Electrophysiological pulmonary vein antrum isolation with a multielectrode basket catheter is feasible and effective for curing paroxysmal atrial fibrillation: Efficacy of minimally extensive pulmonary vein isolation

BACKGROUND

How extensive should an appropriate pulmonary vein (PV) ablation be is a matter of controversy.

OBJECTIVE

The study's aim was to investigate the efficacy of minimally extensive PV ablation for isolating the PV antrum (PVA) with the guidance of electrophysiological parameters.

METHODS

Fifty-five consecutive symptomatic paroxysmal atrial fibrillation (PAF) patients underwent PV mapping with a multielectrode basket catheter (MBC). A 31-mm MBC was deployed in 3-4 PVs as proximally as possible without dislodgement, and the longitudinal PV mapping enabled us to recognize single sharp potentials formed by the total fusion of the PV and left atrial potentials around the PV ostium or the transverse activation patterns that were observed. Those potentials were defined as PVA potentials. Radiofrequency ablation was performed circumferentially targeting PVA potentials with the end point being their elimination.

RESULTS

After circumferential PVA ablation, electrical disconnection was achieved in 77% and residual PVA conduction gaps were observed in 23% of all targeted PVs. Those residual conduction gaps were mainly located at the border between ipsilateral PVs (42%) and between the left PVs and left atrial appendage (33%) and were eliminated by a mean of 3 +/- 2 minutes of local radiofrequency deliveries. During the follow-up period (11 +/- 5 months), 46 (84%) patients were free of symptomatic PAF without any anti-arrhythmic drugs. No PV stenosis or spontaneous left atrial flutter occurred.

CONCLUSIONS

Electrophysiological PVA ablation with an MBC is feasible and effective for curing PAF because this minimally extensive PVA isolation technique targets the optimal sites, achieving both high efficacy and safety.

Incidence, location, and cause of recovery of electrical connections between the pulmonary veins and the left atrium after pulmonary vein isolation

AIMS

The aim of this study was to reveal the incidence, location, and cause of recovery of the electrical connections (ECs) between the left atrium and the pulmonary veins (PVs) after the segmental ostial PV isolation (PVI).

METHODS AND RESULTS

Pulmonary vein mapping and successful PVI were performed using a computerized three-dimensional mapping system (QMS2trade mark) with a basket catheter in 167 PVs in 53 consecutive patients with atrial fibrillation (AF). In 14 patients with recurrent AF after PVI, the same PV mapping and isolation as in the first procedure were performed, and the PV potential maps constructed by QMS2 in two different procedures were compared. Forty-nine recovered ECs were observed in 27 PVs, and all were eliminated by a few local radiofrequency (RF) applications. Thirty-four (69%) of those ECs recovered at the edge of original ECs, and another 15 (31%) recovered at the mid-portion of the continuous broad original ECs.

CONCLUSION

Electrical connection recovery occurred most commonly at the edges of original ECs and occasionally at the mid-portion of continuous broad original ECs after PVI probably due to tissue oedema neighbouring the segmental RF lesions. Further RF lesions at the edge of original ECs and linear ablation to the continuous broad ECs may help reduce AF recurrence.

Can Segmental Pulmonary Vein Ablation Reduce the Recurrence of Atrial Fibrillation When Using a Higher RF Power, Larger Tip Electrode Catheter, and Additional RF Deliveries? The limitations of point-by-point RF ablation

The aim of this study was to investigate whether segmental ostial catheter ablation (SOCA) designed to prevent the electrical connections (ECs) between the left atrium and pulmonary veins (PVs) might help increase the efficacy of SOCA in paroxysmal atrial fibrillation (PAF). PV mapping and successful SOCA were performed with a basket catheter in 108 consecutive patients with PAF. Radiofrequency energy was delivered using a maximum output of 30 W with a 4 mm tip catheter (group I; 47) or 40 W with an 8 mm tip catheter (group II; 61). Only in the group II patients were additional radiofrequency deliveries to the specific sites where the ECs tended to recover performed after successful SOCA. After the first procedure, PAF recurred in 47% of the group I patients and 32% of the group II patients. In all 27 patients who underwent repeat procedures, EC recoveries were observed more frequently in group I than in group II (69% versus 49%; P < 0.05). After multiple procedures, there was more freedom from PAF in group II (84%) than in group I (66%) (P < 0.05). SOCA with a higher RF power, larger tip catheter, and additional RF deliveries could achieve a more effective SOCA.

Clinical Protocol for Angiogenesis by Intramyocardial Injection of Autologous Bone Marrow Mononuclear Cells in Patients With Severe Coronary Artery Disease TACT-NAGOYA-HEART

BACKGROUND

Despite recent improvements in the treatments of coronary artery disease (CAD), there are a considerable number of patients who can not receive complete revascularization because of severe or total arterial occlusion. Intramyocardial injection of autologous bone marrow mononuclear cells (ABMMCs) has been shown to induce neovascularization of ischemic myocardium.

METHODS AND RESULTS

The study will investigate the safety and feasibility of intramyocardial injections of ABMMCs and test the hypothesis that this treatment would promote neovascularization and improve left ventricular (LV) global and/or regional function in patients with severe CAD who have no other option. ABMMCs (approximately 10(6) cells) will be injected into the area of ischemic myocardium where the coronary artery is not graftable, in combination with bypass surgery to the other coronary branches. Myocardial perfusion and LV global and regional function will be evaluated, based on the micromanometer-tipped catheter method, single-photon emission tomography, and myocardial enhanced and color tissue Doppler echocardiography at baseline and during 12 month follow-up.

CONCLUSIONS

This project will demonstrate that intramyocardial injection of ABMMCs with or without coronary artery bypass surgery could be a safe and effective method for therapeutic neovascularization, resulting in an improvement of cardiac function in patients with severe CAD.

Computerized Three-Dimensional Potential Mapping with a Multielectrode Basket Catheter Can be Useful for Pulmonary Vein Electrical Disconnection

INTRODUCTION

Pulmonary vein (PV) isolation (PVI) has been recently proposed as an effective technique to cure atrial fibrillation (AF).

AIMS OF THE STUDY

The aim of this study was to investigate the efficacy of a novel technique utilizing a computerized three-dimensional mapping system (QMS2) with a multielectrode basket catheter (MBC) for PVI and to reveal the relation between the style of breakthrough and the network of the PV musculature.

METHODS

Sixty-five consecutive patients with frequent AF attacks underwent PV mapping with a 31-mm MBC, and a three-dimensional color animation of the potential map was constructed by the QMS2. The animation color schema was arranged to minimize the low-amplitude left atrial (LA) potentials and emphasize the high-amplitude PV potentials (PVPs). The longitudinal PVP map enabled us to recognize the true breakthroughs and reveal the network of the PV musculature.

RESULTS

A total of 205 PVs (65 left superior PVs, 65 right superior PVs, 57 left inferior PVs and 18 right inferior PVs) were mapped and successful PVI was achieved in all PVs, except one that had no PVPs, with a mean radiofrequency duration of 7 +/- 5 minutes per PV. In about 90% of the PVs, a final radiofrequency application eliminated all the distal PVPs simultaneously because the PVI was performed at the appropriate LA-PV junction. A single segmental breakthrough was detected in 17 PVs, single broad breakthrough in 83 PVs, multiple separate breakthroughs with a distal connection between the PV musculatures extending from each separate breakthrough in 88 PVs and multiple separate breakthroughs without that connection in 16 PVs. During the follow-up period, fifty-one (78%) patients were free of symptomatic AF without any antiarrhythmic drugs after multiple procedures (thirty-three (51%) of those patients after the first procedure) and no PV stenosis was found.

CONCLUSIONS

Computerized three-dimensional potential mapping can be useful for PVI because it can not only identify the true breakthrough, but can also confirm the elimination of the breakthroughs by the change in the activation sequence through the network of the PV musculature.

Simple and accurate catheter mapping technique to predict atrial fibrillation foci in the pulmonary veins or posterior right atrium

OBJECTIVES

The purpose of this study was to investigate the efficacy of a novel catheter mapping technique for predicting atrial fibrillation (AF) foci.

BACKGROUND

Most AF originates from pulmonary veins (PVs), but some originate from the right atrium.

METHODS

We developed an algorithm by correlating the cardiac recordings obtained from multielectrode catheters placed in the posterior right atrium (RA) and esophagus during pacing from the PVs and superior vena cava (SVC) or crista terminalis (CT) in 10 AF patients. We tested the algorithm's accuracy prospectively in 46 AF patients.

RESULTS

During pacing from the left PVs, the esophageal potentials preceded all other potentials. During pacing from both the right PVs and SVC-CT, the first component (FP) of the double potential (DP) recorded in the posterior RA preceded all other potentials. The amplitude of the FP was higher than that of the second DP component during pacing from the SVC-CT, whereas the reverse occurred from the right PVs. The activation sequence of the FPs and esophageal potentials was from superior to inferior during pacing from the superior PVs, whereas the reverse occurred from the inferior PVs. The accuracy of predicting 34 foci in the right PVs, 28 foci in left PVs, and 6 foci in SVC-CT was 100% for all, respectively. The accuracy of discriminating foci in the superior PVs from those in the inferior PVs was 97% in the right PVs and 96% in the left PVs.

CONCLUSIONS

The technique using mapping catheters placed in the posterior RA and esophagus is feasible and effective for mapping and ablating AF.

Smoking Cessation Rapidly Increases Circulating Progenitor Cells in Peripheral Blood in Chronic Smokers

OBJECTIVE

Circulating endothelial progenitor cells (EPCs) contribute to postnatal angiogenesis. The number of circulating EPCs has an inverse correlation with coronary risk scores. However, the effect of smoking on the number of circulating EPCs is not well-known.

METHODS AND RESULTS

We examined the effects of chronic smoking and of smoking cessation on EPC levels. Circulating EPCs were quantified by flow cytometry as CD45lowCD34+CD133+ (progenitor cells [PCs]) or CD45lowCD34+CD133+VEGFR2+ (EPCs) in 14 nonsmokers and in 15 smokers. All smokers quit smoking. Eight quit smoking with nicotine patch and 7 without nicotine patch. PC/EPC levels were inversely correlated with the number of cigarettes smoked. Circulating PCs/EPCs increased rapidly after cessation (P<0.0001) and decreased again after resumption of smoking to the level similar to that before cessation (P=0.0031). The magnitude of increase in EPCs was greater in light smokers than in heavy smokers.

CONCLUSIONS

The number of circulating PCs/EPCs was reduced in chronic smokers. Smoking cessation led to a rapid restoration of PC/EPC levels. The recovery of EPC levels was greater in light smokers than in heavy smokers. The decreased number of circulating EPCs would make smokers susceptible to cardiovascular disease, and even short-time cessation of smoking may be an effective means to reduce cardiovascular risk.

Electrophysiologic Characteristics of Atrial Tachycardia Originating from the Right Pulmonary Veins or Posterior Right Atrium:. Double Potentials Obtained from the Posterior Wall of the Right Atrium Can Be Useful to Predict Foci of Atrial Tachycardia in the Right Pulmonary Veins or Posterior Right Atrium

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.

Diagnostic usefulness of postexercise systolic blood pressure response for detection of coronary artery disease in patients with echocardiographic left ventricular hypertrophy

BACKGROUND

Although exercise-induced electrocardiographic ST segment changes are used to detect coronary artery disease (CAD), their diagnostic value is markedly decreased in patients with left ventricular (LV) hypertrophy. There have been no reports concerning postexercise systolic blood pressure (SBP) response in patients with ultrasound echocardiographic (UCG) LV hypertrophy and CAD.

METHODS

Sixty-six patients with both UCG-LV hypertrophy (LV mass index 134 g/m2 or greater for men or 110 g/m2 or greater for women) and positive ST depression of at least 0.1 mV during treadmill exercise testing were studied. Coronary cineangiograms showed normal coronary arteries in 19 patients (group 1) and significant CAD in 47 patients (group 2). The SBP ratio was calculated by dividing the SBP 3 min after exercise (3 min SBP) by the SBP at peak exercise (peak SBP).

RESULTS

There were no significant differences between the two groups in LV mass index, SBP at rest, exercise duration, ST depression (at rest and exercise-induced) or 3 min SBP. However, the SBP ratio was significantly higher in group 2 compared with group 1 (0.87+/-0.11 versus 1.01+/-0.18; P=0.004). Analysis of relative cumulative frequency distributions revealed an SBP ratio of 0.92 as the cutoff point for distinguishing a UCG-LV hypertrophy patient with CAD from one without CAD. The sensitivity, specificity and accuracy with an SBP ratio of 0.92 and an ST segment depression of at least 0.1 mV on treadmill exercise testing for detecting CAD in patients with UCG-LV hypertrophy were 77%, 74% and 76%, respectively.

CONCLUSION

These findings suggest that the ratio of early post-exercise SBP to peak exercise SBP may be diagnostically useful in detecting CAD in patients with positive ST depression during an exercise test and UCG-LV hypertrophy.

Effects of antiarrhythmic agents on left ventricular function during exercise in patients with chronic left ventricular dysfunction

This study was designed to determine the effects of antiarrhythmic agents on global left ventricular (LV) function during exercise in patients with chronic LV dysfunction. Thirty-five patients with LV dysfunction [LV ejection fraction (LVEF) < 45%] and ventricular arrhythmias were studied. They were randomly classified into 3 groups: patients who received a single oral dose of 6 mg/kg disopyramide phosphate (n = 12), those who received a single oral dose of 4 mg/kg mexiletine hydrochloride (n = 12), and those who received a single oral dose of 4 mg/kg pilsicainide hydrochloride (n = 11). First, all patients were subjected to baseline rest and peak exercise, equilibrium-gated cardiac-pool scintigraphy with 99mTc-human serous albumin of 740 MBq (baseline data). Second, on a separate day, they were given drugs once, and were subsequently subjected to rest and peak exercise equilibrium-gated cardiac-pool scintigraphy. Exercise LVEF and peak ejection rate (PER) after administration were significantly lower in the disopyramide and pilsicainide groups than in the mexiletine group (p < 0.05, respectively). The changes in LVEF and PER from rest to peak exercise after administration were significantly less than the baseline changes in those in the disopyramide and pilsicainide groups (p < 0.05, respectively). However, no significant changes in functional parameters were recognized in the mexiletine group. Due care should be taken when disopyramide and pilsicainide are administered to patients with chronic LV dysfunction since they reduce systolic LV function during exercise.

Identification of the Amino Acid Residues of the Platelet Glycoprotein Ib (GPIb) Essential for the von Willebrand Factor Binding by Clustered Charged-to-Alanine Scanning Mutagenesis

At the site of vascular injury, von Willebrand factor (VWF) mediates platelet adhesion to subendothelial connective tissue through binding to the N-terminal domain of the alpha chain of platelet glycoprotein Ib (GPIbalpha). To elucidate the molecular mechanisms of the binding, we have employed charged-to-alanine scanning mutagenesis of the soluble fragment containing the N-terminal 287 amino acids of GPIbalpha. Sixty-two charged amino acids were changed singly or in small clusters, and 38 mutant constructs were expressed in the supernatant of 293T cells. Each mutant was assayed for binding to several monoclonal antibodies for human GPIbalpha and for ristocetin-induced and botrocetin-induced binding of 125I-labeled human VWF. Mutations at Glu128, Glu172, and Asp175 specifically decreased both ristocetin- and botrocetin-induced VWF binding, suggesting that these sites are important for VWF binding of platelet GPIb. Monoclonal antibody 6D1 inhibited ristocetin- and botrocetin-induced VWF binding, and a mutation at Glu125 specifically reduced the binding to 6D1. In contrast, antibody HPL7 had no effect for VWF binding, and mutant E121A reduced the HPL7 binding. Mutations at His12 and Glu14 decreased the ristocetin-induced VWF binding with normal botrocetin-induced binding. Crystallographic modeling of the VWF-GPIbalpha complex indicated that Glu128 and Asp175 form VWF binding sites; the binding of 6D1 to Glu125 interrupts the VWF binding of Glu128, but HPL7 binding to Glu121 has no effect on VWF binding. Moreover, His12 and Glu14 contact with Glu613 and Arg571 of VWF A1 domain, whose mutations had shown similar phenotype. These findings indicated the novel binding sites required for VWF binding of human GPIbalpha.

Sinoatrial node dysfunction and early unexpected death of mice with a defect of klotho gene expression

BACKGROUND

Homozygous mutant mice with a defect of klotho gene expression (kl/kl) show multiple age-related disorders and premature death from unknown causes.

METHODS AND RESULTS

The kl/kl mice subjected to 20-hour restraint stress showed a high rate (20/30) of sudden death, which was associated with sinoatrial node dysfunction (conduction block or arrest). Heart rate and plasma norepinephrine of kl/kl mice, unlike those of wild-type (WT) mice, failed to increase during the stress. Intrinsic heart rate after pharmacological blockade of autonomic nerves in kl/kl mice was significantly lower than that in WT mice (380+/-33 versus 470+/-44 bpm; n=7). The sinus node recovery time after an overdrive pacing (600 bpm, 30 seconds) in kl/kl mice was significantly longer than in WT mice (392+/-37 versus 233+/-24 ms; n=6). In isolated sinoatrial node preparations, the positive chronotropic effect of isoproterenol was significantly less, whereas the negative chronotropic effect of acetylcholine was significantly greater in kl/kl than in WT mice. There was no degenerative structural change in the sinoatrial node of kl/kl mice. The precise localization of klotho was analyzed in newly prepared klotho-null mice with a reporter gene system (kl(-geo)). Homozygous kl(-geo) mice showed characteristic age-associated phenotypes that were almost identical to those of kl/kl mice. In the kl(-geo) mice, klotho expression was recognized exclusively in the sinoatrial node region in the heart in addition to parathyroid, kidney, and choroid plexus.

CONCLUSIONS

In the heart, klotho is expressed solely at the sinoatrial node. klotho gene expression is essential for the sinoatrial node to function as a dependable pacemaker under conditions of stress.

Increased expression of plasminogen activator inhibitor-1 in cardiomyocytes contributes to cardiac fibrosis after myocardial infarction

Plasminogen activator inhibitor-1 (PAI-1) plays a critical role in tissue fibrosis by inactivating matrix metalloproteinases, which might effect on the progression of left ventricular dysfunction. However, little has been known about the expression of PAI-1 during cardiac remodeling. We used a mouse model of myocardial infarction (MI) by coronary ligation, in which the progression of left ventricular remodeling was confirmed by echocardiography. Histological examination showed that interstitial and perivascular fibrosis progressed in the post-MI (PMI) heart at 4 weeks after the procedure. We observed the dramatic induction of cardiac PAI-1 mRNA and PAI-1 antigen in plasma in the PMI mice, as compared with the sham-operated (sham) mice. In situ hybridization analysis demonstrated that strong signals for PAI-1 mRNA were localized to cardiomyocytes in the border of infarct area and around fibrous lesions, and to perivascular mononuclear cells, which seemed to be mast cells, only in hearts of the PMI mice. Importantly, less development of cardiac fibrosis after MI was observed in mice deficient in PAI-1 as compared to wild-type mice. The mRNA expression of cytokines, transforming growth factor-beta, and tumor necrosis factor-alpha, was also increased in hearts of the PMI mice, but not in the sham mice. These observations suggest that cardiomyocytes and mast cells contribute to the increased PAI-1 expression, resulting in the development of interstitial and perivascular fibrosis in the PMI heart, and that the regional induction of cytokines may be involved in this process.

Ionic mechanisms of acquired QT prolongation and torsades de pointes in rabbits with chronic complete atrioventricular block

BACKGROUND

The ionic basis of acquired QT prolongation and torsade de pointes (TdP) unrelated to drugs is not fully understood.

METHODS AND RESULTS

We created a rabbit model with chronic complete atrioventricular block (AVB) (n=34), which showed prominent QT prolongation (by 120%), high incidence of spontaneous TdP (71%), and cardiac hypertrophy. Patch-clamp experiments were performed in left ventricular myocytes from 9 rabbits (8 with TdP, 1 without TdP) at approximately 21 days of AVB and from 8 sham-operated controls with sinus rhythm. Action potential duration was prolonged in AVB myocytes compared with control (+61% at 0.5 Hz, +21% at 3 Hz). Both rapidly and slowly activating components of the delayed rectifier K(+) current (I(Kr) and I(Ks)) in AVB myocytes were significantly smaller than in control by 50% and 55%, respectively. There was no significant difference in Ca(2+)-independent transient outward current (I(to1)). L-type Ca(2+) current (I(Ca,L)) in control and AVB myocytes was similar in peak amplitude, but the half voltage for activation was shifted to the negative direction (5.9 mV) in AVB myocytes. Voltage dependence of I(Ca,L) inactivation was not different in control and AVB myocytes. The inward rectifier K(+) current (I(K1)) significantly increased in AVB myocytes compared with control.

CONCLUSIONS

In the rabbit, chronic AVB leads to prominent QT prolongation and high incidence of spontaneous TdP. Downregulation of both I(Kr) and I(Ks) in association with altered I(Ca,L) activation kinetics may underlie the arrhythmogenic ventricular remodeling.

Ventricular activation and recovery measured in electrocardiographic limb leads correlate with measurements from specific areas in body surface mapping

AIMS

Dispersion of ventricular depolarization-repolarization in 12-lead electrocardiograms (ECGs) has been reported to provide noninvasive information on arrhythmogenicity. However, there are two methods to calculate the dispersion from ECGs including and excluding limb leads. The aim of this study was to examine whether temporal parameters from limb leads represent activation and repolarization of a particular part of the body surface.

METHODS AND RESULTS

We compared the temporal parameters of activation time (AT), activation-recovery interval (ARI), and recovery time (RT) from limb leads of ECGs with those from an 87-lead body surface maps. The study population consisted of 50 normal subjects (25 men and 25 women, 19.4 +/- 1.6 years). The temporal parameters in leads I, II, and III were highly (r > 0.9) correlated with those in unipolar leads over the left lateral, left lower, and right lower chest, respectively. The temporal parameters in leads aVR, aVL, and aVF showed a significant correlation (r > 0.8) with those in unipolar leads over the right upper, left upper, and lower anterior chest, respectively. The mean AT, ARI, and RT from each limb lead of ECG were almost the same as those of unipolar leads over the corresponding areas of the body surface.

CONCLUSIONS

These findings suggest that ATs, ARIs, and RTs from limb leads may represent those from unipolar leads of particular areas over the body surface in normal subjects. The temporal parameters from limb leads of ECGs may provide information on activation and repolarization as well as the precordial leads of ECGs.

Repetitive atrial flutter as a complication of the left-sided simple maze procedure

BACKGROUND

Of 41 patients who had undergone a left-sided simple maze procedure, 4 (9.8%) developed repetitive tachycardia due to atrial flutter, and required radiofrequency catheter ablation. Linear ablation of the right atrial isthmus was effective to treat atrial flutter.

METHODS

We conducted an electrophysiologic study of atrial flutter and determined its reentry circuit on the atrium. We consider how to reduce atrial flutter after the left-sided simple maze procedure.

RESULTS

Common atrial flutter through the right atrial isthmus was induced in all 4 patients, and linear ablation on the right atrial isthmus was effective in 3 of these. An incisional atrial flutter around the right atriotomy was also induced in 2 of 4 patients; both were successfully treated by linear ablation between the right atriotomy and the inferior vena cava.

CONCLUSIONS

Common atrial flutter through the right atrial isthmus is a risk after the left-sided simple maze procedure. When a left-sided simple maze procedure is performed, sufficient cryoablation on the right atrial isthmus of the arrested heart should be administered to prevent postoperative atrial flutter.

Changes in repolarization properties with long-term cardiac memory modify dispersion of repolarization in patients with Wolff-Parkinson-White syndrome

INTRODUCTION

Transient T wave changes after cessation of preexcitation have been attributed to cardiac memory. However, there have been no reports on the effects of long-term cardiac memory on repolarization dispersion before and after catheter ablation in patients with Wolff-Parkinson-White (WPW) syndrome.

METHODS AND RESULTS

We investigated 47 patients with an accessory pathway (AP; 24 manifest left-sided, 14 manifest right-sided, and 9 concealed left-sided). Repolarization dispersion was analyzed by two methods, recovery time (RT) dispersion and newly proposed T wave width (WT), from 87-lead body surface maps before, 1 day after, and 7 days after catheter ablation. RT dispersion and WT were significantly correlated before, 1 day after, and 7 days after catheter ablation (r = 0.78). In patients with preexcitation, RT dispersion and WT increased significantly (P < 0.05) 1 day after catheter ablation (178 +/- 32 msec and 172 +/- 30 msec) compared with those before (154 +/- 24 msec and 156 +/- 18 msec) and 7 days after catheter ablation (147 +/- 19 msec and 156 +/- 16 msec), respectively. However, there were no significant changes in RT dispersion and WT before and after catheter ablation in concealed WPW syndrome.

CONCLUSION

The findings suggest that the abrupt changes in activation sequence increase repolarization dispersion in the presence of previous cardiac memory, and that the dispersion decreases days or weeks after alteration of activation sequence by catheter ablation, with development of new cardiac memory in patients with manifest WPW syndrome.

Effects of coagulation Factor VII polymorphisms on the coronary artery disease in Japanese: Factor VII polymorphism and coronary disease

We investigated the relationships among Factor VII coagulant activity (FVIIc), genetic polymorphisms of Factor VII (FVII) and coronary artery disease (CAD) in 380 unrelated Japanese individuals (mean 64 years) who underwent coronary angiography and whose cholesterol levels were within normal range. CAD subjects were defined as those in whom one of the three major coronary arteries showed >50% narrowing after nitroglycerin administration. FVIIc was measured and the following polymorphisms of FVII were determined: R353Q polymorphism (M1, M2 alleles), -323 0/10 bp polymorphism (0, 10 alleles), hypervariable region 4 of intron 7 (HVR4; H5, H6, H7 alleles). FVIIc was slightly lower in M1M2/M2M2 than M1M1 (89.5+/-8.9%, 93.4+/-17.8%). Those with M2 and/or 10 allele have less chance of developing CAD (M2: OR 0.36, 95% CI 0.18-0.69, 10: OR 0.50, 95% CI 0.26-0.97). However, both alleles did not associate with myocardial infarction (MI). HVR4 was unrelated with CAD, nor with MI. In conclusion, M2 and/or 10 allele has protective effects on the developing CAD in individuals with a normal cholesterol level.

Prolongation of activation-recovery interval over a preexcited region before and after catheter ablation in patients with Wolff-Parkinson-White syndrome

INTRODUCTION

Preexisting changes in repolarization properties play an important role in T wave abnormalities (cardiac memory) after ablation in patients with Wolff-Parkinson-White (WPW) 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.

Activation-recovery intervals of 12-lead electrocardiograms before and after catheter ablation in patients with Wolff-Parkinson-White syndrome

Preexcitation in Wolff-Parkinson-White syndrome (WPW) has been reported to induce long-lasting changes in ventricular recovery properties. However, there has not been a report concerning changes in the activation-recovery interval (ARI) in 12-lead ECGs before and after catheter ablation (CA) in patients with WPW syndrome. The present study compared changes in ARIs from 12-lead ECGs with those from body surface unipolar leads before and after CA to examine whether ARIs from limb leads of 12-lead ECGs provide useful information on changes in recovery properties in addition to the ARIs from precordial leads. The study population consisted of 27 manifest WPW patients with a left- (n=18, group A) or right-sided accessory pathway (n=9, group B). ARIs in leads I, II, and III were strongly correlated with those in unipolar leads over the left lateral, left lower, and right lower chest, respectively. ARIs in leads aVR, aVL, and aVF showed a significant correlation with those in unipolar leads over the right upper, left upper, and lower anterior chest, respectively. These correlations were maintained before and after CA. Furthermore, in group A, ARIs in lead V1 tended to increase on day 7 post CA compared with before CA and on day 1. In group B, ARIs in lead III significantly decreased on day 7 compared with before CA and on day 1. These findings suggest that ARIs from the limb leads of 12-lead ECGs may represent those from unipolar leads of a particular area over the body surface, and that ARIs from 12-lead ECGs may provide useful quantitative information on changes in recovery properties before and after CA in patients with manifest WPW syndrome.

Comparison of vectorcardiographic and 12-lead electrocardiographic detections of abnormalities in repolarization properties due to preexcitation in patients with Wolff-Parkinson-White syndrome: proposal of a novel concept of a "remodeling gradient"

Repolarization abnormalities after radiofrequency ablation in patients with manifest Wolff-Parkinson-White syndrome (WPW) have been attributed to cardiac memory of pre-existing changes in repolarization properties. We compared spatial ventricular gradient (VG) from vectorcardiograms with QRST values of 12-lead ECG in 41 patients with WPW (group A, manifest WPW due to left-sided accessory pathway (n = 20); group B, manifest WPW due to right-sided accessory pathway (n = 12); group C, concealed WPW (n = 9)) before and after ablation. Group N (n = 607) served as control. In groups A and B, the abnormalities of spatial VG and QRST values of 12-lead ECG that existed before and 1 day after ablation significantly decreased 1 week after ablation. In group C, spatial VG and QRST values of 12-lead ECG showed no significant changes. The diagnostic ability of spatial VG is almost equivalent to that of the QRST value of ECG in detecting repolarization abnormalities in patients with WPW before and after ablation. We propose a new concept of a "remodeling gradient" directing from the preexcited area to the opposite side of the ventricle as a result of preexcitation-induced electrical remodeling.

Antiarrhythmic efficacy of dipyridamole in treatment of reperfusion arrhythmias : evidence for cAMP-mediated triggered activity as a mechanism responsible for reperfusion arrhythmias

BACKGROUND

Intracellular calcium overload is believed to play an important role in development of reperfusion arrhythmias. Dipyridamole, an inhibitor of cellular uptake of adenosine, may prevent or terminate reperfusion arrhythmias by reducing intracellular calcium overload.

METHODS AND RESULTS

First, we tested for a preventive effect of dipyridamole. Sixty-one patients who underwent primary PTCA for treatment of acute anterior wall myocardial infarction were enrolled in this prospective study. Patients were divided into dipyridamole (DP) and nondipyridamole (non-DP) groups. The 2 groups had similar baseline characteristics. In the DP group, dipyridamole 0.5 mg/kg was infused intravenously for 3 minutes immediately before reperfusion during primary PTCA. Arrhythmias after reperfusion were analyzed from continuous ECG recordings. None of the patients in the DP group (n=23) had accelerated idioventricular rhythms (AIVR) or ventricular tachycardia (VT). In contrast, 7 (18.4%) had AIVR and 3 (7.9%) had VT in the non-DP group (n=38; P<0.01). Second, we tested for a termination effect of dipyridamole. Dipyridamole 0.5 mg/kg was infused intravenously while continuous ECG recordings were obtained in 9 patients who had either sustained AIVR (n=7) or sustained VT (n=2) after reperfusion of occluded coronary artery. Arrhythmias were terminated in all patients.

CONCLUSIONS

These results indicate that administration of dipyridamole can prevent and terminate reperfusion arrhythmias such as AIVR and VT. cAMP-mediated triggered activity may, at least in part, be responsible for reperfusion-induced AIVR and VT.

Localization of precise origin of idiopathic ventricular tachycardia from the right ventricular outflow tract by a 12-lead ECG: a study of pace mapping using a multielectrode "basket" catheter

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 12-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 ECG.

Inverse relation of body-surface activation-recovery interval and recovery time to activation time in normal subjects: stronger correlation and more heterogeneous distribution in activation-recovery interval than in recovery time

The activation-recovery interval (ARI), measured directly from the myocardium, has shown a good correlation with the action potential duration (APD) in experiments. APD has 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 had 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.

Body-surface distribution of changes in activation-recovery intervals before and after catheter ablation in patients with Wolff-Parkinson-White syndrome: clinical evidence for ventricular 'electrical remodeling' with prolongation of action-potential duration over a preexcited area

BACKGROUND

T-wave abnormalities after catheter ablation in patients with manifest Wolff-Parkinson-White (WPW) syndrome have been attributed to a continuation of repolarization abnormalities induced by preexcitation (cardiac memory).

METHODS AND RESULTS

To clarify changes in repolarization properties, we analyzed the activation-recovery interval (ARI) obtained from body-surface maps and the relationship between the activation time (AT) and ARI in 30 patients with WPW syndrome (group A, 18 patients with manifest left-sided accessory pathway; group B, 7 patients with manifest right-sided accessory pathway; and group C, 5 patients with concealed left-sided accessory pathway) before, 1 day after, and 1 week after ablation. The ARI significantly decreased 1 week after ablation compared with before and 1 day after ablation over the preexcited area in groups A and B. Correlation coefficients between the AT and ARI showed a significantly (P<.01) stronger inverse relationship before (r=-.58) and 1 week after (r=-.64) ablation than 1 day after ablation (r=-.46) in groups A and B. In group C, the ARI and correlation coefficients between the AT and ARI showed no significant changes.

CONCLUSIONS

These findings suggest a prolongation of the action-potential duration over the preexcited area before and just after ablation as ventricular "electrical remodeling," a decrease in the inverse relationship between the AT and action-potential duration 1 day after ablation, and a gradual recovery of the action-potential duration over the preexcited area and inverse relationship 1 week after ablation.

Body surface distribution of significant changes in QRST time-integral values after radiofrequency catheter ablation in patients with Wolff-Parkinson-White syndrome

We analyzed 87-lead body surface QRST time-integral values (QRST values) in 29 patients with Wolff-Parkinson-White syndrome (group A, 17 patients with manifest left-sided accessory pathway; group B, 6 patients with manifest right-sided accessory pathway; and group C, 6 patients with concealed left-sided accessory pathway), before, 1 day after, and 1 week after radiofrequency catheter ablation (RCA). The number of leads with abnormal QRST values was significantly lower 1 week after RCA compared with those before RCA and 1 day after RCA in groups A and B (p < 0.05); there was no significant difference in QRST values before and 1 day after RCA in groups A and B. The QRST values over areas with preexisting repolarization abnormalities were significantly altered 1 week after RCA compared with before and 1 day after RCA in groups A and B (p < 0.01). However, there was no significant difference in the QRST values over areas without preexisting abnormalities before RCA. In group C, there were no significant differences in the QRST values or the number of leads with abnormal QRST values before, 1 day and 1 week after RCA. In conclusion, RCA did not significantly influence repolarization properties over areas without preexisting abnormalities, but gradually reduced preexisting repolarization abnormalities, which were closely related to the location of the accessory pathway in patients with manifest Wolff-Parkinson-White syndrome. Our results suggest that body surface QRST values are useful for assessment of repolarization abnormalities during the periablation period.

QRST time integral values in 12-lead electrocardiograms before and after radiofrequency catheter ablation in patients with Wolff-Parkinson-White syndrome

OBJECTIVES

We investigated the usefulness of QRST values obtained from 12-lead electrocardiograms (ECGs) for identification of repolarization abnormalities before and after radiofrequency ablation in patients with Wolff-Parkinson-White syndrome.

BACKGROUND

Marked T wave abnormalities often appear after ablation and have been attributed to a continuation of repolarization abnormalities present before ablation (cardiac memory). However, to our knowledge repolarization properties before and after ablation have not been assessed quantitatively.

METHODS

We calculated the ECG QRST values from 53 patients with Wolff-Parkinson-White syndrome and compared these values before, immediately after and 1 day and 1 week after successful ablation in 25 patients.

RESULTS

QRST values were abnormally high in lead V1 in 7 of 28 patients with a left-sided accessory pathway and abnormally low in leads III and aVF and high in lead aVL in 12, 9 and 10 of 20 patients, respectively, with a right-sided accessory pathway. Preexisting QRST abnormalities were still present immediately and 1 day after ablation but were usually absent by 1 week after ablation. QRST values before, immediately after and 1 day after ablation were not significantly different in any lead. In 14 patients with ablation of a left-sided accessory pathway, QRST values before, immediately after and 1 day after ablation in lead V1 and immediately after ablation in leads I, aVR and V2 were significantly different from QRST values in those leads 1 week after ablation. In six patients with ablation of a right-sided accessory pathway, QRST values before, immediately after and 1 day after ablation in leads III, aVL and aVF and immediately after ablation in lead II were significantly different from QRST values in those leads 1 week after ablation.

CONCLUSIONS

Electrocardiographic QRST values may provide useful quantitative information with respect to repolarization properties before and after ablation in patients with Wolff-Parkinson-White syndrome that is otherwise difficult to obtain by conventional ECG analysis.

Body surface distribution of abnormally low QRST areas in patients with Wolff-Parkinson-White syndrome. Evidence for continuation of repolarization abnormalities before and after catheter ablation

BACKGROUND

Whether the Wolff-Parkinson-White syndrome (WPW) is associated with repolarization abnormalities is controversial. The QRST isointegral map (I-map) is theoretically independent of the activation sequence and dependent on repolarization properties. There have been no reports concerning the effects of radiofrequency (RF) catheter ablation of accessory pathway (AP) on repolarization properties analyzed by I-mapping.

METHODS AND RESULTS

I-maps were constructed from data recorded in 38 patients with WPW to investigate repolarization properties and their body surface distribution in a physiological state, without pharmacological influences, and in 13 ablated patients to elucidate the effects of RF ablation on repolarization properties. Patients were divided into three groups: group A, 15 patients with type A WPW (left-sided AP); group B, 10 patients with type B (right-sided AP); and group C, 13 patients who were successfully ablated. Group C consisted of three subgroups: subgroup CA, 7 patients with type A WPW; subgroup CB, 3 patients with type B WPW; and subgroup CC, 3 patients with concealed WPW. Controls consisted of 608 normals. Although I-maps of WPW were highly (r = .87) correlated with the mean normal I-map, the location of the minimum in groups A and B differed significantly from that in normals. The minimum was located over the upper right anterior chest in normal subjects, over the back in 82% of 22 patients with type A WPW including ablated patients (groups A+CA), and over the mid to lower right anterior chest in 62% of 13 patients with type B WPW including ablated patients (groups B+CB). Groups A+CA and B+CB had an abnormally low QRST area ("-2SD area") over the back and right anterior chest, respectively. The abnormally located minimum and the "-2SD area" were present in 7 of 10 ablated patients with manifest WPW (groups CA+CB). After RF ablation, the distribution of the minimum, initially abnormal, became normal over a period of days or weeks, and the "-2SD area" disappeared over 1 week in all 7 patients. Correlation coefficients between I-maps and the mean normal I-map increased after RF ablation.

CONCLUSIONS

(1) WPW is often associated with abnormalities in repolarization properties. (2) Repolarization abnormalities were located over the back in type A WPW and over the right mid to lower chest in type B WPW: (3) The abnormalities remain immediately after RF ablation and gradually normalize. These findings support the concept that ST-T abnormalities in 12-lead ECGs following RF ablation are attributable to "cardiac memory."

[A carcinoma of the right breast arising after a mastectomy in primary malignant lymphoma of the left breast]

In 1987, a 51-year-old woman visited our hospital, having noticed a painless 1.5 x 1.5 cm tumor of the left breast. On biopsy, it was pathologically diagnosed as being a primary malignant lymphoma of the breast. Thus we performed a modified radical mastectomy (Patey's method), in combination with chemotherapy (Cyclophosphamide, Vincristine, Prednisolone). Two years after the operation, a tumor of the right breast, 1.0 x 1.0 cm in size, was noticed. At this time, since an excised specimen was pathologically determined as being a scirrhous carcinoma, we performed a modified radical mastectomy (Auchincloss' method), followed by chemotherapy (Tegafur).