Underutilization of Implantable Cardioverter Defibrillators Post Coronary Artery Bypass Grafting in Patients with Systolic Dysfunction

Background: Evaluation of the need for prophylactic internal cardiac defibrillators among patients with ischemic cardiomyopathies should be deferred until at least 3 months after revascularization procedures to allow adequate time for recovery of ventricular function. Methods: Among patients with left ventricular systolic dysfunction (LVSD) who undergo coronary artery bypass grafting (CABG), the proportion of patients who are risk stratified postoperatively with reassessment of left ventricular ejection fraction (LVEF) is unknown. Results: One hundred and six patients with LVSD (LVEF < 40%) who underwent CABG during 2004–2006 and survived 3 months post CABG were evaluated. Follow‐up was assessed by chart review and telephone contact. LVEF was not reassessed in 24% (25/106) of the population, none of whom underwent internal cardioverter defibrillator (ICD) implantation. Of those with LVEF reassessed, persistent LVSD was present in 20/81 (25%), 12 of whom were referred for prophylactic ICD placement. Conclusion: One‐fourth of patients with LVSD who undergo CABG do not have LVEF reassessed postoperatively which may lead to underutilization of ICDs. (PACE 2010; 33:727–733)     

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.     

Outcomes of Pregnancy in Patients with Preexisting Postural Tachycardia Syndrome

Background: Postural orthostatic tachycardia syndrome (POTS) occurs more commonly in women than in men and often affects women of childbearing age. Many of these women wish to have children, yet there are little reported data on the outcomes of pregnancy in patients with POTS. To date there has been one report of two patients with POTS who successfully completed pregnancy. We report the outcomes of 22 women with preexisting POTS who became pregnant.
Objective: To assess the outcome of pregnancy in patients with preexisting POTS.
Methods and Results: Twenty-two patients, age 30 ± 7 years, with POTS became pregnant. Migraine was the common comorbidity found in 40% of patients. Medications used were β- blockers (18%), midiodrine (31%), selective serotonin reuptake inhibitors (31%), fludrocortisone (13%), combination (40%), and none (18%). During pregnancy, symptoms of POTS remained unchanged in three (13%), improved in 12 (55%), and worsened in seven (31%) patients. One patient who had recurrent episodes of syncope without aura was found to have complete heart block and received a cardiac pacemaker. All patients completed pregnancy successfully. There were no stillbirths. One patient developed hyperemesis. Eighteen patients had vaginal delivery and four patients delivered by cesarian section. No other complications of pregnancy were encountered. Congenital abnormalities were encountered in the form of one atrial septal defect, one ventricular septal defect, and one Down's syndrome. Postpartum symptoms of POTS remained stable in 15 (69%) patients and worsened in seven (31%) patients.
Conclusion: Based on our observation, patients with POTS can safely complete pregnancy if they desire to do so. POTS should not be considered a contraindication to pregnancy per se.     

An Anatomic‐Based Approach for the Placement of Implantable Loop Recorders

Introduction: Placement of the Reveal implantable loop recorder (ILR; Medtronic Inc., Minneapolis, MN, USA) has previously involved preoperative cutaneous mapping to determine the optimal location. We describe an anatomic‐based approach to ILR placement that does not require cutaneous mapping. Method: A total of 63 patients (40 women, 23 men, mean age 38 ± 15 years) were included in the study. Each underwent implantation of a Reveal ILR in the left upper chest area midway between the supraclavicular notch and the left breast area. Thirty‐two patients received a Medtronic Reveal DX ILR and 31 received Reveal XT device. Results: In all 62 patients, adequate electrocardiographic tracings were obtained at implant without the need for preoperative cutaneous mapping, and all were followed for a period of 10 ± 4 months afterwards. The mean P wave amplitude was 0.12 ± 0.20 mV at implant and at follow‐up (6–14 months postimplant); the amplitude was 0.11 ± 0.19 mV. The peak‐to‐peak QRS amplitude was 0.48 ± 0.15 mV at implant and 0.44 ± 0.16 mV at a follow‐up of 6–14 months. The P waves were not detected in two patients at follow‐up. In one patient, decreased amplitude of QRS complex resulted in the autoactivation of the device and in one other patient noise was inappropriately oversensed and recorded. Conclusion: A simple anatomic approach can be used for reveal ILR placement. (PACE 2010; 33:1149–1152)     

Development of hepatocellular carcinoma in a man with auto-immune chronic active hepatitis

A 57 year old man with auto-immune chronic active hepatitis, regularly treated with immunosuppressive therapy, had hepatocellular carcinoma (HCC) 10 years after diagnosis of the hepatitis. Assays of the hepatitis C virus antibodies against capsid and non-structural proteins revealed seronegativity in serial serum samples of this patient stored in the previous 10 years during follow up. The seronegative hepatitis C antibodies excluded hepatitis C virus as the cause of the HCC. The occurrence of HCC in this case suggests the necessity of surveillance for early detection of liver cancer in patients with auto-immune chronic active hepatitis undergoing long-term immunosuppressive therapy.     

Utility of High‐Output His Pacing during Difficult AV Node Ablation. An Underutilized Strategy

Atrioventricular (AV) node ablation is a commonly performed procedure for patients with chronic drug refractory atrial fibrillation (AF) with episodes of rapid ventricular response. We report on a 72‐year‐old man who had difficulty managing chronic drug refractory AFs with frequent hospitalizations for rapid ventricular rate. The patient was taken to the electrophysiology laboratory for AV node ablation. Extensive mapping and localization techniques of the compact AV node and ablation in the region were unsuccessful. Subsequently, high‐output His bundle pacing using 20 mA at 2 ms of output energy was performed in an attempt to localize the His bundle in areas where high‐output pacing resulted in a narrower QRS complex. Further ablations in the areas where pacing produced a narrower QRS complex resulted in complete heart block. This case highlights the importance of using this simple pacing maneuver to achieve complete heart block in patients in whom standard strategies to localize and ablate the compact AV node are unsuccessful.     

Psychogenic Syncope? A Cautionary Note

Introduction: In some patients with recurrent syncope, the etiology may remain unclear despite extensive evaluation. These patients may sometimes be labeled as having a "psychogenic" cause for their syncope.
Methods: We report on three patients with recurrent unexplained syncope (despite extensive evaluation) who were labeled as having a psychogenic cause for their events. In each patient following placement of an implantable loop recorder, their syncopal events were found to be due to periods of prolonged asystole and/or complete heart block. One patient had prolonged asystole for 44 seconds. In each patient, episodes of syncope were eliminated following permanent pacemaker implantation.
Conclusion: We conclude that physicians should exercise great caution before labeling any patient's syncope as psychogenic and that prolonged monitoring may be necessary to exclude a potential cardiac rhythm-related etiology.     

Postural Orthostatic Tachycardia Syndrome: A Rare Complication Following Electrical Injury

We report on two previously healthy patients who developed severe form of postural orthostatic tachycardia syndrome (POTS) following an electric injury. Both the patients developed symptoms of orthostatic intolerance in the form of dizziness, fatigue, lightheadedness, and palpitations, weeks to months after electrical injury. Orthostatic intolerance produced considerable functional impairment in these patients. Early recognition of POTS when it occurs after an electrical injury allows for prompt evaluation and management to occur. (PACE 2010; 33:e59–e61)