Norman Qureshi

High incidence of acute sub-clinical circumflex artery ‘injury’ following mitral isthmus ablation

AIMSnMitral isthmus (MI) ablation is technically challenging, requiring long endocardial ablation times and frequently coronary sinus (CS) ablation. The circumflex artery lies in the epicardium in close proximity to the CS and the mitral annulus and may potentially be injured during radiofrequency ablation.nnnMETHODS AND RESULTSnFifty-four patients underwent catheter ablation procedures that included MI ablation for treatment of atrial fibrillation. Irrigated ablation catheters were used with the following settings: endocardial surface (max power: 40/50 W at the annular end; max temperature: 48°C); CS (max power: 25/30 W; max temperature: 48°C). Coronary angiography was performed pre- and post-ablation and analysed by two cardiologists with quantitative coronary angiography. Mitral isthmus block was achieved in 89% of patients (60% required CS ablation). Fifteen patients (28%) had angiographic changes following ablation: eight had mid-circumflex narrowing only, one had circumflex and obtuse marginal (OM) artery narrowing, one had OM narrowing only, and five had distal circumflex occlusion/narrowing. Five patients had significant narrowing (50-84%), which resolved with intracoronary glycerine trinitrate. Fourteen (93%) of the patients with circumflex injury had CS ablation and a longer mean CS ablation time (5.0 ± 3.0 vs. 2.6 ± 3.3 min, P = 0.03). Patients with distal circumflex occlusion had significantly smaller vessel diameter (1.0 ± 0.1 vs. 2.1 ± 0.2 mm, P = 0.03). A shorter distance between the circumflex and the CS was also associated with circumflex injury (3.2 ± 1.9 vs. 5.6 ± 3.2 mm, P = 0.04). There were no electrocardiographic or echocardiographic abnormalities and no angina symptoms during follow-up.nnnCONCLUSIONnAcute sub-clinical circumflex injury following MI ablation is not uncommon. Ablation within the CS, proximity of the circumflex and the CS, and a small distal circumflex were risk factors for injury.

Balloon occlusion of the distal coronary sinus facilitates mitral isthmus ablation

BACKGROUNDnMitral isthmus ablation is challenging. Blood flow in the coronary sinus (CS) may act as a heat sink and reduce the efficacy of radiofrequency ablation.nnnOBJECTIVEnThis study investigates whether balloon occlusion of CS facilitates mitral isthmus ablation.nnnMETHODSnThis single-center, prospective, randomized controlled trial included patients undergoing ablation for atrial fibrillation. After circumferential pulmonary vein isolation and roof line ablation, mitral isthmus ablation was performed during left atrial appendage pacing using an irrigated ablation catheter (endocardium: maximum power: 40/50 W, maximum temperature: 48°C; CS: maximum power: 25/30 W, maximum temperature: 48°C). An air-filled 40 × 10-mm percutaneous transluminal angioplasty balloon (Opta Pro, Cordis Europa, LJ Roden, The Netherlands) was used to occlude the CS on the epicardial aspect of the ablation line. Left coronary and CS angiography were performed before and after the procedure.nnnRESULTSnForty-six patients were studied. The balloon was successfully positioned in the distal CS in 20 of 23 patients (87%). Mitral isthmus block was achieved in 41 of 46 patients (91%). According to intention-to-treat analysis, there was significant reduction in the need for epicardial CS ablation (48% vs. 83%, P = .01) in the CS occlusion group but no difference in acute success rate. Secondary analysis showed reduction in mean total ablation time (9.4 ± 5.5 vs. 13.3 ± 4.6 minutes, P <.02) and mean CS ablation time (1.5 ± 2.8 vs. 3.4 ± 2.7 minutes, P <.05) in patients who had CS occlusion.nnnCONCLUSIONnBalloon occlusion of the CS during mitral isthmus ablation is feasible and safe. It significantly reduces ablation time and the need for CS ablation to achieve mitral isthmus block. The results support the hypothesis that heat sink is one of the obstacles to successful mitral isthmus ablation.

Larger coronary sinus diameter predicts the need for epicardial delivery during mitral isthmus ablation

AIMSnMitral isthmus ablation is technically challenging, often requiring both endocardial and epicardial coronary sinus (CS) ablation. Blood flow in the CS and circumflex artery may act as a heat sink and reduce the efficacy of radiofrequency ablation. This study investigates how the CS and circumflex artery diameters affect mitral isthmus ablation.nnnMETHODS AND RESULTSnThirty-five patients underwent ablation for atrial fibrillation. Irrigated-tip catheters were used during mitral isthmus ablation with the following settings: endocardial surface (maximum power: 40-50 W at the annular end of line; maximum temperature: 48°C); CS (maximum power: 25-30 W; maximum temperature: 48°C). The absence of block after 10 min of endocardial ablation led to CS ablation for up to 5 min. If there was still no block, further ablation was at the discretion of the physician. Coronary angiography and CS venography were performed and analysed with quantitative coronary angiography. Mitral isthmus block was achieved in 31 patients (89%). Twenty-three patients (74%) required CS ablation to achieve block. These patients were found to have significantly larger CS diameters (6.5 ± 1.2 vs. 5.4 ± 0.5 mm, P< 0.02). Coronary sinus diameter >59 mm predicted the need for CS ablation (specificity: 100%; sensitivity: 78%). Coronary sinus diameter correlated significantly with total mitral isthmus ablation time (r = 0.52, P < 0.003) and CS ablation time (r = 0.59, P < 0.0005), whereas circumflex diameter did not.nnnCONCLUSIONnLarger-diameter CS is associated with a need for CS ablation during mitral isthmus ablation. Coronary sinus but not circumflex diameter was significantly correlated with total and CS ablation time, supporting the hypothesis that the CS but not the circumflex artery acts as a heat sink.

Mitral Isthmus Ablation Using Steerable Sheath and High Ablation Power: A Single Center Experience

Case Series of Mitral Isthmus Ablation.u2003Background: Mitral isthmus ablation is challenging. The use of steerable sheath and high ablation power may improve success rate.

Inter- and intravein differences in cardiac output with cardiac resynchronization pacing using a multipolar LV pacing lead.

Quadripolar left ventricular pacing leads permit a variety of pacing configurations from different sites within a coronary vein. There may be advantages to selecting a specific pacing vector. This study examines whether the range of cardiac outputs obtained at cardiac resynchronization therapy (CRT) implantation is greater between different poles within a vein, or greater between two different veins.

Local activation times at the high posterior wall of the left atrium during left atrial appendage pacing predict roof line block with high specificity and sensitivity.

AIMSnEnsuring complete block after left atrial (LA) linear lesions is important as partial block may be pro-arrhythmic. Techniques to confirm roof line block may be time consuming and challenging and have not been well described. This study investigates whether local activation times (LAT) during left atrial appendage (LAA) pacing help in the assessment of roof line block.nnnMETHODS AND RESULTSnForty-five patients underwent ablation for atrial fibrillation (AF) including circumferential pulmonary vein isolation, roof, and mitral isthmus lines. Local activation times were measured at pre-defined points on the posterior wall and high anterior wall during LAA pacing at the following stages: (i) baseline; (ii) incomplete roof line; (iii) roof block; and (iv) roof and mitral isthmus block. Time from pacing at high posterior wall to LAA was also recorded at each stage. Receiver operator curve analyses were performed on different parameters to assess if they could confirm roof line block. There was a stepwise increase in mean high posterior wall LAT: 83 ± 16 ms (baseline); 105 ± 20 ms (incomplete roof block); 133 ± 26 ms (roof block), and 152 ± 35 ms (roof and MI block; one way analysis of variance, P< 0.0001). Increased LA diameter, amiodarone use, and adjunctive complex fractionated atrial electrogram ablation were associated with longer LATs. For patients with persistent AF, LAA to high posterior wall times of >133 ms, high posterior wall to LAA times of >125 ms and double potential >77 ms predict roof line block with high specificity and sensitivity especially if there was also mitral isthmus block.nnnCONCLUSIONnParameters derived from the measurement of LAT of the high posterior and anterior LA wall help guide the assessment of roof line block.

A Pacemaker Magnet Check Alone Is Sufficient for the Majority of Patients Postpacemaker Implant

Patients postpacemaker implant can undergo a full assessment by pacing system programmer (PSP) or a magnet check. The former takes longer, but provides more detailed information; a magnet‐mode assessment is faster, but provides only capture data in an asynchronous pacing mode. A magnet‐mode assessment alone may be sufficient in most cases, and current clinical practice varies considerably.

158 Is it cost effective to use a plugged LV port

Background Many patients receiving ICD implants do not meet criteria for CRT therapy, yet are often felt likely to benefit from CRT in the future. The reasons for this include less severe NYHA class of HF symptoms at the time of implant, narrow QRS, and (progressive) atrio-ventricular conduction delay. Management options include only implanting DDD / VVI devices, and then upgrading to CRT if required; implanting CRT-D devices but without an LV lead, with the LV port “plugged”, such that if an upgrade were to become necessary, only a new LV lead (and implant kit) would be required; and finally, implanting CRT-D devices with LV leads in all patients in the first instance, as has been suggested by the recent Madit-CRT and RAFT studies. It is not clear which of these strategies is superior in terms of the cost-benefit ratio. Purpose This study analyses a retrospective cohort of patients who received CRT-D devices but without LV leads, to examine the cost implications of this approach, and to compare this cost to that of merely implanting a DDD device, or implanting a full CRT-D system initially. Method A retrospective analysis of all patients receiving CRT-ICDs with plugged LV ports between September 2004 and June 2009 at our institution. Patient characteristics, indication for a plugged LV port, subsequent addition of a LV lead and reasons for doing so were taken from patient records. The total cost (surgery and hardware) was compared with the estimated cost of initially implanting single or dual chamber ICDs and upgrading the entire system, and to the cost of implanting full CRT-D systems up front. Results 35 patients (27 male) were identified. Mean (SD) age was 67±8u2005years. 26 had ischaemic heart disease and 9 non-ischaemic dilated cardiomyopathy. All had LV EF<30%. Indications for a plugged LV port were LBBB and NYHA class I or II symptoms in 29 and NYHA class I or II with a narrow QRS but a high chance of becoming pacemaker dependent in 6. During a mean (SD) FU of 40 ±16u2005months, 6 (17%) patients had an LV lead added, all for the development of NYHA III symptoms, at 10, 11, 15, 17, 17 and 21u2005months respectively. Total cost at end of FU period was £ 654u2008000. If all patients had initially been implanted with VVI or DDD ICDs and 6 new CRT systems implanted, the estimated cost would have been £ 598u2008000. If all patients had received full CRT-D the cost would have been £ 665u2008000. Taking into account the time to develop symptoms, it is predicted that an upgrade rate of 26%–31% would be required before using a plugged LV port becomes cost-effective. Furthermore, full CRT-D system implantation is even less cost effective. Conclusion In this series of ICD patients with potential CRT indications but minimal heart failure symptoms, only a small proportion subsequently required biventricular pacing. Using a CRT-ICD with a plugged LV port is not a cost effective strategy (Abstract 158 figure 1).Abstract 158 Figure 1 Per cent freedom from upgrade to LV lead.

138 Catheter ablation of atrial fibrillation whilst taking therapeutic warfarin: a british experience: Abstract 138 Table 1

Introduction Peri-procedural anticoagulation of patients undergoing catheter ablation of atrial fibrillation (AF) reduces thromboembolism risk but with potential haemorrhagic complications. In the UK, warfarin is generally discontinued pre-procedure and low molecular weight heparin (LMWH) used to bridge the sub-therapeutic period. In some institutions around the world ablation is performed with a therapeutic International Normalised Ratio (INR) and problems with LMWH administration are reduced, but the trans-septal puncture is usually performed under intracardiac echo (ICE) guidance. In the UK, cost prevents routine ICE use but we aimed to see if this could still be done safely within our system. Methods Fifty-six consecutive AF ablation patients were studied prospectively (warfarin group). A target INR of 2–3 was used for the procedure. A double trans-septal puncture technique was used. Unfractionated heparin was still used to maintain ACT between 300 and 350. Wide area circumferential ablation was performed along with any other ablation clinically indicated. If the INR was less than two at the time of ablation, LMWH was used afterwards until it was two or more. A group of 56 patients prior (bridging LMWH group) were compared. Endpoints were minor bleeding (haematomas), major bleeding (transfusion requiring), pericardial effusions, and stroke. Results In two patients the INR was >3 so the procedure was delayed. In 11 the INR was <2. In 43 the INR was 2–3 and they were all successfully ablated. The endpoint results are shown in the Abstract 138 table 1. The patient who had a pericardial effusion and tamponade during the procedure had ablation completed after reversal of the heparin and drainage, and warfarin was omitted for 24u2005h only. There were no pseudoaneurysms in the warfarin group and one in the bridging LMWH group. Abstract 138 Table 1 Minor bleeding Major bleeding Pericardial effusion Stroke Warfarin 6 0 1 0 Bridging LMWH 11 0 0 0 In the warfarin group LMWH had to be used for <24 h in the 9/11 patients with an INR <2. In the bridging LMWH group duration of treatment was 3±1 days. Conclusions AF ablation can be performed safely with therapeutic warfarin in the UK, with a low rate of procedure cancellation. Although the number of patients studied was relatively small, there was a lower incidence of minor bleeding with this approach than with bridging LMWH and a low rate of other complications in both groups. This strategy also reduces the need for LMWH after ablation which has both cost and patient comfort implications.