Cardiac resynchronization therapy for critically ill patients with left ventricular systolic dysfunction

Intensive Care Management of the Cardiogenic Shock Patient

Optimal management of patients with cardiogenic shock requires a detailed and systematic assessment of all organ systems, balancing the risks and benefits of any investigation and intervention, while avoiding the complications of critical illness. Overall prognosis depends upon a number of factors, including that of the underlying cardiac disease and its potential reversibility, the severity of shock, the involvement of other organ systems, the age of the patient and comorbidities. As with all intensive care patients, the mainstay of management is supportive, up to and including implementation and management of a number of devices, including acute mechanical circulatory support. The assessment and management of these most critically ill patients therefore demands in-depth knowledge and skill relating to cardiac intensive care, extending well beyond standard intensive care or cardiology practice.

Bradyarrhythmias and Physiologic Pacing in the ICU

Bradyarrhythmias represent a common pathology in the intensive care unit (ICU) with etiologies of varying severity. Treatment has often been focused on correcting underlying causes and may require pacing for urgent hemodynamic support. In recent years, there has been interest in physiologic pacing modalities which avoid the dyssynchrony from right ventricular (RV) only pacing. Cardiac resynchronization therapy (CRT) through biventricular pacing is a well-established device-based electrical therapy in patients with wide QRS and heart failure. Recently, it has been shown that biventricular pacing may also be pursued for hemodynamic rescue in the ICU setting. Efforts to re-engage the conduction system with His bundle pacing or further downstream have also emerged as alternative means to deliver resynchronization, with early applications in the ICU now being reported. The goal of the review is to examine bradyarrhythmia causes and management in the ICU as well as investigate new approaches in physiologic pacing and their potential roles in critically ill patients.

Weaning failure of cardiovascular origin: how to suspect, detect and treat-a review of the literature

Among the multiple causes of weaning failure from mechanical ventilation, cardiovascular dysfunction is increasingly recognized as a quite frequent cause that can be treated successfully. In this review, we summarize the contemporary evidence of the most important clinical and diagnostic aspects of weaning failure of cardiovascular origin with special focus on treatment. Pathophysiological mechanisms are complex and mainly include increase in right and left ventricular preload and afterload and potentially induce myocardial ischemia. Patients at risk include those with preexisting cardiopulmonary disease either known or suspected. Clinically, cardiovascular etiology as a predominant cause or a contributor to weaning failure, though critical for early diagnosis and intervention, may be difficult to be recognized and distinguished from noncardiac causes suggesting the need of high suspicion. A cardiovascular diagnostic workup including bedside echocardiography, lung ultrasound, electrocardiogram and biomarkers of cardiovascular dysfunction or other adjunct techniques and, in selected cases, right heart catheterization and/or coronary angiography, should be obtained to confirm the diagnosis. Official clinical practice guidelines that address treatment of a confirmed weaning-induced cardiovascular dysfunction do not exist. As the etiologies of weaning-induced cardiovascular dysfunction are diverse, principles of management depend on the individual pathophysiological mechanisms, including preload optimization by fluid removal, guided by B-type natriuretic peptide measurement, nitrates administration in excessive afterload and/or myocardial ischemia, contractility improvement in severe systolic dysfunction as well as other rational treatment in specific indications in order to lead to successful weaning from mechanical ventilation.

"Doubtful accepting": A grounded theory study of living with cardiac resynchronization therapy

Heart failure is associated with low quality of life and a high mortality rate. There is limited information about patients' experiences of living with cardiac resynchronization therapy (CRT). In the present study, we sought to explore the process of living with CRT defibrillator. This qualitative study was completed from December 2014 to April 2016 using a grounded theory approach. Twenty semistructured interviews were held with 17 patients with heart failure. Data analysis was done via a previously-published approach. The core category of the process of living with the device is "doubtful accepting". This process includes three sequential phases: losing integrity, attempting to cope with the device, and coexisting. The process takes place in a context of barriers and facilitators, and results in a wide spectrum of outcomes, from frustration to empowerment. Nurses' awareness of this process can help them provide higher quality care, strengthen facilitators and reduce barriers to the process, and enable patients to effectively use coping strategies.

Resolution of Cardiogenic Shock Using Echocardiography-Guided Pacing Optimization in Intensive Care: A Case Series

OBJECTIVE

Inotropic and vasopressor drugs are routinely used in critically ill patients to maintain adequate blood pressure and cardiac output in patients with cardiogenic shock although potentially at the expense of increasing myocardial oxygen demand. Pacing optimization has been demonstrated as effective in reducing catecholamine requirements in patients with chronic heart failure by improving cardiac efficiency; however, there are no reports relating to the effectiveness of pacemaker optimization on cardiac output in critically ill patients with cardiogenic shock in the intensive care.

DATA SOURCES

Retrospective data analysis.

STUDY SELECTION

Twenty-bed adult tertiary cardiothoracic ICU, university hospital.

DATA EXTRACTION

Eight sequential patients receiving dual chamber pacemaker with DDD modality with cardiogenic shock and hemodynamic instability refractory to catecholamines underwent echocardiography-guided pacemaker optimization of cardiac output. An iterative method with Doppler echocardiography was used to assess changes in cardiac output, left ventricular filling time, ejection time, total isovolumic time, mitral regurgitation, ejection fraction, and blood pressure at different increments of heart rate, and atrioventricular and interventricular delay. All results are shown as median (minimum/maximum level) or mean ± SD.

DATA SYNTHESIS

Using echocardiography-guided pacemaker optimization on cardiac output, the cardiac output increased from 3.2 (2.3/3.8) to 5.7 L/min (4.85/7.1) and cardiac index from 1.64 (1.1/1.9) to 2.68 L/min/m (2.1/3.2) and the total isovolumic time reduced from 22.8 to normal values (<14). In association, the glomerular filtration rate increased significantly except in one patient with stage IV chronic kidney disease. All inotropes and vasopressors were discontinued within 12 hours of pacemaker optimization on cardiac output, and all patients were discharged from the ICU within 1 week.

CONCLUSIONS

Echocardiography-guided pacemaker optimization of cardiac output is a feasible bedside therapeutic option, which should be considered when standard medical treatments are insufficient for the treatment of cardiogenic shock refractory to inotropic support, thereby minimizing the detrimental effect of catecholamines.

Cardiac Resynchronization Therapy Device Implantation in a Patient with Cardiogenic Shock under Percutaneous Mechanical Circulatory Support

65-year-old woman was admitted to our hospital with acute decompensated heart failure with reduced left ventricular ejection fraction and severe mitral regurgitation. Electrocardiography revealed a typical left bundle branch block and atrial fibrillation. Her condition deteriorated despite administering high-doses of inotropes and vasopressors. Pending a decision to therapy, venoarterial extracorporeal membrane oxygenation (ECMO) was performed when the patient underwent a cardiogenic shock. Although the hemodynamic status stabilized with ECMO support, weaning the patient from ECMO was not possible. Thus, we decided to perform cardiac resynchronization with defibrillator implantation as a “rescue” therapy. Five days post-implantation, the patient was successfully weaned from ECMO.

Impact of cardiac resynchronization therapy on clinical outcomes in patients with continuous-flow left ventricular assist devices

BACKGROUND

Implantable cardioverter-defibrillators (ICDs) can improve survival in left ventricular assist device (LVAD) recipients. However, the impact of cardiac resynchronization therapy (CRT-D) on outcomes in continuous-flow left ventricular assist device (CF-LVAD) patients is not known. We sought to determine if CRT-D improved clinical outcomes in CF-LVAD patients compared with ICDs alone.

METHODS AND RESULTS

Sixty-one consecutive CF-LVAD patients with an ICD or CRT-D were evaluated. Impacts of CRT-D on mortality, all-cause hospitalization, and incidence of atrial (AA) and ventricular (VA) arrhythmias after LVAD implantation was compared with patients with ICD alone. Of the 61 LVAD patients, 31 (age 59.8 ± 16 years, 84% male) had CRT-D and 30 (age 57.2 ± 13 years, 74% male) had ICD. Before LVAD implantation, no significant differences were noted between the groups in demographic and clinical characteristics, LVAD indications, and incidence of AA and VA. Over 682 ± 45 days of LVAD support, 8 patients (25.8%) died in the CRT-D arm versus 5 (16.7%) in the ICD arm (P = .35). No differences were noted between the CRT-D and ICD groups in all-cause (96.8 vs 93.3%; P = .63) and HF (19.4 vs 26.7%; P = .78) hospitalizations, left ventricular (LV) end-diastolic diameter (6.4 ± 1.5 vs 6.2 ± 1.1 cm, P = .47), and incidence of AA (35.4% vs 33.3%; P = .80), VA (29% vs 26.6%; P = .86), and ICD shocks (22.6% vs 16.7%; P = .93). Beta-blocker and antiarrhythmic drug use after LVAD implantation was similar in both groups.

CONCLUSIONS

In patients with refractory HF who received CF-LVADs, CRT-D, compared with ICD, did not significantly improve mortality, all-cause hospitalization, LV dimensions, and incidence of AA and VA.