Akihito Miyoshi

Comparison of longevity and clinical outcomes of implantable cardioverter-defibrillator leads among manufacturers

BACKGROUND An early failure of the Biotronik Linox S/SD implantable cardioverter-defibrillator (ICD) lead has been reported. We have also experienced several cases with early failure of Linox leads. OBJECTIVE Our aim was to assess the longevity of Linox S/SD (Biotronik, Berlin, Germany) compared with Sprint Fidelis (Medtronic, Minneapolis, MN), Sprint Quattro (Medtronic), and Endotak Reliance (Boston Scientific, Natick, Massachusetts) leads. METHODS We retrospectively reviewed patients who had undergone implantation of Linox S/SD (n = 90), Sprint Fidelis (n = 37), Sprint Quattro (n = 27), or Endotak Reliance (n = 50) leads between June 2000 and December 2013 at our hospital. Variables associated with lead failure were assessed by the Kaplan-Meier method and Cox survival modeling. RESULTS Failure rates of Linox, Sprint Fidelis, and Endotak leads were 3.2%/year (7-year survival rate, 81.0%), 3.4%/year (7-year survival rate, 77.2%), and 0.61%/year (7-year survival rate, 95.8%), respectively. No lead failure was found with Sprint Quattro leads. The survival probability of Linox leads was significantly lower than that of Endotak leads (P = .049) and comparable to that of Sprint Fidelis leads (P = .69). In univariate analysis, age was the only predictor of Linox lead failure. Patients <58 years old were at significantly increased risk of lead failure compared with patients ≥58 years old (hazard ratio, 9.0; 95% confidence interval, 1.13-71.3; P = .037). CONCLUSION In our single-center experience, the survival rate of Linox leads was unacceptably low. The only predictor of Linox lead failure was age at implantation. This is the first description of a lower survival rate for Linox leads in an Asian population.

Epicardially placed implantable cardioverter-defibrillator for a child with congenital long QT syndrome

A 7‐year‐old boy presented at our hospital with syncope. At birth, electrocardiography had shown a long QT interval with torsade de pointes (TdP). Congenital long QT syndrome (LQTS) had been diagnosed by genetic testing, and was successfully controlled with oral propranolol. At age 7, TdP had recurred with syncope. Electrocardiography revealed a prominent long QT interval with T‐wave alternans. The propranolol dose was increased, but TdP remained uncontrolled. A cardioverter‐defibrillator (ICD) was implanted epicardially, and TdP completely resolved with atrial pacing. We report this rare case of ICD implantation in a child with LQTS.

Complete right bundle branch block and QRS-T discordance can be the initial clue to detect S-ICD ineligibility

BACKGROUND In order to minimize inappropriate shocks of subcutaneous implantable cardioverter-defibrillators (S-ICD), it is important to recognize who is suitable for S-ICD indication. This study aimed to clarify what types of cardiac disease are likely to fulfill the S-ICD screening criteria and ineligible factors for S-ICD in the standard 12-lead electrocardiogram (ECG). METHODS A total of 348 patients with heart disease were enrolled. They were assessed by supine and standing ECG recording to simulate the 3 S-ICD sensing vectors and standard 12-lead ECG, simultaneously. Clinical and ECG characteristics were analyzed to compare the patients who are eligible and ineligible with S-ICD screening ECG indication. RESULTS The mean age of study patients was 49±21 years and 244 (70%) were men. Nineteen percent of patients were unsuitable for S-ICD. There was no significant difference in ineligibility for S-ICD among cardiac diseases (p=0.48). Univariate analysis showed complete right bundle branch block (CRBBB), QRS-T discordance in lead II, and QRS-T discordance in 3 leads (I, II, and aVF) were more frequent in patients who were ineligible for S-ICD than in the eligible group. Multivariate regression analysis showed CRBBB and QRS-T discordance in 3 leads were independent predictors for ineligibility of S-ICD. CONCLUSION There are no differences in eligibility of S-ICD among types of cardiac diseases. CRBBB and QRS-T discordance were independent predictors for ineligibility.

Initial experience with the subcutaneous implantable cardioverter-defibrillator in a single Japanese center

The subcutaneous implantable cardioverter‐defibrillator (S‐ICD) is recognized as a viable alternative to the transvenous ICD. The safety and efficacy of this device has been demonstrated in Western countries, but studies with S‐ICD implantation in Japanese patients have not been reported.

Analysis of arrhythmic events is useful to detect lead failure earlier in patients followed by remote monitoring

Remote monitoring (RM) has been advocated as the new standard of care for patients with cardiovascular implantable electronic devices (CIEDs). RM has allowed the early detection of adverse clinical events, such as arrhythmia, lead failure, and battery depletion. However, lead failure was often identified only by arrhythmic events, but not impedance abnormalities.

Percutaneous lead extraction for patients with large vegetations using an unusual technique

From the *Department of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan, Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan, and Department of Cardiovascular Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.

The feasibility of substituting left atrial wall strain for flow velocity of left atrial appendage

Abstract Objective: Non-valvular atrial fibrillation (NVAF) is frequently complicated by thromboembolism. Left atrial appendage (LAA) flow is a predictor of LAA thrombosis. LAA flow is measured by transesophageal echocardiography (TEE), which is a semi-invasive diagnostic tool. Recently, speckle-tracking methods have been adapted for the evaluation of local cardiac function. We hypothesised that if we could determine LAA wall motion utilising a speckle tracking technique, we could non-invasively analyse LAA flow. Methods: Sixty-three NVAF patients including 38 with chronic atrial fibrillation (CAF), 14 with paroxysmal AF (PAF) and 11 with atrial flutter (AFL) were enrolled in this study. Normal sinus rhythm (NSR) patients with non-thromboembolic cerebral infarction were also included. Immediately after obtaining a 2D movie of the LAA through the aortic oblique short axis view by transthoracic echocardiography, LAA flow velocity was measured by TEE. Mean strains between the posterior and anterior walls were measured using a speckle-tracking technique. Results: Ten patients exhibited a thrombus and 11 had spontaneous echo contrast (SEC) in the auricle. Mean strain value was similar between CAF and PAF, although LAA flow velocity for CAF was significantly reduced compared with PAF (median value 13.7 cm/s versus 36.1 cm/s, p = <.00001). Mean strain of CAF with thrombus/SEC was significantly reduced compared with NSR patients (median value 1.52% versus 3.17%, p = .00181). Furthermore, mean strain was correlated with LAA flow velocity (R = 0.399, R2 = 0.1595, p = .000615). Conclusions: LAA wall strain identified via speckle-tracking methods may presage LAA peak flow velocity. This technique may contribute to stratification of thrombosis risks in the LAA.

An improved algorithm calculated from intrathoracic impedance can precisely diagnose preclinical heart failure events: Sub-analysis of a multicenter MOMOTARO (Monitoring and Management of OptiVol Alert to Reduce Heart Failure Hospitalization) trial study

BACKGROUND Ambulatory measurement of intrathoracic impedance (ITI) with an implanted device has potential to assess fluid accumulation in patients with heart failure (HF), but it has failed to reduce HF-related hospitalization because of a high false-positive rate. OBJECTIVE We aimed to examine whether a modified algorithm (OptiVol 2.0) could reduce false-positive HF events documented in our multicenter trial (MOMOTARO). METHODS The MOMOTARO trial assessed the potential that fluid index could predict fluid accumulation and therefore HF. The MOMOTARO trial assessed whether HF events could be detected based on fluid accumulation as assessed by fluid index. We re-analyzed raw data of ITI trends of the threshold-crossing events with the modified algorithm. RESULTS The study consisted of 195 patients who had been implanted with a high-energy device. During a mean follow-up period of 658±165 days, there were 154 primary HF events detected by the previous algorithm (OptiVol 1.0). With the previous algorithm, there was no significant difference in log concentration of brain natriuretic peptide (BNP) between baseline and alert (p=0.21). Among 150 alerts of the previous algorithm, only 37 reached the threshold by the modified algorithm, and log BNP was significantly higher in these 37 events compared with the baseline value (2.40±0.46 vs. 2.27±0.52, p<0.01). CONCLUSION Our simulation study demonstrates that fluid index calculated with the modified algorithm reduces the number of false-positive threshold-crossing HF events and is promising for accurate diagnosis of fluid accumulation in patients.

Two cases of inappropriate implantable cardioverter-defibrillator therapies due to T wave oversensing induced by body twisting

T wave oversensing (TWOS) is a common cause of inappropriate implantable cardioverter‐defibrillator (ICD) therapies. Various algorithms to avoid inappropriate ICD therapy are available; however, they are not helpful to avoid TWOS. Although the reproduction of TWOS is useful to resolve the problem of TWOS, it is sometimes difficult to reproduce TWOS. We report two cases of inappropriate ICD therapy due to TWOS, which were induced only by body twisting. We can successfully manage the device based on the evidence of reproduced TWOS.