Implantable cardioverter-defibrillators in patients with long QT syndrome: a multicentre study.
TL;DR: ICD therapy is effective in nearly half the patient population; however, the rates of early and late complica-tions are high and the number of unnecessary ICD shocks and reimplantation procedures may be lowered by modern programming and increased longevity of newer ICD generators.
Abstract: Background: Implantable cardioverter-defibrillator (ICD) therapy has been proven effective in the prevention of sudden cardiac death, but data on outcomes of ICD therapy in the young and otherwise healthy patients with long QT syndrome (LQTS) are limited. Aim: We sought to collect data on appropriate and inappropriate ICD discharges, risk factors, and ICD-related complications. Methods: All LQTS patients implanted with an ICD in 14 centres were investigated. Demographic, clinical, and ICD therapy data were collected. Results: The study included 67 patients (88% female). Median age at ICD implantation was 31 years (12–77 years). ICD indication was based on resuscitated cardiac arrest in 46 patients, syncope in 18 patients, and malignant family history in three patients. During a median follow-up of 48 months, 39 (58%) patients received one or more ICD therapies. Time to first appropriate discharge was up to 55 months. Inappropriate therapies were triggered by fast sinus rhythm, atrial fibrillation, and T-wave oversensing. No predictors of inappropriate shocks were identified. Risk factors for appropriate ICD therapy were: (1) recurrent syncope despite b-blocker treatment before ICD implantation, (2) pacemaker therapy before ICD implantation, (3) single-chamber ICD, and (4) noncompliance to b-blockers. In 38 (57%) patients, at least one complication occurred. Conclusions: ICD therapy is effective in nearly half the patient population; however, the rates of early and late complications are high. Although the number of unnecessary ICD shocks and reimplantation procedures may be lowered by modern programming and increased longevity of newer ICD generators, other adverse events are less likely to be reduced.
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01 Jan 2015
TL;DR: This research presents a novel and scalable approach called “SmartCardiology” that addresses the challenge of “spatially aggregating” ACEs in the blood.
Abstract: 美国心脏病学院（ACC）、美国心脏协会（AHA）、美国心律学会（HRS）专家工作组历时1年，于近期联合发布了新版成人室上性心动过速（SVT）指南，全文于2015年9月23日全文刊登在Circulation、Journal of the American College of Cardiology和Heart Rhythm Journal三大重要杂志上。
135 citations
Journal Article•
13 citations
TL;DR: The subcutaneous defibrillator (S-ICD) as discussed by the authors is an ICD with an electrode system that is placed entirely subcutaneously, outside the thoracic cavity.
Abstract: In the past years, cardiovascular mortality has decreased but despite these cardiovascular diseases are responsible for millions of deaths every year in the world and approximately 25% of which are sudden cardiac death (SCD). Implantable defibrillators (ICD) is proven therapy used in primary and secondary SCD prevention. Currently majority of devices use transvenous leads inserted predominantly into the right heart for both pacing and defibrillation. On the other hand, ICD may cause complications, including inappropriate shocks, device-related infection and lead failure. Problems with transvenous leads prompted the development of a subcutaneous defibrillator (S-ICD) with an electrode system that is placed entirely subcutaneously, outside the thoracic cavity. The device may be useful when venous access is difficult, in young patients and in patients at particular risk of infection. S-ICD is not suitable for patients with indications for bradycardia pacing, cardiac resynchronisation therapy and in cases with tachyarrhythmia easily terminated by antitachycardia pacing.
8 citations
TL;DR: Entirely subcutaneous ICD for SCD prevention is a feasible and safe therapy in young recipients and severe TR might be a serious clinical problem in some patients.
Abstract: Background: Over the last several years the evolution of transvenous implantable cardioverter‑defibrillator (T‑ICD) system and the introduction of subcutaneous ICD (S‑ICD) have contributed to the development of the sudden cardiac death (SCD) prevention in clinical practice. Aims: To report our clinical experience with ICD therapy in children and young adults during the twenty‑ ‑two years of the follow‑up. Methods: We reviewed the database of ICD recipients choosing 80 consecutive patients (pts) implanted at the age of 6–21 in 1996–2018. We analyzed the rate of appropriate (AT) and inappropriate therapies (IT), mortality, complications and new treatment options. Results: A total of 21/80 patients (26.25%) received ≥1 AT for ventricular tachycardia/ventricular fibrillation (anti‑tachycardia pacing or shock) and 25/80 patients (31.25%) had one or multiple IT (P = 0.47). Nine patients (11%) had both AT and IT interventions. During follow‑up, 2 (2.5%) cardiac resynchronization therapy (CRT) systems, and 8 (10%) S‑ICDs were implanted, 3 heart transplantations were performed, and 1 severe tricuspid valve regurgitation occurred. A total of 6/80 patients (7.5%) died. All deaths occurred in the hypertrophic cardiomyopathy group. Conclusions: The mortality rate was 6/80 (7.5%) in the twenty‑two‑year follow‑up. The rate of AT vs. IT was almost equal and remained steady in the long observation period. Severe TR might be a serious clinical problem in some patients. Entirely S‑ICD for SCD prevention is a feasible and safe therapy in young recipients.
7 citations
TL;DR: Wang et al. as discussed by the authors identified a novel KCNH2 mutation W410R in the patient with long QT syndrome 2 (LQT2), but the electrophysiological functions of this mutation remain unknown.
Abstract: Mutations in hERG (human ether-a-go-go-related gene) potassium channel are closely associated with long QT syndromes. By direct Sanger sequencing, we identified a novel KCNH2 mutation W410R in the patient with long QT syndrome 2 (LQT2). However, the electrophysiological functions of this mutation remain unknown. In comparison to hERGWT channels, hERGW410R channels have markedly decreased total and surface expressions. W410R mutation dramatically reduces hERG channel currents (IKr) and shifts its steady-state activation curve to depolarization. Moreover, hERGW410R channels make dominant-negative effects on hERGWT channels. Significantly, we find hERG channel blocker E-4031 could partially rescue the function of hERGW410R channels by increasing the membrane expression. By using in silico model, we reveal that hERGW410R channels obviously elongate the repolarization of human ventricular myocyte action potentials. Collectively, W410R mutation decreases the currents of hERG channel, because of diminished membrane expression of mutant channels, that subsequently leads to elongated repolarization of cardiomyocyte, which might induce the pathogenesis of LQT2. Furthermore, E-4031 could partially rescue the decreased activity of hERGW410R channels. Thus, our work identifies a novel loss-of-function mutation in KCNH2 gene, which might provide a rational basis for the management of LQT2.
3 citations
References
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TL;DR: The availability of effective therapy for this often lethal disease emphasizes the importance of early and accurate diagnosis, and there is frequently a delay in the diagnosis of LQTS, and patients with syncope are often misdiagnosed.
Abstract: T he idiopathic long QT syndrome (LQTS) is a congenital disease with frequent familial transmission, characterized primarily by prolongation of the QT interval and by the occurrence of life-threatening tachyarrhythmias, particularly in association with emotional or physical stress.1-5 Among untreated symptomatic patients, lethality is high, with 20% mortality in the first year after the initial syncope and approximately 50% within 10 years3; however, the risk of death varies among different families. This poor prognosis has been significantly improved by the use of pharmacological or surgical antiadrenergic therapy or both, which has reduced long-term mortality to <5%.3,4,6 The availability of effective therapy for this often lethal disease emphasizes the importance of early and accurate diagnosis. Unfortunately, there is frequently a delay in the diagnosis of LQTS, and patients with syncope are often misdiagnosed, most commonly as affected by a seizure disorder. In its most characteristic presentation, with obvious QT prolongation and stress-induced syncope, the diagnosis of LQTS is quite straightforward for physicians aware of the disease. In cases of borderline QT prolongation and/or absence of symptoms, however, a correct diagnosis may be more difficult. It was for this reason that a first set of diagnostic criteria (Table 1) was proposed in 1985.3 The major merit of that proposal was that it provided a logical and quantitative approach to the clinical diagnosis of LQTS by giving a different weight to major and minor criteria. Its major limitation was that it used the traditional, but untested for diagnostic purposes, cutoff value of QT, >440 msec '2. This also resulted in a rather black-and-white situation in which patients were judged to have an entirely normal or abnormal duration of ventricular repolarization on the basis of a difference of a few milliseconds in a measurement fraught with difficulties, such as interobserver variability.7
1,106 citations
TL;DR: Authors/Task Force Members: Silvia G. Priori (Chairperson), Carina Blomström-Lundqvist (Co-chairperson) (Sweden), Andrea Mazzanti† (Italy), Nico Blom (The Netherlands), Martin Borggrefe (Germany), John Camm (UK), Perry Mark Elliott (UK).
Abstract: 2015 ESC Guidelines for the Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death
945 citations
"Implantable cardioverter-defibrilla..." refers background in this paper
...The following clinical data were collected in all 14 participating centres: circumstances of diagnosis and indications for ICD implantation, age at first symptoms and at diagnosis, sex, family history of LQTS and SCD ( 40 years of age), and the efficacy of previous treatment....
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...Family history of SCD, while important for establishing the diagnosis, is not considered helpful for risk stratification [10]....
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...By providing explicit data regarding the risks and benefits of long-term ICD therapy, our findings may be useful in informing patients and physicians who need to make decisions regarding ICD implantation, particularly in the primary prevention of SCD. Funding: This work was supported by the Polish Scientific Committee grant no. 2P05B09826 (to A.L., A.Z.K.)....
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...In 21 patients, an ICD was implanted in primary prevention of SCD; in 18 of those 21 patients, it was implanted because of syncope or recurrent syncope despite b-blocker/pacemaker therapy....
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...However, the known risk factors of SCD, including sex and QTc [14], did not predict the occurrence of appropriate shocks, whereas the number of genotyped patients was too small to impact statistics....
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719 citations
TL;DR: Compared with shocks, empirical ATP for FVT is highly effective, is equally safe, and improves quality of life, measured with the SF-36.
Abstract: Background— Successful antitachycardia pacing (ATP) terminates ventricular tachycardia (VT) up to 250 bpm without the need for painful shocks in implantable cardioverter-defibrillator (ICD) patients. Fast VT (FVT) >200 bpm is often treated by shock because of safety concerns, however. This prospective, randomized, multicenter trial compares the safety and utility of empirical ATP with shocks for FVT in a broad ICD population. Methods and Results— We randomized 634 ICD patients to 2 arms—standardized empirical ATP (n=313) or shock (n=321)—for initial therapy of spontaneous FVT. ICDs were programmed to detect FVT when 18 of 24 intervals were 188 to 250 bpm and 0 of the last 8 intervals were >250 bpm. Initial FVT therapy was ATP (8 pulses, 88% of FVT cycle length) or shock at 10 J above the defibrillation threshold. Syncope and arrhythmic symptoms were collected through patient diaries and interviews. In 11±3 months of follow-up, 431 episodes of FVT occurred in 98 patients, representing 32% of ventricular ta...
708 citations
670 citations
"Implantable cardioverter-defibrilla..." refers background in this paper
...Long QT syndrome was diagnosed when QTc interval prolongation > 440 ms in men and > 460 ms in women was recorded in the absence of QT-prolonging drugs....
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...QTc, sex, and locus were not shown to be risk factors....
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...Parameters expressed as continuous data were categorised, and borderline values for each category were as follows: age at first symptoms and at ICD implantation — 40 years, QTc — 500 ms; number of syncopal episodes — three; Schwartz score — 4; R-wave amplitude — 5 mV, defibrilla- www.kardiologiapolska.pl tion threshold (DFT) — 10 J. Subsequently, the variables with a p-value < 0.05 in the log-rank analysis were entered in the multivariable Cox regression analysis for proportional hazards assumptions....
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...However, the known risk factors of SCD, including sex and QTc [14], did not predict the occurrence of appropriate shocks, whereas the number of genotyped patients was too small to impact statistics....
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...The clinical data included previous cardiac arrest, documented TdP, prior syncope and recurrent syncope despite b-blocker treatment, QTc interval in leads II and V5, LQT locus, Schwartz score, family history of SCD, as well as age at first symptoms and at ICD implantation....
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