Electrophysiological Alterations After Mechanical Circulatory Support in Patients With Advanced Cardiac Failure

Harding, John J.; Piacentino, Valentino; Gaughan, John; Houser, Steven R.; Margulies, Kenneth B.

doi:10.1161/hc3601.095718

Cited by 127 publications

(89 citation statements)

References 41 publications

(35 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…14 In explanted hearts after LVAD treatment, AP shortening has been described previously. 15 In this study, we show that this phenomenon is associated with clinical recovery. These results support the importance of electrical reverse remodeling in the clinical improvement observed in our patients.…”

Section: Discussionsupporting

confidence: 52%

Clinical Recovery From End-Stage Heart Failure Using Left-Ventricular Assist Device and Pharmacological Therapy Correlates With Increased Sarcoplasmic Reticulum Calcium Content but Not With Regression of Cellular Hypertrophy

et al. 2004

View full text Add to dashboard Cite

Background-Left ventricular assist device (LVAD) treatment is known to lead to structural and functional cellular modifications in the heart. The relevance of these changes for clinical recovery is unknown. Methods and Results-We compared properties of cardiomyocytes obtained from tissue taken at explantation of the LVAD in patients with clinical recovery with those obtained from hearts of patients who did not show clinical recovery, thus requiring transplantation. Compared with myocytes taken at implantation, both the recovery and nonrecovery groups showed Ϸ50% reduction in cell capacitance, an index of cell size. However, action potential duration shortened, L-type Ca 2ϩ current fast inactivation was more rapid, and sarcoplasmic reticulum Ca 2ϩ content was increased in the recovery compared with the nonrecovery group. Conclusions-These results show that specific changes in excitation-contraction coupling, and not regression of cellular hypertrophy, are specifically associated with clinical recovery after LVAD and further identify sarcoplasmic reticulum Ca Key Words: mechanical devices Ⅲ electrophysiology Ⅲ heart failure Ⅲ myocytes Ⅲ sarcoplasmic reticulum H eart transplantation is currently the only effective longterm treatment for patients in end-stage heart failure. Recently, left ventricular assist device (LVAD) treatment has been used successfully as a bridge to transplantation, as destination therapy in patients with contraindications to transplantation, 1 or to obtain recovery in a small number of patients. 2,3 We have shown that in some patients with idiopathic dilated cardiomyopathy in end-stage heart failure, combined LVAD and pharmacological therapy induced clinical recovery to allow explantation of the device without recurrence of heart failure. 3 LVAD treatment results in numerous changes in cardiomyocyte phenotype, excitation-contraction coupling, gene expression, and function. 2 Whether these changes are beneficial is not known. Regression of hypertrophy is thought to be an important factor in recovery. 2 However, several studies have also shown that hypertrophy is not required as a compensatory response to pressure overload, 4 and its regression is not necessarily associated with normalization of electrophysiological parameters. 5 Cardiomyocytes isolated from biopsies taken at explantation of the LVAD in patients with clinical recovery showed reductions in cell volume and cell surface area. L-type Ca 2ϩ current and sarcoplasmic reticulum (SR) Ca 2ϩ content were increased in myocytes during recovery, suggesting a critical role for intracellular Ca 2ϩ homeostasis. 6 Increased SR Ca 2ϩ uptake in cardiac tissue after LVAD treatment has also been described previously. 7 However, whether these specific cellular changes are related to clinical recovery remained unclear.In this study, we compared findings in cardiomyocytes obtained from tissue taken from patients who recovered with those obtained from patients who, despite identical treatment, did not. This allowed correlation between cellular electroph...

show abstract

Section: Discussionsupporting

confidence: 52%

Clinical Recovery From End-Stage Heart Failure Using Left-Ventricular Assist Device and Pharmacological Therapy Correlates With Increased Sarcoplasmic Reticulum Calcium Content but Not With Regression of Cellular Hypertrophy

et al. 2004

View full text Add to dashboard Cite

show abstract

“…Atrophic remodeling of the human heart is commonly associated with disease and unloading by mechanical devices such as left ventricular assist devices (LVADs) and cardiopulmonary bypass pumps [10,32]. Decreases in cardiac mass as well as electrophysiological changes have also been observed in healthy humans during periods of prolonged inactivity and/or during space travel [29,30,36].…”

Section: Introductionmentioning

confidence: 99%

Extreme Respiratory Sinus Arrhythmia Enables Overwintering Black Bear Survival—Physiological Insights and Applications to Human Medicine

Laske

Harlow

Garshelis

et al. 2010

J. of Cardiovasc. Trans. Res.

View full text Add to dashboard Cite

American black bears survive winter months without food and water while in a mildly hypothermic, hypometabolic, and inactive state, yet they appear to be able to return to near-normal systemic function within minutes of arousal. This study's goal was to characterize the cardiovascular performance of overwintering black bears and elicit the underlying mechanisms enabling survival. Midwinter cardiac electrophysiology was assessed in four wild black bears using implanted data recorders. Paired data from early and late winter were collected from 37 wild bears, which were anesthetized and temporarily removed from their dens to record cardiac electrophysiological parameters (12-lead electrocardiograms) and cardiac dimensional changes (echocardiography). Left ventricular thickness, primary cardiac electrophysiological parameters, and cardiovascular response to threats ("fight or flight" response) were preserved throughout winter. Dramatic respiratory sinus arrhythmias were recorded (cardiac cycle length variations up to 865%) with long sinus pauses between breaths (up to 13 s). The accelerated heart rate during breathing efficiently transports oxygen, with the heart "resting" between breaths to minimize energy usage. This adaptive cardiac physiology may have broad implications for human medicine.

show abstract

“…In LVAD-treated subjects, QRS-and both QT-and QTc duration decreased, suggesting that QRS-and QT-duration are significantly influenced by mechanical load and that the shortening of the action potential duration contributes to the improved contractile performance after LVAD support. 2 Despite the increasing use of LVAD supporting either continuous or pulsatile blood flow in patients with severe HF, the benefit of this treatment in dealing with the risk of arrhythmias is still controversial.…”

mentioning

confidence: 99%

Cytoskeletal Basis of Ion Channel Function in Cardiac Muscle

Vatta

Faulkner

2006

Future Cardiol.

View full text Add to dashboard Cite

SummaryThe heart is a force-generating organ that responds to self-generated electrical stimuli from specialized cardiomyocytes. This function is modulated by sympathetic and parasympathetic activity.In order to contract and accommodate the repetitive morphological changes induced by the cardiac cycle, cardiomyocytes depend on their highly evolved and specialized cytoskeletal apparatus. Defects in components of the cytoskeleton, in the long term, affect the ability of the cell to compensate at both functional and structural levels. In addition to the structural remodeling, the myocardium becomes increasingly susceptible to altered electrical activity leading to arrhythmogenesis. The development of arrhythmias secondary to structural remodeling defects has been noted, although the detailed molecular mechanisms are still elusive. Here I will review the current knowledge of the molecular and functional relationships between the cytoskeleton and ion channels and, I will discuss the future impact of new data on molecular cardiology research and clinical practice.

show abstract

Electrophysiological Alterations After Mechanical Circulatory Support in Patients With Advanced Cardiac Failure

Cited by 127 publications

References 41 publications

Clinical Recovery From End-Stage Heart Failure Using Left-Ventricular Assist Device and Pharmacological Therapy Correlates With Increased Sarcoplasmic Reticulum Calcium Content but Not With Regression of Cellular Hypertrophy

Clinical Recovery From End-Stage Heart Failure Using Left-Ventricular Assist Device and Pharmacological Therapy Correlates With Increased Sarcoplasmic Reticulum Calcium Content but Not With Regression of Cellular Hypertrophy

Extreme Respiratory Sinus Arrhythmia Enables Overwintering Black Bear Survival—Physiological Insights and Applications to Human Medicine

Cytoskeletal Basis of Ion Channel Function in Cardiac Muscle

Contact Info

Product

Resources

About