An Unusual Complication of the Unremoved Unwanted Pacing Wire

A ease of external jugular vein thrombosis is described. This occurred following failure to remove on unwanted pacing wire by sustained traction and its subsequent migration from the subclavian vein into the external jugular vein.     

Effect of coronary artery disease and myocardial ischaemia on transmyocardial platelet aggregability

Twenty-five patients with coronary artery disease and six ‘normal’subjects were studied during routine catheter investigationfor chest pain. In vitro platelet aggregation responses weremeasured in arterial and coronary sinus blood samples takenat rest and after pacing. Platelet aggregability was found tobe increased in coronary sinus blood from patients with coronaryartery disease at rest, but it was reduced with pacing. We concludethat platelets are affected by passage through a stenosed coronaryartery and that acute myocardial ischaemia exerts an anti-aggregatoryeffect.     

Platelet counts and aggregates in coronary artery disease

Platelet counts and aggregates have been measured in arterial,coronary sinus and peripheral venous blood in groups of patientswith and without coronary artery disease, and under variousconditions associated with myocardial ischaemia. No changesin platelet counts were observed. An increase in platelet aggregatesacross the coronary vascular bed was observed during spontaneousor ergometrine-induced ischaemia, but not with pacing-inducedangina nor at the onset of coronary occlusion causing infarction.Platelet aggregates were high in systemic blood samples frompatients with frequent episodes of spontaneous angina but notin samples from patients with stable effort angina, nor werethey increased with exercise-induced angina or after myocardialinfarction. The findings suggest that platelet aggregates arefound in coronary sinus blood when there is very severe proximalnarrowing (but not complete occlusion) of a coronary arterysufficient to cause cardiac pain at rest, but not when proximalconstriction is less severe and the ischaemia is pacing-induced.Increased platelet aggregates in systemic blood samples maybe a marker of recent episodes of rest pain.     

Clinical and haematological features in a compound heterozygote (HBB:c.92 + 5G > C/HBB:c.93-2A > C) case of thalassaemia major

An Indian Muslim boy was diagnosed with thalassaemia major at 3 months of age. His blood investigations revealed haemoglobin: 5.3 gm%, MCV: 68 fl, MCH 26.6 pg, MCHC: 39%, haemoglobin variant analysis: HbA₂: 2.8%, HbF: 20.3% and HbA: 75.2% (post-transfusion). His fathers’ haemoglobin was 10.2 gm%, MCV: 68 fl, MCH: 23.9 pg, MCHC: 35% HbA₂: 4.7%, HbF: 0.7% and HbA: 85.2% and his mothers’ haemoglobin was 10.9 gm%, MCV: 67.4 fl, MCH 22.6 pg, MCHC: 33.5%, HbA₂: 5.3%, HbF: 0% and HbA: 85.4%. The boy was found to be compound heterozygote for beta globin gene mutations (HBB:c.92 + 5G > C/HBB:c.93-2A > C). The mutation HBB:c.93-2A > C was inherited from his father. This report confirms the presence of HBB:c.93-2A > C in the Indian subcontinent and has important implications for screening and prenatal diagnosis of beta thalassaemia. This report also supports inclusion of this mutation in the beta globin gene mutation database.     

Incidence and Predictors of Left Atrial Thrombus Prior to Catheter Ablation of Atrial Fibrillation

Background: Transesophageal echocardiography (TEE) is commonly used prior to catheter ablation of atrial fibrillation (AF) in order to exclude left atrial (LA) thrombus. However, the incidence and predictors of LA thrombus detected with TEE have not been systematically examined in this setting.
Methods: This study included 732 cases (mean age 57 ± 11 years; 23% female; 353 persistent AF) in 585 consecutive patients referred for catheter ablation of AF. Patients were anticoagulated for at least 4 weeks prior to the procedure and then bridged with enoxaparin. TEE was performed in all cases within 24 hours prior to ablation.
Results: Preprocedural TEE revealed LA thrombus in 12 of 732 cases (1.6%), all located in the LA appendage. Among these 12 patients, 9 had persistent AF and 3 had paroxysmal AF. All patients with thrombus had an LA size ≥ 4.5 cm. LA thrombus was present in 0.3%, 1.4%, and 5.3% of patients with CHADS₂ scores of 0, 1, and ≥ 2, respectively. In multivariate analysis, a CHADS₂ score ≥ 2 and larger LA diameter remained significant predictors of LA thrombus.
Conclusions: Despite oral anticoagulation treatment, there is a small but significant incidence of LA thrombus by TEE prior to AF ablation. A CHADS₂ score ≥ 2 and larger LA diameter are independent predictors of LA thrombus in this patient population, while type of AF or rhythm at the time of TEE is not. The risk of LA thrombus is low in patients with a CHADS₂ score of 0 and in patients with an LA diameter < 4.5 cm.     

Controlled ventilation in dental outpatients

This study compares anaesthesia with controlled ventilation of the lungs with atracurium and alfentanil analgesia with halothane anaesthesia. Recovery time, the incidence of dysrhythmias and postoperative morbidity were evaluated. Anaesthesia with controlled ventilation was found to reduce significantly the incidence of cardiac dysrhythmias during dental surgery, and to produce a significantly more rapid recovery than halothane anaesthesia. The incidence of subjective postoperative complications is similar. It is concluded that controlled ventilation with atracurium and alfentanil is a suitable outpatient dental technique.     

A Prospective Randomized Trial of Defibrillation Thresholds from the Right Ventricular Outflow Tract and the Right Ventricular Apex

Background: Right ventricular outflow tract (RVOT) pacing has been suggested to improve hemodynamics and to help prevent pacing-induced cardiomyopathy. Pacing from the RVOT is feasible and equivalent in terms of sensing and stimulation threshold. However, physicians have been reluctant to use RVOT pacing because of concerns that defibrillation efficacy might be adversely affected. To date, there have been no randomized-controlled trials published comparing the defibrillation threshold in leads implanted in the RVOT and the right ventricular apex (RVA).
Objective: The purpose of this study was to compare defibrillation thresholds (DFT) in the RVOT and RVA. Ventricular sensing and stimulation thresholds were also compared.
Methods: This prospective, randomized, multicenter study included 87 patients (70 males, age 69 ± 11 years). At implantation, the patient's ventricular implantable cardioverter-defibrillator (ICD) lead position was randomized to either the RVOT or RVA. A four-shock Bayesian up-down method was used to determine the DFT. Patients were followed for 3 months postimplant.
Results: DFTs were not significantly different in leads implanted in the RVOT (median 8.8 J [6.28, 12.9] vs. 7.9 J [6.20, 12.6], P = 0.65). Threshold and impedance measurements were stable in both RVOT and RVA groups from implant to follow-up. All ICD leads remained stable chronically at the 3-month follow-up.
Conclusion: DFTs in leads placed in the RVOT and RVA are comparable. RVOT ICD lead placement is safe and exhibits similar lead stability, threshold, and impedance measurements as the traditional RVA location.     

Incidence and Predictors of Periprocedural Cerebrovascular Accident in Patients Undergoing Catheter Ablation of Atrial Fibrillation

Background: Cerebrovascular accident (CVA) is a serious complication of catheter ablation of atrial fibrillation (AF). The incidence and clinical predictors of periprocedural CVA in patients undergoing AF ablation are not fully understood. Methods: This study included 721 cases (age 57 ± 11 years; 23% female; 345 persistent AF) in 579 consecutive patients referred for AF ablation. Periprocedural CVA was defined as onset of a new neurologic deficit that occurred anytime between the start of the procedure and 30 days after the AF ablation, and was confirmed by a neurologist. Cranial imaging with CT and/or MRI was performed in each case. Patients were anticoagulated with warfarin for at least 4 weeks pre‐ and immediately postprocedure and were bridged with enoxaparin. Transesophageal echocardiography was performed within 24 hours prior to ablation in all cases. Results: Periprocedural CVA occurred in 10 of 721 cases (1.4%). The risk of periprocedural CVA did not vary significantly during the course of the study. Among these 10 patients (age 62 ± 11 years; 1 female; 5 persistent AF), 6 manifested neurological deficits within 24 hours, 3 after 24–48 hours, and 1 patient had a CVA 6 days following AF ablation despite a therapeutic INR level. All CVAs were ischemic. Five patients had residual deficits after 30 days. Four of 43 patients (9.3%) with a prior history of CVA had periprocedural CVA. Periprocedural CVA occurred in 0.3%, 1.0%, and 4.7% of patients with CHADS₂ scores of 0, 1, and ≥ 2 (P < 0.001). In 2 separate multivariate analyses, a CHADS₂ score ≥ 2 (OR 7.1, P = 0.02) and history of CVA (OR 9.5, P < 0.01) remained independent predictors of periprocedural CVA. Conclusions: Despite periprocedural anticoagulation and transesophageal echocardiography, we found a 1.4% incidence of periprocedural CVA in AF ablation patients. A CHADS₂ score ≥ 2 and a history of CVA are independent predictors of CVA after AF ablation. The CVA risk is low in patients with CHADS₂ score of 0.