An Inappropriate Shock Case Early after Implantation of a Subcutaneous Cardiac Defibrillator by Subcutaneous Entrapped Air.

A 17-year-old woman was resuscitated from cardiac arrest due to ventricular fibrillation and was diagnosed with concealed long QT syndrome. She underwent subcutaneous implantable cardiac defibrillator (S-ICD) implantation at our hospital. The device electrogram immediately after implantation was normal. Four days after implantation, she received an inappropriate shock. The device interrogation revealed a continuous baseline shift and frequent oversensing for low amplitude signals, followed by a shock. A chest radiograph in the orthogonal view showed entrapped subcutaneous air surrounding the distal electrode. Entrapped subcutaneous air can cause inappropriate shocks in the early period after S-ICD implantation.

Characteristics and Prognosis of Pacemaker-Identified New-Onset Atrial Fibrillation in Japanese People.

BACKGROUND: The characteristics and prognosis of implanted pacemaker-identified new-onset atrial fibrillation (AF) in Japanese people has not been well evaluated.Methods and Results:A total of 395 consecutive patients with newly implanted pacemakers were retrospectively analyzed between January 2010 and December 2015 at Yokohama City University Hospital. Patients with a prior history of AF, VVI mode pacemaker, congenital heart disease, severe valvular heart disease, and cardiovascular surgery before pacemaker implantation were excluded. Among the remaining patients, 44 (21.3%) developed new AF during follow-up (mean follow-up, 1,115±651 days; range, 9-2,176 days). Patients with new-onset AF had a significantly higher CHADS2score (2.09±1.27 vs. 1.31±1.08, P<0.001) and CHA2DS2-VASc score (3.00±1.39 vs. 2.26±1.19, P<0.001) compared with those without new-onset AF. On Cox regression analysis only age at implantation was significantly correlated with new-onset AF. Interestingly, the incidence of hospitalization due to heart failure was significantly higher in the new-onset AF than in the without new-onset AF group. CONCLUSIONS: A total of 21.3% of pacemaker-implanted patients with high CHADS2and CHA2DS2-VASc scores developed new-onset AF during a mean follow-up of 3.1 years; and pacemaker-identified AF was associated with an increased risk of worsening heart failure.

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.

J-waves in patients with an acute ST-elevation myocardial infarction who underwent successful percutaneous coronary intervention: prevalence, pathogenesis, and clinical implication.

AIMS: The prevalence, clinical significance, and pathogenesis of J-waves were studied in the patients with an ST-elevation myocardial infarction (MI) after percutaneous coronary intervention (PCI). METHODS AND RESULTS: One hundred and fifty-two consecutive patients with an acute ST-elevation MI were included. The mean age was 68.6 ± 13.5 years, and 78.3% of the patients were male. Following successful PCI, 12-lead electrocardiograms (ECGs) were monitored, and J-waves were measured 1 week after the MI and analysed in relation to the location of the MI and arrhythmias. Clinical and ECG parameters were compared between the groups with and without J-waves. The rate dependency of the J-wave amplitude was analysed in the conducted atrial premature beats (APBs). J-waves were present in 60.5% (≥0.1 mV) or 48.9% (≥0.2 mV) of the 152 patients. The J-waves were more often located in the inferior leads and more frequently in an inferior MI. The presence of J-waves was associated with ventricular arrhythmias, including ventricular fibrillation. The J-wave amplitude increased in the conducted APB, mechanistically suggesting a phase 3 block. CONCLUSION: Many patients in the early recovery phase after an acute MI had J-waves. This ECG phenomenon was associated with an increased incidence of ventricular arrhythmias. The tachycardia-dependent augmentation of the J-wave amplitude suggested a mechanistic role of conduction delay.

The association between obesity and acute myocardial infarction is age- and gender-dependent in a Japanese population.

Controversies concerning the association between obesity and acute myocardial infarction (AMI) are still ongoing in Japan. We investigated the association between obesity defined by body mass index of 25 kg/m(2) or higher and AMI by a case-control study using data from 1199 AMI cases and 4056 apparently healthy controls. The analysis was performed in age- and sex-matched samples of 621 case-control pairs younger than 80 years and in crude samples aged 40-79 years divided into 10-year age groups. Prevalence of obesity, diabetes, current smoking, hypertension, and hypercholesterolemia were compared between cases and controls, and a multivariable odds ratio (OR) of AMI was calculated for each risk factor in various age groups. The OR (95 % confidence interval (CI)) of AMI for obesity was 1.63 (1.23-2.17), P = 0.0008 in men younger than 80 years; 2.65 (1.41-5.00), P = 0.0025 in women younger than 80 years; 2.23 (1.46-3.41), P = 0.0002 in men aged 59 years or younger; 1.34 (0.90-2.01), P = 0.1510 in men aged 60-79 years; and 2.98 (1.56-5.71), P = 0.0010 in women aged 60-79 years using paired samples. The OR (95 % CI) of AMI for obesity was 4.92 (2.53-9.58), P < 0.0001 in men aged 40-49 years; 1.54 (1.07-2.21), P = 0.0197 in men aged 50-59 years; 1.07 (0.69-1.66), P = 0.7717 in men aged 60-69 years; 2.24 (1.20-4.20), P = 0.0118 in men aged 70-79 years; 2.48 (1.12-5.48), P = 0.0245 in women aged 60-69 years; and 3.05 (1.46-6.37), P = 0.0029 in women aged 70-79 years using crude samples. The association between obesity and AMI was age- and gender-dependent in a Japanese population.

Successful screening of sleep-disordered breathing using a pacemaker-based algorithm in Japan.

BACKGROUND: Recent pacemakers with transthoracic impedance sensors have a specific algorithm identifying sleep apnea (SA). Our aim was to evaluate the algorithm in Japanese patients. METHODS: Consecutive patients implanted with a pacemaker with sleep apnea monitoring algorithm at our hospital were enrolled prospectively. After implantation, patients underwent polysomnography (PSG). The respiratory disturbance index measured by pacemaker (RDI-PM) was extracted in the morning after PSG. RESULTS: Forty-five patients were recruited; 78% of patients underwent overnight PSG completely, and among them RDI-PM was invalid for one patient. Then the analysis was performed in 34 patients. Moderate/severe SA (apnea hypopnea index, AHI≥15events/h) and severe SA (AHI≥30events/h) by PSG were diagnosed in 65% and 41% of patients. The mean AHI-PSG and RDI-PM were 30.4±22.6 and 21.7±14.2events/h, respectively. There was a significant positive correlation between AHI-PSG and RDI-PM (r=0.543; p=0.001). The correlation was stronger in the severe SA group (r=0.664; p=0.010), in a group whose apnea index was higher than hypopnea index (r=0.822; p=0.002), and in a group whose central sleep apnea (CSA) index was higher than obstructive sleep apnea index (r=0.977; p<0.001). RDI-PM cut-off value for identifying severe SA was 22 (area under the curve, 0.682; sensitivity, 64%; specificity, 75%). CONCLUSIONS: The pacemaker-based algorithm is a useful screening tool for SA in Japanese individuals, especially in the severe SA group, apnea-dominant group, and CSA-dominant group.

Right-sided cardiac resynchronization therapy with defibrillator implantation in a patient with corrected transposition of great arteries and persistent left superior vena cava.

Patients with corrected transposition of great arteries (c-TGA) are generally known to develop atrioventricular block, systemic right ventricular dysfunction, and tricuspid regurgitation over time, which are associated with tachyarrhythmia and progressive heart failure. A 76-year-old man had been diagnosed with c-TGA. He developed a cardiopulmonary arrest while playing tennis, and an automated external defibrillator detected ventricular fibrillation (VF). Immediate cardiopulmonary resuscitation and intensive treatment were performed. He fully recovered without neurological sequelae. QRS duration was 172 ms. Echocardiography showed marked dysfunction and dyssynchrony of the systemic right ventricle (systemic right ventricular end-diastolic diameter/end-systolic diameter = 73/60 mm, systemic right ventricular ejection fraction = 34%). For secondary prevention and treatment of progressive heart failure, cardiac resynchronization therapy with defibrillator (CRT-D) implantation was recommended. Venography via the left cubital superficial vein revealed a persistent left superior vena cava (PLSVC) and giant coronary sinus that did not connect with the right superior vena cava (SVC). Because of the acute angle between the PLSVC and great cardiac vein, we selected a right-sided approach via the right SVC. We were finally able to deliver a coronary sinus lead to the lateral vein. CRT-D implantation can be achieved even in patients with c-TGA and PLSVC. .

Significance of change in serum bilirubin in predicting left ventricular reverse remodeling and outcomes in heart failure patients with cardiac resynchronization therapy.

BACKGROUND: Research on the correlation of serum bilirubin level with cardiac function as well as outcomes in heart failure patients with cardiac resynchronization therapy (CRT) has not yet been reported. The aim of this study was to analyze the relationship between change in serum bilirubin level and left ventricular reverse remodeling, and also to clarify the impact of bilirubin change on clinical outcomes in CRT patients. METHODS: We evaluated 105 consecutive patients who underwent CRT. Patients who had no serum total-bilirubin data at both baseline and 3-9 months' follow-up or had died less than 3 months after CRT implantation were excluded. Accordingly, a total of 69 patients were included in the present analysis. The patients were divided into two groups: decreased bilirubin group (serum total-bilirubin level at follow-up≤that at baseline; n=48) and increased bilirubin group (serum total-bilirubin level at follow-up>that at baseline; n=21). RESULTS: Mean follow-up period was 39.3 months. In the decreased bilirubin group, mean left ventricular end-systolic diameter decreased from 54.5mm to 50.2mm (p=0.001) and mean left ventricular ejection fraction increased significantly from 29.8% to 37.0% (p=0.001). In the increased bilirubin group, there was no significant change in echocardiographic parameters from baseline to follow-up. In Kaplan-Meyer analysis, cardiac mortality combined with heart failure hospitalization in the increased bilirubin group was significantly higher than that in the decreased bilirubin group (log-rank p=0.018). Multivariate Cox regression analysis revealed that increased bilirubin was an independent predictor of cardiac mortality combined with heart failure hospitalization (OR=2.66, p=0.023). CONCLUSIONS: The change in serum bilirubin is useful for assessment of left ventricular reverse remodeling and prediction of outcomes in heart failure patients with CRT.

Shock Lead Dislodgement Related To Its Small Hair-Pin Curve In A Pocket -A Case Of Ratchet Syndrome.

There have been few reports about ratchet syndrome. We report a case of ratchet syndrome caused by small hair-pin curve of lead that triggered the lead retract itself. A 69-year-old man with a past history of inferior wall myocardial infarction, presented with progressive congestive heart failure. He underwent implantation of cardiac resynchronization therapy with an implantable cardiac defibrillator (CRTD) at our hospital. At 33 days after implantation, shock lead dislodgement was revealed. X-ray showed that the lead tip was in left subclavian vein, leaving its screw out, and a large part of the proximal portion of the lead was retracted into the pocket, while the other two leads remained in appropriate positions and the device had not rotated. An X-ray series showed that a hair-pin curve had been expanding gradually from just after implantation. In this case, relatively stiff shock lead was markedly bent and expanded the curve in the pocket, and ratchet-like movement occurred. We here report a new type of ratchet syndrome.

Validation of prone myocardial perfusion SPECT with a variable-focus collimator versus supine myocardial perfusion SPECT with or without computed tomography-derived attenuation correction.

OBJECTIVE: The purpose of this study is to evaluate whether prone myocardial perfusion single-photon emission computed tomography (MPS) with thallium-201 acquired through a variable-focus collimator (IQ-SPECT) can correct for soft-tissue attenuation. METHODS: Thirty-nine patients underwent thallium-201 stress MPS with IQ-SPECT. Delayed images acquired with the patients in the prone position were compared with delayed images obtained with the patients in the supine position with computed tomography-derived attenuation correction (CTAC) (S-CTAC images) or without CTAC (S-NCTAC images). Quantitative tracer uptake (QTU) and semi-quantitative defect scores were determined for the 17 standard myocardial segments. Segments were categorized into anterior-anteroseptal, lateral, inferior, and apex, and areas with defect decision were determined by using the defect scores. RESULTS: Image quality in the prone images was similar to that of S-NCTAC and S-CTAC images. In male patients, QTU in prone images was equivalent to that in S-CTAC images in the anterior-anteroseptal area, but was significantly lower than that in S-CTAC images in the inferior area. In female patients, QTU in prone images was similar to that in S-CTAC images in the anterior-anteroseptal, lateral, and inferior areas. In male and in female patients, QTU in the apex was significantly greater in the prone images than that in the S-CTAC images. In the combined male and female patient group, the defect decision for prone images was similar to that for S-CTAC images in the anterior-anteroseptal, lateral, and inferior areas. Apical defects were observed more frequently in S-CTAC images than in prone or S-NCTAC images. CONCLUSIONS: Fewer artificial defects were observed in the apex of images acquired by prone imaging than by S-CTAC imaging. Prone images improved attenuation and had similar defect decision as S-CTAC images in the anterior-anteroseptal, lateral, and inferior areas.

Validation of a short-scan-time imaging protocol for thallium-201 myocardial SPECT with a multifocal collimator.

OBJECTIVE: IQ-SPECT (Siemens AG, Munich, Germany) is a highly sensitive single-photon-emission computed tomography (SPECT) myocardial perfusion imaging (MPI) system that uses a multifocal collimator. We searched for a suitable protocol for short-time imaging by IQ-SPECT in thallium-201 (Tl-201) MPI by evaluating phantom images and also by comparing human IQ-SPECT images with conventional SPECT images as reference standards. METHODS: We assessed the image quality using the normalized mean square error (NMSE) and drew up count profiles in Tl-201 SPECT images acquired with IQ-SPECT in a phantom study. We also performed Tl-201 stress myocardial SPECT/CT in 21 patients and compared delayed images acquired by using IQ-SPECT with 36 or 17 views per head with images obtained by using conventional SPECT. RESULTS: The NMSE of SPECT images from IQ-SPECT with 36 views was approximately one-fifth of that with 17 views. The myocardial count profile of images with 17 views was lower than those of images with 36 or 104 views in some regions. Defect scores were significantly lower, and image quality scores higher, in images from conventional SPECT than in those from IQ-SPECT with 17 views. Defect scores and image quality scores were equivalent in images from conventional SPECT and those from IQ-SPECT with 36 views. Agreement with the results of conventional SPECT in terms of coronary artery territory-based defect judgment was the best in IQ-SPECT with 36 views with computed tomography-derived attenuation correction (CTAC): the kappa values for IQ-SPECT with 36 views were 0.76 (without CTAC) and 0.83 (with CTAC), and those for IQ-SPECT with 17 views were 0.62 (without CTAC) and 0.59 (with CTAC). The difference in quantitative tracer uptake between conventional SPECT images and IQ-SPECT images was significantly greater for IQ-SPECT images with 17 views than for those with 36 views. CONCLUSIONS: Scanning with 36 views per head with CTAC may be appropriate for Tl-201 MPI using IQ-SPECT, because it provides images equivalent to those using conventional SPECT.

Long-term PT-INR levels and the clinical events in the patients with non-valvular atrial fibrillation: a special reference to low-intensity warfarin therapy.

BACKGROUND: Anticoagulation therapy is essential in atrial fibrillation (AF), and in Japan, less intense control is popular. PURPOSE: To assess the efficacy and safety with a special reference to low intensity warfarin therapy. SUBJECTS AND METHODS: In 488 out of 508 patients with non-valvular AF, prothrombin time-international normalized ratio (PT-INR) was kept at 1.6-2.59, and they were followed for 49.5 months: 2098 person-years. The mean age was 73.7±9.9 years and 62% were male. The patients were divided by age: ≥70 years and <70 years, and by the intensity of warfarin therapy: PT-INR at 1.6-1.99 and at 2.0-2.59, respectively. The clinical data and event rates, ischemic stroke and major bleeding, were compared among the subgroups. RESULTS: Heart failure, previous stroke, and higher CHADS2 score were more often reported in patients ≥70 years while males were involved more often as younger patients. A total of 166 of 339 patients ≥70 years and 69 of 149 patients <70 years belonged to the low intensity group. Ischemic stroke and major bleeding occurred in 1.47%/year and 1.27%/year, respectively but there was no difference between the two age groups and between the two intensities of warfarin therapy. Time in therapeutic range was a predictor for ischemic stroke. A fall of PT-INR to <1.6 was found in 41.9% with ischemic stroke and a rise >2.61 in 40.0% with major bleeding at the time of the events. Blunt trauma and concomitant use of antiplatelets were risks for intracranial hemorrhage in the patients ≥70 years. CONCLUSIONS: The event rates were similar between the low- (1.6-1.99) and high- (2.0-2.59) intensity warfarin therapy groups in aged patients: <70 years and ≥70 years. Time in therapeutic range and a transient fall or rise in PT-INR were risks for clinical events. Blunt head trauma and concomitant use of antiplatelets were risks for intracranial hemorrhage.

Unmasking of J waves during right coronary angiography in patients with spontaneous coronary spasms and ventricular fibrillation.

We encountered two consecutive cases with spontaneous ST elevation due to right coronary spasms and subsequent ventricular fibrillation (VF). Their 12-lead ECGs on anterior chest pain showed elevation of ST-segments in the inferior leads, but coronary angiography (CAG) revealed no significant stenosis. Both cases showed dramatically evolving J waves in the inferior leads during the right CAG, but it was not observed during angiography of the left CAG. Neither Brugada-type ECG nor long-QT was evident. In summary, J waves can be produced without ST-segment elevation, and contrast media-induced J waves might be related to the arrhythmogenesis of subsequent VF evoked by right coronary spasms.

Renal Dysfunction was an Independent Predictor of In-Hospital Death and Ventricular Rupture in Patients With Acute Myocardial Infarction.

BACKGROUND: Apart from the severity of myocardial infarction and coronary artery disease, several predictors of in-hospital death (In-HD) are suggested in patients with acute myocardial infarction (AMI). METHODS: We investigated predictors of In-HD and ventricular rupture (VR) including ventricular septal rupture (VSR) and free wall rupture (FWR) with stepwise multivariable logistic regressions in 1,042 patients admitted to our Cardiovascular Center within 48 hours from symptom onset for the first attack of AMI. RESULTS: In-HD, VSR, and FWR were observed in 78 cases (7.5%), 14 cases of which 13 cases were In-HD, and 13 cases of which 6 cases were In-HD, respectively. Apart from the disease severity, age and renal dysfunction (RD) defined by estimated glomerular filtration rate of lower than 60 mL/min/ 1.73 m2 were independent positive predictors of In-HD (the odds ratios (ORs) (95% confidence interval (CI)): 1.04 (1.01 - 1.06) P = 0.0069 and 5.75 (3.12 - 10.59) P < 0.0001, respectively) and hypercholesterolemia was an independent negative predictor for In-HD (OR (95% CI): 0.34 (0.17 - 0.67) P = 0.0017). After including the categories of coronary disease, ventricular rupture, and ejection fraction in predictors, RD remained an independent predictor of In-HD (OR (95% CI): 6.65 (2.67 - 16.60) P < 0.0001). Age (OR (95% CI): 1.07 (1.02 - 1.12) P = 0.0064), RD (OR (95% CI): 2.77 (1.18 - 6.49) P = 0.019), and diabetes (OR (95% CI): 2.52 (1.12 - 5.71) P = 0.026) were independent predictors of VR. CONCLUSIONS: RD was an independent predictor of In-HD and VR in patients with initial AMI.