Feasibility of Biventricular Pacing in Patients With Recent Myocardial Infarction: Impact on Ventricular Remodeling

Chung, Eugene S.; Menon, Santosh; Weiss, Raul; Schloss, Edward J.; Chow, Theodore; Kereiakes, Dean J.; Mazur, Wojciech; Salo, Rodney W.; Galle, Elizabeth; Pastore, Joseph

doi:10.1111/j.1527-5299.2007.05868.x

Cited by 23 publications

(13 citation statements)

References 23 publications

(36 reference statements)

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“…15 A study in patients 30 to 45 days after MI with reduced ejection fraction and narrow QRS suggests biventricular pacing attenuated LV dilation compared with a nonpaced group. 20 The present animal data support these findings and suggest a possible mechanism for these beneficial effects. Using regional strain and stroke work to assess regional loading characteristics, we showed that pacing preexcitation can preferentially reduce these loading characteristics.…”

Section: Discussionsupporting

confidence: 80%

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Ventricular Preexcitation Modulates Strain and Attenuates Cardiac Remodeling in a Swine Model of Myocardial Infarction

et al. 2007

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Background-Myocardial infarction modifies the distribution of stress within the heart, increasing wall stress in ischemic and surrounding tissue, which often leads to adverse left ventricular remodeling. Electrical preexcitation pacing with appropriate timing of high-stress regions can reduce local strain and may attenuate global remodeling. Methods and Results-Myocardial infarction was induced in 24 swine to study the short-term (nϭ12) and long-term (nϭ12) effects of therapy. Sonomicrometry and hemodynamic measurements were used to show the mechanistic effects of preexcitation and to determine the optimal stimulation site and atrioventricular delay. Lagrangian strain was used to assess regional loading characteristics. Long-term study animals were randomized to 8 weeks of preexcitation (therapy) or no pacing (control). Echocardiograms were performed 2 days after myocardial infarction and repeated at 60 days, when tissue weights and apoptosis were assessed. Preexcitation reduced regional strain in the short term, with the best results achieved when the border region was paced at an atrioventricular delay of 50% of the intrinsic PR interval. In the long term, the changes in left ventricular internal diameter and left atrial size were decreased in therapy animals versus control animals (0.9Ϯ0.3 versus 1.5Ϯ0.5 cm, Pϭ0.03, and 1.06Ϯ0.78 versus 2.32Ϯ0.88 cm, PϽ0.04, respectively). Heart weight was significantly lower in the therapy animals than in the control animals (319.8Ϯ20.8 versus 359.6Ϯ29.3 g, Pϭ0.02). Although not significant, cardiomyocyte apoptosis trended lower in the therapy group. Conclusions-Preexcitation of the left ventricle after myocardial infarction reduced strain and stroke work in the infarct and border regions in the short term and attenuated adverse ventricular remodeling in the long term.

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Section: Discussionsupporting

confidence: 80%

“…Recent clinical data suggest that long-term pacing starting 30 to 60 days after MI may attenuate ventricular remodeling. 20 However, no studies exist that have assessed the mechanistic effects of preexcitation and regional unloading on short-term hemodynamics and long-term ventricular remodeling after acute MI.…”

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confidence: 99%

Ventricular Preexcitation Modulates Strain and Attenuates Cardiac Remodeling in a Swine Model of Myocardial Infarction

et al. 2007

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“…There is an emerging interest in using electrical stimulation of the myocardium as a means to attenuate and/or prevent adverse LV remodeling after MI (4,5,18). For example, in a clinically relevant porcine MI model, Shuros et al (18) demonstrated that early electrical activation of the border region attenuated the increase in LV dimensions 8 wk after MI induction.…”

Section: Discussionmentioning

confidence: 99%

“…For example, in a clinically relevant porcine MI model, Shuros et al (18) demonstrated that early electrical activation of the border region attenuated the increase in LV dimensions 8 wk after MI induction. In a group of MI patients with narrow QRS complexes implanted with cardiac resynchronization devices, Chung et al (5) reported that early electrical activation of the MI border region was associated with a reduction in LV end-diastolic volumes 12 mo after the initiation of pacing.…”

Section: Discussionmentioning

confidence: 99%

Short-term disruption in regional left ventricular electrical conduction patterns increases interstitial matrix metalloproteinase activity

Mukherjee

Zavadzkas

Rivers

et al. 2010

American Journal of Physiology-Heart and Circulatory Physiology

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Increased matrix metalloproteinase (MMP) abundance occurs with adverse left ventricular (LV) remodeling in a number of cardiac disease states, including those induced by long-standing arrhythmias. However, whether regionally contained aberrant electrical activation of the LV, with consequent dyskinesia, alters interstitial MMP activation remained unknown. Electrical activation of the LV of pigs (n ϭ 10, 30 -35 kg) was achieved by pacing (150 beats/min) at left atrial and LV sites such that normal atrioventricular activation (60 min) was followed by regional early LV activation for 60 min within 1.5 cm of the paced site and restoration of normal atrioventricular pacing for 120 min. Regional shortening (piezoelectric crystals) and interstitial MMP activity (microdialysis with MMP fluorogenic substrate) at the LV pacing site and a remote LV site were monitored at 30-min intervals. During aberrant electrical stimulation, interstitial MMP activity at the paced site was increased (122 Ϯ 4%) compared with the remote region (100%, P Ͻ 0.05). Restoration of atrioventricular pacing after the 60-min period of aberrant electrical activation normalized segmental shortening (8.5 Ϯ 0.4%), but MMP activity remained elevated (121 Ϯ 6%, P Ͻ 0.05). This study demonstrates that despite the restoration of mechanical function, disturbances in electrical conduction, in and of itself, can cause acute increases in regional in vivo MMP activation and, therefore, contribute to myocardial remodeling. myocardium; interstitium ACUTE AS WELL AS CHRONIC ACTIVATION of matrix metalloproteinases (MMPs) within the myocardium can disrupt the integrity of the extracellular matrix (ECM) and, consequently, affect interstitial protein content, stability, and bioactive signaling pathways (9,14,19). Mechanical stimuli, such as abnormal myocardial stress and strain patterns, can also result in MMP induction (8,12,20). In this context, Garcia et al. (11) demonstrated that acute arrhythmias can disrupt electrical activation pathways and, therefore, induce alterations in the stretch/ contraction patterns of the myocardium and serve as a primary impetus for MMP activation and a potential nidus for stimuli to propagate a remodeling process. For example, previous studies (1, 22) have shown that short-duration disruption of electrical conduction induced in the atria can progress to the development of a sustained arrhythmia with associated remodeling of the myocardium. However, whether and to what degree an increase in MMP induction as a result of acute changes in electrical activation persist after the restoration of normal conduction patterns remain unknown. Therefore, the present study was designed to test the hypothesis that short-term (i.e., acute) alterations in the electrical activation of the myocardium would cause in vivo MMP activation and that the restoration of electrical conduction would normalize interstitial MMP activity. METHODS Instrumentation. Animals were treated and cared for in accordance with the National Institutes of Health Guide for the C...

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“…19 In this observational pilot study of 18 patients, no deaths occurred, no patients receiving CRT-D devices deteriorated in NYHA class, and therapy patients had improved quality of life at 1 year (similar to controls). Although 1 patient had a lead dislodgement, no unanticipated adverse events were reported.…”

Section: Discussionmentioning

confidence: 99%

Effect of Peri-Infarct Pacing Early After Myocardial Infarction

Chung

Dan

Solomon

et al. 2010

Circ: Heart Failure

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Background-Left ventricular (LV) remodeling has been attributed to the segmental loss of viable myocardium due to myocardial infarction (MI), which results in redistribution of cardiac workload, with increased regional wall stress in and around the infarct zone. Because ventricular pacing has been shown to reduce regional wall stress and workload in regions near the pacing site, this trial was designed to test whether chronic pacing near the infarct attenuates LV remodeling. Methods and Results-Eighty patients with an anterior MI, peak creatine kinase Ͼ2000 mU/mL, ejection fraction Յ35%, wall motion abnormality (WMA)

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Feasibility of Biventricular Pacing in Patients With Recent Myocardial Infarction: Impact on Ventricular Remodeling

Cited by 23 publications

References 23 publications

Ventricular Preexcitation Modulates Strain and Attenuates Cardiac Remodeling in a Swine Model of Myocardial Infarction

Ventricular Preexcitation Modulates Strain and Attenuates Cardiac Remodeling in a Swine Model of Myocardial Infarction

Short-term disruption in regional left ventricular electrical conduction patterns increases interstitial matrix metalloproteinase activity

Effect of Peri-Infarct Pacing Early After Myocardial Infarction

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