Combined Epicardial and Endocardial Electroanatomic Mapping in a Porcine Model of Healed Myocardial Infarction

Reddy, Vivek Y.; Wrobleski, David; Houghtaling, Christopher; Josephson, Mark E.; Ruskin, Jeremy N.

doi:10.1161/01.cir.0000074280.62478.e1

Cited by 100 publications

(72 citation statements)

References 14 publications

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“…Mapping studies in a porcine model of healed MI after chronic occlusion of the IRA revealed large, homogeneous areas of very low voltages surrounded by only a small scar border zone. 7 These very low-voltage areas, arbitrarily defined as Ͻ0.5 mV, are likely to reflect dense, transmural scar typical of chronic occlusion of the IRA without collateral circulation, whereas the surrounding border zone may reflect nontransmural scar areas that are partly supplied by nonIRAs. A similar pattern of a central homogeneous dense scar area surrounded by the electroanatomic border zone was found in the majority of nonreperfused patients in this study.…”

Section: Reperfusion and Myocardial Scarmentioning

confidence: 99%

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Early Reperfusion During Acute Myocardial Infarction Affects Ventricular Tachycardia Characteristics and the Chronic Electroanatomic and Histological Substrate

et al. 2010

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Background-Reperfusion therapy during acute myocardial infarction results in myocardial salvage and improved ventricular function but may also influence the arrhythmogenic substrate for ventricular tachycardia (VT). This study used electroanatomic mapping and infarct histology to assess the impact of reperfusion on the substrate and on VT characteristics late after acute myocardial infarction. Methods and Results-The study population consisted of 36 patients (32 men; age, 63Ϯ15 years) referred for treatment of VT 13Ϯ9 years after acute myocardial infarction. Fourteen patients with early reperfusion during acute myocardial infarction were compared with 22 nonreperfused patients. Spontaneous and induced VTs and the characteristics of electroanatomic voltage maps were analyzed. Twenty-seven patients were treated by radiofrequency catheter ablation. Ten patients (6 nonreperfused) were treated by ventricular restoration with intraoperative cryoablation in 9. During surgery, biopsies were obtained from the resected core of the infarct. VT cycle length of spontaneous and induced VTs was shorter in reperfused patients (reperfused, 299Ϯ52/270Ϯ58 ms; nonreperfused, 378Ϯ77/362Ϯ74 ms; Pϭ0.01). An electroanatomic patchy scar pattern was present in 71% of reperfused and 14% of nonreperfused patients (Pϭ0.004). The proportion of electroanatomic dense scar was smaller in reperfused patients (24Ϯ18% versus 45Ϯ21%; Pϭ0.02). Histological assessment in 10 patients revealed thick layers of surviving myocardium in 75% of reperfused but in none of the nonreperfused patients. Conclusions-Scar size and pattern defined by electroanatomic mapping are different between VT patients with and without reperfusion during acute myocardial infarction. Less confluent electroanatomic scars match with thick layers of surviving myocardium on histology. Early reperfusion and less confluent electroanatomic scar are associated with faster

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Section: Reperfusion and Myocardial Scarmentioning

confidence: 99%

“…2,3,6 Animal studies to validate this substrate-based ablation approach were performed in a chronically occluded infarct-related artery (IRA) model resulting in a homogeneous dense scar surrounded by a small scar border zone. 7 …”

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confidence: 99%

Early Reperfusion During Acute Myocardial Infarction Affects Ventricular Tachycardia Characteristics and the Chronic Electroanatomic and Histological Substrate

et al. 2010

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“…Typically, a bipolar voltage map of the chamber was displayed: normal tissue and dense scar were defined as bipolar voltage amplitude Ͼ1.5 or Ͻ0.5 mV, respectively. 7,10,12 Accordingly, the color display was set with a range of 0.5 to 1.5 mV for bipolar voltage maps. With this SEAM voltage map, the mapping catheter was used to deliver ablation lesions to the epicardial aspect of the scar.…”

Section: Electroanatomic Mapping and Localization Of The Ablation Lesmentioning

confidence: 99%

“…Although the pericardial cavity is a virtual space, if the catheter tip is oriented such that the parietal pericardium is stretched away from heart, the distal electrode may achieve poor contact with the epicardium while manifesting "normal" electrogram characteristics because of myocardial contact with the proximal electrode. 12 Regarding this point, SEAM was helpful in verifying that the electrode orientation was directed toward the myocardium. Among the biophysical parameters examined, the magnitude of the impedance drop correlated best with lesion dimension.…”

Section: D'avila Et Al Epicardial Cooled-tip Rf Ablation 2367mentioning

confidence: 99%

Catheter Ablation of Ventricular Epicardial Tissue

et al. 2004

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Background-Transthoracic epicardial catheter ablation is an emerging catheter ablation strategy being used clinically at increasing frequency. However, the efficacy of standard RF ablation on the epicardial surface of the heart is hindered by (1) the lack of convective cooling of the ablation electrode and (2) the varying presence of epicardial adipose tissue interposed between the ablation electrode and the target site. This experimental animal study examines the biophysical characteristics of radiofrequency (RF) ablation lesions generated by either standard or cooled-tip ablation of the ventricular epicardium. Methods and Results-Nonsurgical subxyphoid pericardial access was achieved in 10 normal goats and 7 pigs with healed myocardial infarctions. A 4-mm cooled-tip RF ablation catheter (continuous 0.9% saline circulation at 0.6 mL/s; goal temperature, 40°C; 60 seconds) was used to deliver epicardial ventricular lesions: 47 in normal tissue and 22 in infarcted tissue. Standard RF ablation lesions (nϭ33) using a 4-mm top catheter (goal temperature, 70°C; 60 seconds) were also placed on normal epicardial tissue. Lesions created with standard and cooled-tip RF ablation were 3.7Ϯ1.3 mm (25Ϯ16.8 W) and 6.7Ϯ1.7 mm (44.8Ϯ6.8 W) in depth, respectively. On scar tissue, lesions made with the cooled-tip catheter measured 14.6Ϯ2.7 mm in length, 11.8Ϯ2.9 mm in width, and 5.6Ϯ1.2 mm in depth (35.6Ϯ7.1 W). In areas covered by epicardial fat (3.1Ϯ1.2 mm thick), standard RF energy did not generate any appreciable lesions, but cooled-tip RF lesions were 4.1Ϯ2 mm in depth (45Ϯ4.4 W). Conclusions-Cooled-tip RF ablation can generate epicardial lesions more effectively than standard RF ablation and appears to be of particular benefit in ablating areas with overlying epicardial fat.

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“…The procedure is generally safe even in the setting of myocardial infarction in the large animal model. 45 Moreover, this method has also proven its value in the clinical setting and is routinely performed. From 334 patients reported by Koruth et al 46 2-5% undergoing the procedure experienced complications, most common complications being post-procedure pericarditis and inadvertent RV puncture.…”

Section: Percutaneous Methods Of Vector Delivery D Ladage Et Almentioning

confidence: 99%