Team Management of the Ventricular Tachycardia Patient

Overlooked Ventricular Septal Defect Post-Myocardial Infarction and Coronary Artery Bypass Grafting

Ventricular septal defect (VSD) represents a severe complication that may manifest after a myocardial infarction (MI), typically occurring between 2 and 7 days later. Due to advancements in reperfusion management, the incidence of VSDs after MI has become very rare, occurring in approximately 0.2% of MIs. The current guidelines recommend urgent post-infarction VSD (PI-VSD) closure. We report a case of a patient with a VSD, which was diagnosed 2.5 years after MI. At the time of acute inferior MI, the patient was managed with primary percutaneous intervention in the culprit artery, and 1 month later coronary artery by-pass grafting (CABG) was completed. Twenty and thirty months after AMI patient presented with ventricular tachycardia (VT). Following the second VT episode patient was hospitalized for further examination. Echocardiography revealed the presence of VSD at the site of inferioseptal wall aneurysm. An ICD was implanted owing to recurrent malignant rhythm disorders. In conclusion, although the PI-VSD might have been overlooked and the patient missed the chance of concomitant CABG and VSD repair, this case has reached a 3-year survival, which appears to be the longest survival recorded in a medically treated patient with PI-VSD.

Presentation and Outcomes of Patients With Preoperative Critical Illness Undergoing Cardiac Surgery

BACKGROUND

Little is known about the prevalence and post-surgical outcomes associated with cardiac intensive care unit (CICU) therapeutics among CICU patients referred for cardiac surgery.

OBJECTIVES

The purpose of this study was to investigate the clinical characteristics and outcomes of CICU patients referred for cardiac surgery from the intensive care unit.

METHODS

We analyzed characteristics and outcomes of CICU admissions referred from the CICU for cardiac surgery during 2017 to 2020 across 29 centers. The primary outcome was in-hospital mortality.

RESULTS

Among 10,321 CICU admissions, 887 (8.6%) underwent cardiac surgery, including 406 (46%) coronary artery bypass graftings, 201 (23%) transplants or ventricular assist devices, 171 (19%) valve surgeries, and 109 (12%) other procedures. Common indications for CICU admission included shock (33.5%) and respiratory insufficiency (24.9%). Preoperative CICU therapies included vasoactive therapy in 52.2%, mechanical circulatory support in 35.9%, renal replacement in 8.2%, mechanical ventilation in 35.7%, and 17.5% with high-flow nasal cannula or noninvasive positive pressure ventilation. In-hospital mortality was 11.7% among all CICU admissions and 9.1% among patients treated with cardiac surgery. After multivariable adjustment, pre-op mechanical circulatory support and renal replacement therapy were associated with mortality, while respiratory support and vasoactive therapy were not.

CONCLUSIONS

Nearly 1 in 12 contemporary CICU patients receive cardiac surgery. Despite high preoperative disease severity, CICU admissions undergoing cardiac surgery had a comparable mortality rate to CICU patients overall; highlighting the ability of clinicians to select higher acuity patients with a reasonable perioperative risk.

Structure and function of the ventricular tachycardia isthmus

Catheter ablation of postinfarction reentrant ventricular tachycardia (VT) has received renewed interest owing to the increased availability of high-resolution electroanatomic mapping systems that can describe the VT circuits in greater detail, and the emergence and need to target noninvasive external beam radioablation. These recent advancements provide optimism for improving the clinical outcome of VT ablation in patients with postinfarction and potentially other scar-related VTs. The combination of analyses gleaned from studies in swine and canine models of postinfarction reentrant VT, and in human studies, suggests the existence of common electroanatomic properties for reentrant VT circuits. Characterizing these properties may be useful for increasing the specificity of substrate mapping techniques and for noninvasive identification to guide ablation. Herein, we describe properties of reentrant VT circuits that may assist in elucidating the mechanisms of onset and maintenance, as well as a means to localize and delineate optimal catheter ablation targets.

Mexiletine and False Positive Urine Drug Screen for Amphetamine: A Case Review

Advanced heart failure patients commonly suffer from ventricular arrhythmias which can be managed by antiarrhythmic drugs like mexiletine. These ventricular arrhythmias can be complicated by illicit drug use which alter outcomes and can potentially impact the patient-physician relationship through countertransference. However, mexiletine can lead to false positive urine drug screen testing for amphetamine, and these false-positive urine drug screen test results can affect the decision-making process. Health care providers should be aware of this fact and should either use confirmatory testing or look for confounding compounds in patients who deny using illicit substances and have a positive urine drug screen. Our patient is 64 years old who arrived at the emergency department after experiencing a shock by his intracardiac defibrillator. The patient tested positive for amphetamine on his urine drug screen and was later ruled out by confirmatory quantitative testing.

Transient ventricular arrhythmia as a rare cause of dizziness during exercise: A case report

BACKGROUND

Dizziness is a common symptom in adults and usually due to peripheral causes affecting semicircular canal function or central causes affecting the pons, medulla, or cerebellum. Arrhythmia is a recognized cause of dizziness in people with structural or ischemic heart disease. We report a case of exercise-induced transient ventricular tachycardia and dizziness in a man with no evidence of organic heart disease.

CASE SUMMARY

A 42-year-old man presented with a 6 mo history of transient exercise-induced dizziness and prodromal palpitations. The patient was otherwise asymptomatic. Physical examination, otoscopy, vestibular tests, cerebellar tests, laboratory investigations, and imaging investigations were all unremarkable. Twenty-four hour Holter monitoring revealed four episodes of transient ventricular tachycardia during exercise. The patient was started on metoprolol and subsequently underwent radiofrequency catheter ablation. The patient reported a full recovery and no dizziness during daily activities. These results were maintained at the 6 mo follow-up.

CONCLUSION

Ventricular tachycardia is an uncommon but potentially serious cause of dizziness. The outcome of this case illustrates the benefits of careful clinical examination and communication with specialized centers. High clinical suspicion of arrhythmia in a patient with dizziness merits consultation with a cardiologist and referral to a specialized center to ensure timely diagnosis and treatment.

CHA2DS2-VASC score predicts coronary artery disease progression and mortality after ventricular arrhythmia in patients with implantable cardioverter-defibrillator

AIM

The CHA2DS2-VASC score has expanded its use beyond the initial purpose of predicting the risk of stroke in patients with atrial fibrillation. We aimed to investigate the value of the CHA2DS2-VASC score as a risk assessment tool to predict relevant coronary artery disease (CAD) leading to percutaneous coronary intervention (PCI), and all-cause mortality after detected ventricular arrhythmia (VA) in patients with an Implantable Cardioverter-Defibrillator (ICD).

METHODS

A total of 183 ICD-patients who underwent coronary angiography after VA were included and classified according to their CHA2DS2-VASC score in a low(1-3), intermediate(4-5) and high(6-8) score group. We evaluated the predictive value of CHA2DS2-VASC score for the presence of relevant CAD leading to percutaneous coronary intervention (PCI), as well as late all-cause mortality.

RESULTS

A total of 60 patients (32.8%) had significant CAD and underwent successful PCI. After adjustment for relevant parameters such as ischemic cardiomyopathy, angina pectoris, left ventricular ejection fraction, CHA2DS2-VASC score remained the only independent predictor of CAD leading to PCI [HR 1.73 (1.07-2.80)]. The Area under curve was 0.64 (0.56-72, p = 0.002). Kaplan-Meier analysis and log-rank showed an increased three-year mortality of ICD-patients with an intermediate or high score after VA (p = 0.003). Multivariate cox-regression analysis revealed that CHA2DS2-VASC score was also independently associated with all-cause mortality following adjustment for clinically relevant variables (HR 2.20, 1.17-4.14).

CONCLUSIONS

CHA2DS2-VASC score can be a predictor of CAD leading to PCI in ICD-patients after VA. ICD-Patients with a high score have an increased risk for reduced three-year all-cause mortality after VA.

A case report reappraising the usefulness of Valsalva manoeuvre in drug-refractory ventricular tachycardia

BACKGROUND

Ventricular tachycardia (VT) is often misdiagnosed as supraventricular tachycardia with aberrancy. Twelve-lead electrocardiogram remains a key diagnostic tool to differentiate them while providing insights to aid localization of VT. The use of Valsalva manoeuvre (VM) in terminating VT is not conventionally recommended due to lack of robust evidence of its effectiveness and poor understanding of its mechanism in terminating VT.

CASE SUMMARY

A 74-year-old man with history of ischaemic heart disease was admitted with broad complex tachycardia. VT-1 was diagnosed following failed tachycardia termination by adenosine. Haemodynamic compromise necessitated synchronized cardioversion with successful reversion. However, a different VT-2 occurred after cardioversion. VM led to successful termination of VT-2. Subsequently, recurrent episodes of VT-2 occurred with consistent termination by VM. Transthoracic echocardiogram, cardiac magnetic resonance imaging, and a coronary angiogram were performed. Findings suggested that these are likely scar-related VT. VT-1 originated from an anteroseptal scar, whilst VT-2, responsive to VM, likely originated from the Purkinje fibres. Patient remained eurhythmic after Day 1 following amiodarone and beta-blocker initiation. An implantable cardioverter-defibrillator was implanted prior to discharge.

DISCUSSION

VM is one of the vagal manoeuvres which are commonly used as initial management of supraventricular tachycardia. Its role in management of VT is obscure. Anecdotal case series recorded its successful use for managing particular VT. Exact mechanism remains elusive although postulated to involve change in cardiac size during strain and release of acetylcholine.

The Electrophysiology Laboratory: Anesthetic Considerations and Staffing Models

The electrophysiology laboratory facilitates complex procedures on patients, many of whom have advanced disease processes and extensive comorbidities. Historically, nurses administered sedation as required, but in recent years a shift to anesthesiologist-led sedation has been promoted for patient safety and advanced therapeutic considerations. Uncertainty remains, however, regarding whether the electrophysiology laboratory is best staffed with general or cardiothoracic anesthesiologists. In this article, the authors discuss the anesthetic considerations of some commonly performed electrophysiology and structural cardiac procedures and the pros and cons of staffing with general or cardiothoracic anesthesiologists.

Radiofrequency catheter ablation of ventricular tachycardia in pediatric patients

Background

Radiofrequency catheter ablation (RFCA) has been accepted as an efficient therapy for tachycardia, and substantial improvement in the outcomes of RFCA in pediatric patients has been seen. However, there is not enough data on the clinical outcomes of RFCA for ventricular tachycardia (VT) in pediatric patients. The objective of this study was to elucidate the efficacy and safety of RFCA for VT in pediatric patients.

Methods

We performed a retrospective study involving 35 consecutive pediatric VT ablation procedures in 28 patients at a single institution.

Results

The median age at ablation was 14.0 years (range 6.9–19.2 years). There were 24 patients with a structurally normal heart and four patients with congenital heart disease (CHD). The left ventricular posteroseptal area was the most common site of VT origin (22/28, 78.6%). However, there was an unusual case of VT which involved a papillary muscle as its origin. Acute success was achieved in 30 (85.7%) of 35 procedures. The recurrence rate after successful RFCA was 14.2% (5/35) at a median follow-up of 6.7 years (range 1.0–16.7 years). There were five procedural failures due to the inability to induce VT for complete mapping. Ultimately, long-term success was achieved in 27 patients (96.4%) after repeated procedures and no major complications occurred. Long-term success was associated with VT inducibility (p =  < 0.001).

Conclusions

Difficulty in inducing VT for precise mapping was a significant obstacle to successful RFCA. RFCA was identified as safe and effective therapy to eliminate VT in the selected pediatric VT patients.

Modulating the Infarcted Ventricle's Refractoriness with an Epicardial Biomaterial

Patients diagnosed with heart failure with reduced ejection fraction (HFrEF) are at increased risk of monomorphic ventricular tachycardia (VT) and ventricular fibrillation. The presence of myocardial fibrosis provides both anatomical and functional barriers that promote arrhythmias in these patients. Propagation of VT in a reentrant circuit depends on the presence of excitable myocardium and the refractoriness of the circuit. We hypothesize that myocardial refractoriness can be modulated surgically in a model of HFrEF, leading to decreased susceptibility to VT.Male Sprague-Dawley rats were infarcted via permanent left coronary artery ligation. At 3 weeks post-infarction, engineered grafts composed of human dermal fibroblasts cultured into a polyglactin-910 biomaterial were implanted onto the epicardium to cover the area of infarction. Three weeks post-graft treatment, all rats underwent a terminal electrophysiologic study to compare monophasic action potential electroanatomic maps and susceptibility to inducible monomorphic VT.HFrEF rats (n=29) demonstrated a longer (p=0.0191) ventricular effective refractory period (ERP) and a greater (p=0.0394) VT inducibility compared with sham (n=7). HFrEF rats treated with the graft (n=12) exhibited no change in capture threshold (p=0.3220), but had a longer ventricular ERP (p=0.0029) compared with HFrEF. No statistically significant change in VT incidence was found between HFrEF rats treated with the graft and untreated HFrEF rats (p=0.0834).Surgical deployment of a fibroblast-containing biomaterial in a rodent ischemic cardiomyopathy model prolonged ventricular ERP as measured by programmed electrical stimulation. This hypothesis-generating study warrants additional studies to further characterize the antiarrhythmic or proarrhythmic effects of this novel surgical therapy.

Thalassemia in the emergency department: special considerations for a rare disease

Thalassemia is characterized by a defect in the synthesis of one or more of the globin subunits of hemoglobin. This defect results in imbalance in the α/β-globin chain ratio, ineffective erythropoiesis, chronic hemolytic anemia, and iron overload. With advances in diagnosis, treatment, and transfusion support, the prognosis of patients with thalassemia has improved over the past few decades. An increasing number of patients with thalassemia is living with long-term complications, including cardiomyopathy, chronic liver disease, endocrinopathy, and infections. In this paper, we review common complications that bring the patient with thalassemia to urgent or emergent medical attention. We also discuss the aspects of emergency care that are most relevant while caring for the patient with thalassemia in the emergency department.