Effects of 4 Statins on Regression of Coronary Plaque in Acute Coronary Syndrome.

BACKGROUND: There is no information on differences in the effects of moderate- and low-intensity statins on coronary plaque in patients with acute coronary syndrome (ACS). The aim of this study was to compare the effects of 4 different statins in patients with ACS, using intravascular ultrasound (IVUS). METHODS AND RESULTS: A total of 118 patients with ACS who underwent IVUS before percutaneous coronary intervention and who were found to have mild to moderate non-culprit coronary plaques were randomly assigned to receive either 20 mg/day atorvastatin or 4 mg/day pitavastatin (moderate-intensity statin therapy), or 10 mg/day pravastatin or 30 mg/day fluvastatin (low-intensity statin therapy). IVUS at baseline and at end of 10-month treatment was available in 102 patients. Mean percentage change in plaque volume (PV) was -11.1±12.8%, -8.1±16.9%, 0.4±16.0%, and 3.1±20.0% in the atorvastatin, pitavastatin, pravastatin, and fluvastatin groups, respectively (P=0.007, ANOVA). Moderate-intensity statin therapy induced regression of PV, whereas low-intensity statin therapy produced insignificant progression (-9.6% vs. 1.8%, P<0.001). On multivariate linear regression analysis, moderate-intensity statin therapy (P=0.02) and uric acid at baseline (P=0.02) were significant determinants of large percent PV reduction. LDL-C at follow-up did not correlate with percent PV change. CONCLUSIONS: Moderate-intensity statin therapy induced regression of coronary PV, whereas low-intensity statin therapy resulted in slight progression of coronary PV in patients with ACS. (Circ J 2016; 80: 1634-1643).

Development of Atrioventricular Block and Diagnostic Value of Stored Electrograms in Patients With Sick Sinus Syndrome and Implanted Pacemaker.

BACKGROUND: The incidence of atrioventricular block (AVB) in pacemaker patients with sick sinus syndrome (SSS) is not yet known. The aim of this study was to analyze AVB episodes in SafeR mode based on stored electrograms (EGM), and determine the occurrence rate and risk factors for advanced AVB in a pacemaker population with SSS. METHODS AND RESULTS: The study included 50 consecutive patients with SSS without a history of advanced AVB who had a dual-chamber pacemaker programmed in SafeR mode. A total of 377 EGM stored in the pacemakers as AVB episodes fulfilling the second- or third-degree criterion were analyzed. Of 377 EGM, 73 EGM (19.4%) were appropriate episodes, whereas the other EGM did not show actual AVB, and showed atrial tachyarrhythmia, ventricular event in the blanking period, or premature atrial contractions with block. On EGM analysis, advanced AVB occurred in 9 patients (18%), and the occurrence rate was 11.7% per year. Moreover, on multivariate analysis ß-blocker use was an independent risk factor for advanced AVB (OR, 9.10; P=0.004). CONCLUSIONS: The occurrence rate of advanced AVB in patients with SSS is much higher than previously reported, and ß-blocker use is an independent risk factor for advanced AVB. SafeR is useful to detect latent AVB. Stored EGM, however, sometimes include inaccurately classified events.

Association between gait speed as a measure of frailty and risk of cardiovascular events after myocardial infarction.

OBJECTIVES: This study sought to determine the additional clinical value of gait speed to Framingham risk score (FRS), cardiac function, and comorbid conditions in predicting cardiovascular events in patients with ST-segment elevation myocardial infarction. BACKGROUND: There is growing evidence that gait speed is inversely associated with all-cause mortality, particularly cardiovascular mortality, among the elderly. METHODS: We undertook a single-center prospective observational study of gait speed in 472 patients with ST-segment elevation myocardial infarction in Japan, between 2001 and 2008. Gait speeds were measured using a 200-m course before discharge in all patients, and we followed up cardiovascular events, which consist of cardiovascular deaths, nonfatal myocardial infarctions, and nonfatal ischemic strokes. RESULTS: During the 2,596 person-years of follow-up, 83 patients (17.6%) experienced cardiovascular events. Cardiovascular events increased across decreasing tertiles of gait speed (fastest tertile: n = 5, 3.2%; middle tertile: n = 20, 12.6%; slowest tertile, n = 58, 36.7%). By multiple adjusted Cox proportional hazards analysis, gait speed was a significant and independent predictor of cardiovascular events (hazard ratio for increasing 0.1 m/s of gait speed: 0.71, 95% confidence interval [CI]: 0.63 to 0.81, p < 0.001). The addition of gait speed to the model incorporating FRS, B-type natriuretic peptide levels, and comorbidity index improved reclassification (net reclassification index: 32.8%, 95% CI: 17.4 to 48.3, p < 0.001) and the C-statistics with a reasonable global fit and calibration (C-statistics: from 0.703 [95% CI: 0.636 to 0.763] to 0.786 [95% CI: 0.738 to 0.829]). CONCLUSIONS: Among patients with ST-segment elevation myocardial infarction, slow gait speed was significantly associated with an increased risk of cardiovascular events. (Gait Speed for Predicting Cardiovascular Events After Myocardial Infarction; NCT01484158).

A case of giant coronary artery aneurysm and literature review.

A 40-year-old man was referred to our hospital because of an abnormal shadow on the left cardiac border on the chest roentgenogram at the regular medical health examination without any symptoms. A giant coronary artery aneurysm of left anterior descending artery with a maximum diameter of approximately 50 mm was detected with computed tomography and coronary angiography. The patient was treated and followed up medically. Four years later, the size of the coronary artery aneurysm became larger. Then resection of the coronary artery aneurysm and coronary artery bypass grafting were successfully performed. Coronary artery aneurysms are rare in adults and are usually found in association with Kawasaki disease, coronary atherosclerosis, and so on. We also review the literature of giant coronary artery aneurysms exceeding 50 mm in diameter.

Optimal programming of the atrioventricular delay using the phonocardiogram.

PURPOSE: To predict the optimal atrioventricular (AV) delay using the phonocardiogram (PCG). METHODS: We studied 12 recipients of cardiac resynchronization therapy (CRT) system and eight recipients of dual-chamber pacemakers implanted for AV block with normal left ventricular (LV) function. The amplitude of the first heart sound (S1) was recorded by PCG and the LV outflow tract (OT) time-velocity integral (TVI) was measured by pulsed Doppler echocardiography. The AV delay was prolonged in 20-ms increments, from 60 ms to 240 ms. Ishikawa's method was used for the echocardiographic optimization of the AV delay. The relation between S1 amplitude and the AV delay was analyzed. RESULTS: The correlation between the amplitude of S1 and the length of AV delay showed an S-shaped curve. The AV delay at the inflection point of each patient's S-shaped curve (161.2 +/- 19.5 ms) was positively correlated with the optimal AV delay determined by echocardiography (148.3 +/- 16.9 ms, r = 0.83, P < 0.001). In addition, there was a positive correlation between the AV delay at the maximal TVI of LVOT (150.8 +/- 22.7 ms) and the AV delay at the inflection point of the S-shaped curve (159.5 +/- 24.9 ms, r = 0.87, P < 0.001). In two CRT system recipients, an optimal AV delay could not be found by echocardiography; however, an optimal AV delay could be determined by PCG. CONCLUSIONS: A high correlation was observed between the optimal AV delay determined by phonocardiography versus echocardiography.

Novel method of predicting the optimal atrioventricular delay in patients with complete AV block, normal left ventricular function and an implanted DDD pacemaker.

BACKGROUND: The optimal atrioventricular (AV) delay setting is important for achieving optimal AV synchrony in patients with an implanted DDD pacemaker. Using pulsed Doppler echocardiography is the most common method of predicting the optimal AV delay, but it is a complicated and time-consuming method. Therefore, an automatic optimizing function of the AV delay at different atrial rates is desirable for achieving a favorable hemodynamic state. This study aimed to predict the optimal AV delay using phonocardiography. METHODS AND RESULTS: The amplitude of the first heart sound (S1) recorded on the phonocardiogram was measured with different AV delays in 6 patents with complete AV block, normal left ventricular function and an implanted DDD pacemaker. The correlation between the amplitude of S1 and the length of the AV delay was a cubic curve (y=974.15x(3)-23.084x(2)-8.0074x+0.7495, R2=0.9511). The length of the AV delay at the inflection point of the curve showed a significant positive correlation with the optimal AV delay determined by pulsed Doppler echocardiography (R=0.9254, P<0.01). CONCLUSIONS: This study demonstrated a novel simple method of predicting the optimal AV delay using phono-cardiography.

Long-term electrocardiographic follow-up from childhood of an adult patient with Brugada syndrome associated with sick sinus syndrome.

We had the unique opportunity of following the electrocardiographic (ECG) course of a 13-year-old male with sinus dysfunction and atrial flutter who subsequently developed a Brugada-type ECG pattern associated with sick sinus syndrome at 25 years old. Family history showed that the patient's mother and maternal grandfather suddenly died while sleeping at night. When the patient was 13 years old, he lost consciousness after running a marathon. The patient was diagnosed with sinus dysfunction and atrial flutter, and he underwent pacemaker implantation at 15 years old. ECG examinations performed between 13 and 20 years old showed incomplete right bundle branch block and ST elevation with early depolarization. On ECG examinations performed when the patient was 21 years old and thereafter, the V(2) lead always showed a saddleback-type ST elevation. At 25 years old, the late potential was positive and the electrophysiological study induced ventricular fibrillation. A challenge test with pilsicainide showed remarkable ST elevation by the V(2) lead. The 24-h Holter ECG monitoring showed remarkable ST elevation after eating a snack and during night time when the patient was asleep. The patient was diagnosed with Brugada syndrome and an implantable cardioverter-defibrillator was implanted. Genetic analysis did not reveal mutation of the SCN5A gene.

Efficacy of consistent atrial pacing algorithm for suppression of atrial arrhythmias in patients with sick sinus syndrome and atrial fibrillation.

Atrial overdrive provides the best opportunity to suppress atrial arrhythmias. Atrial preference pacing (APP) algorithm has been designed to achieve a high percentage of atrial pacing. The aim of this study was to assess the efficacy of APP algorithm in patients with implanted pacemakers and tachycardia-bradycardia syndrome. The subjects were 17 patients (mean age, 71.7+/-9.0 years old, 4 males) implanted with a DDDR pacemaker Thera DR (Medtronic, Minneapolis, MN, USA). All patients had sick sinus syndrome and paroxysmal atrial fibrillation before pacemaker implantation. Informed consent was obtained from each participant before enrollment. DDDR and mode switch or APP were randomly programmed. After two weeks, the pacing mode was switched to another mode. The percentage of atrial pacing was significantly higher in APP than in DDDR (97.7+/-1.4 versus 52.3+/-30.8, P<0.0001). Atrial premature beat counts were significantly greater in DDDR than in APP (30689+/-42534 versus 7717+/-10700, P<0.005). There was no significant difference in mode switch episode counts between DDIR and APP (2.6+/-5.5 versus 8.4+/-19.2, NS). Although there was no significant difference in mode switch episode counts between DDDR and APP, APP algorithm can successfully prevent atrial premature beats in patients with tachycardia-bradycardia syndrome.

Effects of right atrial pacing preference in prevention of paroxysmal atrial fibrillation: Atrial Pacing Preference study (APP study).

BACKGROUND: Several preliminary studies have indicated that atrial pacing can prevent atrial tachyarrhythmias. The suggested mechanisms by which pacing may be effective include suppression of premature atrial beats. METHODS AND RESULTS: The Atrial Pacing Preference (APP; Guidant, St Paul, MN, USA) algorithm allows the pacemaker to maintain a pacing rate slightly higher than the sinus rate. The preventive effects of APP on paroxysmal atrial fibrillation (AF) were studied in 51 patients (70+/-11 years). Nine patients did not complete the protocol. The pacemaker was programmed in random order to APP off and APP on at 3 different settings (ie, 8, 16 and 32 cycles) for 4 weeks each, using a cross-over design. Percentage atrial pacing was lower in APP off than at the other settings. Premature beat counts were greater in APP off than at the other settings. There was a significant difference in mode switch episode counts between APP off and the most effective setting (3,818+/-15,356 vs 596+/-1,719; p<0.01). CONCLUSIONS: The APP algorithm is a promising method for preventing atrial tachyarrhythmia in patients with an implanted pacemaker and AF. Optimizing the setting of the APP algorithm is an important issue in the prevention of AF.

Reducing ventricular pacing in sinus node dysfunction.

BACKGROUND: The use of DDIR mode has been limited since the advent of mode switch in the DDDR mode. In patients with AV block, DDDR is necessary to maintain AV synchrony. However, DDIR mode may still be beneficial for patients with intact AV conduction. The aim of this study was to compare the incidence of ventricular pacing and atrial tachyarrhythmia in DDIR and DDDR with mode switch in a randomized, single-blind, crossover study, and discuss the utility of both modes. METHODS AND RESULTS: Twenty-four patients (8 males) with bradycardia-tachycardia syndrome and no signs of AV block (mean age 70.1 +/- -9.1 years) were enrolled and randomized to DDIR or DDDR modes with the leads placed at the right atrial appendage and right ventricular apex. After 12 weeks, patients were switched to the opposite mode. During the study period, atrial high rate episodes and other pacemaker diagnostic data were collected. Significantly less ventricular pacing was observed in DDIR mode (DDIR versus DDDR; 48.9%, 76.5%, P = 0.0002) and atrial high rate episodes were significantly lower in DDIR mode (DDIR versus DDDR; 1.32, 1.85 per day, P < 0.05). CONCLUSION: In patients with sinus node dysfunction and intact AV conduction, DDIR mode may have important implications for simplifying device programming, device longevity, and to avoid atrial tachyarrhythmia.

Reverse perfusion-metabolism mismatch predicts good prognosis in patients undergoing cardiac resynchronization therapy: a pilot study.

BACKGROUND: Cardiac resynchronization therapy (CRT) improves glucose metabolism in the septum of patients with heart failure, so in the present study the predictive value of combined fluorodeoxyglucose (FDG)-positron emission tomography (PET) and metoxy-isobutyl isonitrile (MIBI)-single photon emission computed tomography (SPECT) for the prognosis of patients undergoing CRT was investigated. METHODS AND RESULTS: Fourteen patients (70.3+/-8.2 years) who underwent FDG-PET and MIBI-SPECT before implantation of a biventricular pacemaker were enrolled. The total number of matches, mismatches, reverse mismatches, summed difference score (SDS: sum total of FDG - MIBI scores) and SDS per segment (%SDS) in each of 5 areas of myocardium (septum, anterior, lateral, inferior area, apex) was calculated and compared between the survival groups (all survival: survival group; survival without ischemic heart disease (IHD): non-IHD survival group) and non-survival group. Both the number of reverse mismatch segments and the %SDS in the septum in the non-IHD survival group were significantly greater than in the non-survival group (3.2+/-1.6 vs 0.5+/-0.6, p<0.05; 0.62+/-0.61 vs -0.11+/-0.19, p<0.05). The receiver-operating characteristics curves for prognosis showed that the area under the curve for the number of reverse mismatch segments in the septum (0.93; confidence interval 0.61-0.98) was significantly greater. CONCLUSION: A reverse mismatch pattern in the septum can predict a good prognosis for patients treated with CRT.

Suppression of atrial fibrillation by atrial pacing.

BACKGROUND: Atrial fibrillation (AF) is a common arrhythmia in patients with an implanted pacemaker, but the role of atrial pacing in preventing AF is still unclear. METHODS AND RESULTS: Sixty-six patients (67.8+/-12.1 years) were enrolled: 54 with sick sinus syndrome (SSS), 11 with atrioventricular blocks (AVB), and 1 with SSS and AVB. The prevalence of AF was investigated. In 22 patients with AF, the AF burden was estimated under "back-up pacing" (40-50 beats/min), then under "atrial pacing" (60-85 beats/min). The prevalence of AF in the SSS group tended to be higher than that in the AVB group (48.1% vs 18.2%, p=0.06). The AF burden in patients with a percentage of atrial pacing (% atrial pacing) <50% was significantly greater than that in patients with % atrial pacing >or=50% (12.5+/-21.1% vs 4.2+/-10.3%, p<0.05). AF disappeared immediately after "atrial pacing" in 4 patients (18.2%). In 9 patients (40.9%), the AF burden decreased gradually, and AF disappeared in 6 patients (27.3%) after 207.9+/-130.2 days. CONCLUSION: The prevalence of AF may be higher in patients with SSS than in those with AVB. Atrial pacing has a preventive effect on AF, and the effect of atrial pacing is not always immediate but is progressive in some patients.

Daily shock impedance measured by implantable cardioverter defibrillator is useful in the management of congestive heart failure.

BACKGROUND: Clinical data suggest that changes in intrathoracic impedance and fluid accumulation in the lung are inversely related. METHODS AND RESULTS: Daily shock impedance (S-IMP) was evaluated in 29 patients in whom a Ventak Prizm 2 was implanted (61+/-14 years old). The mean follow-up period was 45+/-18 weeks, during which 6 patients had episodes of decompensated heart failure (DHF group) and the others did not (NHF group). There was no significant difference between the DHF group and NHF group in the mean value of the S-IMP (46.4 +/-3.3 vs 45.4+/-5.4 Omega). The range of S-IMP in individual patients in the DHF group was significantly greater than that in the NHF group (13.8+/-0.38 vs 7.0+/-3.1 Omega, p<0.0001). Mean weekly change of S-IMP in individual patients in the DHF group was significantly greater than that in the NHF group (1.583+/-0.630 vs 1.092+/-0.361 Omega, p<0.0176). When the cut-off value was set at >1.242 Omega, sensitivity was 100% and specificity was 69.6% for a diagnosis of DHF. There was a significant negative correlation between the percent increases in brain natriuretic peptide (BNP) and S-IMP (correlation coefficient: -0.775 p<0.0001) in the DHF group. There was an inverse relation between BNP and S-IMP. CONCLUSIONS: Measurement of shock impedance may be useful in the management of congestive heart failure.

Assessment of atrial regional wall motion using strain Doppler imaging during biatrial pacing in the bradycardia-tachycardia syndrome.

INTRODUCTION: Biatrial pacing is expected to have preventive effects on atrial fibrillation. METHODS: We evaluated atrial regional wall motion by strain Doppler imaging (SDI) in 6 patients (62.5 +/- 11.3 [SD] years), who suffered from atrial fibrillation, with an implanted biatrial pacemaker. SDI was performed and atrial regional wall motion was estimated during biatrial (BiA) and right atrial appendage (RAA) pacing. RESULTS: There was no significant difference in the interval from the pacing spike to the peak strain of the atrium in the lateral right atrium (LRA) between BiA and RAA pacing. However, there was a significant difference in the septal atrium (SA) between BiA and RAA pacing (225.0 +/- 19.9 vs 267.2 +/- 15.7 ms, P < 0.0001) and in the lateral left atrium (LLA) between BiA and RAA pacing (216.7 +/- 21.6 vs 275.0 +/- 16.2 ms, P < 0.0001). There were significant differences in the time difference of peak strain between BiA and RAA pacing in each atrial segment (LRA-AS: 2.2 +/- 5.9 vs 45.0 +/- 11.9 ms, P = 0.0016, SA-LLA: -8.3 +/- 5.5 vs 7.8 +/- 2.7 ms, P < 0.0011, LRA-LLA: -6.1 +/- 3.9 vs 52.8 +/- 13.2 ms, P = 0.0002). There was no significant difference in the interval from the pacing spike to the inflection point of atrial strain (S-I) of LRA. However, there were significant differences in S-I of SA (83.9 +/- 24.1 vs 129.9 +/- 30.6 ms, P = 0.0086) and LLA (102.2 +/- 37.9 vs 166.1 +/- 13.4 ms, P = 0.0028). CONCLUSION: BiA pacing improved the synchronicity of regional wall motion of both atrium.

Comparison of nifekalant and lidocaine for the treatment of shock-refractory ventricular fibrillation.

BACKGROUND: Although nifekalant is a class III antiarrhythmic agent without negative inotropic activity, its effect in patients with shock-refractory ventricular fibrillation remains unclear. METHODS AND RESULTS: Patients who had an out-of-hospital cardiac arrest with ventricular fibrillation that persisted after 3 shocks from an external defibrillator, intravenous epinephrine, and another shock were retrospectively studied. The patients received lidocaine from January 1997 through June 2001 and nifekalant from July 2001 through December 2004. Short-term survival rates (survival to hospital admission and 24-h survival) were compared between the groups. The study group comprised 120 patients (mean age: 62+/-16 years): 55 received nifekalant and 65 received lidocaine. Age, sex, history of ischemic heart disease, whether arrest was witnessed or not and time to arrival at the hospital did not differ significantly between the groups. As compared with lidocaine, nifekalant was associated with significantly higher rates of survival to hospital admission (67% vs 37%, p<0.001) and 24-h survival (53% vs 31%, p=0.01). Multivariate analysis showed that treatment with nifekalant and early initiation of cardiopulmonary resuscitation were independent predictors of 24-h survival. CONCLUSIONS: As compared with lidocaine, nifekalant may improve short-term survival in patients with out-of-hospital cardiac arrest due to shock-refractory ventricular fibrillation.

Evaluation of myocardial glucose metabolism before and after recovery of myocardial function in patients with tachycardia-induced cardiomyopathy.

BACKGROUND: We assessed left ventricular (LV) function and myocardial glucose metabolism by fluoro-18-deoxyglucose (18F-FDG) positron emission tomography (PET) in patients with tachycardia-induced cardiomyopathy (TC). METHODS: The subjects were 42 patients with heart disease, consisting of 7 patients with TC (61.4 +/- 19.0 years, LVEF 34.1%+/- 10.6%) and 35 with ischemic heart disease (IHD) (63.1 +/- 10.8 years, LVEF 49.9%+/- 13.5%). Five volunteers with normal ECG were the control group. All of the patients underwent 18F-FDG PET and echocardiography, and all of the patients with TC underwent 18F-FDG PET and echocardiography before and 6 months after antitachycardia therapy. Six patients underwent radiofrequency catheter ablation (RFCA) and 1 patient was medically treated with antitachycardia therapy. Myocardial glucose metabolism was assessed semiquantitatively by using the % dose uptake of 60 kg of BW (% dose uptake). RESULTS: Mean % dose uptake of the control group was 5.52 +/- 0.54%. After antitachycardia therapy, LVEF significantly improved (34.1 +/- 10.6% vs 54.3 +/- 13.6%, P < 0.01), and % dose uptake also significantly improved (1.26 +/- 0.55% vs 1.49 +/- 0.62%, P < 0.05). Patients with IHD showed higher % dose uptake than those with TC before antitachycardia therapy (3.18 +/- 1.36 vs 1.26 +/- 0.55%, P < 0.01), controls showed higher value of % dose uptake than TC before antitachycardia therapy (5.52 +/- 0.54% vs 1.26 +/- 0.55%, P < 0.01). CONCLUSION: Semiquantitative analysis of 18F-FDG PET showed that antitachycardia therapy improved myocardial glucose metabolism in patients with TC.

[Improvement of central sleep disordered breathing with severe congestive heart failure by biventricular pacing therapy: a case report].

A 74-year-old man with ischemic cardiomyopathy was repeatedly admitted for congestive heart failure. His left ventricular ejection fraction was 21% and diastolic left ventricular dimension was 73.5mm by echocardiography. He was treated with biventricular pacing and heart failure improved from New York Heart Association class III to II. Before the treatment, brain natriuretic peptide was 600.5 pg/ml. Apnea hypopnea index was 23.8 and all events were central type. After biventricular pacing, apnea hypopnea index was improved to 21.9 after 11 days, 14.0 after 33 days, and 4.8 after 48 days. His left ventricular ejection fraction was 36%, diastolic left ventricular dimension was 71.4mm, and brain natriuretic peptide was 383.8 pg/ml. In this patient, central sleep disordered breathing was improved by biventricular pacing therapy after only 48 days.

Beneficial effects of biatrial pacing on cardiac function in patients with bradycardia -- tachycardia syndrome.

BACKGROUND: Biatrial (BiA) pacing prevents atrial fibrillation. By an unknown mechanism. The purpose of this study was to use Doppler echocardiography to evaluate the hemodynamic effects during BiA pacing. METHODS AND RESULTS: The subjects were 7 patients with bradycardia - tachycardia syndrome with an implanted pacemaker. Atrial pacing sites were the right atrial appendage (RAA) and coronary sinus. P wave duration during BiA pacing (123 +/-16 ms) was significantly shorter than during either RAA pacing (167+/-19 ms, p<0.05) or sinus rhythm (148+/-12 ms, p<0.05). Doppler echocardiography revealed a greater cardiac output during BiA pacing than during RAA pacing (4.1+/-1.1 vs 3.5+/-0.7 L/min, p=0.042). The Doppler waveform of transmitral flow indicated that the left ventricular contraction interrupted the atrial filling wave during RAA pacing. The interval between the end of the atrial filling wave of transmitral flow and the mitral valvular closing sound was significantly increased by BiA pacing compared with RAA pacing (56+/-65 vs 40+/-57 ms, p=0.047). CONCLUSION: Cardiac hemodynamics were improved by BiA pacing and reduction of left atrial load may be one of the mechanisms.

[Neurally mediated syncope with significant cardiac arrest and asymptomatic multiple cerebral infarctions: a case report].

A 32-year-old man had suffered episodes of loss of consciousness since childhood. He was admitted to another hospital because of three syncopal episodes in one day. He was referred to our hospital because of asymptomatic multiple lacunae indicating cerebral infarction on magnetic resonance imaging. He lost consciousness with convulsion followed by a 70-second interval of cardiac arrest during blood sampling. He reported the onset of his usual prodromal symptoms after 1 min in the 80 degrees head-up tilt position. He lost consciousness 2 min after returning to the supine position. Electrocardiography demonstrated a 10-second interval of cardiac arrest. Magnetic resonance angiography, carotid arterial echography, brain perfusion scintigraphy, and laboratory chemistry and hematology examinations identified no significant findings. Cerebral infarction had occurred in watershed areas, so hemodynamic change during cardiac arrest may be the main cause of the infarctions. He suffered no further syncopal or presyncopal episodes after implantation of a DDD pacing system.

[Successful defibrillation by disconnection of superior vena cava electrode for high defibrillation threshold: a case report].

A 72-year-old man with dilated cardiomyopathy and sustained ventricular tachycardia was treated with amiodarone. He visited another hospital because of loss of consciousness. Electrocardiography showed 2: 1 atrioventricular block. Ambulatory electrocardiography showed total heart beats were 59,700 per day. He was referred to our hospital to evaluate his heart. Several types of ventricular tachycardia and ventricular fibrillation were induced by program stimulation during the electrophysiological study. Therefore, an implantable cardioverter-defibrillator was introduced. During defibrillation threshold tests, ventricular fibrillation could not be terminated by the maximal output of 31J. Despite changing the polarity and lead position, stable defibrillation could not be obtained. Finally, successful defibrillation could only be achieved by disconnection of the superior vena cava electrode.