Tamami Fujiishi

Polytherapy with sodium channel-blocking antiepileptic drugs is associated with arrhythmogenic ST-T abnormality in patients with epilepsy

PURPOSE Recent reports have documented the appearance of Brugada-type ST elevation in cases of overdose of antiepileptic drugs (AEDs). However, little is known about changes on electrocardiographs (ECGs) during AED use at therapeutic doses. AEDs may cause Brugada-type ST elevation or J-wave-like intraventricular conduction delays through an ion channel-blocking effect. In the present study, we sought to elucidate ECG abnormalities in patients on AED therapy. METHODS The study population consisted of 120 consecutive patients with epilepsy who continued to take AEDs and had ECGs recorded during these therapies. Their clinical background and ECGs were retrospectively analyzed. Brugada-type ST elevation was classified according to the consensus report on Brugada syndrome. A J-wave-like ECG abnormality was defined as the appearance of notching or slurring of the QRS complex (>0.1mV) in the inferior/lateral leads. RESULTS Of the 120 patients, 15 (12.5%) exhibited Brugada-type ST elevation and 35 (29.2%) showed a J-wave-like ECG abnormality. Polytherapy with sodium channel-blocking AEDs (e.g., carbamazepine, phenytoin, lamotrigine) was more frequently observed in patients with Brugada-type ST elevation (p=0.048). However, the serum concentrations of these medicines did not differ between patients with and without ECG abnormalities (carbamazepine: 7.9±4.1 vs. 7.2±5.9μg/dL; phenytoin: 12.7±4.1 vs. 15.5±9.5μg/dL, NS). CONCLUSION ST-T abnormalities were frequently seen in patients using AEDs. The presence of Brugada-type ST elevation was associated with polytherapy with sodium channel-blocking AEDs.

An appropriate shock of the wearable cardioverter-defibrillator in an outpatient setting

The wearable cardioverter‐defibrillator (WCD) represents an alternative clinical approach to prevent sudden cardiac death as a bridge to therapy when making a final decision regarding the need for an implantable cardioverter defibrillator (ICD), especially in patients who are in the so‐called gray zone according to ICD guidelines. Although the WCD system was introduced in Japan in April 2014, data regarding its usage and experience are limited. We report the first case of appropriate shock therapy using the WCD in an outpatient setting in Japan. We describe the case of a 22‐year‐old‐woman who received the first case of successful appropriate WCD shock therapy in an outpatient setting in Japan.

The J-wave as a Predictor of Life-Threatening Arrhythmia in ICD Patients

The J-wave has been reported to be associated with life-threatening ventricular arrhythmia. However, the clinical implication of the J-wave is still unclear in patients with an implantable cardioverter defibrillator (ICD).The study population consisted of 170 ICD patients (age, 56 ± 16 years, 79.4% male) treated at Kitasato University Hospital between 2003 and 2014. Ventricular fibrillation (VF) and ventricular tachycardia (VT) events were documented via ICD interrogation, and the patients were divided into 3 groups: 1) VF event group, 2) VT event group, and 3) No-event group. To predict VT or VF events, univariate and multivariate analysis of clinical data including ECG findings were performed. A J-wave was defined as the presence of notching or slurring of the QRS complex (≥ 0.1 mV) in inferior/lateral leads. Among the 170 patients examined, 23 experienced VF and 38 experienced VT during 54 ± 39 months follow-up. In the multivariate Cox proportional hazards model, the J-wave was identified as an independent predictor for a VF event (HR: 3.886, 95% CI: 1.313-10.568, P = 0.012). In contrast, BNP (HR: 1.002, 95% CI: 1.000-1.003, P = 0.043) and left ventricular diastolic diameter (HR: 1.039, 95% CI: 1.002-1.081, P = 0.049) were independent predictors for a VT event.The results suggest J-waves in the stable phase in an ECG may be a useful predictor for a VF event in ICD patients.

Efficacy and Limitations of Tachycardia Detection Interval Guided Reprogramming for Reduction of Inappropriate Shock in Implantable Cardioverter-Defibrillator Patients

The avoidance of inappropriate shock therapy is an important clinical issue in implantable cardioverter-defibrillator (ICD) patients. We retrospectively analyzed therapeutic events in ICD patients, and the effect of tachycardia detection interval (TDI) and tachycardia cycle length (TCL) guided reprograming on the reduction of inappropriate ICD therapy. The clinical determinants of after reprogramming were also evaluated.A total of 254 consecutive ICD patients were included in the study, and the incidence of antitachycardia therapy was evaluated during the follow-up period of 27.3 ± 18.7 months. When inappropriate antitachycardia therapy appeared, TDI was reprogrammed not to exceed the detected TCL and the patients continued to be followed-up. Various clinical parameters were compared between patients with and without inappropriate ICD therapy. During the initial follow-up period of 18.6 ± 15.6 months, ICD therapy occurred in 127/254 patients (50%) including inappropriate antitachycardia pacing (ATP) (12.9%) and shock (44.35%). Determinants of initial inappropriate therapy were dilated cardiomyopathy (DCM), history of therapeutic hypothermia, and QRS duration. Of the 61 patients with inappropriate therapy, 24 received TCL guided reprogramming. During the additional observation period of 17.0 ± 16.8 months, inappropriate therapy recurred in 5/24 patients (2 ATP, 3 shocks). The determinant of these inappropriate therapy events after reprogramming was the presence of supraventricular tachycardia.By applying simple TCL and TDI guided reprogramming, inappropriate therapy was reduced by 79%. The determinant of inappropriate therapy after reprogramming was the presence of supraventricular tachycardia.

Discrimination of Paroxysmal and Persistent Atrial Fibrillation in Patients With New-Onset Atrial Fibrillation

Discrimination between paroxysmal and persistent atrial fibrillation (PAF and persistent AF) is important for determining the therapeutic strategy in patients with new-onset AF. We evaluated various clinical factors and P wave morphology to discriminate PAF and persistent AF patients in patients with new-onset AF.The study population consisted of 79 patients with new-onset AF (70.3 ± 10.8 years, female:male 33:46) who were retrospectively selected from 8,632 AF patients in the Kitasato University Hospital ECG storing system. PAF (n = 38) and persistent AF (n = 41) patients were diagnosed by whether the initial PAF episode continued for 1 week. The P wave morphologies were analyzed using the most recent 12 lead-ECG recording of sinus rhythm. P wave dispersion was defined as the difference between the maximum and minimum durations of all leads. Along with these data, various clinical factors were evaluated and compared between PAF and persistent AF patients.Multivariate analysis identified P wave dispersion (56.6 ± 14.8 versus 66.5 ± 12.8 msec, P = 0.002) and left atrial dimension (LAD: 40.2 ± 7.0 versus 47.7 ± 8.2 mm, P < 0.001) as independent factors for discrimination between PAF and persistent AF patients. Combining these two parameters achieved a specificity of 88.9%, a positive predictive value of 81.8%, a sensitivity of 95.3%, and a negative predictive value of 88.9%.In patients with new-onset AF, P wave dispersion and LAD were independent factors for discrimination between PAF and persistent AF.

Pacing failure caused by automatic pacing threshold adjustment system

Ventricular capture management is an automatic pacing threshold adjustment algorithm that automatically measures pacing threshold through detection of the evoked response after a pacing stimulus. Although it is principally designed to save device battery under the maintenance of the patient׳s safety, we experienced a rare case with serious pacing failure due to a weakness of this algorithm. This pacing failure might be explained by a large variation in the ventricular pacing threshold depending on the atrioventricular interval and daily variation of pacing threshold and concomitant steroid use in this patient.

Cardiac troponin T as a predictor of cardiac death in patients with left ventricular dysfunction

Cardiac troponin T (cTnT) has been reported to be associated with cardiac mortality.

Arrhythmogenic left atrial roof vein

A seventy year‐old male was referred to our hospital to undergo radiofrequency catheter ablation (RFCA) for drug‐refractory paroxysmal atrial fibrillation (AF). Pre‐operative three‐dimensional computed tomography revealed a unique left atrial (LA) roof vein. Electrophysiological findings showed expansion of the myocardial sleeve and local firing in the LA roof vein. We performed isolation of this arrhythmogenic abnormal vein concomitant with general pulmonary vein isolation in this case, and AF did not recur after the procedure.

Novel Scoring System for Distinction Between Paroxysmal and Non-Paroxysmal Atrial Fibrillation

BACKGROUND Distinction of paroxysmal atrial fibrillation (PAF) from non-PAF is important in clinical practice, but this is often difficult at the time of first documented AF. Given that fibrillation cycle length (FCL) is longer in PAF than in non-PAF, the aim of this study was to compare various clinical parameters including FCL to establish a scoring system to distinguish PAF and non-PAF.Methods and Results:The subjects consisted of 382 consecutive patients with AF on digital ECG at the present institute between 2008 and 2011. They were divided into PAF and non-PAF groups according to the following clinical course. Propensity score matching yielded 88 matched patient pairs with similar mean age and gender between the 2 groups. FCL was evaluated using customized fibrillation wave analyzer with fast Fourier transform analysis. On multivariate analysis, higher HR, longer FCL, and smaller LAD were independent predictors of PAF. For the scoring, cut-offs for each parameter were determined according to highest sensitivity and specificity on the ROC curves, and 1 point assigned for each parameter. Using this scoring system, 2 points detected PAF with 64% sensitivity and 84% specificity. CONCLUSIONS We propose a scoring system including FCL to distinguish PAF from non-PAF. Further studies are needed to validate the results.