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Background: Due to the absence of differential guidelines for heart failure with tachyarrhythmia, it is difficult to diagnose tachycardia-induced cardiomyopathy (TIC) at the initial visit. Furthermore, clinical outcomes of rate versus rhythm control in TIC are unclear., Hypothesis: Because the etiology of TIC is different from dynamic cardiomyoplasty (DCMP), differential parameters may be present., Methods: We assessed 21 patients with TIC (15 men; mean age, 50+/-14 years) and 21 control patients with idiopathic DCMP. We assessed clinical courses, echocardiographic parameters, as well as outcomes by treatment., Results: In the TIC group, the related tachyarrhythmias were atrial fibrillation (n=12), atrial flutter (n=5), atrial tachycardia (n=3) and paroxysmal supraventricular tachycardia (n=1). After treatment, all patients became asymptomatic and the ejection fraction (EF) improvement (DeltaEF>or=15%) was observed in all patients (left ventricular ejection fraction [LVEF], 30+/-11%initial versus 58+/-6%last). In the idiopathic DCMP group, no patient showed EF improvement (EF increase

Background: Patients with atrial fibrillation (AF) or congestive heart failure (CHF) are more vulnerable to inappropriate shocks from implantable cardioverter-defibrillators (ICDs), but the effect of antiarrhythmic drugs in these patients remains unknown., Methods and Results: A total of 55 patients with AF and/or CHF (New York Heart Association functional class > or =III) who had ICDs were divided into 3 groups [amiodarone (n=24), sotalol (n=12), beta-blocker (n=19)] and the cumulative rates of inappropriate shocks were compared. The baseline characteristics of the 3 groups were not significantly different. The 4-year event rate of inappropriate shocks was 27.3% in the amiodarone group, 54.3% in the sotalol group, and 70.6% in the beta-blocker group (amiodarone vs beta-blocker: log-rank p=0.003; sotalol vs beta-blocker: log-rank p=0.16; amiodarone vs sotalol: log-rank p=0.29). Amiodarone reduced the risk of inappropriate shocks significantly as compared with beta-blockers (hazard ratio (HR) 0.17; 95% confidence interval (CI) 0.05-0.64; p=0.008), whereas sotalol did not (HR 0.57; 95%CI 0.19-1.68; p=0.3). Amiodarone was discontinued in 4 patients (16.7%) because of pulmonary toxicity and the dose was reduced in 4 patients (16.7%) because of a thyroid function abnormality., Conclusions: Amiodarone is more effective than sotalol or beta-blockers in preventing inappropriate ICD shocks in patients with AF or CHF, but it has a significant risk of drug-related adverse effects.

Background: The prevalence and clinical significance of white-coat hypertension (WCHT) and masked hypertension (MHT) are unknown in Koreans. Here we measure the frequency of WCHT and MHT in hypertensive subjects and identify the epidemiologic and/or clinical factors that predict it in Korean subjects., Methods: This study is a retrospective analysis of a random sample from February 2004 to October 2005. All patients had measurements of blood pressure (BP) in the clinic and 24-hour ambulatory blood pressure monitoring (ABPM). Subjects were classified into four groups on the basis of daytime ambulatory BP and clinic BP level: 1) Normotension (NT), 2) MHT, 3) WCHT, and 4) sustained hypertension (SHT)., Results: For all 967 patients, the mean clinic BP was 157.7 +/- 22.0/ 95.3 +/- 13.1 mmHg, and the mean daytime ambulatory BP was 136.4 +/- 15.0/ 86.2 +/- 10.7 mmHg. The NT, MHT, WCHT, and SHT groups consisted of 51 (5.3%), 55 (5.7%), 273 (28.2%), and 588 (60.8%) subjects, respectively. The left ventricular mass index was significantly higher in SHT than in the other groups, and was positively correlated with BP, especially ABPM. Compared with NT, the factors associated with MHT were younger age, male gender, higher BMI, clinic BP > or = 130 mmHg, and alcohol consumption. Compared with SHT, the factors associated with WCHT were female gender, lower BMI, and clinic BP < 150 mmHg., Conclusions: WCHT and MHT were prevalent in the hypertensive population. ABPM was more predictive of target organ damage than clinic BP, and could be useful in identifying subjects at risk for WCHT and MHT.

Objective: We sought to test if assessment of ventricular longitudinal contractility (LC) by Doppler tissue imaging (DTI) can predict reverse remodeling (RR) of left ventricular (LV) dysfunction resulting from medical treatment., Methods: DTI was performed in 35 patients with nonischemic LV dysfunction (ejection fraction 26 +/- 7%) and LC was assessed at the 4 different basal segments of the LV walls (septal, lateral, inferior, and anterior) using myocardial velocity curves and strain measurements; the peak systolic or delayed longitudinal contraction velocity of LV walls only with concomitant negative strain were measured and added to represent LC of each patient (LC by DTI). Successful RR was defined as a reduction of LV end-systolic volume of greater than 15%., Results: RR was observed in 13 patients (37%, group A). Initial LV ejection fraction was similar in patients who did and did not achieve RR (group B). Compared with group B, group A showed shorter QRS interval (110 +/- 36 vs 136 +/- 28 milliseconds, P = .022), shorter symptom duration (2.3 +/- 3.5 vs 4.2 +/- 3.4 years, P = .047), lower prevalence of left bundle branch block (23% vs 59%, P = .039), and higher value of LC by DTI (9.6 +/- 3.5 vs 6.3 +/- 3.6 cm/s, P = .011). Multivariate analysis revealed that symptom duration less than 2 years (odds ratio = 8.0, 95% confidence interval = 1.3-47.2, P = .022) and LC by DTI (odds ratio = 1.3, 95% confidence interval = 1.0-1.7, P = .019) were independent predictors of RR., Conclusions: DTI provides a new index of LC, which is useful for predicting RR in patients with severe LV dysfunction.

Introduction: The presence of atrionodal connections and coronary sinus (CS) breakthrough in atrioventricular nodal reentrant tachycardia (AVNRT) has been suggested. However, the incidence, anatomic relationship with reentrant circuit, and results of catheter ablation are unknown., Methods and Results: Fifty-two patients with typical slow/fast AVNRT and 10 patients with atypical slow/intermediate or fast/slow AVNRT were included. Eccentric activation of the CS (EACS) was observed in 3 of 52 patients with typical and 8 of 10 patients with atypical AVNRT. The earliest CS activation in patients with an EACS was recorded at a site 10-20 mm inside the CS ostium. The postpacing interval after transient entrainment at the proximal CS in patients with EACS was 23 +/- 21 msec longer than the pacing cycle length. Modification or ablation of the slow pathway was successful in all patients with typical slow/fast AVNRT and in 7 of 9 patients with atypical AVNRT by RF energy delivered at the right septal tricuspid annulus (TA). In 2 patients with atypical AVNRT and an EACS, RF delivery inside the CS targeting the earliest CS activation eliminated the sustained AVNRT., Conclusion: Eccentric coronary sinus activation is observed in some rare cases of typical AVNRT, and in a majority of atypical AVNRT. Entrainment results suggest that the proximal coronary sinus may be part of the reentrant circuit. RF ablation of atypical AVNRT, if it fails from the standard right-side approach, can be targeted at the site of earliest retrograde atrial activation inside the CS.

To determine the presence of memory in human atria, we recorded monophasic action potential (MAP) at the high right atrium (HRA) in 21 patients. After reaching a steady state at 600 ms, HRA pacing was switched to the coronary sinus (CS) pacing to alter the activation sequence. After 20 minutes of CS pacing, pacing was continued at HRA to record the memory effect of CS pacing. Atrial memory was defined as the change in HRA MAP duration (MAPd) after 20 minutes of altered activation sequence. Baseline MAPd was 229 +/- 31 ms, which was shortened to 226 +/- 24 ms immediately after CS pacing. After 20 minutes of CS pacing, HRA MAPd during HRA pacing was 220 +/- 28 ms, which was significantly shorter than the baseline MAPd (P = 0.003). The degree of atrial memory was associated with the degree of initial electrotonic MAPd changes caused by the altered activation sequence. These results suggest that memory phenomenon exists in human atria, and it can be expressed as a change in MAPd.

Background: Mutations in the ryanodine 2 receptor (RyR2) gene have been identified in patients with catecholaminergic polymorphic ventricular tachycardia. We examined the cellular basis for the ECG features and arrhythmia mechanisms using low-dose caffeine to mimic the defective calcium homeostasis encountered under these conditions., Methods and Results: A transmural ECG and action potentials were recorded simultaneously from epicardial, M, and endocardial cells in arterially perfused canine ventricular wedge preparations. Caffeine alone produced no change (10 to 100 micromol/L) or a slight abbreviation (300 micromol/L) of the QT interval and no change in transmural dispersion of repolarization. Isoproterenol (100 nmol/L) alone induced sustained monomorphic ventricular tachycardia (VT) that originated in the epicardium in 3 of 14 wedge preparations. Isoproterenol in the presence of caffeine (100 to 300 micromol/L) induced epicardial VT in 9 of 16 wedge preparations. Delayed afterdepolarization-induced triggered beats that originated in the epicardium were associated with an increased Tpeak-Tend interval and transmural dispersion of repolarization. Bidirectional VT developed in 11 of 16 wedge preparations as a consequence of alternation in the origin of ectopic activity between endocardial, M, and epicardial regions. Single extrastimuli delivered during sustained epicardial VT induced a rapid polymorphic VT/ventricular fibrillation (VF) in 3 of 9 wedges. Spontaneous polymorphic VT was observed in 3 of 16 preparations. Propranolol (1.0 micromol/L) or verapamil (1.0 micromol/L) completely suppressed ectopic activity that arose from the epicardium and prevented induction of polymorphic VT., Conclusions: Our data suggest delayed afterdepolarization-induced extrasystolic activity serves to trigger catecholamine-induced VT/VF under conditions of defective calcium handling. Epicardial origin of the ectopic beats increases transmural dispersion of repolarization, thus providing the substrate for the development of reentrant tachyarrhythmias that underlie rapid polymorphic VT/VF.

The VDD pacemaker is useful for sequential pacing with a single lead but carries a risk of sensing failure. This study was designed to evaluate the relationship between the relative position of atrial lead and atrial sensitivity in different postures in patients with VDD pacemakers. Atrial sensitivity determination and chest roentgenography was performed in the supine and standing position 3 months after implantation in 25 patients with VDD pacemakers. Measurements of cardiac longitudinal length (from the top of the aortic arch to the diaphragm) and distances from the floating electrode to the upper margin of the seventh thoracic vertebra (D-T7), to the top of the aortic arch (D-knob), to the lateral wall of right atrium (D-wall), and the D-knob/cardiac longitudinal length (D-Ratio) were performed. Atrial signal amplitude decreased with the standing compared to the supine position in eight patients (group I) and increased or did not change in the other 17 patients (group II). In group I, the change of the D-ratio was greater (0.073 vs 0.035, P < 0.01), and the change of the cardiac longitudinal length with standing position was greater (18.4 +/- 7.3 vs 12.1 +/- 8.8 mm, P < 0.05) than in group II. The change of atrial sensitivity was related to the change of the atrial electrode position with different postures. Decreased atrial-sensed amplitude was observed in patients who had a greater change in the cardiac longitudinal length while standing. Thus, a decrease in atrial sensitivity with standing may be predicted by the positional changes of the cardiac silhouette on roentgenography before the procedure.

This report describes a case of transient paresis of the right diaphragm following the transcatheter radiofrequency ablation for the electrical disconnection of pulmonary veins, which recovered completely during the observational period in a 61-year-old woman with paroxysmal atrial fibrillation. For electrical disconnection of pulmonary veins, careful preventive measures for phrenic nerve damage are required.

This study devised an automatic monophasic action potential (MAP) measurement program, and compared the computer-measured MAP durations with those measured manually by two independent observers in order to facilitate the analysis of MAP data obtained during a clinical electrophysiology study. The results were compared at various cycle lengths and during pharmacologic or physiologic interventions. This program identified the onset, plateau, and baseline accurately using the MAP data. The automatically measured MAP durations at the 90% repolarization level (MAPd) strongly correlated with those measured manually (r = 0.99). The MAPd shortened in parallel as the pacing cycle length was progressively shortened from 800 to 600, 400 and 300 ms.

To demonstrate systolic and diastolic asynchrony in patients with left bundle branch block (LBBB), tissue Doppler imaging (TDI) of 4 different walls was performed in 27 normal controls, 29 patients with right ventricular pacing and normal left ventricular (LV) ejection fraction (EF; pacing LBBB), and 35 patients with idiopathic LBBB. Patients with idiopathic LBBB were further classified into those with LVEF >50% and those with LVEF <35%. Asynchrony was calculated as the coefficient of variation of the time intervals from the QRS complex to the peak systolic velocity and to the peak of early diastolic relaxation. Patients with pacing and idiopathic LBBB had significantly longer QRS durations (162 +/- 20 vs 92 +/- 7 ms, p <0.001) and larger systolic (15.9 +/- 5.0% vs 4.1 +/- 2.1%, p <0.001) and diastolic (3.7 +/- 2.0% vs 1.4 +/- 0.6%, p <0.001) asynchrony than controls. Those with idiopathic LBBB and low EF had significantly larger diastolic asynchrony (5.7 +/- 2.1%) than those with pacing LBBB (2.9 +/- 1.1%) and those with idiopathic LBBB and normal EF (2.0 +/- 0.6%). Diastolic asynchrony was the only independent factor that correlated with LVEF (r = -0.64, p <0.001). Thus, idiopathic LBBB with LV dysfunction is characterized not only by systolic but also by diastolic asynchrony.

The objective of this study was to investigate the clinical features of Korean patients with Brugada syndrome (BS). Between June 1998 and April 2002, 15 consecutive patients with BS (13 men, 2 women; mean age, 44+/-10 years) were identified. Eight patients had experienced at least 1 episode of aborted sudden death, 5 patients had had an episode of syncope or chest pain, and 2 patients were asymptomatic at diagnosis. The electrocardiographics (ECGs) of all patients showed spontaneous ST-segment elevation in leads V(1-3) at baseline and 13 patients (87%) showed transient normalization of the ST-segment elevation during follow-up. Twelve patients received an implantable cardioverter-defibrillator (6 patients with aborted sudden death, 5 patients with syncope or chest pain, 1 asymptomatic patient). During a mean follow-up of 19+/-14 months, arrhythmic events occurred in 5 of the 6 patients with aborted sudden death and in 1 of the 5 patients with syncope or chest pain. None of the asymptomatic patients developed any symptoms suggestive of an arrhythmic event. The clinical and ECG manifestation of BS in Korean patients is diverse, but the dynamic nature of the ST segment provides an important clue to the diagnosis of BS. Recurrence of malignant arrhythmia is extremely high in those patients who initially present with aborted sudden death.

Background: The benefits of residual flow to the infarct zone have been demonstrated in acute myocardial infarction (AMI), but its relation to ventricular tachyarrhythmias remains uncertain., Hypothesis: This study was undertaken to test the hypothesis that residual flow is an important determinant of lethal ventricular tachyarrhythmias (sustained ventricular tachycardia or ventricular fibrillation) during the acute phase of AMI., Methods: We investigated the determinants of lethal ventricular tachyarrhythmias within 24 h after the onset of symptoms in 310 consecutive patients (256 men; age 57.4 +/- 11.5 years) with AMI undergoing primary angioplasty. Patients were divided into two groups: those with (Group 1, n = 40) and those without (Group 2, n = 270) lethal ventricular tachyarrhythmias. Residual flow was defined as the presence of anterograde flow (> or = Thrombolysis in Myocardial Infarction [TIMI] 2 flow) or good angiographic collaterals (> or = grade 2) on a preintervention angiogram., Results: Univariate determinants of lethal ventricular tachyarrhythmias were cardiogenic shock, systolic blood pressure, peak level of creatine kinase, culprit artery, spontaneous reperfusion, and residual flow. In multivariate analysis, however, cardiogenic shock (odds ratio [OR] = 4.79, 95% confidence interval [CI] 1.63-14.11, p = 0.004), residual flow (OR = 0.34, 95% CI 0.14-0.81, p = 0.015), and the right coronary artery as the culprit artery (OR = 2.09,95% CI 1.03-4.22, p = 0.040) were independent determinants of these arrhythmias. In-hospital death occurred in 10 patients and was more common in Group 1 than in Group 2 (12.5% vs. 1.9%, respectively, p < 0.001)., Conclusion: The absence of residual flow was associated with greater risk of lethal ventricular tachyarrhythmias during the acute phase of AMI, suggesting a protective role of residual flow against these arrhythmias in AMI.

A retrospective analysis of clinical data of 71 patients with constrictive pericarditis (CP) diagnosed by echo-Doppler technique (mean age, 49+/-17) was done. In 27 patients (38%), the etiology was unknown, and the three most frequent identifiable causes were tuberculosis (23/71, 32%), cardiac surgery (8/71, 11%), and mediastinal irradiation (6/71, 9%). Pericardiectomy was performed in 35 patients (49%) with a surgical mortality of 6% (2/35), and 11 patients (15%, 11/ 71) showed complete resolution of constrictive physiology with medical treatment. Patients with transient CP were characterized by absence of pericardial calcification, shorter symptom duration, and higher incidence of fever, weight loss, and tuberculosis. The 5-yr survival rates of patients with transient CP and those undergoing pericardiectomy were 100% and 85+/-6%, respectively, which were significantly higher than that of patients without undergoing pericardiectomy (33+/-17%, p=0.0083). Mediastinal irradiation, higher functional class, low voltage in ECG, low serum albumin, and old age were the independent variables associated with a higher mortality. Tuberculosis is still the most important etiology of CP in Korea, and not infrequently, it may cause transient CP. Early diagnosis and decision-making using follow-up echocardiography are crucial to improve the prognosis of patients with CP.

Background: Atrial mechanical dysfunction and its recovery time course after successful radiofrequency ablation of chronic atrial flutter (AFL) has been largely unknown. We serially evaluated left atrial function by echocardiography after successful ablation of chronic atrial flutter., Methods: In 13 patients with chronic AFL, mitral E wave A wave, and the ratio of A/E velocity were measured at 1 day, 1 month, 3 months and 6-12 months after successful radiofrequency (RF) ablation. Doppler tissue imaging (DTI) technique was also used to avoid load-dependent variation in the flow velocity pattern., Results: Left atrial mechanical function, assessed by A wave velocity and the annular motion, was depressed at 1 day, but improved significantly at 1 month and maintained through 6-12 months after the ablation. Left atrial size did not change significantly., Conclusion: Left atrial mechanical function was depressed immediately after successful RF ablation of chronic AFL, but it improved significantly after 1 month and was maintained over one year.

We have investigated the effect of alpha(1)-adrenergic agonist phenylephrine (PE) on acetylcholine-activated K(+) currents (I(KACh)). I(KACh) was recorded in mouse atrial myocytes using the patch clamp technique. I(KACh) was activated by 10 microm ACh and the current decreased by 44.27 +/- 2.38% (n = 12) during 4 min due to ACh-induced desensitization. When PE was applied with ACh, the extent of desensitization was markedly increased to 69.34 +/- 2.22% (n = 9), indicating the presence of PE-induced desensitization. I(KACh) was fully recovered from desensitization after a 6-min washout. PE-induced desensitization of I(KACh) was not affected by protein kinase C inhibitor, calphostin C, but abolished by phospholipase C (PLC) inhibitor, neomycin. When phophatidylinositol 4,5-bisphosphate (PIP(2)) replenishment was blocked by wortmannin (an inhibitor of phophatidylinositol 3-kinase and phophatidylinositol 4-kinase), desensitization of I(KACh) in the presence of PE was further increased (97.25 +/- 7.63%, n = 6). Furthermore, the recovery from PE-induced desensitization was inhibited, and the amplitude of I(KACh) at the second exposure after washout was reduced to 19.65 +/- 2.61% (n = 6) of the preceding level. These data suggest that the K(ACh) channel is modulated by PE through PLC stimulation and depletion of PIP(2).

Objectives: This study was performed to evaluate the usefulness of temperature-guided radiofrequency catheter ablation for the elimination of accessory pathway conduction in patients with Wolff-Parkinson-White syndrome., Methods: Temperature-guided radiofrequency catheter ablation was attempted in 138 patients with 144 accessory pathways (88 pathways along the left free wall, 5 in the anteroseptal region, 2 in the midseptal region, 19 in the posteroseptal region and 30 along the right free wall). The energy source was a HAT 200S which regulated the power automatically to the set temperature of 70 degrees C. Radiofrequency current was delivered through a thermocatheter to the atrial or ventricular side of mitral or tricuspid annulus., Results: Accessory pathway conduction was eliminated in 130 of 144 pathways (90.3%). The mean power outputs of the successful ablations at the atrial side of the annulus were higher than those at the ventricular side (34.0 +/- 8.9W versus 20.0 +/- 7.6W, p < 0.01), but the maximum temperatures were lower at the atrial side of the annulus than those at the ventricular side (66.4 +/- 14.0 degrees C versus 77.2 +/- 6.4 degrees C, p < 0.01). There were 3 non-fatal complications (2.1%), 2 patients with hemopericardium and 1 with femoral artery thrombus, during or after ablation procedures. Recurrences of AV re-entrant tachycardia or delta wave on the electrocardiogram occurred in 4 patients (2.8%) who had successful second procedures. There were no late complications during a mean follow-up period of 41 +/- 25 months (range, 3 to 55)., Conclusion: We conclude that 1) temperature-guided radiofrequency catheter ablation can be performed reliably and safely in eliminating accessory pathway conduction in patients with WPW syndrome, and 2) temperature monitoring and adjustment of the power to the set temperature during ablation would be useful for the avoidance of impedance rises and coagulum formation.

Rupture of the heart as a complication of myocardial infarction is one of the most common causes of in-hospital mortality. Rupture of the free wall of the ventricle or interventricular septum has a poor prognosis when treated conservatively. So, rupture of the heart after infarction requires prompt diagnosis and early surgical repair despite the high overall incidence of early operative mortality before hemodynamic deterioration and multiorgan failures develop. Rupture of the left ventricle results in pseudoaneurysm if the overlying pericardium adhers to the surface of the heart. Pseudoaneurysms which rarely develop after infarction, tend to rupture. Their presence alone is an indicator for operation because of the very poor prognosis following rupture. We experienced successful management of 2 rare complications after acute myocardial infarction: ventricular septal defect and pseudoaneurysm. The first patient was a 49-year-old man who had an apical septal defect. His electrocardiogram showed Q wave in leads V2-V6, II, III, and aVF but a coronary angiogram showed normal findings. He was successfully treated by patch closure of the septal defect. The second patient was a 65-year-old female who had false aneurysm of the left ventricle. She had neither chest pain nor abnormality on the electrocardiogram. A coronary angiogram showed complete occlusion of the distal circumflex artery. Under cardiopulmonary bypass, the neck of the aneurysmal sac was successfully closed with a prolene suture.