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Background: Although several prognostic factors of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) have been investigated, the accurate prediction of AF recurrence remains difficult. We propose an electrocardiogram (ECG) index, the P-wave force (PWF), which is the product of the amplitude of the negative terminal phase of the P wave in the V1 electrode and the filtered P-wave duration, obtained by a signal-averaged P-wave analysis. This study was conducted to evaluate the impact of the PWF on the recurrence of AF after PVI., Methods: We retrospectively evaluated 79 paroxysmal AF patients (64 ± 9 years, 56 males) who underwent PVI by cryoballoon ablation. Standard 12-lead ECG and a P-wave signal-averaged electrocardiogram (SAECG) were recorded the day before and 1 month after the PVI procedure., Results: During the mean follow-up of 10.2 months, AF recurred in 11 (14%) patients. The PWF 1 month after ablation was significantly higher in the recurrence group compared to that in the nonrecurrence group (8.8 ± 3.1 mVms vs 6.5 ± 2.9 mVms, P = 0.017). The patients with a PWF value ≥9.3 mVms had a significantly greater risk of recurrence after the ablation compared to the patients with a PWF value <9.3 mVms (log-rank test, P < 0.001)., Conclusion: Higher PWF after cryoballoon ablation was associated with poor prognosis during follow-up. The PWF may be a useful and noninvasive marker to predict the recurrence of AF., (© 2016 Wiley Periodicals, Inc.)

Background: The left atrial appendage (LAA) is one of the major sources of focal atrial tachycardias (ATs)., Objective: The purpose of this study was to investigate the detailed electrophysiologic characteristics and catheter ablation of focal ATs originating from the LAA., Methods: The study population consisted of 47 consecutive patients with 50 focal ATs originating from the left atrium (LA): LAA in 13, left pulmonary veins (PVs) in 14, right PVs in 12, and mitral annulus in 11. Programmed electrical stimulation and pharmacologic testing were performed to examine the mechanism of LAA AT. Left atriography was performed prior to radiofrequency ablation to identify the focus in the LAA., Results: The mechanism of LAA AT was automaticity in 11 and triggered activity in 2. The 13 LAA foci were located mainly at the LAA base: 11 on the medial side and 2 on the lateral side. Atrial activation sequences within the distal coronary sinus were helpful in differentiating these LAA foci. The criterion of a negative P wave in leads I and aVL indicating an LAA AT focus was associated with sensitivity of 92.3%, specificity 97.3%, positive predictive value 92.3%, and negative predictive value 97.3%. No complications occurred in any of the 13 patients. All 13 patients were free of atrial arrhythmias without any antiarrhythmic drugs during follow-up of 8 +/- 3 years., Conclusion: LAA ATs have typical electrophysiologic and electrocardiographic characteristics that are helpful in guiding radiofrequency catheter ablation.

Background: The physiological mechanism of the increase in the electrocardiographic (ECG) R-wave voltage after revascularization in patients with acute myocardial infarction (MI) needs to be elucidated., Methods and Results: One hundred and thirty-eight MI patients (83: anterior MI, 45: inferior MI, 10: lateral MI) underwent ECG and echocardiography in both the acute and subacute phases after emergency revascularization, as well as a resting thallium-201/iodine-123 15-p-iodophenyl-3-(R,S)-methyl pentadecanoic acid myocardial scintigraphy in the acute phase. The total sum of the R-wave voltage (SigmaR) was calculated over multiple leads on ECG for each infarcted lesion. Scintigraphic defect on each tracer was expressed as the percentage (%) defect of the total left ventricular (LV) myocardium. The % defect-discordance on both images in the acute phase and the % increase in SigmaR and the absolute increase in LV ejection fraction from the acute to the subacute phase (DeltaEF) were also calculated. The SigmaR in the subacute phase was significantly greater than that in the acute phase (p<0.0001). The % increase in SigmaR significantly correlated with the DeltaEF (r=0.57, p<0.0001). The % increase in SigmaR also correlated with the % defect-discordance (r=0.68, p<0.0001)., Conclusions: The increase in the ECG R-wave voltage reflects not only the improvement in myocardial perfusion but also the presence of salvaged myocardium after revascularization in acute MI patients.

Introduction: The right pulmonary veins (RPVs) and posterior wall of the right atrium (PRA) are anatomically located adjacent to each other. The aim of this study was to demonstrate the electrophysiologic characteristics of atrial tachycardia (AT) originating from the PRA or RPVs., Methods and Results: A total of 26 consecutive patients with AT originating from the RPVs or PRA underwent detailed atrial endocardial mapping and successful radiofrequency catheter ablation. Eight foci were found in the PRA and 18 foci in the RPVs. Analysis of P wave configuration showed that lead V1 was the most helpful in distinguishing the AT foci between these two sites. In all cases, double potential (DP) configurations were recorded from several electrodes of a multielectrode catheter placed in the PRA, and the first DP component (FP) was the earliest potential recorded from the right atrium during the tachycardia. The amplitude of the FP was higher than that of the second DP component (SP) for AT foci originating in the PRA, whereas the reverse occurred for those in the RPV. The activation sequence of the FP was from superior to inferior for the AT foci in the superior RPV, whereas the reverse occurred for the AT foci in the inferior RPV., Conclusion: P wave configuration in lead V1 is helpful in distinguishing AT foci between those originating in the PRA and RPVs. The DPs obtained from the PRA can be useful in predicting whether AT foci originate from the PRA or RPVs.

This article aims to clarify the clinical significance of changes in electrocardiographic (ECG) R-wave voltage on chest leads from 1 to 4 weeks in patients with acute anterior myocardial infarction (MI) in combination with echocardiographic findings and dual scintigraphic findings. Seventy-one patients with acute anterior MI who underwent emergency revascularization were subjected to ECG and echocardiography, at both 1 and 4 weeks, and to thallium-201 (TI) and iodine-123-beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP) single-photon emission computed tomography (SPECT) about 1 week after the onset of MI. The total sum of ECG R-wave voltage on each chest lead was calculated. The mean defect ratio on TI and that on BMIPP derived from circumferential profile curve analysis were calculated. The percentage defect-discordant ratio of both SPECT images [(%) discordance on TI/BMIPP] was obtained. The percentage increase ratio of ECG R-wave voltage on chest leads [(%) increase of R wave] and the increase of left ventricular ejection fraction (DeltaEF) from 1 to 4 weeks were obtained. There were significant correlations between the (%) increase of R wave and the DeltaEF as well as between the (%) increase of R wave and the (%) discordance on TI/BMIPP (r =.63, P <.001; r =.74, P <.001). The reversibility of ECG R-wave voltage was related to cardiac functional improvement in addition to the discordance on the 2 images. Monitoring of changes in ECG R-wave voltage on chest leads is useful to detect the presence of myocardial viability and to evaluate functional evolution in patients with acute anterior MI.

Aims and objectives: The present study investigated whether morning or afternoon activity is more effective at increasing the high‐frequency (HF) index, a parasympathetic index, in patients with cardiovascular risk factors. Background: A decreased HF index, a heart rate variability (HRV) parameter, is a well‐established marker of poor cardiovascular prognosis. Because blood pressure and sympathetic tone are higher in the morning, physical activity and exercise in the afternoon has been recommended for patients with cardiovascular diseases. However, there have been no reports concerning the superior effects of afternoon exercise on parasympathetic activity and sleep. Design: This observational study was a post hoc comparison. Methods: Patients' physical activity was measured for 1 month to determine their habits. Patients' HF index was measured by 24‐h Holter electrocardiography. The study enrolled 56 patients. Each patient's morning step count (before lunch) and afternoon step count (between lunch and dinner) were compared. We adhered to the STROBE guidelines in the present study. Results: Thirty‐one patients took more steps in the morning, and 25 patients took more steps in the afternoon. The present study showed that those who took more steps in the afternoon had a significantly higher HF index during the first hour after sleep onset and during sleep than those who took more steps in the morning (p =.003,.047). Conclusions: The present study showed that those who took more steps in the afternoon had a significantly higher HF index during the first hour after sleep onset and a higher HF index during sleep than those who took more steps in the morning. Relevance to clinical practice: Exercise in the afternoon may improve the prognosis in patients with cardiovascular disease by not only preventing excessive blood pressure, afterload, and sympathetic tone but also positively influencing the parasympathetic system and sleep. [ABSTRACT FROM AUTHOR]

Introduction: Cardiac memory is recognized as altered T‐waves when the sinus rhythm resumes after an abnormal myocardial activation period that recovers slowly over several weeks. The T‐wave changes after ablation of frequent premature ventricular contractions (PVCs) as cardiac memory was not known. Objective: This study identified whether cardiac memory exists after successful ablation of PVCs from the right ventricular outflow tract (RVOT). Methods: We investigated 45 patients who underwent successful ablation of PVCs from RVOT and 10 patients who underwent unsuccessful ablation. We analyzed the amplitude of the T‐wave, QT intervals, and QRST time‐integral values of a 12‐lead electrocardiogram before ablation and 1 day, 3 days, and 1 month after ablation. Results: In the successful ablation group, the amplitude of the T‐wave and QRST time‐integral values of lead II, III, aVR, aVL, and aVF significantly changed after ablation and gradually normalized within 1 month. In addition, if the number of pre‐ablation PVCs was small, then the corresponding impact was also small. However, the greater the number of pre‐ablation PVCs, the more prominent the changes. Significant changes were not observed in the unsuccessful ablation group. Conclusion: When ablation of PVCs from RVOT was successful, primary T‐wave changes because of cardiac memory and the gradual normalization of the amplitude of the T‐wave were observed. No significant T‐wave changes were detected after unsuccessful ablation. [ABSTRACT FROM AUTHOR]

Introduction: Preexisting changes in repolarization properties play an important role in T wave abnormalities (cardiac memory) after ablation in patients with Wolff-Parkinson-White (VVPW) syndrome. However, no report has provided direct evidence for prolongation of action potential duration (APD) over a preexcited region before and after ablation. Methods and Results: We studied 10 patients with ventricular preexcitation due to a left-sided accessory pathway (AP) (group M) and 12 patients with concealed left-sided AP (group C) to clarify prolongation of APD using activation-recovery intervals (ARIs) from epicardial and endocardial unipolar electrograms in patients with WPW syndrome. ARI was calculated from unipolar electrograms at the His bundle and the coronary sinus adjacent to the AP during atrial pacing (100 beats/min) before and 30 minutes after ablation. Before ablation, ARIs at the AP site were significantly longer in group M than in group C (255 ± 21 msec vs 211 ± 24 msec; P < 0.01), whereas ARIs at the His bundle did not differ between the two groups (255 ± 20 msec vs 245 ± 27 msec; P = NS). After ablation, group M showed no significant changes in ARIs at the AP and His bundle (256 ± 19 msec and 253 ± 15 msec) compared with before ablation. Conclusion: We found by direct analysis of ARIs from the epicardium that APD prolongation over the preexcited region was present before catheter ablation and persisted after catheter ablation. The gradual changes in repolarization properties, including APD prolongation after discontinuation of AP, may be one mechanism of cardiac memory after catheter ablation in patients with WPW syndrome. [ABSTRACT FROM AUTHOR]

Radiofrequency catheter ablation guided by pace-mapping techniques has proven effective in eliminating idiopathic ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT). A method for rapidly identifying the origin of VT from 12-lead electrocardiogram (ECG) findings would be helpful for the catheter ablation procedure. The purpose of this study is to precisely localize the origin of idiopathic VT from the RVOT by a 124-lead ECG from a study of multipoint pace mapping. In one patient with premature ventricular complex (PVC) and 3 with VT, a "basket" catheter was deployed in the RVOT for bipolar pacing from 56 sites in the endocardium of RVOT. Under fluoroscopy the pacing sites were classified into the septum and free wall. We investigated the QRS morphology in leads. I, II, and III; the depth of the QS wave in leads aVR and aVL; and the height of the initial r wave in leads V1 and V2. Pacing was captured in 30-47 of 56 sites (54%-84%). As the pacing sites changed from the anterior to posterior of the septum, the QS notch (-) type in lead I shifted through rs to R, while a shift from R type to rR' or Rr' was noted in leads II and III. As the pacing sites changed from the anterior to posterior of the free wall, lead I showed a shift from the QS notch (+) type to R, while a shift from rR' to Rr' (or rR' unchanged) was found in leads II and III. The depth of the QS wave in leads aVR and aVL showed a tendency for aVR to be deeper than aVL toward the posterolateral attachment of both the septum and free wall, whereas aVL tended to be deeper than aVR toward the anterior attachment. The initial r waves in V1 and V2 became greater as the pacing site was positioned at a higher or more posterior location. These findings may provide more precise and clinically useful diagnostic information on the site of the origin of idiopathic VT originating from the RVOT by a 12-lead FCG. [ABSTRACT FROM AUTHOR]

The activation-recovery interval (ARI), measured directly from the myocardium, has shown a good correlation with the action potential duration (APD) in experiments. APD bas been reported to be inversely related to the activation time (AT). However, no studies have examined the correlation between the body-surface ARI and AT in normal subjects. Fifty normal subjects (25 men and 25 women) were studied to elucidate the relationship between the body-surface ARI and AT. The body-surface AT was defined as the duration between the QRS onset and the minimum dV/dt of the QRS wave, and ARI as the interval between the minimum dV/dt of the QRS wave and the maximum dV/dt of the T wave in each lead of an 87 unipolar lead system. We also measured the recovery time (RT) defined as the duration between the QRS onset and the maximum dV/dt of the T wave. ARI was inversely correlated with AT (r = -0.73). RT was also inversely correlated with AT (r = -0.61), however, RT bad a less heterogeneous distribution than ARI (148 ms vs 159 ms). there were no differences between male and female subjects in the relation between ARI and RT or in the body-surface distribution of ARI and RT. These findings suggest that the body-surface ARI may reflect recovery properties over the cardiac surface and that APD may distribute inhomogeneously over the human cardiac surface with a longer RT over an area with a shorter AT, ARI calculated from body-surface ECG may be a useful noninvasive and repeatedly measurable estimate of APD. [ABSTRACT FROM AUTHOR]