Michael Essandoh

Role of Exercise Electrocardiogram to Screen for T Wave Oversensing After Implantation of Subcutaneous Implantable Cardioverter Defibrillator

BACKGROUND During early experience with subcutaneous implantable cardioverter-defibrillators (S-ICD), several patients had inappropriate shocks from T-wave oversensing (TWOS) during exercise. This prompted some operators to perform routine treadmill exercise tests after implantation of S-ICD to screen for TWOS. Meanwhile, improvements have been made in the detection algorithms by the manufacturer. OBJECTIVE To assess whether routine treadmill exercise post S-ICD implantation is warranted. METHODS Patients undergoing S-ICD implantation from October 2012 to December 2016 who were able to complete a treadmill exercise were included in the study. The amplitude of R and T waves as assessed by the device programmer at rest and peak exercise was calculated and incidence of TWOS recorded. RESULTS Eighty-seven patients with complete treadmill exercise test data were included in the final analysis. The majority of the patients received S-ICD for primary prevention. Nine percent of the included patients had hypertrophic obstructive cardiomyopathy. During treadmill exercise, there was significant increase in the heart rate from rest (77 ± 14 beats per minute) to peak exercise (133 ± 14 beats per minute; P < .0001). There was no significant difference between R-wave amplitude at rest (2 ± 0.77 mV) and peak exercise (1.88 ± 0.94 mV; P = .36). Similarly, there was no significant difference between T-wave amplitude at rest (0.27 ± 0.19 mV) and peak exercise (0.33 ± 0.23 mV; P = .06). The incidence of TWOS during exercise was zero. CONCLUSIONS With current screening and detection algorithms for S-ICD, routine treadmill exercise does not result in additional discrimination of patients susceptible to TWOS.

Refractory Hypotension after Liver Allograft Reperfusion: A Case of Dynamic Left Ventricular Outflow Tract Obstruction

Hypotension after reperfusion is a common occurrence during liver transplantation following the systemic release of cold, hyperkalemic, and acidic contents of the liver allograft. Moreover, the release of vasoactive metabolites such as inflammatory cytokines and free radicals from the liver and mesentery, compounded by the hepatic uptake of blood, may also cause a decrement in systemic perfusion pressures. Thus, the postreperfusion syndrome (PRS) can materialize if hypotension and fibrinolysis occur concomitantly within 5 min of reperfusion. Treatment of the PRS may require the administration of inotropes, vasopressors, and intravenous fluids to maintain hemodynamic stability. However, the occurrence of the PRS and its treatment with inotropes and calcium chloride may lead to dynamic left ventricular outflow tract obstruction (DLVOTO) precipitating refractory hypotension. Expedient diagnosis of DLVOTO with transesophageal echocardiography is extremely vital in order to avoid potential cardiovascular collapse during this critical period.

Anesthesia for subcutaneous implantable cardioverter-defibrillator implantation: Perspectives from the clinical experience of a U.S. panel of physicians: ESSANDOH et al.

Worldwide adoption of the subcutaneous implantable cardioverter‐defibrillator (S‐ICD) for preventing sudden cardiac death continues to increase, as longer‐term evidence demonstrating the safety and efficacy of the S‐ICD expands. As a relatively new technology, comprehensive anesthesia guidance for the management of patients undergoing S‐ICD placement is lacking. This article presents advantages and disadvantages of different periprocedural sedation and anesthesia options for S‐ICD implants including general anesthesia, monitored anesthesia care, regional anesthesia, and nonanesthesia personnel administered sedation and analgesia.

Echocardiographic assessment for ventricular assist device placement

While many factors depend on successful implantation and outcome of left ventricular assist devices (LVAD), echocardiography remains an integral part and is vital to the success of this process. Transesophageal echocardiography (TEE) allows interrogation of all the cardiac structures and great vessels. The pre-implantation TEE exam establishes a baseline and may identify potential problems that need palliation. Among these, most significant are aortic insufficiency (AI), intracardiac thrombi, poor right ventricular (RV) function, and intracardiac shunts. The post-implantation exam allows for adequate de-airing of the heart and successful LVAD initiation. The position and flow profiles of the inflow and outflow cannulas of the LVAD may be assessed. Finally, it assists in the astute management and vigilant identification and correction of a number of complications in the immediate post-implantation period. TEE will continue to remain vital to the successful outcomes LVAD patients.

Transesophageal Echocardiography Should Be Considered During Pulmonary Artery Catheter Insertion in Cardiac Surgery

The pulmonary artery catheter (PAC) is a hemodynamic monitor commonly used during cardiac surgery. Conventionally, the PAC is inserted intraoperatively using the pressure waveform transduction technique. The measurement of changes in pressure as the PAC traverses the superior vena cava to the main pulmonary artery helps guide PAC insertion. This approach to PAC insertion, however, can be challenging in patients with certain pathologic conditions such as: systolic heart failure, moderate-to-severe tricuspid regurgitation, right atrial enlargement, right ventricular enlargement, right ventricular outflow tract obstruction, and in those with intracardiac leads. As a consequence, multiple attempts may be required during PAC insertion using the pressure waveform transduction technique, which may lead to complications such as arrhythmias, PAC kinking, tricuspid valve injury, and pulmonary artery injury. Considering that the pressure transduction technique does not provide the operator the ability to visualize the location of the PAC during insertion, transesophageal echocardiography (TEE) may be of value during PAC placement. In a prior issue of the Journal, Cronin et al reported on the successful use of TEE guidance for PAC catheter insertion in 20 patients with chronic thromboembolic pulmonary hypertension undergoing pulmonary thromboendarterectomy. During PAC placement, 11 of 20 patients required PAC manipulation

Afterload Mismatch After MitraClip Implantation: The Potential Impact of Pharmacologic Support

MITRAL REGURGITATION (MR) remains one of the most prevalent valvular pathologies worldwide. Moderateto-severe MR (Z3þon echocardiographic imaging) chronically alters the loading conditions of the left ventricle (LV) by increasing preload and reducing afterload (low left trial impedance). The alterations in loading conditions may induce LV remodeling and LV systolic failure over time. Accordingly, patients with symptomatic moderate-to-severe MR, LV dilatation, and/or LV systolic failure are currently recommended to undergo mitral valve surgery due to the poor outcomes associated with refractory medical therapy. However, a vast majority of these patients have comorbidities that may preclude conventional mitral valve surgery (mitral valve repair or replacement). The limited efficacy of medical therapy in patients considered at high risk for mitral valve surgery influenced the development of a nonsurgical, minimally invasive approach to mitral valve repair, the percutaneous MitraClip system (Abbott Vascular, Menlo Park, CA). Although the MitraClip has demonstrated excellent efficacy and safety in MR therapy, patients with baseline severe LV systolic dysfunction may be at risk of developing acute left heart failure after device deployment due to afterload mismatch.

Perioperative Management of Dual-Antiplatelet Therapy in Patients With New-Generation Drug-Eluting Metallic Stents and Bioresorbable Vascular Scaffolds Undergoing Elective Noncardiac Surgery

Dual-antiplatelet therapy (DAPT) is considered mandatory after new-generation drug-eluting coronary stent implantation to reduce ischemic complications such as stent thrombosis, but the need for DAPT makes the timing of elective surgery difficult. Interrupting DAPT places patients at risk for stent thrombosis, and surgery in the setting of DAPT may lead to bleeding. The 2016 American College of Cardiology/American Heart Association guideline recommends delaying elective noncardiac surgery for a minimum 6-month period to reduce ischemic risks after the implantation of a second-generation metallic drug-eluting stent (DES). However, the guideline fails to appropriately stratify surgical patients based on the indication for second-generation metallic DES implantation and other patient characteristics. The Absorb bioresorbable vascular scaffold (Abbott Vascular, Abbott Park, IL), which has a higher propensity for stent thrombosis compared with second-generation metallic DES, also produces DAPT management challenges in patients presenting for elective noncardiac surgery. Due to the novelty of bioresorbable vascular scaffold therapy, there are no guidelines available for the management of patients undergoing elective noncardiac surgery. This review addresses DAPT management in patients undergoing noncardiac surgery less than 12 months after new-generation metallic DES or bioresorbable vascular scaffold implantation and provides further guidance for anesthesiologists who encounter these challenging cases.

Anesthetic Management of a Patient With a Giant Right Atrial Myxoma

Cardiac myxomas account for 50% of all benign primary cardiac tumors. Rarely, these tumors occur in the right atrium (RA; 10% to 20%), with a stalk frequently attached to the interatrial septum. Right atrial myxomas can lead to RA enlargement, arrhythmias, functional tricuspid stenosis, right heart failure, and catastophic pulmonary embolization resulting in sudden cardiac death. Anesthetic management of patients with RA myxomas can be complicated by the mass effect of the myxoma, preload limitations, and the potential for cardiovascular collapse. Multimodal cardiac imaging inclusive of echocardiography, computed tomography, and magnetic resonance imaging helps with the diagnosis, preoperative optimization, and formulation of anesthetic and surgical plans. We present a case report highlighting the importance of multimodal imaging, adequate preoperative patient optimization, and the anesthetic considerations in the successful management of a patient with a giant 8.3 × 4.7 cm RA myxoma.

CASE 9—2015 Anesthetic Management of a Patient With Esophago-Pericardial Fistula Complicating Atrial Fibrillation Radiofrequency Ablation

AF is tailored toward rhythm and heart rate control using anti- arrhythmic medications and anticoagulation therapy to prevent embolic stroke. However, antiarrhythmic therapy fails in a significant number of patients. Drug-refractory AF currently is managed with catheter ablation (CA) procedures, which are associated with a complication rate of about 5% and a mortality rate of approximately 0.001%. 3-11 CA procedures, such as cryoablation and radiofrequency ablation (RFA), can be associated with the following early periprocedure complications: bleeding from cardiovascular injury, cardiac tamponade, pericarditis, pulmonary vein (PV) thrombosis, and embolic stroke. Late CA-related complications include esophago-pericardial fistula (EPF), left atrial-esophageal fistula (LAEF), stroke, PV stenosis, and death. 3,4,7,9-13 The mechanism of LAEF and EPF formation is not clear. However, direct thermal injury and ischemia to the esophagus have been described as inciting complications after RFA and cryoablation procedures. These complications typically occur during posterior ablation of the left atrium (LA) and the PVs. Post-thermal injury esophageal inflammation, necrosis, and/or adhesion to the heart

Acute Hypotension After MitraClip Implantation due to Acute Left Ventricular Failure

The MitraClip is a percutaneously implanted device approved for the treatment of symptomatic organic mitral regurgitation in poor surgical candidates. Despite its proven efficacy and safety for mitral regurgitation treatment, the MitraClip may unmask the true afterload of the left ventricle by removing the low-pressure left atrial system and may cause acute left ventricular systolic failure (afterload mismatch). Rapid diagnosis and treatment of afterload mismatch is crucial to ensure optimal patient outcomes. The authors present a case of acute hemodynamic deterioration after MitraClip implantation in a patient with chronic severe left ventricular systolic dysfunction. Transesophageal echocardiography was pivotal for the rapid recognition of acute left ventricular failure and aided in the intraoperative decision-making process and therapy.