Koroush Khalighi

Natural History and Predictors of Temporary Epicardial Pacemaker Wire Function in Patients after Open Heart Surgery

Study Objectives: To assess the short-term reliability of temporary epicardial pacing wires in patients after open heart surgery and to determine the influence of preoperative factors on the performance of these wires. Patients and Methods: In this prospective, longitudinal cohort study, 60 patients (41 men) with a mean age of 66.8 ± 8.9 years were studied for 5.3 ± 1.1 days postoperatively. Each patient’s history, physical findings, hemodynamics and echocardiographic data were analyzed. Postoperatively, capture threshold, the electrogram amplitude and slew rate, and the lead impedance were determined daily in both chambers. Results: Both atrial and ventricular thresholds increased significantly (p < 0.001) by the 4th postoperative day. The P-wave amplitudes were consistently less than half of the R-wave amplitudes. Both P- and R-wave amplitudes deteriorated significantly by the 2nd postoperative day (p < 0.001 and p < 0.02, respectively). Atrial and ventricular slew rates and lead impedance decreased significantly during the observation period (p < 0.002). Conclusion: Although both atrial and ventricular temporary epicardial leads are reliable for short-term use, their function deteriorates on a daily basis. Perioperative factors are generally not helpful in predicting the performance of temporary epicardial pacing wires.

Reducing radiation exposure in an electrophysiology lab with introduction of newer fluoroscopic technology

The use of fluoroscopic devices exposes patients and operators to harmful effects of ionizing radiation in an electrophysiology (EP) lab. We sought to know if the newer fluoroscopic technology (Allura Clarity) installed in a hybrid EP helps to reduce prescribed radiation dose. We performed radiation dose analysis of 90 patients who underwent various procedures in the EP lab at a community teaching hospital after the introduction of newer fluoroscopic technology in June of 2016. Watchman device insertion, radiofrequency ablation procedures, permanent pacemaker (PPM)/implantable cardioverter defibrillator (ICD) placement and battery changes were included in the study to compare radiation exposure during different procedures performed commonly in an EP lab. In all cases of watchman device placement, radiofrequency ablation procedures, PPM/ICD placement and battery changes, there was a statistically significant difference (<0.05) in radiation dose exposure. Significant reduction in radiation exposure during various procedures performed in an EP lab was achieved with aid of newer fluoroscopic technology and better image detection technology.

Development of New Deep Venous Thrombosis While on Apixaban

The efficacy of novel oral anticoagulants (NOACs) in preventing deep venous thrombosis (DVT) has been established in large multicenter trials. Predictable pharmacokinetics, avoidance of routine laboratory monitoring, and lesser drug interactions have made NOACs safer and more tolerable treatment option in comparison to warfarin. However, cases of treatment failure mainly due to interindividual variation in plasma drug levels can be seen rarely. In this report we describe a case of acute DVT of right lower extremity in a patient who was on apixaban for prevention of venous thromboembolism (VTE) due to underlying nonvalvular atrial fibrillation (NVAF).

A Case of Late Implantable Cardiac Device Infection with Aspergillus in an Immunocompetent Host

Patient: Female, 67 Final Diagnosis: Infected pacemaker device secondary to Aspergillus fumigatus Symptoms: Swelling over the left pectoral region Medication: Voriconazole Clinical Procedure: Pacemaker explantation Specialty: Cardiology Objective: Unusual clinical course Background: With the increasing use of cardiac implantable electronic devices (CIED), there has been an associated increase in rate of complications. Infection accounts for about 1% of these, of which only a handful were reported secondary to Aspergillus fumigatus. All of these were seen in chronically-ill patients with several co-morbid conditions within a few years of implantation. None have been reported in an otherwise immunocompetent patient at 7 years after CIED implantation. Case Report: A 67-year-old woman with symptomatic sick sinus syndrome required a pacemaker 15 years ago with subsequent revision 7 years prior due to battery depletion. She now presented with a left pectoral non-tender mass that developed over several weeks. She denied history of recent fever, trauma, or infection. An elective pacemaker revision and pocket exploration led to the drainage of 150 cc of serosanguineous discharge from the pocket. She received peri-procedural prophylaxis with Vancomycin, but later, wound cultures grew Aspergillus fumigatus. She underwent complete removal of the pacemaker system along with a 6-week course of voriconazole and is doing well. Conclusions: Even though Staphylococcus aureus causes most CIED infections, there should be a suspicion for fungal organisms, especially in culture-negative infections, in immunocompromised states like diabetes mellitus or with minimal improvement on antibiotics. If not treated appropriately, aspergillosis may have catastrophic outcomes, including endocarditis, often leading to death. Appropriate treatment should include immediate initiation of antifungals and removal of the CIED. It is still unclear why an immunocompetent patient developed aspergillosis, but appropriate management helped avoid a grave outcome.

Application of ICD guidelines and indications in a community-based academic hospital: a case series-based discussion

Background Implantable cardioverter defibrillators (ICDs) are indeed beneficial in selected patients as evidenced by multiple large randomized controlled trials (RCTs) since 1980. A systematic method for stratification of patients and hospital-wide criteria/guidelines to ascertain appropriate device implantation became necessary. Methods Major ICD/CRT (cardiac resynchronization therapy) clinical studies and relevant guidelines were reviewed, and an institution-wide inclusion and exclusion criteria for ICD/CRT was formulated. A retrospective analysis of selected cases was performed to discuss the criteria and special clinical situations. Results We have translated the evolving ICD/CRT studies into a standard of care at our hospital by formulating a standard, practical, and update-to-date ICD inclusion and exclusion criteria. Thirteen cases were selected to represent major indications and contraindications of ICDs in our practice. These cases cover indications of ICD for secondary prevention of sudden cardiac death (SCD), primary prevention of SCD in patients with CHF resulted from either ischemic or non-ischemic cardiomyopathy, as well as for infiltrative cardiomyopathy and inherited conditions. We discussed the application of CRT in patients with CHF associated with prolonged QRS duration. We then covered the potential benefits of ICD with/without CRT in certain special populations of patients that have not been adequately evaluated by currently available RCTs; these include alcoholic, elderly, female, and ESRD/HD patients. Finally, we addressed risks, complications and contraindications of ICD, as well as application of an external wearable defibrillator in AMI, or status post-CABG patient during the mandatory waiting period for an ICD. Conclusions Establishment of the ICD/CRT criteria represents a practical translation of emerging CRTs and helps to standardize patient care in our hospital. It also improves cost-effectiveness as well as appropriate utilization of institute and device resources.

Ensemble of machine learning algorithms using the stacked generalization approach to estimate the warfarin dose

Warfarin dosing remains challenging due to narrow therapeutic index and highly individual variability. Incorrect warfarin dosing is associated with devastating adverse events. Remarkable efforts have been made to develop the machine learning based warfarin dosing algorithms incorporating clinical factors and genetic variants such as polymorphisms in CYP2C9 and VKORC1. The most widely validated pharmacogenetic algorithm is the IWPC algorithm based on multivariate linear regression (MLR). However, with only a single algorithm, the prediction performance may reach an upper limit even with optimal parameters. Here, we present novel algorithms using stacked generalization frameworks to estimate the warfarin dose, within which different types of machine learning algorithms function together through a meta-machine learning model to maximize the prediction accuracy. Compared to the IWPC-derived MLR algorithm, Stack 1 and 2 based on stacked generalization frameworks performed significantly better overall. Subgroup analysis revealed that the mean of the percentage of patients whose predicted dose of warfarin within 20% of the actual stable therapeutic dose (mean percentage within 20%) for Stack 1 was improved by 12.7% (from 42.47% to 47.86%) in Asians and by 13.5% (from 22.08% to 25.05%) in the low-dose group compared to that for MLR, respectively. These data suggest that our algorithms would especially benefit patients requiring low warfarin maintenance dose, as subtle changes in warfarin dose could lead to adverse clinical events (thrombosis or bleeding) in patients with low dose. Our study offers novel pharmacogenetic algorithms for clinical trials and practice.

Postapproval Community Hospital Experience in the United States with Left Atrial Appendage Closure Device (Watchman)

BACKGROUND To review the procedural safety and postimplantation complications of Watchman device implanted at 2 community hospitals for primary prevention of systemic embolization in patients with nonvalvular atrial fibrillation (NVAF) who were not candidates for long-term oral anticoagulation (OAC). METHODS This was a retrospective case series of 48 patients carried out in 2 community hospitals in the United States. Patients with NVAF who had a CHADS2 higher than 2 or CHADS2VASc2 (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or transient ischemic attack [TIA] or thromboembolism, vascular disease, age 65-74 years, and female gender) score of 3 or higher and were not candidates for long-term OAC. These patients were selected for implantation of Watchman device. They were followed up at 45 days, 6 months, 9 months, and 12 months after implantation of Watchman device to assess for complications involving the device and to determine if anticoagulation could be discontinued at the 45 days follow-up. They were monitored for any systemic thromboembolism while off anticoagulation. RESULTS The success rate of device implantation was 98% (48 of 49). Only a single patient could not get Watchman implantation because of unfavorable left atrial appendage anatomy. Access-related and device implantation-related complications were zero (0%). At 45 days follow-up and end of follow-up duration, the rate of thrombus formation on the Watchman device was 4% (2 of 48). One patient had TIA after warfarin discontinuation. CONCLUSION With improved procedural technique and well-trained operators, Watchman implantation is feasible in a community hospital also.

Opposite impact of Methylene tetrahydrofolate reductase C677T and Methylene tetrahydrofolate reductase A1298C gene polymorphisms on systemic inflammation

Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been found to be related with many diseases. Systemic inflammation is now considered as a major predisposition factor for diseases including diabetes mellitus (DM), coronary arterial disease (CAD), stroke, and cancer. This study aimed to investigate whether systemic inflammation is a possible underlying pathogenesis for MTHFR gene polymorphism‐related disease.

Elevated troponin and left bundle branch block in the setting of suspected septicemia and demand ischemia: to treat or not to treat

Elevated troponin and atypical chest pain in the setting of septicemia and Type II Non ST elevation myocardial infarction is frequently encountered. These cases are not necessarily scheduled for emergent cardiac catheterization. High index of clinical suspicion and continuous in-patient cardiac monitoring with serial trending of cardiac enzymes are important in such cases. Subsequent sudden development of electrocardiogram changes requires prompt investigation with emergent coronary catheterization. These types of cases may be missed especially in females who present with atypical chest pain and in patients with Left bundle branch block.

Anomalous Left Main Coronary Artery Arising from the Right Sinus of Valsalva in a Young Man Presenting with Recurrent Syncope and Myocardial Infarction

A 19-year-old man with the left main coronary artery (LMCA) arising from the right sinus of Valsalva presented with recurrent episodes of syncope and myocardial infarction (MI). Anomalous aortic origin of a coronary artery (AAOCA) is an uncommon but extremely important differential diagnosis that should not be missed in patients presenting with syncope, MI, ventricular arrhythmias, or cardiac arrest. A definitive diagnosis with coronary angiography and prompt surgical intervention is imperative in such symptomatic patients.