RESUMO
AIMS: Signal averaged electrocardiography is a noninvasive method to evaluate the presence of the potentials that are generated by tissues, activated later than their usual timing in the cardiac cycle. The purpose of this study was to demonstrate the correlation of data obtained via signal averaged electrocardiography and left ventricular dyssynchrony. METHODS: We included the patients with advanced systolic left ventricular dysfunction (ejection fraction = 35%) and intraventricular conduction delay. All patients underwent surface 12-lead electrocardiography, signal averaged ECG, and tissue Doppler echocardiography. RESULTS: The study included 72 patients with mean age of 56.45+/-13.59 years. Mean QRS duration was 0.14 +/- 0.02 sec; 63.9% of patients had left bundle branch block. Linear regression demonstrated significant correlations between filtered QRS duration and interventricular mechanical delay (P<0.000, Y= 0.41X-24.76), root mean square 40 and peak velocity difference (P: 0.001, Y=-0.39X+109.72), root mean square 40 and Ts-SD-12 (P:0.026, Y=-o.26X+40.08), low amplitude signals duration and peak velocity difference (P<0.000, Y=0.44X+67.3) and finally low amplitude signals duration and Ts-SD-12 (P:0.31, Y=0.26X+28.23) as well. Area under the curve in ROC of filtered QRS duration was significant for the detection of interventricular mechanical delay. Areas under the curves in ROC of low amplitude signal duration and root mean square 40 were significant for the detection of peak velocity difference. CONCLUSIONS: Signal averaged electrocardiography can have a role in predicting the amount of ventricular dyssynchrony. The duration of low amplitude signals and root mean square 40 have significant linear relations to some indices of intraventricular dyssynchrony.
RESUMO
BACKGROUND: Emergence of junctional rhythm (JR) during radiofrequency (RF) current delivery directed at the periatrioventricular nodal region has been shown to be a marker of success in atrioventricular nodal reentrant tachycardia (AVNRT). Whereas the characteristics of JR during RF ablation of slow pathway have already been studied, the electrophysiologic features of different patterns of JR are yet to be evaluated. The aim of this study was to investigate in detail the characteristics of the JR that develops during the RF ablation of the slow pathway. MATERIALS AND RESULTS: The study population consisted of 95 patients: 56 women and 33 men (mean age, 47.2 +/- 16.3 years) who underwent slow pathway ablation because of AVNRT. A combined anatomical and electrogram mapping approach was used, and AVNRT was successfully eliminated in all patients. This study identified 7 patterns for JR during the RF ablation of slow pathway: junction-junction-junction, sinus-junction-sinus, intermittent burst, sparse, no junction, sinus-junction-junction, and sinus-junction-block . The characteristics of JR, such as mean cycle length and total number, were gathered. The incidence of JR was significantly higher during effective applications of RF energy than during ineffective applications (P = .001). The mean number of junctional ectopy was 19.6 +/- 19. The total number of junctional ectopy was significantly higher during effective applications of RF energy than during ineffective applications (24.6 +/- 18.8 vs 8.4 +/- 13.2; P < .001). We found a significant difference between the effective and ineffective applications of RF energy in the mean cycle length of the junctional ectopy (464.6 +/- 167.5 vs 263.4 +/- 250.2; P < .01). The patterns of JR were compared between effective and ineffective applications. We managed to show a significant correlation between patterns of JR and successful ablation (P = .01). Logistic regression analysis revealed that the presence of sinus-junction-sinus, sinus-junction-junction, and sinus-junction-block patterns of JR was a predictor of a successful RF ablation (confidence interval [CI], 1.67-15.92 [P < .004]; CI, 1.02-85.62 [P = .048]; and CI, 1.06-32.02 [P = .042], respectively). CONCLUSION: This study confirms that JR is often present during successful slow pathway ablation. The pattern of JR is useful as indicator of success.
Assuntos
Ablação por Cateter/estatística & dados numéricos , Eletrocardiografia/estatística & dados numéricos , Taquicardia por Reentrada no Nó Atrioventricular/diagnóstico , Taquicardia por Reentrada no Nó Atrioventricular/cirurgia , Taquicardia Ectópica de Junção/diagnóstico , Taquicardia Ectópica de Junção/prevenção & controle , Comorbidade , Feminino , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Prognóstico , Taquicardia por Reentrada no Nó Atrioventricular/epidemiologia , Taquicardia Ectópica de Junção/epidemiologia , Resultado do TratamentoRESUMO
BACKGROUND: Approximately 30% of all accessory pathways (APs) are located in the septal area, and understanding the electrocardiographic and electrophysiologic of these APs is crucial for safe and effective ablation of these pathways. OBJECTIVE: In this study, the electrocardiographic and electrophysiologic characteristics of anteroseptal, midseptal, and posteroseptal APs were investigated in detail to elucidate unique electrical properties of APs in each location. METHODS: From April 2002 to October 2006, a total of 120 patients with a septal AP-mediated tachycardia were enrolled in the study. A detailed examination including electrocardiographic analysis and electrophysiologic study was performed in all patients. RESULTS: A total of 120 patients, including 98 patients with posteroseptal APs, 14 patients with anteroseptal APs, and 8 patients with midseptal APs, were studied. The anteroseptal APs could be differentiated from the midseptal APs by the 2 or more positive delta waves in inferior leads, whereas there is significant overlap in electrocardiographic features of midseptal and posteroseptal APs. The mean tachycardia cycle length was significantly shorter in patients with midseptal AP compared with those with anteroseptal and posteroseptal APs (284 +/- 49 ms vs 342 +/- 46 ms vs 350 +/- 68 ms, P = .03). The AH interval during tachycardia was also shorter in patients with midseptal APs (149 +/- 16 ms vs 200 +/- 51 ms vs 168 +/- 48 ms, P = .04). The patients with posteroseptal AP had a significantly higher incidence of atrial fibrillation (35%) than those with either midseptal (12%) or anteroseptal (14%) APs (P = .04). The patients with posteroseptal APs also had a significantly shorter antegrade effective refractory period of the AP (276 +/- 54 ms) than those with either midseptal (313 +/- 71 ms) or anteroseptal (325 +/- 61) APs (P = .036). CONCLUSION: Electrocardiographic analysis is a reliable method for differentiation of the anteroseptal from the midseptal APs, whereas the same is not true for the midseptal and posteroseptal APs. Midseptal APs were characterized by faster orthodromic tachycardia, whereas posteroseptal APs had a higher inducibility of atrial fibrillation.