Recurrence after pulmonary vein isolation is associated with low contact force.

OBJECTIVES: Recurrent arrhythmia after pulmonary vein isolation (PVI) by radiofrequency (RF) ablation in patients with atrial fibrillation (AFIB) remains a significant challenge. Using contact force (CF) sensing ablation catheters, we aimed to identify procedure related parameters associated with recurrence after de-novo PVI in patients with AFIB. METHODS: Consecutive patients undergoing a de-novo PVI procedure (n = 120, 63% paroxysmal and 37% persistent AFIB) employing a force-sensing ablation catheter were included. A clinical control including electrocardiogram and 120 hour of Holter-recording at 12-months was performed in all patients. Recurrence was defined as any documented AFIB or atrial flutter more than 30 seconds on Holter-recording after an initial blanking period of three months. RESULTS: Recurrence occurred in 44 patients (37%). Mean CF was lower in patients with recurrent arrhythmia (22.2 ± 9.5 vs. 28.8 ± 9.3 g, p < .001). In multi-variable analyses lower mean CF (OR 0.9 (95% CI 0.8-1.0), p = .03), and higher percentage of ablation time with a CF <10 grams (OR 1.1 (95% CI 1.0-1.1), p = .004) were both associated with recurrence in two distinct models. Dragging during ablation compared with point-by-point ablation technique was associated with recurrence in both models (OR 19.2 (95% CI 2.9-130.0), p = .002, and OR 21.7 (95% CI 2.7-176.2), p = .004). CONCLUSIONS: Low CF and dragging during ablation as compared with point-by-point ablation technique were associated with recurrent arrhythmia in patients with AFIB undergoing de-novo PVI by RF ablation.

Is the knowledge of contact force beneficial in pulmonary vein antrum isolation?

OBJECTIVE: To investigate the effect of the operator knowing the real-time contact force (CF) on the efficacy of pulmonary vein antrum isolation (PVAI). METHODS: Fifty patients with paroxysmal atrial fibrillation (AF) or short lasting persistent AF were randomized to CF guided PVAI (n = 25) or conventional PVAI (n = 25). In the CF guided group, CF between 10 and 40 g was aimed at. Efficacy of PVAI was measured as reduction in AF burden (AFB) and time to AF recurrence detected by implantable cardiac monitor (ICM), inserted three months before PVAI. Blanking period was three months and follow-up 12 months. RESULTS: All pulmonary veins were isolated in the CF guided group and all but one in the conventional group. Mean CF was 25 g in the CF guided group and 24 g in the conventional group (p = 0.75). Compared to pre-ablation, median [IQR] relative reduction in AFB 3-12 months after ablation was 100 [99-100]% in the CF guided group (p < 0.001) and 99.4 [25-100]% in the conventional group (p < 0.001), not different between groups (p = 0.09). Nine patients (36%) had AF recurrence in the CF guided group and 13 (52%) in the conventional group (p = 0.21, log-rank test). CF differed between operators. When adjusted for operator by regression analysis, patients without recurrent AF had lower proportion of ablation time with CF <10 g than recurrent patients (p = 0.034). No complications occurred. CONCLUSIONS: Operator knowledge of real-time CF had no significant effect on AFB reduction or time to AF recurrence. Larger trials should be done to study benefit of real-time CF.

Veno-occlusive unloading of the heart reduces infarct size in experimental ischemia-reperfusion.

Mechanical unloading of the left ventricle reduces infarct size after acute myocardial infarction by reducing cardiac work. Left ventricular veno-occlusive unloading reduces cardiac work and may reduce ischemia and reperfusion injury. In a porcine model of myocardial ischemia-reperfusion injury we randomized 18 pigs to either control or veno-occlusive unloading using a balloon engaged from the femoral vein into the inferior caval vein and inflated at onset of ischemia. Evans blue and 2,3,5-triphenyltetrazolium chloride were used to determine the myocardial area at risk and infarct size, respectively. Pressure-volume loops were recorded to calculate cardiac work, left ventricular (LV) volumes and ejection fraction. Veno-occlusive unloading reduced infarct size compared with controls (Unloading 13.9 ± 8.2% versus Control 22.4 ± 6.6%; p = 0.04). Unloading increased myocardial salvage (54.8 ± 23.4% vs 28.5 ± 14.0%; p = 0.02), while the area at risk was similar (28.4 ± 6.7% vs 27.4 ± 5.8%; p = 0.74). LV ejection fraction was preserved in the unloaded group, while the control group showed a reduced LV ejection fraction. Veno-occlusive unloading reduced myocardial infarct size and preserved LV ejection fraction in an experimental acute ischemia-reperfusion model. This proof-of-concept study demonstrated the potential of veno-occlusive unloading as an adjunctive cardioprotective therapy in patients undergoing revascularization for acute myocardial infarction.

[Initial evaluation and management of paroxysmal supraventricular tachycardia]. / Diagnostik og behandling af paroksystisk supraventrikulær takykardi.

The paroxysmal supraventricular tachycardias (SVT) are commonly encountered arrhythmias and include atrioventricular nodal re-entrant tachycardia, atrioventricular reciprocating tachycardia, and focal atrial tachycardia. These tachycardias share several clinical features as well as similar management strategies. The probable mechanism of paroxysmal SVT can often be diagnosed from the clinical findings and a 12-lead ECG. This review describes the initial evaluation and treatment of patients with paroxysmal SVT, including distinctive features from the most important differential diagnoses.