventricular slices) superfused with extracellular medium. The ratio of phosphocreatine concentration to ATP concentration was approximately 2.1. Also, intracellular pH and Mg(2+) concentration ([Mg(2+)](i)), estimated from the chemical shifts of inorganic phosphate and ATP, were comparable with those under retrograde perfusion. [Mg(2+)](i) was significantly increased by the removal of extracellular Na(+), supporting the essential role of Na(+)-coupled Mg(2+) transport in Mg(2+) homeostasis of the heart. Heart slice preparation could also be used to evaluate the potency of cardiac drugs, regardless of their possible effects on coronary microcirculation.