Effect of empagliflozin on ventricular arrhythmias in patients with type 2 diabetes treated with an implantable cardioverter-defibrillator: the EMPA-ICD trial.

BACKGROUND: Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of hospitalization for heart failure and cardiovascular death with type 2 diabetes; however, their effect on arrhythmias is unclear. The purpose of this study was to investigate the effects of empagliflozin on ventricular arrhythmias in patients with type 2 diabetes. METHODS: A total of 150 patients with type 2 diabetes who were treated with an implantable cardioverter-defibrillator or cardiac resynchronization therapy defibrillator (ICD/CRT-D) were randomized to once-daily empagliflozin or placebo for 24 weeks. The primary endpoint was the change in the number of ventricular arrhythmias from the 24 weeks before to the 24 weeks during treatment. Secondary endpoints included the change in the number of appropriate device discharges and other values. RESULTS: In the empagliflozin group, the number of ventricular arrhythmias recorded by ICD/CRT-D decreased by 1.69 during treatment compared to before treatment, while in the placebo group, the number increased by 1.79. The coefficient for the between-group difference was - 1.07 (95% confidence interval [CI] - 1.29 to - 0.86; P < 0.001). The change in the number of appropriate device discharges during and before treatment was 0.06 in the empagliflozin group and 0.27 in the placebo group, with no significant difference between the groups (P = 0.204). Empagliflozin was associated with an increase in blood ketones and hematocrit and a decrease in blood brain natriuretic peptide and body weight. CONCLUSIONS: In patients with type 2 diabetes treated with ICD/CRT-D, empagliflozin reduces the number of ventricular arrhythmias compared with placebo. Trial registration jRCTs031180120.

Predictors of long-term survival in Japanese patients with heart failure with reduced ejection fraction (HFrEF) treated with cardiac resynchronization therapy-defibrillators (CRT-D).

BACKGROUND: Reports on the factors predicting long-term survival of CRT-D cases from Western countries are increasing, however, those from Asia including Japan are still sparse. We aimed to clarify the factors predicting long-term survival of Japanese CRT-D cases. METHODS: We retrospectively analyzed consecutive 133 patients who underwent CRT-D implantation between 2006 and 2021. We compared clinical factors between patients who died within 5 years after implantation (short-survival group: n = 31) and who had survived for more than 5 years (long-survival group: n = 36) after implantation. RESULTS: Major underlying heart diseases were dilated cardiomyopathy (45%) and ischemic heart disease (12%). There was no difference between the short-survival group and the long-survival group in incidence of CLBBB (32% vs. 30%), whereas CRBBB was more common in the short-survival group (26% vs. 0%, p = .004). Mechanical dyssynchrony at implantation was more frequent in the long-survival group (48% vs. 78%, p = .02). The incidence of response to CRT at 1 year after implantation was higher in long-survival group (19% vs. 50%, p = .02). Multiple logistic regression analysis identified NYHA class, mechanical dyssynchrony at implantation, and response at one year as predictors of long-term survival. CONCLUSIONS: In Japanese CRT-D cases, lower NHYA class, preexisting mechanical dyssynchrony, and 1-year response to CRT predict long-term survival.

Clinical impact of nocturnal ventricular tachyarrythmias in electrical storm.

BACKGROUND: The incidence of electrical storm (ES) is significantly higher during the daytime. However, the association between nocturnal ventricular tachyarrythmias during ES and prognosis remains unclear. Therefore, this study aimed to investigate the clinical characteristics and outcomes of ES with midnight ventricular tachyarrythmias. METHODS: We included 48 consecutive patients who had an implantable cardioverter-defibrillator or cardiac resynchronization therapy defibrillator implanted between 2010 and 2020 and those who had experienced the onset of an out-of-hospital ES episode. According to the midnight (0:00 a.m.-6:00 a.m.) occurrence of ventricular arrythmia events consisting of ventricular tachycardia (VT) and ventricular fibrillation (VF), we divided them into two groups (with-midnight group: n = 27, without-midnight group: n = 21). The clinical characteristics and outcomes of the two groups were compared. RESULTS: The patients in the with-midnight group were mostly males, had longer QRS duration, and longer corrected QT-interval than those in the without-midnight group (p < .05). The incidence of all-cause death, especially heart failure death, was higher in the with-midnight group than in the without-midnight group (p < .01). Multivariate analysis showed that the presence of midnight VT/VF during ES was the only independent risk factors for heart failure death (HR = 18.9, 95%CI = 1.98-181, p = .011). CONCLUSIONS: The presence of midnight VT/VF during ES might be associated with the poor prognosis. The loss of a sympathetic circadian pattern of VT/VF distribution during ES might suggest advanced stages of the cardiac disease.

The Risk of Ventricular Tachyarrhythmias in Patients with Antimitochondrial Antibodies-Related Noncardiac Diseases.

Antimitochondrial antibodies (AMA) are serum autoantibodies specific to primary biliary cholangitis and are linked to myopathy and myocardial damage; however, the presence of AMA as a risk factor for ventricular tachyarrhythmias (VTs) has remained unknown. This study aimed to elucidate whether the presence of AMA-related noncardiac diseases indicates VTs risk.This cohort study enrolled 1,613 patients (883 females) who underwent AMA testing to assess noncardiac diseases. The incidence of VTs and supraventricular tachyarrhythmias (SVTs) from a year before the AMA testing to the last visit of the follow-up were retrospectively investigated as primary and secondary objectives. Using propensity score matching, we extracted AMA-negative patients whose covariates were matched to those of 152 AMA-positive patients. In this propensity score-matched cohort, the incidence of VTs and SVTs in the AMA-positive patients were compared with that in AMA-negative patients.The AMA-positive patients had higher estimated cumulative incidence (log-rank, P = 0.013) and prevalence (5.9% versus 0.7%, P = 0.020) of VTs than the AMA-negative patients. The presence of AMA was an independent risk factor for VTs (hazard ratio, 4.02; 95% CI, 1.44-20.01; P = 0.005). Meanwhile, AMA were associated with atrial flutter and atrial tachycardia development. In AMA-positive patients, VTs were associated with male sex, underlying myopathy, high creatine kinase levels, presence of chronic heart failure or ischemic heart disease, left ventricular dysfunction, presence of SVTs, and the electrocardiographic parameters indicating atrial disorders.The presence of AMA-related noncardiac diseases is an independent risk factor for VTs.

Clinical impact of ECG changes on oversensing of subcutaneous implantable cardioverter-defibrillators.

BACKGROUND: Inappropriate shocks delivered by subcutaneous implantable cardioverter-defibrillators (S-ICDs) are most frequently caused by cardiac oversensing. However, the predictors for oversensing of S-ICD remain unclear. OBJECTIVE: We aimed to investigate the predictors for oversensing of S-ICD, especially clinical impact of an electrocardiographic (ECG) change. METHODS: We retrospectively enrolled 99 consecutive patients who underwent S-ICD implantation between 2013 and 2021. Oversensing events were defined as inappropriate charge of the capacitors induced by cardiac or noncardiac signals other than tachycardia. RESULTS: During a median follow-up period of 34 months (interquartile range 20-50 months), 11 of 99 patients (11%) experienced 34 oversensing events and 4 patients (4%) received inappropriate shocks during their events. Six patients exhibited ECG changes (bundle branch block, 3; ventricular pacing, 1; inverted T wave, 1; poor R-wave progression, 1) during the follow-up period. Oversensing events were observed in 4 of 6 patients with ECG change (67%), and 3 patients underwent S-ICD removal because of inevitable shock. Contrastingly, of the remaining patients without ECG change, all 7 patients who experienced oversensing events could continue using S-ICD with the reprogramming sensing vector and/or restriction of excessive exercise. Logistic regression analysis showed that lower voltage of Sokolow-Lyon ECG (V1S + V5R) was the predictor of oversensing in patients without ECG change. When the cutoff value was 2.1 mV, the sensitivity, specificity, positive predictive value, and negative predictive value were 85.7%, 62.7%, 15.7%, and 98.1%, respectively. CONCLUSION: Unavoidable oversensing resulting in S-ICD removal is caused by ECG change. Oversensing in patients without ECG change can be managed.

Efficacy of antitachycardia pacing alert by remote monitoring of implantable cardioverter-defibrillators for out-of-hospital electrical storm.

BACKGROUND: Remote monitoring (RM) has been shown to reduce all-cause mortality in patients with implantable cardioverter-defibrillators or cardiac resynchronization therapy defibrillators (ICD/CRT-D). Not all devices transmit an alert for antitachycardia pacing (ATP) therapy, and it is unknown whether differences of RM alert affect the outcomes of electrical storm (ES). METHODS: We enrolled 42 patients with ICD/CRT-D whose out-of-hospital ES were detected by RM between 2013 and 2020. We divided their 54 episodes into two groups (ATP-alert-on; 22, ATP-alert-off; 32), and clinical outcomes were compared between the two groups. RESULTS: In 35 of 54 episodes of ES, ventricular tachycardia (VT) could be terminated within 24 h of ES onset just by ATP (ATP-alert-on: 14, ATP-alert-off: 21); however, many patients subsequently received shock delivery for VT. Among the 35 episodes, only in ATP-alert-on group, seven patients were prompted to visit our hospital without ICD shock through confirmation of ES by ATP-alert. Episodes that led to shock delivery 24 h or longer after the ES onset were significantly less common in the ATP-alert-on group (ATP-alert-on: 1/14, ATP-alert-off: 9/21, p = .03). Although there were no significant differences in the number of shock deliveries between episodes in the two groups, the number of ATP deliveries were significantly fewer in the ATP-alert-on group (12[7-26] vs. 29[16-53] in ATP-alert-off group, p = .03). Multivariate logistic regression analyses showed that the only ATP-alert significantly reduced ATP deliveries (HR = 0.14, 95%CI = 0.04-0.57, p = .003). CONCLUSION: Remote monitoring with an ATP-alert function during electrical storm may reduce appropriate ICD therapy through prompting early review.

Progressive increase in activation delay during premature stimulation is related to ventricular fibrillation in Brugada syndrome.

INTRODUCTION: The local conduction delay has been deemed to play an important role in the perpetuation of ventricular fibrillation (VF) in Brugada syndrome (BrS). We evaluated the relationship between the activation delay during programmed stimulation and cardiac events in BrS patients. METHODS: This study included 47 consecutive BrS patients who underwent an electrophysiological study and received implantable cardiac defibrillator therapy. We divided the patients into two groups based on whether they had developed VF (11 patients) or not (36 patients) during the follow-up period of 89 ± 53 months. The activation delay was assessed using the interval between the stimulus and the QRS onset during programmed stimulation. The mean increase in delay (MID) was used to characterize the conduction curves. RESULTS: The MID at the right ventricular outflow tract (RVOT) was significantly greater in patients with VF (4.5 ± 1.2 ms) than in those without VF (2.2 ± 0.9 ms) (p < .001). A receiver operating characteristics curve analysis indicated that the optimal cut-off point for discriminating VF occurrence was 3.3 with 88.9% sensitivity and 91.3% specificity. Furthermore, patients with an MID at the RVOT ≥ 3.3 ms showed significantly higher rates of VF recurrence than those with an MID at the RVOT < 3.3 ms (p < .001). The clinical characteristics, including the signal-averaged electrocardiogram measurement and VF inducibility were similar between the two groups. CONCLUSION: A prolonged MID at the RVOT was associated with VF and maybe an additional electrophysiological risk factor for VF in BrS patients.

Regional Disparities in Adherence to Guidelines for the Treatment of Chronic Heart Failure.

Objective The incidence of chronic heart failure (CHF) is likely to keep increasing in Japan as the population ages, placing increased burdens on medical facilities, particularly on the limited numbers of rural hospitals. We explored the appropriateness of CHF treatment in rural areas in Japan. Methods We compared rates of adherence to therapeutic guidelines for CHF between residents with a left ventricular ejection fraction <35% living in urban areas (n = 207) and those in rural areas (n = 180). Treatments included pharmacological [beta-blockers, angiotensin-converting enzyme inhibitors (ACEi)/angiotensin II receptor blocker (ARB), mineralocorticoid receptor antagonist (MRA) and anticoagulants for atrial fibrillation] and non-pharmacological [implantable cardioverter defibrillator (ICD)/cardiac resynchronization therapy (CRT), cardiac rehabilitation and HF education] approaches. Patients This study included 387 patients with CHF, prior myocardial infarction or cardiomyopathy, and a left ventricular ejection fraction (LVEF) <35% as determined by echocardiography. Results The respective rates of treatments administered in urban and rural areas were as follows: beta-blockers, 91.3% vs. 61.7% (p<0.05); ACEi/ARB, 86.5% vs. 68.3% (p<0.05); MRA, 74.4% vs. 59.4% (p<0.01); anticoagulants, 100% vs. 86.5%, (p<0.05); ICD/CRT, 45.4% vs. 5.0% (p<0.05); cardiac rehabilitation, 32.4% vs. 13.3% (p<0.05) and HF education, 33.3% vs. 32.8% (p=0.75). Conclusion Regional disparities in treatment for CHF persist, even in Japan. Improvements in the use of guideline-directed treatment in rural areas might improve the outcomes for CHF patients.

Right ventricular insertion promotes reinitiation of ventricular fibrillation in defibrillation failure.

BACKGROUND: Shocks near defibrillation threshold (nDFT) strength commonly extinguish all ventricular fibrillation (VF) wavefronts, but a train of rapid, well-organized postshock activations (PAs) typically appears before sinus rhythm ensues. If one of the PA waves undergoes partial propagation block (wavebreak), reentry may be induced, causing VF to reinitiate and the shock to fail. OBJECTIVE: The purpose of this study was to determine whether wavebreak leading to VF reinititation following nDFT shocks occurs preferentially at the right ventricular insertion (RVI), which previous studies have identified as a key site for wavebreak. METHODS: We used panoramic optical mapping to image the ventricular epicardium of 6 isolated swine hearts during nDFT defibrillation episodes. After each experiment, the hearts were fixed and their geometry scanned with magnetic resonance imaging (MRI). The MRI and mapping datasets were spatially coregistered. For failed shocks, we identified the site of the first wavebreak of a PA wave during VF reinitiation. RESULTS: We recorded 59 nDFT failures. In 31 of these, the first wavebreak event occurred within 1 cm of the RVI centerline, most commonly on the anterior side of the right ventricular insertion (aRVI) (23/31). The aRVI region occupies 16.8% ± 2.5% of the epicardial surface and would be expected to account for only 10 wavebreaks if they were uniformly distributed. By χ2 analysis, aRVI wavebreaks were significantly overrepresented. CONCLUSION: The anterior RVI is a key site in promoting nDFT failure. Targeting this site to prevent wavebreak could convert defibrillation failure to success and improve defibrillation efficacy.

J point elevation in high precordial leads associated with risk of ventricular fibrillation.

INTRODUCTION: The significance of high precordial electrocardiograms in idiopathic ventricular fibrillation (IVF) is unknown. METHOD: This study included 50 consecutive patients (48 men; age, 42 ± 18 years) who had spontaneous ventricular fibrillation not linked to structural heart disease and received implantable cardiac defibrillator therapy. IVF was diagnosed in 35 patients and Brugada syndrome was diagnosed in other 15 patients. Electrocardiograms in high intercostal space were compared between 35 patients with IVF and 105 age- and sex-matched healthy controls (patient: control ratio, 1:3). RESULTS: The frequency of J point elevation ≥ 0.1 mV in the 4th intercostal spaces was similar between patients with IVF (14%) and healthy controls (7%). However, the frequency of J point elevation ≥ 0.1 mV in the 3rd intercostal space was higher in patients with IVF (40%) than controls (11%) (p < .01). J point elevation was present only in the 3rd intercostal space but not in the 4th intercostal space in 30% of patients with IVF but only in 6% of controls (p < .01). During follow-up, the recurrence of ventricular fibrillation was higher in patients with IVF who had J point elevation in the 3rd intercostal space (36%) and Brugada syndrome(40%) than those with IVF who did not have J point elevation in the 3rd intercostal space(11%) (p < .05 for both). CONCLUSION: J point elevation in the 3rd intercostal space was associated with IVF and recurrences of ventricular fibrillation. Electrocardiogram recordings in the high intercostal space may be useful to identify risk of sudden death.

Placebo-Controlled, Double-Blind Study of Empagliflozin (EMPA) and Implantable Cardioverter-Defibrillator (EMPA-ICD) in Patients with Type 2 Diabetes (T2DM): Rationale and Design.

INTRODUCTION: Type 2 diabetes (T2DM) is associated with cardiovascular death, including sudden cardiac death due to arrhythmias. Patients with an implantable cardioverter-defibrillator (ICD) are also at high risk of developing a clinically significant ventricular arrhythmia. It has been reported that sodium-glucose cotransporter 2 (SGLT2) inhibitors can reduce cardiovascular deaths; however, the physiological mechanisms of this remain unclear. It is, however, well known that SGLT2 inhibitors increase blood ketone bodies, which have been suggested to have sympatho-suppressive effects. Empagliflozin (EMPA) is an SGLT2 inhibitor. The current clinical trial titled "Placebo-controlled, double-blind study of empagliflozin (EMPA) and implantable cardioverter-defibrillator (EMPA-ICD) in patients with type 2 diabetes (T2DM)" was designed to investigate the antiarrhythmic effects of EMPA. METHODS: The EMPA-ICD study is a prospective, multicenter, placebo-controlled, double-blind, randomized, investigator-initiated clinical trial currently in progress. A total of 210 patients with T2DM (hemoglobin A1c 6.5-10.0%) will be randomized (1:1) to receive once-daily placebo or EMPA, 10 mg, for 24 weeks. The primary endpoint is the number of clinically significant ventricular arrhythmias for 24 weeks before and 24 weeks after study drug administration, as documented by the ICD. The secondary endpoints of the study are the change from baseline concentrations in blood ketone and catecholamine 24 weeks after drug treatment. CONCLUSION: The EMPA-ICD study is the first clinical trial to assess the effect of an SGLT2 inhibitor on clinically significant ventricular arrhythmias in patients with T2DM and an ICD. TRIAL REGISTRATION: Unique trial number, jRCTs031180120 ( https://jrct.niph.go.jp/latest-detail/jRCTs031180120 ).

Prevention of postprandial hypotension-related syncope by caffeine in a patient with long-standing diabetes mellitus.

A 74-year-old man who had type 2 diabetes mellitus of a duration of 20 years was admitted for syncope after eating a high carbohydrate meal. Although he had had episodes of pallor or syncope after carbohydrate-rich meals, such as with large amounts of white rice, several times within a year and he had been taken to hospitals emergently, the etiology of these episodes had remained unclear despite his undergoing several studies. Studies did show severe orthostatic hypotension during the head-up tilt test and a decrease in the coefficient of variation of the R-R interval (CVR-R) on resting electrocardiogram, suggesting severe autonomic nervous dysfunction. Because of the episodes of syncope after eating a carbohydrate-rich meal, we investigated whether he had postprandial hypotension (PPH). The 75 g oral glucose tolerance test revealed a significant decrease in his postprandial blood pressure by about 40 mmHg, leading to the diagnosis of PPH. The carbohydrate-rich meal test induced syncope with systolic blood pressure under 40 mmHg. Then 150 mg caffeine was administered before a second carbohydrate-rich meal. The marked decline in postprandial blood pressure was suppressed and plasma noradrenaline levels were gradually increased over a period of 60 minutes. Caffeine could be useful for prevention of postprandial hypotension-related syncope.

Replacement of an Implantable Cardioverter-Defibrillator (ICD) with a New Standard Subcutaneous ICD System in a Patient with Jervell and Lange-Nielsen Syndrome.

A 7-year-old female suffering from syncope attacks and deafness was genetically diagnosed with Jervell and Lange-Nielsen syndrome (JLNS). A transvenous-designed shock lead and implantable cardioverter-defibrillator (ICD) were atypically implanted subcutaneously, because the patient's body was small. Six years after implantation, we confirmed the patient's eligibility for a subcutaneous ICD (S-ICD) based on electrocardiogram screening. The implanted ICD system was replaced with a new standard S-ICD system. Implantation of the S-ICD may be considered a reliable and safe option in young patients with JLNS, even if their electrocardiograms show remarkable prolongation of the QT interval and T-wave alternans.

Early repolarization and risk of lone atrial fibrillation.

INTRODUCTION: Early repolarization syndrome is a recently proposed condition characterized by an early repolarization pattern in the electrocardiogram (ECG) and ventricular fibrillation in the absence of structural heart abnormalities. Although some studies have suggested that early repolarization is associated with frequency of atrial fibrillation, the association of early repolarization with atrial fibrillation is not well known. HYPOTHESIS: Early repolarization indicates the substrate for atrial fibrillation in addition to that for ventricular fibrillation. METHOD: This study included 79 patients (57 men [72%]; age, 45 ± 12 years) aged less than 60 years who had paroxysmal lone atrial fibrillation and 395 age- and sex-matched healthy controls (patient:control ratio, 1:5). Patients who had structural heart disease, hypertension, diabetes, hyperthyroidism, history of successful resuscitation, or the Brugada type ECG were excluded. ECGs recorded during sinus rhythm were compared between patients with atrial fibrillation and healthy controls. RESULTS: Early repolarization in the inferior and/or lateral leads was more common in patients with atrial fibrillation (25%) than controls (10%; P = 0.001). The location and magnitude of early repolarization were similar between the two groups. Other electrocardiographic measurements were not different between the two groups. Among patients with atrial fibrillation, there was no difference in clinical characteristics including age at atrial fibrillation development, sex, and body mass index between patients with early repolarization and those without early repolarization. Electrocardiographic measurements were not different between patients with early repolarization and those without early repolarization. CONCLUSION: Early repolarization was associated with lone atrial fibrillation. Early repolarization may indicate increased susceptibility to atrial fibrillation.

A Steam Pop Detected by Intracardiac Echocardiography During Catheter Ablation of the Left Ventricular Papillary Muscle.

A 60-year-old female with premature ventricular contractions (PVCs) originating from the bottom of the posteromedial papillary muscle of the left ventricle underwent radiofrequency catheter ablation (RFCA) using an irrigated-tip catheter. During ablation of the PVCs, a loud steam pop was observed. Intracardiac echocardiography (ICE) revealed a growing, hyperechogenic intramyocardial microbubble formation around the catheter tip. The formation disappeared slowly and completely, leaving an endocardial laceration without pericardial effusion. ICE imaging is valuable during a difficult RFCA procedure, because ICE reveals the exact anatomical position of the catheter and thus allows rapid evaluation of the occurrence of steam popping and any possible subsequent complication.

Clinical Predictors of Recurrent Ventricular Arrhythmias in Secondary Prevention Implantable Cardioverter Defibrillator Recipients With Coronary Artery Disease　- Lower Left Ventricular Ejection Fraction and Incomplete Revascularization.

BACKGROUND: The implantable cardioverter defibrillator (ICD) is a standard prevention therapy for patients at high risk for sudden cardiac death (SCD) due to life-threatening ventricular arrhythmia (VA), that is, ventricular fibrillation and ventricular tachycardia. However, clinical predictors of recurrent VA in secondary prevention ICD recipients with coronary artery disease (CAD) remain unknown. Methods and Results: We followed up 96 consecutive patients with CAD undergoing ICD implantation for secondary prevention of SCD. Long-term rates and clinical predictors of appropriate ICD therapy (ICD-Tx) for VA were analyzed. Appropriate ICD-Tx occurred in 41 (42.7%) patients during a median follow-up of 2.4 years (interquartile range, 0.9-6.1). These patients had significantly greater left ventricular end-diastolic diameter (62.3±1.3 vs. 54.6±1.1 mm, P<0.001), lower left ventricular ejection fraction (LVEF; 36.3±2.0% vs. 45.7±1.8%, P<0.001), and more incomplete revascularization (ICR; 70.7% vs. 45.5%, P=0.014) than those without appropriate ICD-Tx. Multivariable analysis showed that LVEF (hazards ratio [HR], 0.950; 95% CI: 0.925-0.975; P<0.001) and ICR (HR, 2.293; 95% CI: 1.133-4.637; P=0.021) were significant predictors of appropriate ICD-Tx for VA. CONCLUSIONS: Lower LVEF and ICR were independent predictors of recurrent VA in secondary prevention ICD recipients with CAD.