Biomedical subjects

Jin-Long Huang

Publications and source records attributed to Jin-Long Huang.

At least 19 recordsLinked to original sources

PubMed2006

Immediate and late outcomes of patients undergoing transseptal left-sided heart catheterization for symptomatic valvular and arrhythmic diseases.

BACKGROUND: The transseptal technique has been widely used for diagnostic and therapeutic left-sided heart catheterization. However, its differential immediate and late outcomes among patients with various valvular and arrhythmic diseases are not yet determined. METHODS: Beginning from 1993, all patients undergoing transseptal procedures were screened and categorized into diagnosis, arrhythmia, and valvuloplasty groups according to the purposes of the catheterization. Incidences of transseptum-related acute major events (cardiac perforation, embolic stroke, and bradyarrhythmia during the procedure) and late complications (residual atrial septal defect [ASD], embolic stroke, bradyarrhythmia, and death up to 18 months) were analyzed and compared between groups. RESULTS: From January 1993 to May 2003, a total of 176 patients underwent 184 transseptal procedures for diagnosis of valvular heart diseases (n = 8), catheter ablation of arrhythmogenic foci (n = 29), and mitral valvuloplasty (n = 147). The immediate outcome was similar among the 3 groups, with an overall acute complication incidence of 3.8%. At follow-up, the incidences of bradyarrhythmia, embolic stroke, and death were not different among the 3 groups. Patients undergoing valvuloplasty had a significantly higher prevalence of residual ASD, especially for those with more severe mitral stenosis and less valvuloplasty success. However, presence of ASD did not impose disadvantage over the 1.5-year prognosis. CONCLUSION: Transseptal left-sided heart catheterization can be safely applied to patients with different categories of cardiac diseases with comparably good immediate and late outcomes. Although patients undergoing percutaneous valvuloplasty have a higher chance of permanent ASD creation, their prognosis is not influenced.

Adolescent↗

PubMed2006

The mechanisms of an increased dominant frequency in the left atrial posterior wall during atrial fibrillation in acute atrial dilatation.

BACKGROUND: Previous studies have shown that the highest dominant frequency (DF) is located in the left atrium (LA) during atrial fibrillation (AF) in pacing-induced AF. However, there have been few studies on the mechanisms of the increased DF of AF during acute atrial dilatation. The purpose of this study was to investigate the mechanisms of the increased maximal DF (max DF) in pacing-induced AF during acute atrial dilatation. METHODS: In eight Langendorff-perfused canine hearts (26 +/- 2 kg), noncontact balloon catheters were placed into the right atrium (RA) and LA, respectively. AF was induced by extrastimulation pre- and postdilatation in the atrium (0 and 15 cm H(2)O, respectively). Fast Fourier transformation analysis was performed to analyze the max DF and harmonic index (HI) from the bi-atrial unipolar virtual electrograms during AF. The fibrillation cycle lengths were obtained from different atrial sites. The number of wavefronts was analyzed during AF. The frequency of regional splitting was defined as the number of wavefront splits per second in different atrial regions during AF. The percentage of the low-voltage zones (<0.5 mV) was defined as the ratio of the area of the low-voltage zones to the total atrial surface area. RESULTS: The DF was measured during AF. The shortest fibrillation cycle length was located in the LA posterior wall and became shorter during acute atrial dilatation. The max DF was located in the LA posterior wall and increased during acute atrial dilatation (7.1 +/- 0.8 vs 8.8 +/- 2.1, P = 0.02). The max DF of the LA correlated with the wavefront number (r = 0.797, P < 0.001 predilatation; r = 0.860, P < 0.001 postdilatation). The splitting of wavefronts facilitated the formation of new wavefronts. During acute atrial dilatation, the frequency of regional splitting was closely correlated with the percentage of the low-voltage zones (r = 0.876, P < 0.001). Furthermore, the LA posterior wall had a higher percentage of the low-voltage zones than the other sites. CONCLUSION: In acute atrial dilatation, the percentage of the low-voltage zones increased, especially in the LA posterior wall, which correlated with the regional splitting of the AF wavefronts. The increase in the splitting facilitated the formation of new wavefronts and resulted in a higher max DF during acute atrial dilatation.

Animals↗

PubMed2006

High-resolution mapping around the eustachian ridge during typical atrial flutter.

BACKGROUND: Although the reentrant circuit of typical atrial flutter (AFL) has been well recognized, the activation around the Eustachian ridge (ER) has not been fully characterized. The aim of this study was to delineate the activation patterns around the ER during typical AFL using high-resolution noncontact mapping. METHODS: Fifty-three patients (M/F = 43/10, 62 +/- 14 years) with typical AFL were included. The high-resolution mapping of the right atrium using a noncontact mapping system during AFL and pacing from the coronary sinus (CS) was performed to evaluate the conduction through the ER. RESULTS: Three types of activation patterns around the ER could be classified according to the ER conduction during AFL and CS pacing. Type I (n = 21, M/F = 16/5, 61 +/- 13 years) exhibited conduction block at the ER during AFL and CS pacing. The local unipolar electrograms at the ER exhibited long double potentials (DPs) (109 +/- 12 ms, range 77-153 ms) during AFL and CS pacing (84 +/- 18 ms, range 48-129 ms). Type II (n = 8, M/F = 7/1, 61 +/- 15 years) exhibited conduction block at the ER during AFL, but conduction through the ER during CS pacing. The unipolar electrograms exhibited long DPs (119 +/- 12 ms, range 97-141 ms) at the ER during the tachycardia and an rS pattern during CS pacing. Type III (n = 24, M/F = 20/4, 61 +/- 16 years) exhibited an activation wavefront that passed along the ER, with the sinus venosa as the posterior barrier during AFL. During CS pacing, all cases exhibited conduction through the ER with an rS pattern. CONCLUSIONS: This study is the first to demonstrate the three patterns of activation along the ER during AFL and CS pacing. This finding suggested that the ER is an anatomic and functional barrier during typical AFL.

Aged↗

PubMed2005

Predictors of non-pulmonary vein ectopic beats initiating paroxysmal atrial fibrillation: implication for catheter ablation.

OBJECTIVES: The purpose of this study was to investigate the predictor of non-pulmonary vein (PV) ectopic beats initiating paroxysmal atrial fibrillation (PAF). BACKGROUND: Non-PV ectopic beats can initiate PAF in some patients and play an important role in the recurrence of PAF after PV isolation. Information on the predictors of non-PV ectopic beats initiating PAF is unknown. METHODS: This study included 293 patients (215 men and 78 women, age 60 +/- 14 years) with clinically documented drug-refractory PAF. Of the 94 patients with non-PV ectopic beats initiating PAF, 38 (40%) patients had superior vena cava (SVC) ectopic beats and 32 (34%) had left atrial posterior free wall (LAPFW) ectopic beats. RESULTS: In a univariate analysis, only female gender was related to the presence of non-PV (p = 0.016) and SVC ectopic beats (p = 0.012). Right atrial enlargement (p = 0.005) and left atrial enlargement (p < 0.001) were related to the presence of LAPFW ectopic beats. In a multivariate analysis, female gender (p = 0.043; odds ratio 2.00, 95% confidence interval [CI] 1.02 to 3.92) and left atrial enlargement (p = 0.007; odds ratio 2.34, 95% CI 1.27 to 4.32) could predict the presence of non-PV ectopic beats. Subgroup analysis showed that female gender could predict the presence of SVC ectopic beats (p = 0.039; odds ratio 2.14, 95% CI 1.04 to 4.43). In contrast, left atrial enlargement could predict the presence of LAPFW ectopic beats (p = 0.002; odds ratio 3.89, 95% CI 1.62 to 9.38). CONCLUSIONS: The location of non-PV ectopic beats initiating PAF can be predicted by both gender and left atrial enlargement.

Atrial Fibrillation↗

PubMed2005

Electrophysiological characteristics and catheter ablation in patients with paroxysmal right atrial fibrillation.

BACKGROUND: Catheter ablation of the right atrial (RA) substrate has had variable efficacy in curing paroxysmal atrial fibrillation (PAF), suggesting that RA substrate ablation can play an important role in the treatment of atrial fibrillation (AF) in some patients. The aim of this study was to investigate the electrophysiological characteristics and ablation strategy and its results in a specific group of patients with paroxysmal RA-AF. METHODS AND RESULTS: The study population consisted of 13 patients (8 men; age, 64+/-15 years) with drug-refractory (2+/-1 drugs), frequent episodes of PAF. Provocation maneuvers did not reveal any ectopic beat-initiating AF. However, rapid atrial pacing easily induced AF. Activation mapping during sinus rhythm, atrial pacing, and AF was visualized by using a noncontact mapping system. Noncontact mapping revealed RA reentry (6 patients with single-loop circuits and 7 with double-loop circuits) with conduction through channels between lines of block, crista terminalis gaps, and the cavotricuspid isthmus, which could be identified during sinus rhythm and atrial pacing, resulting in fibrillatory conduction in other parts of the RA. The consistency of wavefront activation was confirmed by frequency analysis from equally distributed mapping sites in the RA. Short lines of ablation lesions were aimed at the conduction channels between the lines of block, crista terminalis gaps, and the cavotricuspid isthmus, resulting in bidirectional block. AF was eliminated in 11 (85%) of 13 patients, and those 11 patients with acute success were free of AF without any antiarrhythmic drugs during the long-term follow-up period (16+/-6 months). CONCLUSIONS: RA ablation still can cure selected patients with PAF. Linear ablation of the RA substrate guided by the electrophysiological characteristics of RA-AF is an effective approach for treating this specific group of patients with AF.

Aged↗

PubMed2005

A new electrocardiographic algorithm to differentiate upper loop re-entry from reverse typical atrial flutter.

OBJECTIVES: This study was performed to differentiate upper loop re-entry (ULR) from reverse typical atrial flutter (AFL). BACKGROUND: Right atrial ULR and reverse typical AFL have different mechanisms and ablation strategies, but similar electrocardiographic characteristics. METHODS: This study included 26 patients with reverse typical AFL and 20 patients with ULR. The noncontact mapping system (EnSite-3000, Endocardial Solutions, St. Paul, Minnesota) was used to confirm diagnosis and guide successful radiofrequency ablation. Flutter wave polarity and amplitude in the 12-lead surface electrocardiogram were determined by two independent electrophysiologists. RESULTS: The flutter wave polarity in leads I and aVL was significantly different between the reverse typical AFL and ULR groups (p < or = 0.001). Voltage measurement revealed significant differences between reverse typical AFL and ULR in leads I, II, aVR, aVF, V1, and V2 (p < 0.001). A new diagnostic algorithm based on negative or isoelectric/flat flutter wave polarity and amplitude < or =0.07 mV in lead I was useful for diagnosis of ULR, with an accuracy of 90% to 97%, a sensitivity of 82% to 100%, and a specificity of 95%. CONCLUSIONS: Polarity and voltage measurement of flutter wave in lead I can differentiate reverse typical AFL from ULR.

Adult↗

PubMed2005

Characterization of right atrial substrate in patients with supraventricular tachyarrhythmias.

UNLABELLED: Right atrial substrate of supraventricular tachyarrhythmias. BACKGROUND: Voltage mapping has been used to detect diseased myocardium. However, accurate determination of the local atrial voltage at the same site, and simultaneous recordings from multiple mapping sites were limited. The purpose of this study was to investigate the right atrial (RA) substrate properties in patients with supraventricular tachyarrhythmias (SVT). METHODS AND RESULTS: Forty patients (aged 55+/-20 years) undergoing noncontact mapping and ablation of SVT constituted the study population. There were eight patients with atrioventricular node reentrant tachycardia (AVNRT), eight patients with focal atrial tachycardia (AT), 14 patients with atrial flutter (AFL), and 10 patients with atrial fibrillation (AF). The mean peak negative voltage (PNV) was analyzed in virtual unipolar electrograms, which were obtained from 256 equally distributed RA endocardial sites during sinus rhythm (SR), atrial pacing, and tachycardia. The mean PNV of global RA during SR (-1.34+/-0.22 vs. -0.90+/-0.40 vs. -1.00+/-0.36 vs. -0.85+/-0.35 mV, P=0.04), atrial pacing at cycle lengths of 500 ms (-1.30+/-0.29 vs. -0.70+/-0.35 vs. -0.76+/-0.25 vs. -0.64+/-0.26 mV, P=0.02), and 300 ms (-1.54+/-0.47 vs. -0.94+/-0.21 vs. -0.75+/-0.27 vs. -0.57+/-0.22 mV, P<0.01) were significantly greater in patients with AVNRT compared to AT, AFL, and AF. Furthermore, the mean PNV decreased during atrial pacing with shorter pacing cycle length was demonstrated only in patients with AFL and AF. CONCLUSION: Negative unipolar voltage analysis of global RA showed different RA substrate characteristics during various SVT. The substrate property of activation and cycle length-dependent voltage reduction may be related to the development of AFL and AF.

Atrial Fibrillation↗

PubMed2005

Catheter ablation of atrial fibrillation versus atrioventricular junction ablation plus pacing therapy for elderly patients with medically refractory paroxysmal atrial fibrillation.

BACKGROUND: Catheter ablation of atrial fibrillation (AF) has become another nonpharmacologic therapeutic option for medically refractory paroxysmal AF. Whether this method is better than atrioventricular (AV) junction ablation plus pacing therapy is unknown. The purpose of this study was to compare the very long-term (longer than 4 years) clinical outcomes of the 2 methods in elderly patients (>65 years old) with medically refractory paroxysmal AF. METHODS: From January 1995 to December 2001, 71 elderly patients with medically refractory paroxysmal AF were included; group 1 included 32 patients with successful AV junction ablation plus pacing therapy and group 2, 37 patients with successful catheter ablation of AF. RESULTS: After a mean follow-up of more than 52 months, the AF was better controlled in the group 1 patients than group 2 (100% vs 81%, P = 0.013), however, they had a significantly higher incidence of persistent AF (69% vs 8%, P < 0.001) and heart failure (53% vs 24%, P = 0.001). Furthermore, the incidence of ischemic stroke and cardiac death was similar between the 2 groups. Compared with the preablation values, a significant increase in the NYHA functional class (1.7 +/- 0.9 vs 1.4 +/- 0.7, P = 0.01) and significant decrease in the left ventricular ejection fraction (44 +/- 8% vs 51 +/- 10%, P = 0.01) were noted in the group 1 patients, but not in the group 2 patients. CONCLUSIONS: Although AV junction ablation plus pacing therapy better controlled the AF in elderly patients with medically refractory paroxysmal AF, that method was associated with a higher incidence of persistent AF and heart failure than catheter ablation of AF in the very long-term follow-up.

Aged↗

PubMed2005

Atropine-induced HRV alteration is not amended by electroacupuncture on Zusanli.

Acupuncture is known to influence autonomic nervous activity. Acupuncture on Zusanli points has been shown to enhance the regularity of gastric myoelectrical activity and accelerate gastric emptying, partly through the vagal pathway, in dogs. The aim of this study was to evaluate whether atropine-induced autonomic nervous alteration, measured by heart rate variability (HRV), could be amended by electroacupuncture on Zusanli points. HRV measurements were recorded in 15 healthy volunteers before, during and after electroacupuncture. Each subject was studied for three sessions in a randomized sequence, which included electroacupuncture on the Zusanli (St 36) points with or without premedication of atropine and placebo stimulation on a non-acupoint. The analysis of low frequency (LF), high frequency (HF) and LF/HF ratios were compared between different sessions. Serum levels of gastrin, motilin and pancreatic polypeptide (PP) levels were also measured. There was an increase in the LF/HF ratio (indicating increased sympathetic activity) during the post-acupuncture period with 2 Hz of electrical stimulation on the Zusanli acupoints. When IV atropine was used immediately before the electroacupuncture, there was a decrease in the LF power and HF power during the acupuncture and post-acupuncture periods. In addition, there was a significant increase in the LF/HF ratio during the acupuncture and post-acupuncture periods. There was a significant decrease in serum PP in the post-acupuncture period after premedication with IV atropine. In conclusion, atropine-induced HRV change might be mediated via the vagal pathway. However, atropine-induced HRV alteration is not amended by electroacupuncture on Zusanli points.

Adult↗

PubMed2004

Characteristics of virtual unipolar electrograms for detecting isthmus block during radiofrequency ablation of typical atrial flutter.

OBJECTIVES: The purpose of this study was to investigate the characteristics of the second component of local virtual unipolar electrograms recorded at the ablation line during coronary sinus (CS) pacing after radiofrequency ablation (RFA) of the cavotricuspid isthmus (CTI) for typical atrial flutter (AFL). BACKGROUND: Radiofrequency ablation of the CTI can produce local double potentials at the ablation line. The second component of unipolar electrograms represents the approaching wavefront in the right atrium opposite the pacing site. We hypothesized that the morphologic characteristics of the second component of double potentials would be useful in detecting complete CTI block. METHODS: Radiofrequency ablation of the CTI was performed in 52 patients (males = 37, females = 15, 62 +/- 12 years) with typical AFL. The noncontact mapping system (Ensite 3000, Endocardial Solutions, St. Paul, Minnesota) was used to guide RFA. Virtual unipolar electrograms along the ablation line during CS pacing after RFA were analyzed. Complete or incomplete CTI block was confirmed by the activation sequence on the halo catheter and noncontact mapping. RESULTS: Three groups were classified after ablation. Group I (n = 37) had complete bidirectional CTI block. During CS pacing, the second component of unipolar electrograms showed an R or Rs pattern. Group II (n = 12) had incomplete CTI block. The second component of unipolar electrograms showed an rS pattern. Group III (n = 3) had complete CTI block with transcristal conduction. The second component of unipolar electrograms showed an rSR pattern. CONCLUSIONS: A predominant R-wave pattern in the second component of unipolar double potentials at the ablation line indicates complete CTI block, even in the presence of transcristal conduction.

Action Potentials↗

PubMed2004

Functional characterization of the crista terminalis in patients with atrial flutter: implications for radiofrequency ablation.

OBJECTIVES: The aim of the study was to investigate the conduction properties and anisotropy of the crista terminalis (CT) in patients with atrial flutter (AFL) using non-contact mapping. BACKGROUND: The CT is a posterior barrier during typical AFL. However, the CT has transverse conduction capabilities in patients with upper loop re-entry (ULR). METHODS: Twenty-two patients (16 males, 63 +/- 15 years) with typical AFL and ULR were included. Non-contact mapping of the right atrium during AFL and pacing from coronary sinus (CS) and low anterolateral right atrium (LARA) was performed to evaluate transverse conduction across the CT. During ULR, the longitudinal (CV(L)) and transverse (CV(T)) conduction velocity along and across the CT were measured. The width of the CT conduction gap was evaluated to guide radiofrequency ablation (RFA). RESULTS: No transverse CT gap conduction was found during typical AFL. Transverse CT gap conduction was found in three patients during CS pacing and in three patients during LARA pacing. During ULR, CV(L) was greater than CV(T) (1.28 +/- 0.43 vs. 0.73 +/- 0.30 m/s, p < 0.001). The CV(L)/CV(T) ratio was 1.95 +/- 0.77, which was inversely related to the CT gap width (15.7 +/- 6.8 mm) (p < 0.001). The RFA of the CT gap was successful in 18 patients. Four patients had recurrence of arrhythmias during the follow-up of 11 +/- 3 months. CONCLUSIONS: Most of the CT conduction gaps were functional and only appeared during ULR. The width of the CT gap was inversely related to the anisotropic ratio of the CT. The RFA of the CT gap was effective in eliminating ULR.

Aged↗

PubMed2004

Predictors of early and late recurrence of atrial fibrillation after catheter ablation of paroxysmal atrial fibrillation.

INTRODUCTION: The outcome of patients with early recurrence of atrial fibrillation (AF) (within one month) after ablation procedure is controversial. Furthermore, the predictors of early and late (up to mean follow-up 30 months) recurrence of AF are not investigated in depth. AIMS OF THE STUDY: The aim of the present study was to investigate the predictors of early and late recurrence of AF after catheter ablation of arrhythmogenic foci initiating AF in patients with paroxysmal AF. METHODS AND RESULTS: The study included 207 patients (155 men; mean age 62 +/- 13 years) who received catheter ablation of paroxysmal AF. Eighty-one (39%) patients had early recurrence of AF. Five clinical variables were related to the early recurrence of AF: (1) old age (>/=65 years) ( P = 0.004); (2) presence of associated cardiovascular disease ( P = 0.01); (3) presence of multiple AF foci ( P = 0.004); (4) presence of AF foci from left atrial free wall ( P = 0.039); (5) left atrial enlargement ( P = 0.038). Multivariate analysis demonstrated that presence of multiple AF foci could predict early recurrence of AF ( P = 0.013; ratio = 2.24; 95% CI 1.18 to 4.25). During the follow-up period (30 +/- 11 months), 70 (34%) patients had late recurrence of AF, and two clinical variables were related to the late recurrence of AF: (1) presence of early recurrence of AF ( P = 0.025); (2) presence of multiple AF foci ( P = 0.034). Multivariate analysis found that presence of early recurrence of AF could predict late recurrence of AF ( P = 0.046; hazard ratio = 1.62; 95% CI 1.01 to 2.59). Late recurrence of AF happened in 35 (43%) of the 81 patients with early recurrence of AF, and in 35 (28%) of the 126 patients without early recurrence of AF. CONCLUSIONS: Early AF recurrence could predict late AF recurrence.

Age Factors↗

PubMed2004

High-resolution mapping around the crista terminalis during typical atrial flutter: new insights into mechanisms.

INTRODUCTION: The aim of this study was to delineate activation patterns around the crista terminalis (CT) using high-resolution noncontact mapping. METHODS AND RESULTS: Twenty-six patients with typical atrial flutter (20 counterclockwise and 6 clockwise) were enrolled in the study. A noncontact mapping system was used to map atrial flutter. There were three activation patterns around the line(s) of block. Type I (n = 6) showed activation around a single complete line of block located in the CT. Type II (n = 17) showed activation around a single incomplete line of block with a conduction gap in the CT. Type III (n = 3) showed activation around double lines of block, one located in the CT and the other located in the sinus venosa region. Simultaneous activation around the tricuspid annulus and through the CT gap could result in double loop reentry (n = 12). After successful ablation of the cavotricuspid isthmus (CTI) in 24 patients, upper loop reentry was still induced in 12 patients with double loop reentry. Subsequent ablation of the CT gap was performed successfully in these 12 patients, and no arrhythmia was inducible thereafter. During the follow-up period of 8.4 +/- 4.1 months, there was no recurrence of atrial flutter in any patient. CONCLUSION: During typical atrial flutter, the CT might be an incomplete barrier. Simultaneous conduction through the CTI and CT gap could result in double loop reentry. Radiofrequency ablation of the CTI and CT gap was effective in eliminating this arrhythmia.

Adult↗

PubMed2004

Mechanism of adenosine-induced termination of focal atrial tachycardia.

INTRODUCTION: Adenosine can terminate most focal atrial tachycardias (ATs). However, information about the termination mechanism is limited. This study investigated the effects and mechanism of adenosine on terminating focal AT using a three-dimensional noncontact mapping system. METHODS AND RESULTS: The study consisted of 7 patients (4 men and 3 women; age 44 +/- 29 years) with focal AT. Cycle length variation and atrial activation pattern at baseline and just before AT termination by adenosine (3-12 mg) were analyzed. Noncontact mapping demonstrated focal AT propagated from the origin (O) with preferential conduction and spread away from the breakout sites to the whole atrium. Compared to baseline AT, termination episodes revealed higher mean beat-to-beat variation of AT cycle length (11.7 +/- 11.7 msec vs 4.7 +/- 4.5 msec, P < 0.001) and standard deviation of normalized AT cycle length (0.033 +/- 0.014 vs 0.011 +/- 0.005, P < 0.001). In termination episodes, adenosine significantly decreased the peak negative voltage of AT-O (-27.2 +/- 15.3%, P < 0.01), preferential conduction (proximal: -32.1 +/- 18.7, mid: -28.4 +/- 22.8, distal portion: -29.6 +/- 21.4%, P < 0.01), and breakout (-31.4 +/- 12.5%, P < 0.01). However, adenosine did not affect voltage in nontermination episodes. Adenosine shifted the locations of AT-O in 5 of 10 AT episodes with termination. Mean number of shifting AT-O was 2.4 +/- 1.5 (range 1-4), with maximum shifting distance of 15.0 +/- 3.1 (range 10-19) mm. Focal activation at AT-O simply disappeared in all termination episodes and therefore was not due to conduction block within preferential conduction or breakout site. Catheter ablation lesions covered 50% of total shifting origins, without late recurrence. CONCLUSION: Adenosine-induced AT termination was associated with significantly decreased electrogram voltage, shifting AT-O locations, and disappearance of focal activation.

Adenosine↗

PubMed2004

Electrophysiological mechanisms and catheter ablation of complex atrial arrhythmias from crista terminalis:.

Paroxysmal atrial fibrillation (PAF) can be initiated by ectopic activation from the crista terminalis. The crista terminalis conduction gap is also a critical isthmus in atrial reentrant arrhythmias like upper and lower loop reentry. The aim of this study was to investigate the mechanism and results of catheter ablation for complex atrial arrhythmias originating from the crista terminalis using the noncontact mapping system (NCM). The study population consisted of six patients (5 men, 1 woman; 70 +/- 9 years) with drug refractory PAF and typical/atypical atrial flutter. NCM identified the earliest ectopic activation originating from the crista terminalis in these six patients. The reentry circuit of atypical atrial flutter propagated around the upper crista terminalis in five patients, and lower crista terminalis in one patient. The reentry circuit of atypical atrial flutter and the initial reentry circuit of AF conducted through the crista terminalis gap in all patients. Radiofrequency applications were delivered on the sites of ectopy, which initiated AF. Substrate modification was also performed over the crista terminalis gap (six patients) and cavotricuspid isthmus (three patients) responsible for the reentry. During a mean follow-up of 9 +/- 5 months (range 5-18 months), five patients were free of AF without antiarrhythmic drugs, and one patient did not have AF or atrial flutter using propafenone. NCM demonstrated the mechanism of crista terminalis ectopy-initiating AF and associated typical/atypical atrial flutter. Catheter ablation of crista terminalis ectopy and substrate for the reentry guided by NCM successfully eliminated these atrial arrhythmias.

Aged↗

PubMed2003

Focal atrial tachycardia: new insight from noncontact mapping and catheter ablation.

BACKGROUND: This study investigated the electrophysiologic characteristics, atrial activation pattern, and effects of radiofrequency (RF) catheter ablation guided by noncontact mapping system in patients with focal atrial tachycardia (AT). METHODS AND RESULTS: In 13 patients with 14 focal ATs, noncontact mapping system was used to map and guide ablation of AT. AT origins were in the crista terminalis (n=8), right atrial (RA) free wall (n=3), Koch triangle (n=1), anterior portion of RA-inferior vena cava junction (n=1), and superior portion of tricuspid annulus (n=1); breakout sites were in the crista terminalis (n=5), RA free wall (n=5), middle cavotricuspid isthmus (n=2), and RA-superior vena cava junction (n=2). ATs arose from the focal origins (11 ATs inside or at the border of low-voltage zone), with preferential conduction, breakout, and spread to the whole atrium. After applications of RF energy on the earliest activation site or the proximal portion of preferential conduction from AT origin, 13 ATs were eliminated without complication. During the follow-up period (8+/-5 months), 11 (91.7%) of the 12 patients with successful ablation were free of focal ATs. CONCLUSIONS: Focal AT originates from a small area and spreads out to the whole atrium through a preferential conduction. Application of RF energy guided by noncontact mapping system was effective and safe in eliminating focal AT.

Adenosine↗

PubMed2003

Catheter ablation of paroxysmal atrial fibrillation initiated by non-pulmonary vein ectopy.

BACKGROUND: Most of the ectopic beats initiating paroxysmal atrial fibrillation (PAF) originate from the pulmonary vein (PV). However, only limited data are available on PAF originating from the non-PV areas. METHODS AND RESULTS: Two hundred forty patients with a total of 358 ectopic foci initiating PAF were included. Sixty-eight (28%) patients had AF initiated by ectopic beats (73 foci, 20%) from the non-PV areas, including the left atrial posterior free wall (28, 38.3%), superior vena cava (27, 37.0%), crista terminalis (10, 3.7%), ligament of Marshall (6, 8.2%), coronary sinus ostium (1, 1.4%), and interatrial septum (1, 1.4%). Catheter ablation eliminated AF with acute success rates of 63%, 96%, 100%, 50%, 100%, and 0% in left atrial posterior free wall, superior vena cava, crista terminalis, ligament of Marshall, coronary sinus ostium, and interatrial septum, respectively. During a follow-up period of 22+/-11 months, 43 patients (63.2%) were free of antiarrhythmic drugs without AF recurrence. CONCLUSIONS: Ectopic beats initiating PAF can originate from the non-PV areas, and catheter ablation of the non-PV ectopy has a moderate efficacy in treatment of PAF.

Adult↗

PubMed2003

Effect of atrial dilatation on electrophysiologic properties and inducibility of atrial fibrillation.

INTRODUCTION: Atrial dilatation may play an important role in the occurrence of atrial fibrillation (AF) in clinical situations. However, the electrophysiologic characteristics of dilated atria are still unclear. METHODS AND RESULTS: In 18 isolated Langendorff-perfused canine hearts (14.6 +/- 2.2 kg), we measured atrial effective refractory periods (ERPs) at four different sites, conduction velocity and percentage of slow conduction on the right atrium (using a high-density electrode plaque), and assessed the inducibility of AF at the baseline (0 cm H(2)O) and high (15 cm H(2)O) atrial pressure. The atrial ERPs did not change significantly, but the dispersion of ERP increased significantly (40 +/- 18 vs 25 +/- 9 vs ms, p = 0.01) during high atrial pressure. The percentage of slow conduction (< 25 cm/s) over the mapping area, and the inducibility of AF increased during high atrial pressure (23.7 +/- 10.2 % vs 32.1 +/- 12.5 %, p = 0.02). The AF inducibility significantly correlated with the ERP dispersion (R = 0.75, p < 0.001) and maximal percentage of slow conduction (R = 0.88, p < 0.001). Furthermore, ERPs were significantly shorter in the induced AF group than those without induced AF (68 +/- 17 vs 84 +/- 16 ms, P < 0.05). CONCLUSIONS: The increased inhomogenity in atrial electrophysiological properties during atrial dilatation contributed to the inducibility of AF.

Animals↗