Characteristics, predictors and outcomes of new-onset QT prolongation in sepsis: a multicenter retrospective study.

BACKGROUND: Sepsis-induced myocardial injury is a serious complication of sepsis. QT prolongation is a proarrhythmic state which reflects myocardial injury in a group of heterogeneous disorders. However, the study on the clinical value of QT prolongation in sepsis is limited. METHODS: We aimed to investigate the clinical characteristics and predictors of new-onset QT prolongation in sepsis and its impact on the outcome in a multicenter retrospective cohort study. Electrocardiographic and clinical data were collected from patients with sepsis from the wards and intensive care units of four centers after exclusion of QT-influencing medications and electrolyte abnormalities. Clinical outcomes were compared between patients with and without QT prolongation (QTc > 450 ms). Multivariate analysis was performed to ascertain whether QT prolongation was an independent predictor for 30-day mortality. The factors predicting QT prolongation in sepsis were also analyzed. RESULTS: New-onset QT prolongation occurred in 235/1024 (22.9%) patients. The majority demonstrated similar pattern as type 1 long QT syndrome. Patients with QT prolongation had a higher 30-day in-hospital mortality (P < 0.001), which was also associated with increased tachyarrhythmias including paroxysmal atrial fibrillation or tachycardia (P < 0.001) and ventricular arrhythmia (P < 0.001) during hospitalization. QT prolongation independently predicted 30-day mortality (P = 0.044) after multivariate analysis. History of coronary artery disease (P = 0.001), septic shock (P = 0.008), acute respiratory (P < 0.001), heart (P = 0.021) and renal dysfunction (P = 0.013) were independent predictors of QT prolongation in sepsis. CONCLUSIONS: New-onset QT prolongation in sepsis was associated with increased mortality as well as atrial and ventricular arrhythmias, which was predicted by disease severity and organ dysfunction.

Orthodromic Reciprocating Tachycardia Relying on Aberrant Conduction: The Need for a Larger Circuit.

Aberrant conduction during orthodromic reciprocating tachycardia (ORT) prolongs the ventriculoatrial conduction time, which can be essential for the maintenance of tachycardia in specific cases. We searched for ORT relying on aberrancy among 220 cases in our center. Three patients showed the phenomenon of aberrancy-dependent ORT. All accessory pathways were located at the lateral regions of the atrioventricular annulus. None of them had a baseline bundle branch block (BBB). Creating a functional BBB was necessary to induce the tachycardias. In two cases, termination of tachycardias was directly associated with resolution of the aberration. In the other case, re-entry required both BBB and slow pathway conduction. We conclude that extra transseptal time caused by aberrancy can be an integral part of the ORT circuit, which explains the infrequent and unsustainable episodes of ORT in certain patients and is useful in understanding the circuit and localizing the pathway.

Acute epicardial pulmonary vein reconnection: Nondurable transmural lesion or late manifestation of conduction through intercaval bundle.

INTRODUCTION: Acute pulmonary vein reconnection (PVR) via epicardial fibers can be found during observation period after PV isolation, the characteristics and related factors have not been fully studied. We aimed to investigate the prevalence, locations, electrogram characteristics, and ablation parameters related to acute epicardial pulmonary vein reconnection (AEPVR). METHODS: Acute PVR was monitored during observation period after PV isolation. AEPVRs were mapped and distinguished from endocardial conduction gaps. The clinical, electrophysiological characteristics and lesion set parameters were compared between patients with and without PVR. They were also compared among AEPVR, gap-related reconnection, and epicardial PVR in repeat procedures. RESULTS: A total of 56.1% acute PVR were AEPVR, which required a longer waiting period (p < .001) than endocardial gap. The majority of AEPVR were connections from the posterior PV carina to the left atrial posterior wall, followed by late manifestation of intercaval bundle conduction from the right anterior carina to right atrium. AEPVR was similar to epicardial PVR in redo procedures in distribution and electrogram characteristics. Smaller atrium (p < .001), lower impedance drop (p = .039), and ablation index (p = .028) on the posterior wall were independently associated with presence of AEPVR, while lower interlesion distance (p = .043) was the only predictor for AEPVR in acute PVR. An integrated model containing multiple lesion set parameters had the highest predictive ability for AEPVR in receiver operating characteristics analysis. CONCLUSIONS: Epicardial reconduction accounted for the majority of acute PVR. AEPVR was associated with anatomic characteristics and multiple ablation-related parameters, which could be explained by nondurable transmural lesion or late manifestation of conduction through intercaval bundle.

Subclinical cardiac involvement present as electrocardiographic abnormalities in various neuromuscular diseases.

Background: Cardiac involvement is commonly present in various neuromuscular diseases which may develop life-threatening consequences. The early manifestation is often asymptomatic which however has been insufficiently studied. Objectives: We aim to characterize electrocardiographic (ECG) changes in neuromuscular diseases without cardiac symptoms. Methods: Adults having genetically and/or pathologically confirmed type 1 myotonic dystrophy (DM1), Becker muscular dystrophy (BMD), limb girdle muscular dystrophies (LGMDs) and mitochondrial diseases (MtDs) but without history of heart diseases and cardiovascular symptoms were enrolled. The 12-lead ECG characteristics and other test results at diagnosis were retrieved and analyzed. Results: 196 patients with neuromuscular diseases (44 DM1, 25 BMD, 82 LGMDs, 45 MtDs) were consecutively enrolled. ECG abnormalities were identified in 107 (54.6%) patients with a prevalence of 59.1% in DM1, 76.0% in BMD, 40.2% in LGMDs and 64.4% in MtDs. Conduction block was more commonly present in DM1 than the other groups (P < 0.01), which had a longest PR interval and QRS duration of 186.1 ± 38.3 ms and 104.2 [90.0-108.0]ms, respectively. QT prolongation was most frequently seen in DM1 (P < 0.001). Left ventricular hypertrophy features were found in BMD, LGMDs and MtDs (P < 0.05) without intergroup difference, while a significantly higher right ventricular amplitude is observed in BMD than in other groups (P < 0.001). Conclusions: Subclinical cardiac involvement is commonly present as ECG abnormalities in multiple adult neuromuscular diseases before associated symptoms occur and show diversity in different groups.

Anatomy-based characteristics of far-field SVC electrograms in right superior pulmonary veins after isolation.

Background. Far-field electrograms from superior vena cava (SVC) can be present in right superior pulmonary vein (RSPV) after pulmonary vein (PV) isolation. Objectives. To analyze the characteristics of far-field SVC potentials in RSPV after PV isolation and the local anatomy difference between patients with and without the potentials. Methods. Patients undergoing PV isolation were retrospectively reviewed, contrast-enhanced computed tomography (CT) was performed before procedure for observing the anatomical relationship between RSPV and SVC. The prevalence and characteristics of far-field SVC electrograms were described and compared to far-field left atrial potentials at the nearest point along the linear ablation lesion. The anatomical proximity of RSPV and SVC on a 2-dimensional horizontal CT view was compared between patients with and without far-field SVC potentials. Results. Far-field SVC electrograms were observed in 35/92(38%) patients with an amplitude of 0.24 ± 0.11 mV and a major deflection slope of 0.051 ± 0.036 mV, both significantly higher than far-field left atrial electrograms (p < .001). In patients with far-field SVC electrograms, 83% had connected RSPV-SVC, defined as distance between RSPV and SVC endocardium less than 3 mm at the layer of RSPV ostium roof, while in patients without far-field SVC electrograms, 70% had disconnected RSPV-SVC. Conclusions. Far-field SVC electrograms appeared in RSPV had a prevalence higher than previously reported and a sharper major deflection compared to far-field left atrial electrograms. Connected RSPV-SVC on CT was associated with the presence of far-field SVC electrograms.

Split accessory pathway potentials in a patient with antidromic AVRT.

INTRODUCTION: Accessory pathway potential often indicates a highly effective ablation target in Wolff-Parkinson-White syndrome. METHODS: A 27-year-old female presenting with palpitation underwent an electrophysiology study, who had mild pre-excitation in surface ECG. RESULTS: An accessory pathway with weak anterograde conduction was found. During isoproterenol infusion, the delta wave became prominent, an antidromic AV reentrant tachycardia was then induced. When the pathway was mapped, widely split double pathway potentials were observed at the 12 o'clock site of the tricuspid annulus during mild pre-excitation, demonstrating an example of intra-pathway conduction delay. Ablation at the site caused accelerated pathway rhythm and eliminated the pathway, rendering the tachycardia noninducible. CONCLUSION: Split pathway potentials can reflect slow conduction in patients with preexcitation.

Pseudo normalization of H-V interval due to intra-His block in a patient with fasciculoventricular accessory pathway.

A 57-year-old male suffering from cardiogenic syncope was found to have preexcited QRS on surface ECG at admission. A dual-chamber ICD was implanted after discovering intermittent high degree A-V block and ventricular tachycardia during hospitalization. An EP study was performed 2 days later. Fasciculoventricular accessory pathway was diagnosed based on the fixed H-V interval with different A-H interval when atrial activation conducted to ventricle. However, the H-V interval was normal, which can be explained by intra-His block based on the findings of two split His potentials, the second of which was closely followed by local ventricular electrogram. The conduction delay in His bundle led to pseudo normalization of H-V interval.

Increased serum interleukin-6 level as a predictive biomarker for atrial fibrillation: A systematic review and meta-analysis.

BACKGROUND: Atrial fibrillation (AF) is related to a higher risk of thromboembolic events and mortality. Some studies have demonstrated that the inflammatory biomarker interleukin-6 (IL-6) is associated with a higher risk of higher thrombosis in AF patients, but the real effect of IL-6 remains a controversy. METHODS: We conducted a systematic review and meta-analysis to investigate the association between IL-6 and thromboembolic events, as well as bleeding events, acute coronary syndrome (ACS) events and all-cause mortality in AF. RESULTS: A total of five studies involving 22 928 patients met our inclusion criteria for the systematic review. The higher level of IL-6 in AF patients is related to long-term thromboembolic events including stroke (RR 1.44, CI 95% 1.09-1.90, p=0.01). IL-6 meant a higher risk of long-term bleeding risk (RR 1.36, CI 95% 1.06-1.74, p=0.02), ACS risk (RR 1.81, CI 95% 1.43-2.30, p<0.001) and all-cause mortality (RR 2.35, CI 95% 2.09-2.65, p<0.001). CONCLUSION: A higher level of IL-6 may predict a greater number of long-term thromboembolic events and bleeding events, ACS events and mortality in AF patients. Further studies such as the cut-off point of IL-6 need to be conducted in the future.

A stricter control of low-density lipoprotein is necessary for thrombosis reduction in "lower thrombosis risk" patients with atrial fibrillation: a multicenter retrospective cohort study.

Patients with atrial fibrillation (AF) are associated with increased thrombotic events. Our previous case-control study showed low-density lipoprotein cholesterol (LDL-C) was an independent predictor of ischemic stroke in AF patients. To investigate the risks of thrombosis in relation to LDL-C among AF patients at different stroke risks by long-time follow-up. Atrial fibrillation patients without history of thrombosis enrolled from five hospitals were classified into low-risk (LR) and high-risk (HR) group according to CHA2DS2VASc score and followed up with a median period of 26 months. Univariate and multivariate logistic regression analysis were performed in each group. The best cut-off value calculated by receiver operating characteristic (ROC) analysis was used to divide patients into low LDL-C (L-LDL) and high LDL-C (H-LDL) subgroups. Propensity score matching (PSM) and inverse probability of treatment weighted (IPTW) were utilized in both subgroups, after which Kaplan-Meier curves for thrombosis were performed. Univariate and multivariate analysis showed LDL-C was significantly related to thrombosis in LR, but less significantly in HR group. The best cut-off value was 2.155 mmol/L in LR and 2.795 mmol/L in HR group. Lower LDL-C was associated with decreased thrombosis in both groups by PSM and IPTW. Kaplan-Meier curves displayed that H-LDL subgroup was at higher thrombosis risk with significant difference at 24th month in LR patients. LDL-C independently predicts thrombosis with different cut-off values in AF patients at different risks. A stricter control of LDL-C level is necessary for thrombosis reduction in patients with lower score.

Mapping and Ablation of Ventricular Arrhythmias in Cardiomyopathies.

Mapping and ablation of ventricular arrhythmias in patients with nonischemic cardiomyopathies remain a major challenge. The electroanatomic abnormalities are frequently inaccessible to conventional endocardial ablations. Diagnostic diligence with a thorough understanding of the potential mechanisms/substrate, coupled with detailed electroanatomic mapping, is essential. Careful procedural planning, advanced imaging, and unipolar recordings help to formulate ablation strategy, facilitate work flow, and improve outcomes. Inaccessibility of arrhythmogenic substrate and disease progression are important causes of ablation failure. Early intervention may help to improve outcome and minimize complications. Several novel adjunctive ablation techniques are capable of serving as alternative options in refractory cases.

Oral anticoagulant prescribing in elderly patients above and below age 80 with atrial fibrillation
.

BACKGROUND: Oral anticoagulation is efficient to prevent ischemic stroke in atrial fibrillation (AF), but in very old patients, physicians always remain cautious to use anticoagulants concerning the bleeding risk. This research aims to investigate the current situation of oral anticoagulation therapy in very old (≥ 80 years) AF patients. MATERIALS AND METHODS: We carried out a cross-sectional study in an urban area in China from 2014 to 2016. Characteristics of the very old patients (age ≥ 80 years) and the younger patients (age < 80 years) were compared. Logistic analysis was used to estimate the association between oral anticoagulation therapy and CHA2DS2-VASc score. RESULTS: A total of 1,000 AF patients were enrolled; 306 were very old patients, and 694 were younger patients. In the very old group, 48.0% were women, and the average age was 84.12 ± 3.62 years. In the younger group, 35.3% were women, and the average age was 66.92 ± 9.02 years. CHA2DS2-VASc score was 2.8 ± 1.7 in the younger group and 4.5 ± 1.5 in the very old group (p < 0.001). The proportion of oral anticoagulation was low in patients with AF (31.8%) and even lower in very old patients compared to younger patients (24.5 vs. 35.0%, p = 0.004). Moreover, oral anticoagulation therapy was strongly associated with CHA2DS2-VASc scores only in the younger group, but not in the very old group, which means the very old patients were not treated with oral anticoagulation according to their elevated CHA2DS2-VASc scores. CONCLUSION: Anticoagulants were underused in AF patients, particularly in very old patients. Evidence is accumulating that the very old patients could still benefit from anticoagulants so that physicians should not exclude such patients from anticoagulation only because of their older age.

Fasciculoventricular accessory pathway unmasked by a pseudo gap phenomenon.

A 28 year old female with manifest preexcitation underwent electrophysiology study for intermittent palpitation. During progressively premature atrial extrastimuli, bypass tract was blocked before relative refractory period of AV node, making it unfeasible to observe the change of H-V interval and QRS morphology during decremental nodal conduction. However, dual AV node physiology, presented as a marked increase of A-H interval, occurred when a short-coupled extrastimulus was delivered, followed by a preexcited QRS with an H-V interval identical to that in sinus rhythm. This was an example of gap phenomenon involving accessory pathway and AV node. Diagnosis of fasciculoventricular bypass tract was made and ablation was therefore not performed.

Essential thrombocythemia presenting as acute coronary syndrome: case reports and literature review.

For the patients with essential thrombocythemia (ET), systemic thrombosis presents as one of the most dangerous complications. It's been widely accepted that acute coronary syndrome (ACS) is a kind of thrombotic diseases. However, there are very few case reports about ET first presenting as ACS. For some patients diagnosed as ACS, but without markedly elevated platelet, underlying ET was missed. And there are some controversies in the principles and target of treatment in those patients. We reported three cases of ACS, in which the patients who did not have common risk factors for coronary artery diseases and presented only mild atherosclerotic stenosis during coronary angiography, one of which had recurrent coronary artery thrombosis. Noticing their elevated blood platelet level and characteristics in angiography, diagnosis of ET was made according to bone marrow morphology and genetic tests. Although they had only mild thrombocytosis, we applied intensive treatment with dual anti-platelet therapy combined with cytoreduction in addition to early coronary intervention, having satisfying outcomes. During the diagnosis and treatment of ACS, if patients present thrombocytosis, but lack common coronary disease risk factors and thrombotic coronary artery occlusion, cardiologists should search for possible ET as an underlying cause of thrombotic coronary event. All those patients were high-risk according to ET risk stratification. Treatment of cytoreduction in combination with anti-thrombosis therapy and revascularization are beneficial. Treatment aims at the target of complete response with platelet count below 400 × 109/L.

Cardiac arrhythmias as the initial manifestation of adult primary Sjögren's syndrome: a case report and literature review.

Two middle-aged female patients presenting with heart palpitation and electrocardiogram revealed complex cardiac arrhythmias. A review of systems was positive for dry mouth and transient arthralgia, while laboratory and instrumental tests enabled us to make the diagnosis of primary Sjögren's syndrome (pSS). Cardiac electrophysiology revealed atrioventricular node dysfunction and impaired intraventricular conduction. Prednisone therapy induced a significant improvement in symptoms and electrocardiographic readings. The diagnosis of pSS should be considered in a patient presenting with complex cardiac arrhythmias.