Mechanisms, Risk Factors, and Management of Acquired Long QT Syndrome: A Comprehensive Review

Long QT syndrome is characterized by prolongation of the corrected QT (QTc) interval on the surface electrocardiogram and is associated with precipitation of torsade de pointes (TdP), a polymorphic ventricular tachycardia that may cause sudden death. Acquired long QT syndrome describes pathologic excessive prolongation of the QT interval, upon exposure to an environmental stressor, with reversion back to normal following removal of the stressor. The most common environmental stressor in acquired long QT syndrome is drug therapy. Acquired long QT syndrome is an important issue for clinicians and a significant public health problem concerning the large number of drugs with this adverse effect with a potentially fatal outcome, the large number of patients exposed to these drugs, and our inability to predict the risk for a given individual. In this paper, we focus on mechanisms underlying QT prolongation, risk factors for torsades de pointes and describe the short- and long-term treatment of acquired long QT syndrome

Anticoagulation with edoxaban in patients with long Atrial High-Rate Episodes ≥24 hours

BACKGROUND AND AIMS: Patients with long atrial high-rate episodes (AHRE) ≥ 24 hours and stroke risk factors are often treated with anticoagulation for stroke prevention. Anticoagulation has never been compared to no anticoagulation in these patients.METHODS: This secondary prespecified analysis of NOAH-AFNET 6 examined interactions between AHRE duration at baseline and anticoagulation with edoxaban compared to placebo in patients with AHRE and stroke risk factors. The primary efficacy outcome was a composite of stroke, systemic embolism, or cardiovascular death. The safety outcome was a composite of major bleeding and death. Key secondary outcomes were components of these outcomes and ECG-diagnosed atrial fibrillation.RESULTS: AHRE ≥24 hours were present at baseline in 259/2389 patients enrolled in NOAH-AFNET 6 (11%, 78 ± 7 years old, 28% women, CHA2DS2-VASc score 4). Clinical characteristics were not different from patients with shorter AHRE. During a median follow-up of 1.8 years, the primary outcome occurred in 9/132 patients with AHRE ≥24 hours (4.3%/patient-year, 2 strokes) treated with anticoagulation and in 14/127 patients treated with placebo (6.9%/patient-year, 2 strokes). AHRE duration did not interact with the efficacy (p-interaction = 0.65) or safety (p-interaction = 0.98) of anticoagulation. Analyses including AHRE as a continuous parameter confirmed this. Patients with AHRE ≥24 hours developed more ECG-diagnosed atrial fibrillation (17.0%/patient-year) than patients with shorter AHRE (8.2%/patient-year; p &lt; 0.001).CONCLUSIONS: This hypothesis-generating analysis does not find an interaction between AHRE duration and anticoagulation therapy in patients with device-detected AHRE and stroke risk factors. Further research is needed to identify patients with long AHRE at high stroke risk.</p

Atrial high-rate episodes and stroke prevention.

While the benefit of oral anticoagulants (OACs) for stroke prevention in patients with atrial fibrillation (AF) is well established, it is not known whether oral anticoagulation is indicated in patients with atrial high-rate episodes (AHRE) recorded on a cardiac implantable electronic device, sometimes also called subclinical AF, and lasting for at least 6 min in the absence of clinically diagnosed AF. Clinical evidence has shown that short episodes of rapid atrial tachycarrhythmias are often detected in patients presenting with stroke and transient ischaemic attack. Patients with AHRE have a higher likelihood of suffering from subsequent strokes, but their stroke rate seems lower than in patients with diagnosed AF, and not all AHRE episodes correspond to AF. The prognostic and pathological significance of AHRE is not yet fully understood. Clinical trials of OAC therapy are being conducted to determine whether therapeutic intervention would be beneficial to patients experiencing AHRE in terms of reducing the risk of stroke

Cost-of-illness study of patients subjected to cardiac rhythm management devices implantation: results from a single tertiary centre

Aims The aim of the present study is to estimate the procedure (implantation) cost, the total hospitalization cost and annual follow-up cost, in patients subjected to pacemaker (PM) and implantable cardioverter-defibrillator (ICD) implantation. Methods and results A single-center, prospective, cost-of-illness study was conducted between August 2008 and July 2009. In total, 464 consecutive patients were recruited (370 were subjected to PM implantation and 94 to ICD implantation). Resource data were assessed at patients’ enrolment in the study and at 6th and 12th months of patients’ follow-up. Then, the procedure cost, the total hospitalization cost as well as the annual patients’ follow up costs were calculated using a bottom-up approach. The mean (95% confidence interval) procedure cost of PM and ICD implantation (including the costs of devices, electrodes, other supplies, and personnel’s time) was calculated to be (sic)1803 ((sic)1758-(sic)1858) and (sic)13 521 ((sic)13 153-(sic)13 892), respectively. The mean total hospitalization cost (including procedure cost, hospitalization cost, cost of laboratory and imaging diagnostic examinations and the indirect cost attributed to productivity lost due to patient’s hospitalization) was (sic)3926 ((sic)3711-(sic)4167) for PM and (sic)17 764 ((sic)16 852-(sic)18 692) for ICD. The mean annual cost (direct and indirect) was (sic)1816 ((sic)1433-(sic)2421) for PM and (sic)2819 ((sic)2115-(sic)3703) for ICD. No difference was detected in the annual cost between patients with initial implantation and replacement. Conclusion These data revealed that although these devices are associated with a relatively high upfront cost, the annual societal cost following the implantation is low. Therefore, implantation of such devices should be encouraged since these devices reduce the morbidity and mortality without a high economic burden to society

Complications Related to Cardiac Rhythm Management Device Therapy and Their Financial Implication: A Prospective Single-Center Two-Year Survey

Cardiac rhythm management devices (CRMDs) have proven their clinical effectiveness for patients with heart rhythm disorders. Little is known about safety and complication rates during the implantation of these devices. This study demonstrated the complication rates related to CRMD implantation, and estimated the additional hospital stay and cost associated with the management of complications. Methods: During a period of one year, a total of 464 consecutive recipients underwent CRMD implantation and were followed for 2 years. Finally, data were analyzed for 398 patients who completed the two-year follow up, resulting in a total of 796 patient-years. Results: Of the 201 patients with initial pacemaker (PM) implantations, 6 (2.99%) had seven complications (5 patients had lead dislodgement, 1 of them twice), and 1 patient developed pocket infection. Of the 117 PM replacements, 1 (0.85%) patient developed a complication (pocket erosion). Two patients with complications (1 with an initial PM and 1 with a replacement) died before completing the follow up for reasons unrelated to cardiac causes. There were no complications in either initial implantations (69 patients) or replacements (11 patients) of implantable cardioverter-defibrillators. The average prolongation of the hospital stay was 7 days, ranging from 1 to 35 days, resulting in €17,411 of total additional direct hospital costs. Conclusion: This study found relatively low rates of complications in patients undergoing CRMD implantation, initial or replacement, in our center, compared with other studies. The additional hospitalization days and costs attributable to these complications depend on the nature of the complication

Long-term clinical outcomes in implantable cardioverter defibrillator recipients on the island of Crete

Purpose: The aim of the current study is to disseminate long-term “real-world” data on mortality and device therapies in primary and secondary prevention implantable cardioverter defibrillator (ICD) recipients on the island of Crete. Methods: We analyzed data for all consecutive patients who received an ICD in our tertiary university hospital from 1993 until December 2013. Follow-up visits were performed every 6 months or more frequently when indicated. Survival status was recorded, and all stored episodes during interrogation were registered and classified as appropriate or inappropriate. Results: In total, 854 patients received an ICD; 623 (73%) for primary and 231 (27%) for secondary prevention. Most of these patients (490) suffered from ischemic cardiomyopathy. During the mean follow-up of 12.4 ± 7.8 years, 218 (25.5%) patients died; 19.7% in the primary prevention group (p=0.008) and 41.1% in the secondary prevention group. Overall, 248 patients (29%) received appropriate therapy; however, the percentage was significantly higher in the secondary prevention group (44.2%) than in primary prevention group (23.4%). The cumulative incidence of inappropriate therapies during the mean follow-up period was 11.6%. Lead-related complications were noted in 49 patients (5.7%), while only 13 patients (1.5%) suffered device-related infections. Conclusions: The long-term data related to clinical outcomes in ICD recipients in our center are in accordance with those of other international centers and confirm the high efficacy and safety of these devices in preventing sudden cardiac death