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ABSTRACT: Right atrial (RA) appendage pacing may prolong atrial conduction time (ACT). This study aimed to investigate if RA appendage pacing can induce intra- and interatrial dyssynchrony and if atrial dysfunction and dyssynchrony can predict atrial high rate episodes (AHREs) in the first year after pacing.
Patients implanted with dual-chamber pacemakers for symptomatic bradycardia were enrolled. Cumulative percentage of RA appendage pacing (Cum%AP) during 1-year follow-up and AHREs were recorded. Full Doppler echocardiography studies were performed before implantation and 1 year after pacing. ACT and peak atrial velocities (Sm-la, Em-la, Am-la) were measured. One hundred ten patients (age 70.5 ± 11 years; 53 males) were recruited and completed 1-year follow-up. ACT of both RA and left atrial (LA) were more prolonged in patients with Cum%AP > 75% than those with <25%. Intra- and interatrial dyssynchrony was more obvious in patients with Cum%AP > 75% (22.3 ± 12.2 milliseconds vs 9.5 ± 6.2 milliseconds; 53.9 ± 29.7 milliseconds vs 19.7 ± 17.3 milliseconds; both P < 0.001). AHREs occurred in 29% of patients. Atrial pump function and interatrial dyssynchrony independently predicted AHREs in multivariate analysis. Receiver operating characteristic curve provided a cutoff value of Am-la <5.3 cm/s, which predicted AHREs with a sensitivity of 71% and a specificity of 75% (area under the curve, 0.822; P < 0.001).
RA appendage pacing causes atrial conduction delay with intra- and interatrial dyssynchrony. Atrial dysfunction and interatrial dyssynchrony are related to AHREs in the first year after pacing.
Journal of Cardiovascular Electrophysiology 11/2011; 23(4):384-90. · 3.06 Impact Factor
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ABSTRACT: Right ventricular apex (RVA) pacing may have deleterious effects on left ventricular (LV) systolic function, but its impact on LV diastolic function has not been explored.
Ninety-seven patients with sinus node dysfunction and ejection fraction (EF) ≥ 50% with permanent RVA pacing were randomly programmed to V-sense and V-pace modes and examined by echocardiography. Tissue Doppler imaging was employed to assess myocardial systolic velocity (S') and early diastolic velocity (E') at the mitral annulus. Systolic dyssynchrony was assessed using 12 LV segmental model (Ts-SD). Switching from V-sense to V-pace resulted in the worsening of both diastolic and systolic functions as shown by the decreased EF, reduced mean E' and S' velocities, as well as increase in LV volume and Ts-SD (all P< 0.001). Reduction of mean E' and S' of ≥ 1 cm/s occurred in 35 (36%) and 45 (46%) patients, respectively. In pre-defined subgroup analysis, only patients with pre-existing LV diastolic dysfunction had a significant reduction of mean E' and S' (both P< 0.001) even after age adjustment. Multivariate logistic regression analysis showed that independent factors for the reduction of mean E' ≥ 1 cm/s or mean S' ≥ 1 cm/s at V-pace were pre-existing LV diastolic dysfunction [odds ratio (OR): 4.735, P= 0.007 for E'; OR: 3.307, P= 0.022 for S'] and systolic dyssynchrony at V-pace (OR: 5.459, P= 0.007 for E'; OR: 2.725, P= 0.035 for S').
In patients with preserved EF, RVA pacing is associated with the deterioration of both LV diastolic and systolic functions, which is particularly obvious in those with pre-existing LV diastolic dysfunction and V-pace-induced systolic dyssynchrony.
European Heart Journal 04/2011; 32(15):1891-9. · 10.48 Impact Factor
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ABSTRACT: To evaluate a novel atrial lead designed to reduce far-field sensing.
Sixty-three patients with standard pacing indications were randomized to receive an OptiSense 1699T (St Jude Medical, USA) or conventional pacing lead in the right atrium. Post-implant follow-up was conducted for all patients at 90 days and for a subset at 360 days. Standard electrical parameters were measured. Thresholds of sensing were determined for far-field ventricular signals. The number of inappropriate mode switches was determined from the stored intracardiac electrogram (IEGM). At 90 days, an IEGM Holter recorded 24 h of IEGM. With atrial sensitivity programmed at 0.3 mV, no far-field sensing occurred in the OptiSense group, but it did occur in 20% and 30% of the control group at 90 and 360 days, respectively. Inappropriate mode switching was observed in 4% of the OptiSense group in contrast to 23% of the control group. The IEGM Holter found no far-field sensing in the OptiSense group, but did find 83 023 far-field events from 22% of control patients. The standard electrical parameters of the OptiSense leads were acceptable.
The OptiSense lead reduced ventricular far-field sensing in the atrium while maintaining satisfactory pacing and sensing performance, resulting in less inappropriate mode switch.
Europace 05/2009; 11(5):618-24. · 1.98 Impact Factor
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ABSTRACT: We sought to determine whether early assessment of left ventricular (LV) dyssynchrony by tissue Doppler imaging may predict progressive ventricular enlargement and cardiac dysfunction after acute myocardial infarction (MI).
Forty-seven patients (mean age 59.9 +/- 11.6 years) with normal QRS duration underwent tissue Doppler imaging and contrast-enhanced cardiac magnetic resonance imaging (Ce-MRI) at days 2 to 6, 3 months, and at 1 year after the index MI. Systolic dyssynchrony index (Ts-SD) was calculated from 12 LV segments, and infarct size (IS) by Ce-MRI.
The remodeling group (n = 16) (defined as an increase in end-systolic volume > or =10% between 1 year and baseline) had greater initial IS (27.2 +/- 9.6 vs 13.7 +/- 4.1%, P < .001) and Ts-SD (50.9 +/- 12.8 vs 33.6 +/- 7.7 milliseconds, P < .001) than nonremodeling group (n = 31). At 1 year, the remodeling group had progressive increase in Ts-SD and decrease in LV ejection fraction (57.3 +/- 18.5 and 36.0 +/- 7.6%, respectively; both P < .05 vs baseline). Both Ts-SD (odds ratio 1.19 [1.07-1.32], P = .001) and IS (odds ratio 1.65 [1.19-2.29], P = .003) were shown to be independent predictors of progressive LV remodeling. A cutoff value of Ts-SD > or =45 milliseconds predicted LV remodeling at 1 year (sensitivity 90.5%, specificity 90.9%, Area-under-curve 0.907) (P = .0005).
Left ventricular systolic dyssynchrony is a newly identified predictor of chronic LV remodeling after acute MI, which is independent and incremental to conventional assessment and IS as measured by Ce-MRI.
American heart journal 01/2009; 156(6):1124-32. · 4.65 Impact Factor
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ABSTRACT: The optimal left ventricular (LV) pacing site for cardiac resynchronization therapy (CRT) is unclear. The current study aims to explore the clinical significance of LV lead concordance to delayed contraction segment in CRT.
Concordant LV lead position was defined as the lead tip located by fluoroscopy at or immediately adjacent to the LV segment with latest contraction determined by tissue Doppler imaging. Echocardiographic and clinical outcomes among 101 consecutive patients with or without concordant LV lead positions were compared. There was no significant difference in changes in LV volumes and clinical parameters between patients with concordant (n = 46) or nonconcordant (n = 55) LV lead positions at 3 and 6 months. In multivariate analysis, the baseline asynchrony index (beta= 1.092, 95% CI: 1.050-1.114; P < 0.001), but not LV lead concordance, was the only independent predictor of LV reverse remodeling. By Cox regression analysis, ischemic etiology, and LV reverse remodeling, but not LV lead concordance, were independent predictors of mortality (beta= 2.475, 95% CI: 1.183-5.178; P = 0.016, and beta= 0.272, 95% CI: 0.130-0.567; P < 0.001, respectively), cardiovascular hospitalization (beta= 1.551, 95% CI: 1.032-2.333; P = 0.035, and beta= 0.460, 95% CI: 0.298-0.708; P < 0.001, respectively), and heart failure hospitalization (beta= 0.486, 95% CI: 0.320-0.738; P = 0.001 for LV reverse remodeling).
LV lead concordance to the delayed contraction segment may not be a major determining factor for favorable echocardiographic and clinical outcomes after CRT.
Journal of Cardiovascular Electrophysiology 12/2008; 20(5):530-5. · 3.06 Impact Factor
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ABSTRACT: Introduction: The optimal left ventricular (LV) pacing site for cardiac resynchronization therapy (CRT) is unclear. The current study aims to explore the clinical significance of LV lead concordance to delayed contraction segment in CRT.Methods and Results: Concordant LV lead position was defined as the lead tip located by fluoroscopy at or immediately adjacent to the LV segment with latest contraction determined by tissue Doppler imaging. Echocardiographic and clinical outcomes among 101 consecutive patients with or without concordant LV lead positions were compared. There was no significant difference in changes in LV volumes and clinical parameters between patients with concordant (n = 46) or nonconcordant (n = 55) LV lead positions at 3 and 6 months. In multivariate analysis, the baseline asynchrony index (β= 1.092, 95% CI: 1.050–1.114; P < 0.001), but not LV lead concordance, was the only independent predictor of LV reverse remodeling. By Cox regression analysis, ischemic etiology, and LV reverse remodeling, but not LV lead concordance, were independent predictors of mortality (β= 2.475, 95% CI: 1.183–5.178; P = 0.016, and β= 0.272, 95% CI: 0.130–0.567; P < 0.001, respectively), cardiovascular hospitalization (β= 1.551, 95% CI: 1.032–2.333; P = 0.035, and β= 0.460, 95% CI: 0.298–0.708; P < 0.001, respectively), and heart failure hospitalization (β= 0.486, 95% CI: 0.320–0.738; P = 0.001 for LV reverse remodeling).Conclusion: LV lead concordance to the delayed contraction segment may not be a major determining factor for favorable echocardiographic and clinical outcomes after CRT.
Journal of Cardiovascular Electrophysiology 11/2008; 20(5):530 - 535. · 3.06 Impact Factor
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ABSTRACT: Left atrial (LA) volume is a predictor of cardiovascular events in patients with heart failure. Improvement of LA function and reverse remodeling was observed after cardiac resynchronization therapy (CRT).
The purpose of this study was to explore the clinical significance of improvement in LA function after CRT.
Echocardiographic studies were performed before and 3 months after CRT in 97 patients (72 men and 25 women; age 63.8 +/- 13.3 years) with standard CRT indication but no history of atrial fibrillation (AF). LA active emptying fraction based on the change in volumes (LAV-EF) were calculated, and significant improvement in LA function (LA responder) was defined as a relative increase >/=50% from baseline LAV-EF. The primary end-points were newly developed AF detected by ECG or device and all-cause mortality.
After 1,200 +/- 705 days of follow-up, LA responders (n = 47 [48.5%]) had a significantly lower incidence of AF (12.8% vs 40%, P = .002) and mortality (17% vs 44%, P = .004) than did LA nonresponders. In Cox proportional hazard analysis, LA responders was the only independent predictor of lower risk of new-onset AF (hazard ratio 0.22, 95% confidence interval 0.08-0.61, P = .003), whereas both LA responders (hazard ratio 0.22, 95% confidence interval 0.09-0.53, P <.001) and left ventricular reverse remodeling (>10% reduction in left ventricular end-systolic volume at 3 months; hazard ratio 0.96, 95% confidence interval 0.93-0.99, P = .03) were independent predictors of lower risk of death after CRT.
Improvement of LA function after CRT was associated with a lower incidence of AF and mortality in AF naïve patients with severe heart failure.
Heart rhythm: the official journal of the Heart Rhythm Society 06/2008; 5(6):780-6. · 4.56 Impact Factor
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ABSTRACT: Renal insufficiency is prevalent in patients with heart failure and indicates poor prognosis. We examine (i) the relationship between left ventricular (LV) reverse remodeling (RR) and renal function and (ii) the prognostic value of renal function in patients receiving cardiac resynchronization therapy (CRT).
The relationship between LV-RR, defined as a 10% reduction in LV end-systolic volume, and renal function was examined in 85 consecutive patients receiving CRT. Echocardiographic assessment and renal function tests were performed before and 3 months after CRT. All-cause mortality and the composite of mortality or heart failure hospitalization between those with preserved or deteriorated renal function at 3 months were assessed by Kaplan Meier analysis.
There was a slight improvement in glomerular filtration rate (GFR) in those with LV-RR (n=44; 51.7+/-20.4 vs. 54.2+/-19.1 ml/min/1.73 m2; p=0.024) while a significant deterioration (n=41; 61.9+/-17 vs. 48.8+/-13.0 ml/min/1.73 m2; p<0.001) was observed in those without LV-RR. The change (Delta) in GFR was significantly correlated with DeltaLV end-systolic/diastolic volumes and DeltaLV ejection fraction. After follow up of 856.4+/-576.8 days, patients with preserved renal function had significant lower all-cause mortality (log rank chi2=4.82, p=0.029) and the composite endpoints (log rank chi2=5.04, p=0.025).
Preservation of renal function was observed in patients with systolic heart failure and renal insufficiency responding to CRT and provided prognostic information. A rapid decline in renal function after CRT was associated with worse clinical outcomes.
International journal of cardiology 11/2007; 122(1):10-6. · 7.08 Impact Factor
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ABSTRACT: To explore the left ventricular (LV) electrical activation pattern in heart failure (HF) and its implication to cardiac resynchronization therapy (CRT).
Observational study at the University Teaching Hospital.
23 optimally treated patients with HF with New York Heart Association class III, QRS duration >120 ms and LV ejection fraction <35%.
The LV endocardial activation pattern and total activation time (Tat) was determined by non-contact mapping and the LV mechanical dys-synchrony was determined by standard deviation (Ts-SD) and maximal difference (Ts-diff) of time to peak systolic contraction (Ts) among 12 LV segments using tissue Doppler imaging before receiving CRT.
Correlation between electrical and mechanical dys-synchrony; volumetric responder to CRT at 3 months; HF hospitalisation or death by Kaplan-Meier analysis.
Homogenous (type I, n = 8) and presence of conduction block (type II, n = 15) patterns were identified. Significant correlation between Tat and Ts-SD/Ts-diff was noted only in type II (r = 0.73/0.56, p = 0.002/0.03). Ts-SD and Ts-diff in type II were significantly longer than type I. 12 patients in type II and 2 in type I were CRT responders (p = 0.01). After 487 (447) days, patients with type II pattern had significantly lower risk of HF hospitalisation or death than those with type I (log rank chi(2) = 5.25; p = 0.02).
Patients with type II LV endocardial activation pattern had a more favourable echocardiographic and clinical response to CRT than those with type I pattern.
Heart (British Cardiac Society) 05/2007; 93(4):432-7. · 4.22 Impact Factor
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PLoS Medicine 05/2007; 4(4):e111. · 16.27 Impact Factor
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ABSTRACT: Proven medical therapy is under-prescribed in heart failure (HF) for various reasons. Cardiac resynchronization therapy (CRT) is of proven value in selected patients with HF; however, the degree of benefit in those without the optimal therapy is not clear.
This is a retrospective study comparing the effect of CRT in 30 patients without optimal combination therapy (group 1; 10 (33%) without ACEi or equivalent and 25 (83%) without beta-blockers) to an age, sex, ejection fraction (EF) and New York Heart Association (NYHA) class matched control but with the combination (group 2; n=30) at baseline. All patients were in NYHA class III or IV with EF < or = 35% and QRS interval > or = 120 ms. Echocardiographic examination and N-terminal pro-brain natriuretic peptide (NT pro-BNP) levels before and 3 months after CRT were compared between the two groups. The composite endpoints of HF hospitalization or death during follow-up were compared by Kaplan-Meier analysis.
There were significantly less improvement in EF (+4.0+/-2.5% vs +10.1+/-3.2%; p<0.05) and degree of reverse remodeling in group 1 after 3 months. Patients in group 1 had significantly higher level of NT pro-BNP levels at 3 months (2221+/-2001 pg/mL vs 1038+/-905 pg/mL; p<0.001) and higher rates of HF hospitalization or death (53.3% vs 23.3%; Log rank chi2 5.52; p=0.019).
Patients receiving CRT but without optimal medical therapy were associated with less echocardiographic and clinical improvement. Optimal medical therapy, if tolerated, before CRT is necessary.
International journal of cardiology 03/2007; 115(2):214-9. · 7.08 Impact Factor
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ABSTRACT: We sought to investigate the effect of cardiac resynchronization therapy (CRT) on disease progression in patients with moderate left ventricular (LV) systolic dysfunction.
This is a prospective study to explore the effect of CRT in 15 optimally treated patients (age: 66.1 +/- 12.8 years; male = 13) with New York Heart Association (NYHA) class III, LV ejection fraction >35% and <45% and QRS duration >120 msec. Echocardiographic examination and standard heart failure assessment was performed before and 3 months after CRT implantation. The magnitude of echocardiographic remodeling measurements was compared with 30 age, sex, NYHA class, and heart failure etiology matched patients with conventional CRT indication. There were significant reductions in LV end-systolic (86.2 +/- 24.1 to 69.7 +/- 22.2 mL, P < 0.01)/end-diastolic (135.5 +/- 36.8 to 120.5 +/- 34.6 mL, P < 0.01) volumes, improvement in LV ejection fraction (39.1 +/- 2.2 to 44.2 +/- 5.5%, P = 0.01), and NYHA class (3.0 +/- 0.0 to 2.07 +/- 0.46, P < 0.001). There was no difference in changes in LV volumes, ejection fraction, NYHA class, and exercise capacity before and after CRT between the study and conventional groups except for greater improvement in the quality of life score in the conventional group.
In this prospective study, significant LV reverse remodeling by CRT in those with a wide QRS complex and moderate LV systolic dysfunction was observed. Further studies to explore the benefit of CRT in patients with less severe heart failure are recommended.
Journal of Cardiovascular Electrophysiology 01/2007; 17(12):1288-92. · 3.06 Impact Factor
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ABSTRACT: Background: We sought to investigate the effect of cardiac resynchronization therapy (CRT) on disease progression in patients with moderate left ventricular (LV) systolic dysfunction.Methods and Results: This is a prospective study to explore the effect of CRT in 15 optimally treated patients (age: 66.1 ± 12.8 years; male = 13) with New York Heart Association (NYHA) class III, LV ejection fraction >35% and <45% and QRS duration >120 msec. Echocardiographic examination and standard heart failure assessment was performed before and 3 months after CRT implantation. The magnitude of echocardiographic remodeling measurements was compared with 30 age, sex, NYHA class, and heart failure etiology matched patients with conventional CRT indication. There were significant reductions in LV end-systolic (86.2 ± 24.1 to 69.7 ± 22.2 mL, P < 0.01)/end-diastolic (135.5 ± 36.8 to 120.5 ± 34.6 mL, P < 0.01) volumes, improvement in LV ejection fraction (39.1 ± 2.2 to 44.2 ± 5.5%, P = 0.01), and NYHA class (3.0 ± 0.0 to 2.07 ± 0.46, P < 0.001). There was no difference in changes in LV volumes, ejection fraction, NYHA class, and exercise capacity before and after CRT between the study and conventional groups except for greater improvement in the quality of life score in the conventional group.Conclusion: In this prospective study, significant LV reverse remodeling by CRT in those with a wide QRS complex and moderate LV systolic dysfunction was observed. Further studies to explore the benefit of CRT in patients with less severe heart failure are recommended.
Journal of Cardiovascular Electrophysiology 11/2006; 17(12):1288 - 1292. · 3.06 Impact Factor
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ABSTRACT: Left ventricular lead dislodgement remained a problem for cardiac resynchronization therapy and is one of the major causes of repeated procedures. We report a 30-year-old lady with possible left ventricular lead dislodgement related to hyperpnea respiration.
Pacing and Clinical Electrophysiology 05/2006; 29(4):425-6. · 1.35 Impact Factor
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ABSTRACT: A nonexcitatory, nonpropagating atrial extrastimulus delivered in the refractory period of the preceding cycle can prolong the atrial effective refractory period (AERP) and prevent the induction of atrial fibrillation by another AE introduced in the vulnerable period. Whether the effect of this nonexcitatory stimulation (NE) is confined only to its application site is unknown.
Sixteen consecutive patients were recruited into the study and 2 patients were excluded because of development of more sustained atrial fibrillation. NE was commenced by introduction of a 2.0 msec, 20-mA impulse at 50 msec after the preceding captured pacing impulse. AERP of right atrial septum, a distant site to NE application, was determined at baseline and after 5 minutes of steady pacing at six different protocols: protocol 1, 2, and 3 were conventional pacing at high right atrium, distal coronary sinus, and biatrial sites, respectively, and protocol 4, 5, and 6 were conventional pacing together with NE applied to the same sites as protocol 1, 2, and 3. Biatrial NE (protocol 6 with median AERP = 212.5 msec) significantly prolonged AERP compared with baseline (median AERP = 202.5 msec and P < 0.05), conventional pacing (protocol 1, 2, and 3 with median AERP = 205.0 msec, 205.0 msec, and 205.0 msec, respectively, and all P < 0.05), and single-site NE (protocol 4 and 5 with median AERP = 207.5 msec and 207.5 msec, respectively, and both P < 0.05).
Biatrial NE resulted in AERP prolongation even at sites distant to NE application. The study result suggests that by adding NE to multi-sites pacing for atrial fibrillation prevention may have additional benefit.
Journal of Cardiovascular Electrophysiology 08/2005; 16(8):853-7. · 3.06 Impact Factor
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Jeffrey W H Fung,
C C Szeto,
Wilson W M Chan,
Leo C C Kum,
Anna K Y Chan,
John T H Wong,
Eugene B Wu,
Gabriel W K Yip, Joseph Y S Chan,
Cheuk M Yu,
Kam S Woo,
John E Sanderson
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ABSTRACT: The effect of N-acetylcysteine (NAC) to prevent contrast nephropathy (CN) in patients with moderate to severe renal insufficiency undergoing coronary angiography or interventions is not clear.
This is a prospective, open-label, randomized, controlled trial. Ninety-one consecutive patients with a serum creatinine level of 1.69 to 4.52 mg/dL (149 to 400 micromol/L) undergoing coronary procedures were recruited and randomly assigned to administration of either oral NAC, 400 mg, thrice daily the day before and day of the contrast procedure (the NAC group) or no drug (the control group). Serum creatinine was measured before and 48 hours after contrast exposure. The primary end point of this study was the development of CN, defined as an increase in serum creatinine concentration of 0.5 mg/dL or greater (> or =44 micromol/L) or a reduction in estimated glomerular filtration rate (GFR) of 25% or greater of the baseline value 48 hours after the procedure.
There were no significant differences between the 2 groups (46 patients, NAC group; 45 patients, control group) in baseline characteristics or mean volume of contrast agent administered. Six patients (13.3%) in the control group and 8 patients (17.4%) in the NAC group developed CN (P = 0.8). Serum creatinine levels increased from 2.27 +/- 0.54 to 2.45 +/- 0.65 mg/dL (201 +/- 48 to 217 +/- 57 micromol/L; P = 0.003) in the NAC group and 2.37 +/- 0.61 to 2.40 +/- 0.70 mg/dL (210 +/- 54 to 212 +/- 62 micromol/L; P = 0.6) in the control group. The increase in serum creatinine levels between the 2 groups had no difference (P = 0.7). Estimated GFR decreased from 30.3 +/- 8.4 to 28.1 +/- 8.4 mL/min (P = 0.01) in the NAC group and 28.4 +/- 8.6 to 27.5 +/- 8.8 mL/min (P = 0.3) in the control group. The decline in estimated GFR between the 2 groups had no difference (P = 0.7).
In the current study, oral NAC had no effect on the prevention of CN in patents with moderate to severe renal insufficiency undergoing coronary angiography or interventions. However, the sample size of our present study is small. Our findings highlight the need for a large-scale, randomized, controlled trial to determine the exact beneficial effect of NAC.
American Journal of Kidney Diseases 05/2004; 43(5):801-8. · 5.43 Impact Factor
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ABSTRACT: Conventional activation or pacemapping is effective in guiding ablation of ventricular tachyarrhythmia originating from right ventricular outflow tract (RVOT). However, in selected patients with hemodynamically unstable or nonsustained tachycardia, noncontact mapping may be an effective alternative method to guide ablation in RVOT. Five patients with symptomatic hypotension during ventricular tachycardia (VT) or nonsustained tachyarrhythmia originating from the RVOT had radiofrequency ablation guided by noncontact mapping. All patients had a history of syncope and the tachyarrhythmias were refractory to antiarrhythmic therapy. Four patients had spontaneous sustained VT of a cycle length from 250 to 300 ms and one had symptomatic ventricular ectopic beats. Two patients were diagnosed to have arrhythmogenic right ventricular cardiomyopathy (ARVC). Sustained VT with hypotension was induced in two patients and nonsustained VT in three patients. Isopotential color maps were used to locate the earliest activation site of the tachyarrhythmia in RVOT. Three patients had tachyarrhythmia exit sites at the septal region and two at lateral region of RVOT. Low voltage area and diastolic activity were detected in the two patients with ARVC. Radiofrequency ablation guided by noncontact mapping was performed during sinus rhythm in all patients. The number of ablation attempts ranged from 1 to 14. After follow-up for 12 +/- 5.8 months, there was no recurrence of tachyarrhythmia and syncope in all five patients. Noncontact mapping is a safe and effective alternative method to guide ablation of hemodynamically unstable or nonsustained ventricular arrhythmia originating from RVOT.
Pacing and Clinical Electrophysiology 09/2003; 26(8):1699-705. · 1.35 Impact Factor
