Xavier Vinolas

Cardioverter defibrillator implantation without induction of ventricular fibrillation: A single-blind, non-inferiority, randomised controlled trial (SIMPLE)

BACKGROUNDnDefibrillation testing by induction and termination of ventricular fibrillation is widely done at the time of implantation of implantable cardioverter defibrillators (ICDs). We aimed to compare the efficacy and safety of ICD implantation without defibrillation testing versus the standard of ICD implantation with defibrillation testing.nnnMETHODSnIn this single-blind, randomised, multicentre, non-inferiority trial (Shockless IMPLant Evaluation [SIMPLE]), we recruited patients aged older than 18 years receiving their first ICD for standard indications at 85 hospitals in 18 countries worldwide. Exclusion criteria included pregnancy, awaiting transplantation, particpation in another randomised trial, unavailability for follow-up, or if it was expected that the ICD would have to be implanted on the right-hand side of the chest. Patients undergoing initial implantation of a Boston Scientific ICD were randomly assigned (1:1) using a computer-generated sequence to have either defibrillation testing (testing group) or not (no-testing group). We used random block sizes to conceal treatment allocation from the patients, and randomisation was stratified by clinical centre. Our primary efficacy analysis tested the intention-to-treat population for non-inferiority of no-testing versus testing by use of a composite outcome of arrhythmic death or failed appropriate shock (ie, a shock that did not terminate a spontaneous episode of ventricular tachycardia or fibrillation). The non-inferiority margin was a hazard ratio (HR) of 1·5 calculated from a proportional hazards model with no-testing versus testing as the only covariate; if the upper bound of the 95% CI was less than 1·5, we concluded that ICD insertion without testing was non-inferior to ICD with testing. We examined safety with two, 30 day, adverse event outcome clusters. The trial is registered with ClinicalTrials.gov, number NCT00800384.nnnFINDINGSnBetween Jan 13, 2009, and April 4, 2011, of 2500 eligible patients, 1253 were randomly assigned to defibrillation testing and 1247 to no-testing, and followed up for a mean of 3·1 years (SD 1·0). The primary outcome of arrhythmic death or failed appropriate shock occurred in fewer patients (90 [7% per year]) in the no-testing group than patients who did receive it (104 [8% per year]; HR 0·86, 95% CI 0·65-1·14; pnon-inferiority <0·0001). The first safety composite outcome occurred in 69 (5·6%) of 1236 patients with no-testing and in 81 (6·5%) of 1242 patients with defibrillation testing, p=0·33. The second, pre-specified safety composite outcome, which included only events most likely to be directly caused by testing, occurred in 3·2% of patients with no-testing and in 4·5% with defibrillation testing, p=0·08. Heart failure needing intravenous treatment with inotropes or diuretics was the most common adverse event (in 20 [2%] of 1236 patients in the no-testing group vs 28 [2%] of 1242 patients in the testing group, p=0·25).nnnINTERPRETATIONnRoutine defibrillation testing at the time of ICD implantation is generally well tolerated, but does not improve shock efficacy or reduce arrhythmic death.nnnFUNDINGnBoston Scientific and the Heart and Stroke Foundation (Ontario Provincial office).

Effects of Open-Irrigated Radiofrequency Ablation Catheter Design on Lesion Formation and Complications: In Vitro Comparison of 6 Different Devices

Open‐irrigated radiofrequency ablation catheters with slight differences in tip architecture are widely used, although limited comparative data are available. The purpose of this study was to compare the lesion size and potential complications produced by commercially available open‐irrigated catheters in an in vitro porcine heart model.

Electrocardiographic and Clinical Precursors of Ventricular Fibrillation: Chain of Events

Precursors of VF. Ventricular fibrillation is the final event in the majority of cases of sudden death. The ECG and clinical precursors of ventricular fibrillation are discussed in this article. Ventricular fibrillation usually appears as a consequence of a chain of events that leads to the appearance of this lethal arrhythmia. We review the markers of the vulnerable myocardium prone to ventricular fibrillation, the triggers and modulators that act on this vulnerable myocardium, and the event(s) that constitute the final step preceding this arrhythmia. The final step may be as unique as a sudden waterfall or present as a cascade of successive phenomena.

Changes in myocardial electrical impedance in human heart graft rejection

Monitoring of post‐transplant heart rejection is currently based on endomyocardial biopsy analysis. This study aimed to assess the effects of heart graft rejection on myocardial electrical impedance.

Risk stratification after myocardial infarction: Role of electrical instability, ischemia, and left ventricular function

SummaryThe problem of risk stratification after myocardial infarction is reviewed. There are three major complications: new ischemic events, congestive heart failure, and malignant arrhythmias and sudden death, related to the presence of residual ischemia, left ventricular dysfunction, and electrical instability. The bidirectional interactions among these three factors is analyzed. The risk is in the middle of a triangle, the three angles of which are the above-mentioned factors. All the “satellite” factors that appear from all three angles are presented. Furthermore, the most important parameters and techniques employed to detect risk, multifactorial approach of risk stratification, and changes of risk stratification in the thrombolytic era are briefly reviewed.

Troponin levels after ICD implantation with and without defibrillation testing and their predictive value for outcomes: Insights from the SIMPLE trial

BACKGROUNDnThe Shockless IMPLant Evaluation trial randomized 2500 patients receiving a first implantable cardioverter-defibrillator (ICD)/cardiac resynchronization therapy-defibrillator device to have either defibrillation testing (DT) or no DT. It demonstrated that DT did not improve shock efficacy or reduce mortality.nnnOBJECTIVEnThis prospective substudy evaluated the effect of DT on postoperative troponin levels and their predictive value for total and arrhythmic mortality.nnnMETHODSnTroponin levels were measured between 6 and 24 hours after ICD implantation in 2200 of 2500 patients.nnnRESULTSnA postoperative serum troponin level above the upper limit of normal (ULN) was more common in patients undergoing DT (n = 509 [46.4%]) than in those not subjected to DT (n = 456 [41.3%]; P = .02). After excluding patients with known preoperative troponin levels above the ULN, consistent findings were observed (42.1% vs 37.5%; P = .04). During a mean follow-up of 3.1 ± 1.0 years, the annual mortality rate was increased in patients with postoperative troponin levels above the ULN (adjusted hazard ratio [HR] 1.43; 95% confidence interval [CI] 1.15-1.76; P = .001) irrespective of DT or no DT. Likewise, patients with elevated troponin levels had a significantly higher risk of arrhythmic death (adjusted HR 1.80; 95% CI 1.23-2.63; P = .002). The rate of first appropriate ICD shock (adjusted HR 0.89; 95% CI 0.71-1.12; P = .32) or failed appropriate shock (adjusted HR 1.02; 95% CI 0.59-1.76; P = .95) was similar in patients with or without troponin elevation.nnnCONCLUSIONnDT at the time of ICD implantation is associated with increased troponin levels, indicating subclinical myocardial injury caused by the procedure. Elevated troponin levels but not DT seem to predict clinical outcomes in ICD recipients.

Wound haematoma following defibrillator implantation: incidence and predictors in the Shockless Implant Evaluation (SIMPLE) trial

AimsnPocket haematoma is a common complication after defibrillator [implantable cardioverter defibrillator (ICD)] implantation, which is not only painful, but also increases the risk of device-related infection, and possibly embolic events. The present study seeks to evaluate the rate and predictors of clinically significant pocket haematoma.nnnMethods and resultsnThis study included 2500 patients receiving an ICD in the SIMPLE trial. A clinically significant pocket haematoma was defined as a haematoma that required re-operation or interruption of oral anticoagulation (OAC) therapy. Clinically significant pocket haematoma occurred in 56 of 2500 patients (2.2%) of which 6 (10.7%) developed device-related infection. Patients who developed pocket haematoma were older (mean age 67.6 ± 8.8 years vs. 62.7 ± 11.6 years, P < 0.001), were more likely to have permanent atrial fibrillation (30.4 vs. 6.7%, P < 0.001) and a history of stroke (17.9 vs. 6.7%, P = 0.004), or were more likely to receive peri-operative OAC (50.0 vs. 28.4%, P < 0.001), unfractionated heparin (16.1 vs. 5.2%, P = 0.003), or low-molecular-weight heparin (37.5 vs. 17.5%, P < 0.001). Independent predictors of wound haematoma on multivariable analysis included the use of heparin bridging (OR 2.65, 95% CI 1.48-4.73, P = 0.001), sub-pectoral location of ICD (OR 2.00, 95% CI 1.12-3.57, P =0.020), previous stroke (OR 2.47, 95% CI 1.20-5.10, P = 0.015), an upgrade from permanent pacemaker (OR 2.52, 95% CI 1.07-5.94, P = 0.035), and older age (OR 1.03, 95% CI 1.00-1.06, P = 0.049).nnnConclusionnPocket haematoma remains an important complication of ICD implantation and is associated with a high risk of infection. Independent predictors of pocket haematoma include heparin bridging, prior stroke, sub-pectoral placement of ICD, older age, and upgrade from a pacemaker.

Fibrinolytic therapy for superior vena cava and right atrial thrombosis: Diagnosis and follow-up with biplane transesophageal echocardiography

Thrombosis of the superior vena cava and other central venous trunks is a complication that is associated with the implantation of pacemakers and central venous catheters that are used for chemotherapy or total parenteral nutrition. This complication occurs somewhat more frequently than expected because many of these thrombi are clinically unnoticed and are finally diagnosed at autopsy. Phlebographic studies have shown that thrombosis is related to central venous catheters in up to 52 “;# of patients who have not received anticoagulation therapy.l This complication may be treated satisfactorily with fibrinolytic agents such as streptokinase (SK), urokinase (UK), and tissue plasminogen activator. We report a patient with ischemic heart disease who had a catheter-related superior vena cava thrombosis with protrusion of the thrombus t,owards the right atrium, successfully treated with SK. Diagnosis and follow-up examinations were carried out by transthoracic and biplane transesophageal echocardiography. The patient was a 59-year-old man who had antecedents

Apical versus Non-Apical Lead: Is ICD Lead Position Important for Successful Defibrillation?

We aim to compare the acute and long‐term success of defibrillation between non‐apical and apical ICD lead position.

Implantable Cardioverter Defibrillator Therapy in Hypertrophic Cardiomyopathy: A SIMPLE Substudy

BACKGROUNDnPatients with hypertrophic cardiomyopathy (HCM) are considered to be at high risk for elevated defibrillation thresholds, periprocedural complications, and failed appropriate shocks.nnnOBJECTIVEnThe purpose of this study was to determine the value of defibrillation testing (DT) in HCM patients undergoing implantable cardioverter-defibrillator (ICD) insertion.nnnMETHODSnDefibrillation thresholds, perioperative complications, and long-term outcomes were compared between patients with HCM and those with ischemic cardiomyopathy (ICM) or dilated cardiomyopathy (DCM) enrolled in the SIMPLE (Shockless IMPLant Evaluation) trial (Clinialtrials.gov Identifier: NCT00800384). In patients with HCM, outcomes were also compared between those randomized to DT vs no DT.nnnRESULTSnAdequate defibrillation safety margin without system change was achieved in 46 of 52 (88.5%) HCM and 948 of 1047 (90.5%) ICM/DCM patients (P = .63). Perioperative complications occurred in 1 of 52 (1.9%) HCM patients with DT compared to 67 of 1047 (6.4%) ICM/DCM patients with DT (P = .37) or 3 of 42 (7.1%) HCM patients without DT (P = .32). During follow-up, there was no significant difference between HCM vs ICM/DCM patients in terms of all-cause mortality (adjusted hazard ratio [HR] 1.02, 95% confidence interval [CI] 0.45-2.34), composite of arrhythmic death or failed appropriate shock (adjusted HR 0.33, 95% CI 0.04-2.42), inappropriate shocks (adjusted HR 1.64, 95% CI 0.69-3.89), or system complications (adjusted HR 1.93, 95% CI 0.88-4.27). All-cause mortality (HR 0.26, 95% CI 0.03-2.20), appropriate (HR 0.24, 95% CI 0.03-2.05), and inappropriate shocks (HR 2.13, 95% CI 0.51-8.94) were similar in HCM patients without or those with DT.nnnCONCLUSIONnWe did not find any difference in intraoperative defibrillation efficacy, perioperative complications, and long-term outcomes between patients with HCM and those with ICM/DCM. DT did not improve intraoperative or clinical shock efficacy in HCM patients.