Electrical storm in an acquired short QT syndrome successfully treated with quinidine.

Short QT syndrome (SQTS) is a malignant heart disorder defined by the presence of ventricular arrhythmias causing syncope and sudden cardiac arrest. The prevalence in the pediatric population is 0.05%. Quinidine is an established agent for pharmacological prophylaxis in SQTS patients, but can also terminate an electrical storm.

Novel approaches for the treatment of ventricular tachycardia.

Ventricular tachycardia (VT) is a crucial cause of sudden cardiac death (SCD) and a primary cause of mortality and morbidity in patients with structural cardiac disease. VT includes clinical disorders varying from benign to life-threatening. Most life-threatening episodes are correlated with coronary artery disease, but the risk of SCD varies in certain populations, with various underlying heart conditions, specific family history, and genetic variants. The targets of VT management are symptom alleviation, improved quality of life, reduced implantable cardioverter defibrillator shocks, prevention of reduction of left ventricular function, reduced risk of SCD, and improved overall survival. Antiarrhythmic drug therapy and endocardial catheter ablation remains the cornerstone of guideline-endorsed VT treatment strategies in patients with structural cardiac abnormalities. Novel strategies such as epicardial ablation, surgical cryoablation, transcoronary alcohol ablation, pre-procedural imaging, and stereotactic ablative radiotherapy are an appealing area of research. In this review, we gathered all recent advances in innovative therapies as well as experimental evidence focusing on different aspects of VT treatment that could be significant for future favorable clinical applications.

Conduction abnormalities after transcatheter aortic valve implantation.

In the last few years, transcatheter aortic valve implantation (TAVI) has become an alternative procedure in patients with severe aortic stenosis and high risk for surgical aortic replacement. Due to the anatomic correlation between aortic valve structure and conduction system of the heart, one of the most common complications after TAVI is conduction system disturbances which including bundle branch block, complete heart block and need for permanent pacemaker implantation. Although these disturbances are usually not lethal, they may have a great influence on patients' state and long term-survival. Several risk factors for conduction disturbances have been identified which including age, anatomy of the heart, periprocedural factors, type of implanted valve, preexisting abnormalities and comorbidities. As this technique becomes more familiar to physicians, patients should be carefully screened for risk factors for the development of conduction abnormalities after TAVI in order to provide effective prevention and proper treatment.

The Role of Echocardiography in the Optimization of Cardiac Resynchronization Therapy: Current Evidence and Future Perspectives.

BACKGROUND: Cardiac resynchronization therapy (CRT) has become a mainstay in the management of heart failure. Up to one-third of patients who received resynchronization devices do not experience the full benefits of CRT. The clinical factors influencing the likelihood to respond to the therapy are wide QRS complex, left bundle branch block, female gender, non-ischaemic cardiomyopathy (highest responders), male gender, ischaemic cardiomyopathy (moderate responders) and narrow QRS complex, non-left bundle branch block (lowest, non-responders). OBJECTIVE: This review provides a conceptual description of the role of echocardiography in the optimization of CRT. METHOD: A literature survey was performed using PubMed database search to gather information regarding CRT and echocardiography. RESULTS: A total of 70 studies met selection criteria for inclusion in the review. Echocardiography helps in the initial selection of the patients with dyssynchrony, which will benefit the most from optimal biventricular pacing and provides a guide to left ventricular (LV) lead placement during implantation. Different echocardiographic parameters have shown promise and can offer the possibility of patient selection, response prediction, lead placement optimization strategies and optimization of device configurations. CONCLUSION: LV ejection fraction along with specific electrocardiographic criteria remains the cornerstone of CRT patient selection. Echocardiography is a non-invasive, cost-effective, highly reproducible method with certain limitations and accuracy that is affected by measurement errors. Echocardiography can assist with the identification of the appropriate electromechanical substrate of CRT response and LV lead placement. The targeted approach can improve the haemodynamic response, as also the patient-specific parameters estimation.

Management of Coronary Artery Disease and Conduction Abnormalities in Transcatheter Aortic Valve Implantation.

OPINION STATEMENT: Transcatheter aortic valve replacement (TAVR) is an expanding, catheter-based technology that allows the implantation of a prosthetic valve without requiring open heart surgery for the treatment of severe aortic stenosis (AS). The frequency of coronary artery disease (CAD) in patients (pts) with severe AS undergoing surgical treatment ranges from 30 to 50 %. This tends to be higher in pts undergoing TAVR with a prevalence of 49-76 % and is more prevalent with older age and the fact that TAVR is commonly performed in high-risk groups with more advanced cardiovascular disease. The overall influence of CAD on TAVR procedural outcomes remains controversial, and the management of concomitant artery disease is still under discussion. There are three major issues that must be addressed: the impact of CAD, optimal timing of percutaneous coronary intervention (PCI) and TAVR, and extent of revascularization. Today, TAVR is commonly performed as a stand-alone procedure with variable degrees of concomitant CAD tolerated without intervention. One of the major potential complications with TAVR is the damage to the conduction system. The requirement of permanent pacemaker (PM) implantation ranges from 9 to 49 % of cases with a mean of ~20 %, whereas surgical aortic valve replacement (sAVR) is associated with a complete heart block that requires permanent PM in 3-12 % of cases. Reports have demonstrated an increased incidence of conduction damage in patients undergoing TAVR with the CoreValve (Medtronic Minneapolis, MN, USA) prosthesis (mean 20.8 %, range 9.3-30.0 %) compared with the Edwards SAPIEN (Edwards Lifesciences LLC; Irvine, CA, USA) prosthesis (mean 5.4 %, range 0-10.1 %). Factors predicting PM implantation include preexisting bundle branch block (BB) or conduction abnormalities. The prognostic significance of new left bundle branch block (LBBB) after TAVR is unclear. In the future, new valve designs may improve the incidence of permanent PM implantation after TAVR.

Permanent pacing after transcatheter aortic valve implantation of a CoreValve prosthesis as determined by electrocardiographic and electrophysiological predictors: a single-centre experience.

AIM: The most frequent conduction complications with transcatheter aortic valve implantation (TAVI) are complete atrioventricular (AV) block and new bundle branch block (BB). The purpose of this study was to assess clinical, electrocardiographic, and electrophysiological predictors of conduction abnormalities in patients (pts) undergoing TAVI with the CoreValve prosthesis. The secondary end points were the long-term rhythm follow-up and the recovery of conduction. METHODS AND RESULTS: Forty-five consecutive pts with severe aortic stenosis, New York Heart Association II/III, and normal or slightly impaired left ventricular function who underwent CoreValve transcatheter implantation were randomized 2:1 to electrocardiographic and electrocardiographic plus electrophysiological evaluations. Pacemakers were implanted in pts with complete AV block. Follow-up was performed at 1, 6, 12, and 24 months. Conduction was affected in the total group of pts undergoing TAVI. The PR lengthened compared with the baseline but did not exceed the normal cut-off of 200 ms, and the QRS widened, basically due to new left bundle branch blocks (LBBBs). Within 1 month of follow-up, 10 pts (22%) developed complete AV block (9 peri-procedurally-20%) and 15 pts (33%) developed a new bundle BB, with LBBBs being the most common (14-31%). In the 30 pts who underwent an electrophysiological study, analysis showed that prolonged HV intervals were prognostic for pacemaker implantation. Follow-up in the total study group revealed that only 4 of the 10 (9%) initial implantations remained completely pacemaker dependent. CONCLUSION: Conduction was affected in all pts undergoing TAVI, but serious complications that required permanent pacing generally occurred in pts with pre-existing conduction abnormalities.

A case-matched comparative study of surgical radiofrequency (RF) ablation for patients with persistent or long-standing atrial fibrillation undergoing concomitant heart surgery.

INTRODUCTION: Recent guidelines from the European Society of Cardiology suggest that surgical ablation should be considered in patients with atrial fibrillation (AF) who present for concomitant surgically correctable disease. This is a case-matched study of radiofrequency ablation during concomitant cardiac surgery versus lone surgery on patients with persistent and long-standing permanent AF. METHODS: Surgical ablation was performed in 21 patients, 14 with persistent and 7 with long-standing permanent AF. Patients with paroxysmal AF, recent onset persistent AF (<6 months), duration >6 years or left atrial diameter >8 cm were excluded. The study patients were matched 1-2 for age, sex, type of operation, type and duration of atrial fibrillation with 42 patients operated during the same period in the same department without ablation. The catheters used deliver continuously monitored radiofrequency energy, creating linear lesions on the inside of the arrested left and/or right atrial wall. Follow up was with regular outpatients' appointments and 24-hour ECG recordings at 6 and 12 months. RESULTS: Sinus rhythm maintenance rate at discharge and 12-month follow up was significantly higher in the ablation group (12 months: 71% vs. 5%, p<0.01). The ablation group had significantly longer operative times. Mean ablation duration was 15.5 minutes (CI: 12-20). There were no deaths. There were no statistically significant differences in postoperative in-hospital stay, NYHA class, left atrial size, or left ventricular ejection fraction. All patients who maintained sinus rhythm during the ablation had echocardiographically confirmed left atrial systole at follow up. CONCLUSION: Epicardial radiofrequency ablation in patients with persistent and long lasting permanent AF, who are being operated for concomitant cardiac surgical disease, is a safe, reproducible method with acceptable sustainability of sinus rhythm at medium-term follow up.

Dislocation of an infected and abandoned pacemaker lead.

We present a case of pacemaker lead dislodgment in an 83-year-old patient with a pacemaker infection. Initially, the generator and the proximal part of the leads were removed, and the remaining leads were severed and abandoned. Twenty-five days later, dislodgment of both abandoned leads and systemic infection were documented. The leads were then surgically removed without further complications.

Long term effects of cardiac resynchronization therapy in non-ambulatory NYHA IV heart failure patients.

BACKGROUND: We aimed at evaluating the long-term effects of cardiac resynchronization therapy (CRT) in nonambulatory New York Heart Association (NYHA) IV heart failure patients (NAIVHFP). METHODS: Eighteen patients, 15 men and three women, eight with ischemic and 10 with nonischemic cardiomyopathy, who underwent biventricular pacemaker implantation while they were in nonambulatory NYHA IV class, were studied. Patients' age was 58 ± 9 years and left ventricular ejection fraction (LVEF) 18 ± 3%. Follow-up data were obtained through review of follow-up visits notes, stored echocardiographic studies, device interrogation data, and death certificates. RESULTS: After a mean duration of 1223 ± 846 days, 11 patients were alive, including five patients who underwent heart transplantation (OCT) and seven dead. Three of 11 patients who received a CRT-defibrillator, experienced at least one appropriate discharge, but eventually they either died or received an OCT during follow-up. Sustained improvements in NYHA class (Z = 2.4, P = 0.015) and 6-minute walk distance (0 vs 212 ± 95 m, P 0.001) were documented after a median duration of 855 days postimplantation. Cumulative proportion of death or OCT at 18 months-when full follow-up data were available-was 18%, which compared favorably with historical controls. Full echocardiographic and clinical follow-up data at 12-months postimplantation were available for 10 patients, documenting a significant reduction in end-systolic volume (248 ± 82 vs 269 ± 97 mL, P = 0.039). CONCLUSIONS: CRT can be safely applied in this subset of extreme severity heart failure patients, achieving encouraging survival rates and reverse remodeling effects. These observations can form an evidence-based rationale for including NAIVHFP in randomized CRT trials.

Disorders of the autonomic nervous system in patients with Brugada syndrome: a pilot study.

INTRODUCTION: The aim of this study was to examine autonomic disorders in patients with Brugada syndrome by performing a cardiac sympathetic innervation evaluation, a head-up tilt-test (HUT) and heart rate variability (HRV) analysis. METHODS AND RESULTS: We enrolled 20 patients with Brugada syndrome (mean age 42.5 +/- 8.8 years), 9 with spontaneous and 11 with an induced type 1 electrocardiogram (ECG) in the setting of symptoms and 20 age-matched controls. All subjects underwent a HUT with parallel measurements of plasma catecholamines and cortisol, a (123)I-metaiodobenzylguanidine single photon emission tomography, and HRV evaluation. Ten control subjects participated in the innervation portion of the study. The tilt-test with clomipramine challenge was positive in 15 of 20 (75%) patients (7 spontaneous, 8 induced) and in 1 in controls (P < 0.01). A sympathoadrenal imbalance was shown in positive tests. The pattern of innervation in all groups was heterogenic and similar to controls with a trend towards lower measurements in patients with a spontaneous type 1 ECG and a positive HUT. HRV analysis did not reveal any significant differences during day and night. Four patients (20%) had sustained ventricular arrhythmias during a follow-up of 31.1 +/- 8.6 months, but no correlations with innervation or response to tilting were found. CONCLUSION: A high susceptibility to vasovagal syncope was observed in patients with Brugada syndrome, which could be disease-related symptoms. Conversely, sympathetic innervation was observed to follow a physiological, heterogenic pattern; however, these factors did not have prognostic value for life-threatening arrhythmias.

Predictive value of cardiac autonomic indexes and MIBG washout in ICD recipients with mild to moderate heart failure.

OBJECTIVE: We aimed at evaluating the combined use of heart rate variability (HRV), baroreflex sensitivity (BRS), and MIBG imaging in the risk stratification for sudden cardiac death (SCD) of patients with mild to moderate heart failure. METHODS: Twenty-five patients (17 male and 8 female, mean age 63 +/- 5 years, mean LVEF 36 +/- 3%) with a recently implanted defibrillator (ICD) and mild (NYHA I-II) heart failure due to either ischemic (n = 15) or dilated (n = 10) cardiomyopathy were studied. One week after ICD implantation they underwent (a) baroreflex sensitivity (BRS) evaluation to bolus phenylephrine by the Oxford method, (b) 24-h heart rate variability (HRV) assessment, and (c) MIBG imaging. The mean patient follow-up was 32 +/- 10 months. Simple correlation and stepwise multiple regression analysis was performed to evaluate (a) if the number of sustained ventricular tachycardia (cycle length <330 ms) or fibrillation episodes per month is related to one or more of MIBG, BRS, and HRV indexes and (b) if MIBG % washout is related to HRV and/or BRS. RESULTS: The frequency of fast ventricular arrhythmic episodes (FVAE) demonstrated an inverse relation to BRS (p < 0.0001), rMSSD (p = 0.001), and pNN50 (p = 0.0034), while it was positively related to LF (p < 0.0001) and MIBG % washout (p = 0.001). BRS, LF, rMSSD, and MIBG washout were also independent predictors of FVAE. MIBG washout was related to only one HRV marker (SDNN-I, p < 0.0001), while no correlation was observed with BRS. CONCLUSIONS: In ICD recipients with well-compensated heart failure, autonomic markers derived from BRS, HRV, and MIBG studies are related to FVAE. These markers have limited inter-dependency and constitute useful means for SCD risk stratification in this subgroup of patients.

Patents in the diagnosis and therapy of neurocardiogenic syncope.

Neurocardiogenic syncope is one of the most common types of syncope, characterized by arterial vasodilatation with or without bradycardia. The regulation of blood pressure and heart rate is the result of a complex reaction between the central and peripheral nervous system with the circulatory system. Multiple therapies, pharmaceutical and interventional, have been applied without any proven effect. The initial positive reports on pacing were not demonstrated in enough number of controlled studies. Neurocardiogenic syncope continues to remain a clinical problem in terms of understanding its underlying mechanisms and therapy needs to be enlightened by future studies. This article provides a background of diagnosis and therapy of neurocardiogenic syncope and reviews some related patents.

The ischemia-modified albumin in relation to pacemaker and defibrillator implantation.

BACKGROUND: Ischemia-modified albumin (IMA) is considered a marker of myocardial ischemia whereas cardiac enzymes are released when cardiac necrosis occurs. It has previously been shown that permanent pacemaker-defibrillator insertion is associated with myocardial injury expressed as cardiac enzyme rise. OBJECTIVE: We assessed whether pacemaker-defibrillator implantation also induces changes in IMA plasma levels and whether, therefore, myocardial ischemia precedes necrosis. METHODS: We studied 64 consecutive patients undergoing pacemaker or defibrillator implantation; 43 were men and 21 women and their age was 70 +/- 11 years (range 23-84 years). Blood samples were collected at baseline, six hours and 48 hours following the procedure. IMA measured by the albumin cobalt binding test (ACB, Integra 800 analyzer), as well as creatine kinase (CK), the MB isoenzyme of creatine kinase (CK-MB) and cardiac troponin I (Tn-I) were evaluated. RESULTS: Data analysis showed that compared to baseline measurements, IMA increased at six hours (P = 0.015) and at 48 hours (P = 0.003)[97.6 +/- 10.2 vs 101.4 +/- 10.7 vs 102.1 +/- 9.2 U/mL at baseline, six hours and 48 hours, respectively]; similarly, CK increased at six hours (P = 0.0001) and remained high at 48 hours (P = 0.0001) [74.9 +/- 49.9 vs 136.1+/-186.7 vs 115.2 +/- 63.9 mIU/mL], while CK-MB increased at six hours (P = 0.0001), but returned to baseline values at 48 hours (P = 0.05) [0.90 +/- 0.89 vs 1.27 +/- 134 vs 0.71 +/- 0.63 ng/mL] and Tn-I increased at six hours (P = 0.0001) and returned to baseline levels at 48 hours (P = 0.32) [0.057 +/- 0.23 vs 0.16 +/- 0.36 vs 0.03 +/- 0.045 ng/mL]. CONCLUSION: Permanent pacemaker-defibrillator insertion is associated with myocardial ischemia and necrosis.

Heart rate turbulence after short runs of nonsustained ventricular tachycardia in chronic heart failure.

BACKGROUND: Heart rate turbulence (HRT) following isolated premature complexes is a baroreceptor-mediated prognostic marker. Short runs of spontaneous, nonsustained ventricular tachycardia (nsVT) exert a greater hemodynamic effect than extrasystoles and may trigger a more potent turbulence-like response (HRT(VT)), possibly related to other risk-related markers, such as heart rate variability (HRV), left ventricular ejection fraction (EF), and original HRT parameters (turbulence slope [TS] and turbulence onset [TO]). METHODS: We studied 27 patients with heart failure (HF) and nsVT (4-7 beats) on 24-hour Holter electrocardiographic recordings (mean age 58 +/- 3.6 years, EF 36%+/- 5.0%). Following nsVT, TS(VT) and TO(VT) were measured according to the original definitions. HRV, TS, and TO were also assessed. RESULTS: HRT(VT) parameters were related to HRV. A significant relation existed between TS(VT) and EF (r= 0.66, P < 0.05). HRT(VT) parameters were related to the originally described (TS and TO), whereas TO(VT) was higher than TO (1.63 +/- 1.6 vs -1.7 +/- 0.65, P < 0.05). CONCLUSIONS: In mild-to-moderate HF, turbulence is observed following short nsVT runs and is related to prognostically important HRV indexes and EF. HRT(VT) is similar to HRT but TO(VT) is shifted toward more positive values than TO. HRT(VT) might be prognostically significant.

Neurocardiogenic mechanisms of unexplained syncope in idiopathic dilated cardiomyopathy.

Syncope in patients with advanced heart failure is a sign of poor prognosis. The cause of syncope in patients with dilated cardiomyopathy (DC) is not fully recognized and may remain elusive even after standardized evaluation. The purpose of the present study was to examine the implication of neurally mediated mechanisms in the pathophysiology of syncopal episodes in patients with DC. Twenty-six patients (21 men, 5 women; mean age 59 +/- 2 years, range 38 to 79) with DC and left ventricular ejection fractions

Ischaemia modified albumin in radiofrequency catheter ablation.

UNLABELLED: Aim Ischaemia modified albumin (IMA) is considered a marker of myocardial ischaemia, in contrast to the biomarkers of myocardial injury [creatine kinase (CK), the MB isoenzyme of CK, and cardiac troponin I (Tn-I)] that are released when cardiac necrosis occurs. Ischaemia modified albumin has been reported to increase following percutaneous coronary intervention and in acute coronary syndromes. We sought to determine whether IMA increases following radiofrequency (RF) ablation. METHODS AND RESULTS: We studied 40 consecutive patients who underwent RF catheter ablation; 20 were men and 20 women and their age was 47 +/- 16 (16-77) years. All patients underwent electrophysiological study and subsequent RF ablation. Peripheral venous samples were collected before the procedure (baseline), immediately after the procedure, 2 h post-procedure and the following day (20 h post-procedure) and assayed for CK, the MB isoenzyme of CK, cardiac Tn-I and IMA. Ischaemia-modified albumin plasma levels did not differ significantly at all four time points, baseline, and following ablation (P = 0.5974), whereas CK, CK-MB, and Tn-I increased significantly at all time points compared with baseline (P < 0.0001). Post-ablation, all but three 3 CK measurements were in the normal range; 14 patients had CK-MB plasma levels above the upper limit of normal; all but one patient had Tn-I elevated. CONCLUSION: The IMA plasma levels do not change significantly following RF ablation, unlike biomarkers of myocardial injury, implying that myocardial necrosis occurs without preceding ischaemia.

Contribution of electroanatomical mapping to the diagnosis of arrhythmogenic right ventricular cardiomyopathy in a patient with sustained ventricular tachycardia.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a primary cardiomyopathy, characterized mainly by anatomic and functional defects of the right ventricle. In many cases its diagnosis is quite difficult in spite of the existence of defined diagnostic criteria for the disease. We describe an interesting case of a patient with sustained ventricular tachycardia derived from the right ventricular outflow tract, in whom the diagnosis of ARVC was made with the contribution of electrophysiologic study and electroanatomical mapping, as the use of all other diagnostic tests and laboratory methods had left many unanswered questions. Based on our case, but also on other studies and case reports in the literature, we conclude that electroanatomical mapping is useful for the documentation of the diagnosis of ARVC, whenever this is not clear from the use of available diagnostic tests according to the defined criteria of the disease.