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074 Reversibility of Left Ventricular Dysfunction Post Atrial Fibrillation Ablation
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arrhythmic medication. Patients maintaining SR were found to have significant structural and substrate differences compared to those reverting to AF. LAV for the group was elevated at a mean of 135.6⫾42.9 mls, and was associated with recurrence (AF recurrence 157.7⫾42.8mls vs. 111.3⫾28.4mls, p⬍0.01). CFAE distribution and type (continuous or discrete) did not differ between groups. Patients with recurrence had a lower CFAE to LA surface area (16.3⫾9.9cm2 vs. 28.5⫾12.3cm2, p⫽0.02), and higher LAV with a significant negative correlation (⫺0.53 (p⫽0.01)). CONCLUSIONS: The proportion of endocardium demonstrating CFAE was significantly less in larger atria, and was associated with recurrence. The reasons for this are not clear but may involve a significant increase in anatomic substrate not able to sustain shorter cycle lengths. Successful outcomes can be achieved in this cohort, however additional strategies to address larger atria - such as linear lesions or ‘slower’ CFAE ablation will be required to improve initial procedure success rates.
073 CARTO BASED PULMONARY VEIN IMPEDANCE ASSESSMENT DURING ATRIAL FIBRILLATION ABLATION (COBRAA) MI Amin, NA Cromie, A Ha, D Arumugam, PG Novak, LD Sterns, RA Leather, AS Tang Victoria, British Columbia
Pulmonary vein (PV) isolation is an effective treatment for PAF. A major complication is PV stenosis and the risk is higher with ablation performed within the PVs rather than the antrum. One approach to avoid ablation within the PVs is impendence monitoring, as impedance is higher inside the PVs than the antrum. A previous study by our group using an impedance-based mapping system (Ensite Velocity, St Jude) showed a significant drop in PV impedance during the procedure. The aim of this study was to evaluate whether these changes were a true phenomenon independent of the mapping system used. METHODS: Patients undergoing PV isolation alone for PAF were included. LA geometry was created using Carto3 (Biosense Webster). For each PV pre-ablation (baseline) impedance measurements were recorded distally (PVdist), midway (PVmid) and in the vein os (PVprox). Reference balls were placed at each site enabling return to the same spot. PVs were isolated in pairs using wide circumferential ablation. Impedance measurements were repeated from the same sites after isolation of the 1st pair of PVs and at the end of the case. RESULTS: 24 patients were included (6 female, average age 59 years). For each of the 16 sites sampled, compared to baseline there was a significant decrease in impedance both after isolation of the 1st pair of veins, as well as at the end of the case (Table). CONCLUSION: During PV isolation using a non-impedance based mapping system there is a significant drop in impedance within the PVs. Therefore using impedance to guide ablation position may lead to inadvertent ablation within the PVs. An awareness of this phenomenon may help avoid PV stenosis. BACKGROUND:
Canadian Journal of Cardiology Volume 28 2012
074 REVERSIBILITY OF LEFT VENTRICULAR DYSFUNCTION POST ATRIAL FIBRILLATION ABLATION A Chin, SM Divakara Menon, GM Nair, CA Morillo Hamilton, Ontario BACKGROUND: Patients with atrial fibrillation (AF) and decreased
left ventricular ejection fraction (LVEF) may have a reversible cardiomyopathy. While poorly-controlled ventricular rates in AF is well-known to cause a tachycardia-induced cardiomyopathy, a previous study has suggested that AF per se (heart rate ⬍ 100bpm) may result in left ventricular (LV) dysfunction. AF ablation results in the restoration of sinus rhythm which may result in improvement in LVEF as it address both the above mechanisms. METHODS: We performed a retrospective review of consecutive patients who underwent an AF ablation procedure at our institution. Patients who had a LVEF⬍50% at the time of the AF ablation and had an improvement in LVEFⱖ5% post AF ablation on a follow-up echocardiogram were included in this study. For each patient, all ECGs and/or 24-hour Holter monitors (average heart rate (HR)) were reviewed up to 6 months prior to the AF ablation to assess the extent of rate control in AF. RESULTS: AF ablation was performed in 551 patients and 20 (3.6%) patients had a LVEF⬍ 50% prior to ablation. LVEF improved in 10 (50%) patients. The mean LVEF increased from 37.5⫾5.7% to 54.3⫾3.4% (P⬍0.001) after ablation. Five patients had paroxysmal and 5 patients had persistent AF. Seven out of 10 patients (70%) were in sinus rhythm on a 3 month 24-hour Holter monitor post ablation. Of the 10 patients, only 3 patients (30%) had a documented tachycardia (⬎100bpm) on ECG or 24-hour Holter monitoring up to 6 months prior to the AF ablation. CONCLUSIONS: A significant proportion of AF patients with a decreased LVEF may have improvement of LVEF after AF ablation. LVEF improvement can be expected in AF patients without a tachycardia prior to AF ablation. Further studies to determine whether AF per se can result in a reversible cardiomyopathy is warranted.
arrhythmic medication. Patients maintaining SR were found to have significant structural and substrate differences compared to those reverting to AF. LAV for the group was elevated at a mean of 135.6⫾42.9 mls, and was associated with recurrence (AF recurrence 157.7⫾42.8mls vs. 111.3⫾28.4mls, p⬍0.01). CFAE distribution and type (continuous or discrete) did not differ between groups. Patients with recurrence had a lower CFAE to LA surface area (16.3⫾9.9cm2 vs. 28.5⫾12.3cm2, p⫽0.02), and higher LAV with a significant negative correlation (⫺0.53 (p⫽0.01)). CONCLUSIONS: The proportion of endocardium demonstrating CFAE was significantly less in larger atria, and was associated with recurrence. The reasons for this are not clear but may involve a significant increase in anatomic substrate not able to sustain shorter cycle lengths. Successful outcomes can be achieved in this cohort, however additional strategies to address larger atria - such as linear lesions or ‘slower’ CFAE ablation will be required to improve initial procedure success rates.
073 CARTO BASED PULMONARY VEIN IMPEDANCE ASSESSMENT DURING ATRIAL FIBRILLATION ABLATION (COBRAA) MI Amin, NA Cromie, A Ha, D Arumugam, PG Novak, LD Sterns, RA Leather, AS Tang Victoria, British Columbia
Pulmonary vein (PV) isolation is an effective treatment for PAF. A major complication is PV stenosis and the risk is higher with ablation performed within the PVs rather than the antrum. One approach to avoid ablation within the PVs is impendence monitoring, as impedance is higher inside the PVs than the antrum. A previous study by our group using an impedance-based mapping system (Ensite Velocity, St Jude) showed a significant drop in PV impedance during the procedure. The aim of this study was to evaluate whether these changes were a true phenomenon independent of the mapping system used. METHODS: Patients undergoing PV isolation alone for PAF were included. LA geometry was created using Carto3 (Biosense Webster). For each PV pre-ablation (baseline) impedance measurements were recorded distally (PVdist), midway (PVmid) and in the vein os (PVprox). Reference balls were placed at each site enabling return to the same spot. PVs were isolated in pairs using wide circumferential ablation. Impedance measurements were repeated from the same sites after isolation of the 1st pair of PVs and at the end of the case. RESULTS: 24 patients were included (6 female, average age 59 years). For each of the 16 sites sampled, compared to baseline there was a significant decrease in impedance both after isolation of the 1st pair of veins, as well as at the end of the case (Table). CONCLUSION: During PV isolation using a non-impedance based mapping system there is a significant drop in impedance within the PVs. Therefore using impedance to guide ablation position may lead to inadvertent ablation within the PVs. An awareness of this phenomenon may help avoid PV stenosis. BACKGROUND:
Canadian Journal of Cardiology Volume 28 2012
074 REVERSIBILITY OF LEFT VENTRICULAR DYSFUNCTION POST ATRIAL FIBRILLATION ABLATION A Chin, SM Divakara Menon, GM Nair, CA Morillo Hamilton, Ontario BACKGROUND: Patients with atrial fibrillation (AF) and decreased
left ventricular ejection fraction (LVEF) may have a reversible cardiomyopathy. While poorly-controlled ventricular rates in AF is well-known to cause a tachycardia-induced cardiomyopathy, a previous study has suggested that AF per se (heart rate ⬍ 100bpm) may result in left ventricular (LV) dysfunction. AF ablation results in the restoration of sinus rhythm which may result in improvement in LVEF as it address both the above mechanisms. METHODS: We performed a retrospective review of consecutive patients who underwent an AF ablation procedure at our institution. Patients who had a LVEF⬍50% at the time of the AF ablation and had an improvement in LVEFⱖ5% post AF ablation on a follow-up echocardiogram were included in this study. For each patient, all ECGs and/or 24-hour Holter monitors (average heart rate (HR)) were reviewed up to 6 months prior to the AF ablation to assess the extent of rate control in AF. RESULTS: AF ablation was performed in 551 patients and 20 (3.6%) patients had a LVEF⬍ 50% prior to ablation. LVEF improved in 10 (50%) patients. The mean LVEF increased from 37.5⫾5.7% to 54.3⫾3.4% (P⬍0.001) after ablation. Five patients had paroxysmal and 5 patients had persistent AF. Seven out of 10 patients (70%) were in sinus rhythm on a 3 month 24-hour Holter monitor post ablation. Of the 10 patients, only 3 patients (30%) had a documented tachycardia (⬎100bpm) on ECG or 24-hour Holter monitoring up to 6 months prior to the AF ablation. CONCLUSIONS: A significant proportion of AF patients with a decreased LVEF may have improvement of LVEF after AF ablation. LVEF improvement can be expected in AF patients without a tachycardia prior to AF ablation. Further studies to determine whether AF per se can result in a reversible cardiomyopathy is warranted.