Influence of intracardiac pressure on spontaneous ventricular arrhythmias in patients with systolic heart failure: insights from the REDUCEhf trial

Implantable Hemodynamic Monitors Improve Survival in Patients With Heart Failure and Reduced Ejection Fraction

BACKGROUND

Trials evaluating implantable hemodynamic monitors to manage patients with heart failure (HF) have shown reductions in HF hospitalizations but not mortality. Prior meta-analyses assessing mortality have been limited in construct because of an absence of patient-level data, short-term follow-up duration, and evaluation across the combined spectrum of ejection fractions.

OBJECTIVES

The purpose of this meta-analysis was to determine whether management with implantable hemodynamic monitors reduces mortality in patients with heart failure and reduced ejection fraction (HFrEF) and to confirm the effect of hemodynamic-monitoring guided management on HF hospitalization reduction reported in previous studies.

METHODS

The patient-level pooled meta-analysis used 3 randomized studies (GUIDE-HF [Hemodynamic-Guided Management of Heart Failure], CHAMPION [CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients], and LAPTOP-HF [Left Atrial Pressure Monitoring to Optimize Heart Failure Therapy]) of implantable hemodynamic monitors (2 measuring pulmonary artery pressures and 1 measuring left atrial pressure) to assess the effect on all-cause mortality and HF hospitalizations.

RESULTS

A total of 1,350 patients with HFrEF were included. Hemodynamic-monitoring guided management significantly reduced overall mortality with an HR of 0.75 (95% CI: 0.57-0.99); P = 0.043. HF hospitalizations were significantly reduced with an HR of 0.64 (95% CI: 0.55-0.76); P < 0.0001.

CONCLUSIONS

Management of patients with HFrEF using an implantable hemodynamic monitor significantly reduces both mortality and HF hospitalizations. The reduction in HF hospitalizations is seen early in the first year of monitoring and mortality benefits occur after the first year.

Implantable devices for heart failure monitoring

Heart failure (HF) is associated with considerable morbidity and mortality. The increasing prevalence of HF and inpatient HF hospitalization has a considerable burden on healthcare cost and utilization. The recognition that hemodynamic changes in pulmonary artery pressure (PAP) and left atrial pressure precede the signs and symptoms of HF has led to interest in hemodynamic guided HF therapy as an approach to allow earlier intervention during a heart failure decompensation. Remote patient monitoring (RPM) utilizing telecommunication, cardiac implantable electronic device parameters and implantable hemodynamic monitors (IHM) have largely failed to demonstrate favorable outcomes in multicenter trials. However, one positive randomized clinical trial testing the CardioMEMS device (followed by Food and Drug Administration approval) has generated renewed interest in PAP monitoring in the HF population to decrease hospitalization and improve quality of life. The COVID-19 pandemic has also stirred a resurgence in the utilization of telehealth to which RPM using IHM may be complementary. The cost effectiveness of these monitors continues to be a matter of debate. Future iterations of devices aim to be smaller, less burdensome for the patient, less dependent on patient compliance, and less cumbersome for health care providers with the integration of artificial intelligence coupled with sophisticated data management and interpretation tools. Currently, use of IHM may be considered in advanced heart failure patients with the support of structured programs.

Association between Arrhythmia and Pulmonary Artery Pressure in Heart Failure Patients Implanted with a Cardiac Defibrillator and Ambulatory Pulmonary Artery Pressure Sensor

The association between ventricular arrhythmia (VA) burden or defibrillator therapy and pulmonary artery pressure (PAP) has not been characterized in an ambulatory setting; thus, we sought in the present research to determine the relationship between ambulatory PAP and VA burden. A retrospective cohort study involving patients with an implantable cardiac defibrillator and CardioMEMS™ PAP sensor (Abbott Laboratories, Chicago, IL, USA) both transmitting remotely into the Merlin.net™ patient care network (Abbott Laboratories, Chicago, IL, USA) was conducted. VA and therapy burden in the six months following sensor implant were stratified by the baseline mean PAP. Patients with PAPs of 25 mmHg to 35 mmHg and those with PAPs of 35 mmHg or more were compared with individuals with PAPs of less than 25 mmHg. The change in VA burden was reported using the averaged mean PAP reduction during the first three months. A total of 162 patients aged 69.4 years ± 10.9 years were included (74% male) with a baseline mean PAP of 36.2 mmHg ± 10.4 mmHg. Twenty patients with a baseline mean PAP of less than 25 mmHg had no VAs over six months. For 61 patients with a baseline mean PAP of between 25 mmHg and 35 mmHg, the annualized number of days with ventricular tachycardia (VT)/ventricular fibrillation (VF) was 1.65/patient-year (p < 0.001), with 8% of patients having VT/VF events. For 81 patients with a baseline mean PAP of 35 mmHg or more, 19% of patients had a VT/VF event and an annualized number of days with VT/VF events of 1.45/patient-year (p < 0.001). When analyzing the treatment effect, a reduction of 3 mmHg or more in mean PAP over three months reduced arrhythmia burden over the next three months as compared with in patients without such an improvement. In conclusion, it is indicated that VAs are associated with high PAPs, and a reduction in PAP may lead to a reduction in VAs in real-world ambulatory patients.

Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm

The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.

Heart failure as a substrate and trigger for ventricular tachycardia

Heart failure (HF) is a major cause of morbidity and mortality with more than 5.1 million individuals affected in the USA. Ventricular tachyarrhythmias (VAs) including ventricular tachycardia and ventricular fibrillation are common in patients with heart failure. The pathophysiology of these mechanisms as well as the contribution of heart failure to the genesis of these arrhythmias is complex and multifaceted. Myocardial hypertrophy and stretch with increased preload and afterload lead to shortening of the action potential at early repolarization and lengthening of the action potential at final repolarization which can result in re-entrant ventricular tachycardia. Myocardial fibrosis and scar can create the substrate for re-entrant ventricular tachycardia. Altered calcium handling in the failing heart can lead to the development of proarrhythmic early and delayed after depolarizations. Various medications used in the treatment of HF such as loop diuretics and angiotensin converting enzyme inhibitors have not demonstrated a reduction in sudden cardiac death (SCD); however, beta-blockers (BB) are effective in reducing mortality and SCD. Amongst patients who have HF with reduced ejection fraction, the angiotensin receptor-neprilysin inhibitor (sacubitril/valsartan) has been shown to reduce cardiovascular mortality, specifically by reducing SCD, as well as death due to worsening HF. Implantable cardioverter-defibrillator (ICD) implantation in HF patients reduces the risk of SCD; however, subsequent mortality is increased in those who receive ICD shocks. Prophylactic ICD implantation reduces death from arrhythmia but does not reduce overall mortality during the acute post-myocardial infarction (MI) period (less than 40 days), for those with reduced ejection fraction and impaired autonomic dysfunction. Furthermore, although death from arrhythmias is reduced, this is offset by an increase in the mortality from non-arrhythmic causes. This article provides a review of the aforementioned mechanisms of arrhythmogenesis in heart failure; the role and impact of HF therapy such as cardiac resynchronization therapy (CRT), including the role, if any, of CRT-P and CRT-D in preventing VAs; the utility of both non-invasive parameters as well as multiple implant-based parameters for telemonitoring in HF; and the effect of left ventricular assist device implantation on VAs.

Vagus nerve stimulation: An evolving adjunctive treatment for cardiac disease

The vagus nerve is a major component of the autonomic nervous system and plays a critical role in many body functions including for example, speech, swallowing, heart rate and respiratory control, gastric secretion, and intestinal motility. Vagus nerve stimulation (VNS) refers to any technique that stimulates the vagus nerve, with electrical stimulation being the most important. Implantable devices for VNS are approved therapy for refractory epilepsy and for treatment-resistant depression. In the case of heart disease applications, implantable VNS has been shown to be beneficial for treating heart failure in both preclinical and clinical studies. Adverse effects of implantable VNS therapy systems are generally associated with the implantation procedure or continuous on-off stimulation. The most serious implantation-associated adverse effect is infection. The effectiveness of non-invasive transcutaneous VNS for epilepsy, depression, primary headaches, heart failure, and other conditions remains under investigation. VNS merits further study for its potentially favorable effects on cardiovascular disease, especially heart failure.

Remote Monitoring of Patients With Heart Failure: A White Paper From the Heart Failure Society of America Scientific Statements Committee

BACKGROUND

After several neutral telehealth trials, the positive findings and subsequent Food and Drug Administration approval of an implantable pulmonary arterial pressure monitor (PAPM) led to renewed interest in remote patient monitoring (RPM). Here we seek to provide contemporary guidance on the appropriate use of RPM technology.

RESULTS

Although early trials of external RPM devices suggested benefit, subsequent multicenter trials failed to demonstrate improved outcomes. Monitoring features of cardiac implantable electronic devices (CIEDs) also did not deliver improved HF outcomes, newer, multisensor algorithms may be better. Earlier technologies using direct pressure measurement via implanted devices failed to show benefit owing to complications or failure. Recently, 1 PAPM showed benefit in a randomized controlled trial. Although not showing cost reduction, cost-benefit analysis of that device suggests that it may meet acceptable standards. Additional research is warranted and is in progress. Consumer-owned electronic devices are becoming more pervasive and hold hope for future benefit in HF management. Practical aspects around RPM technology include targeting of risk populations, having mechanisms to ensure patient adherence to monitoring, and health care team structures that act on the data.

CONCLUSIONS

Based on available evidence, routine use of external RPM devices is not recommended. Implanted devices that monitor pulmonary arterial pressure and/or other parameters may be beneficial in selected patients or when used in structured programs, but the value of these devices in routine care requires further study. Future research is also warranted to better understand the cost-effectiveness of these devices.

Rabbit models of cardiac mechano-electric and mechano-mechanical coupling

Cardiac auto-regulation involves integrated regulatory loops linking electrics and mechanics in the heart. Whereas mechanical activity is usually seen as 'the endpoint' of cardiac auto-regulation, it is important to appreciate that the heart would not function without feed-back from the mechanical environment to cardiac electrical (mechano-electric coupling, MEC) and mechanical (mechano-mechanical coupling, MMC) activity. MEC and MMC contribute to beat-by-beat adaption of cardiac output to physiological demand, and they are involved in various pathological settings, potentially aggravating cardiac dysfunction. Experimental and computational studies using rabbit as a model species have been integral to the development of our current understanding of MEC and MMC. In this paper we review this work, focusing on physiological and pathological implications for cardiac function.