Measuring Electrical Resistance of Different Tissues on the Outer Surface of the Heart

Myocardial Infarction Clinical Trial

Official title:

Impedance Measurement of Epicardial Substrate for Ventricular Arrhythmias: Case Control Series of Patients With and Without Myocardial Scarring

Clinical Trial Details — Status: Terminated

Administrative data

• NCT number: NCT00291174
• Other study ID #: 803272
• Status: Terminated
• Phase: N/A
• First received: February 10, 2006
• Last updated: August 15, 2016
• Start date: April 2006
• Est. completion date: January 2008

Study information

• Verified date: August 2016
• Source: University of Pennsylvania
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Institutional Review Board
• Study type: Observational

Clinical Trial Summary

This is a research study to evaluate the electrical properties of heart tissue. The purpose of this study is to determine the impedance (electrical resistance) of different tissues on the outer surface of the heart. This may be important for distinguishing scarred heart muscle from fat that can be seen on the surface of the heart. This information may eventually be utilized in patients that undergo a procedure (called catheter ablation) for the treatment of life-threatening heart rhythms. Investigators expect a detectable difference between the impedance of normal and infarcted myocardium (approximately 50 ohms).

Description:

The treatment of cardiac arrhythmias with endocardial catheter ablation has evolved rapidly over the past few decades. At the time of this writing, the ablation of almost all atrial and ventricular arrhythmias has been described in the literature. Multiple energy modalities (e.g. radiofrequency, cryotherapy) and approaches (e.g. retrograde aortic, transseptal puncture) have been described, yet ablation of some rhythms is not as successful as others.

The realization that ventricular tachycardia (VT) in the setting of Chagas Disease can originate in the epicardium has lead to the development of a percutaneous, transthoracic epicardial approach to mapping and ablation of this arrhythmia. This approach has now been applied to patients with VT in the setting of ischemic and nonischemic heart disease at many centers throughout the world. Traditional mapping technologies are utilized on the epicardium to define scarred heart tissue and locate the VT circuit.

It is well known that human hearts display a variable amount of fat overlying the epicardium. Not only is the coronary vasculature embedded in a layer of adipose tissue, but the rest of the heart may have areas of epicardial fat. As fat is an insulator and does not generate or easily conduct electrical activity, current mapping techniques may classify epicardial fat incorrectly as myocardial scar. This may have important effects on the ability to diagnose and treat arrhythmias with epicardial ablation.

Recruitment information / eligibility

• Status: Terminated
• Enrollment: 8
• Est. completion date: January 2008
• Est. primary completion date: July 2006
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years to 75 Years

Eligibility

Inclusion Criteria:

• All adult patients undergoing elective cardiac surgery for coronary artery disease (with or without normal heart function) or valvular disease (with normal heart function) at the Hospital of the University of Pennsylvania under the direction of Y. Joseph Woo MD will be eligible.

Exclusion Criteria:

• Patients undergoing emergent surgery and patients with idiopathic cardiomyopathy, infiltrative cardiomyopathies and hypertrophic cardiomyopathies will be excluded.

Study Design

Observational Model: Cohort, Time Perspective: Prospective

Related Conditions & MeSH terms

• Arrhythmia
• Cardiomyopathies
• Infarction
• Myocardial Infarction
• Ventricular Dysfunction

Locations

Country	Name	City	State
United States	Hospital of the University of Pennsylvania	Philadelphia	Pennsylvania

Sponsors (2)

Lead Sponsor	Collaborator
University of Pennsylvania	Biosense Webster, Inc.

Country where clinical trial is conducted

United States, 

References & Publications (17)

Casas O, Bragós R, Riu PJ, Rosell J, Tresànchez M, Warren M, Rodriguez-Sinovas A, Carreño A, Cinca J. In vivo and in situ ischemic tissue characterization using electrical impedance spectroscopy. Ann N Y Acad Sci. 1999 Apr 20;873:51-8. — View Citation

Cinca J, Warren M, Carreño A, Tresànchez M, Armadans L, Gómez P, Soler-Soler J. Changes in myocardial electrical impedance induced by coronary artery occlusion in pigs with and without preconditioning: correlation with local ST-segment potential and ventricular arrhythmias. Circulation. 1997 Nov 4;96(9):3079-86. — View Citation

Cinca J, Warren M, Rodríguez-Sinovas A, Tresànchez M, Carreño A, Bragós R, Casas O, Domingo A, Soler-Soler J. Passive transmission of ischemic ST segment changes in low electrical resistance myocardial infarct scar in the pig. Cardiovasc Res. 1998 Oct;40(1):103-12. — View Citation

Dixit S, Narula N, Callans DJ, Marchlinski FE. Electroanatomic mapping of human heart: epicardial fat can mimic scar. J Cardiovasc Electrophysiol. 2003 Oct;14(10):1128. — View Citation

Ellenby MI, Small KW, Wells RM, Hoyt DJ, Lowe JE. On-line detection of reversible myocardial ischemic injury by measurement of myocardial electrical impedance. Ann Thorac Surg. 1987 Dec;44(6):587-97. — View Citation

Fallert MA, Mirotznik MS, Downing SW, Savage EB, Foster KR, Josephson ME, Bogen DK. Myocardial electrical impedance mapping of ischemic sheep hearts and healing aneurysms. Circulation. 1993 Jan;87(1):199-207. — View Citation

Kléber AG, Riegger CB, Janse MJ. Electrical uncoupling and increase of extracellular resistance after induction of ischemia in isolated, arterially perfused rabbit papillary muscle. Circ Res. 1987 Aug;61(2):271-9. — View Citation

Salazar Y, Bragos R, Casas O, Cinca J, Rosell J. Transmural versus nontransmural in situ electrical impedance spectrum for healthy, ischemic, and healed myocardium. IEEE Trans Biomed Eng. 2004 Aug;51(8):1421-7. — View Citation

Salazar Y, Cinca J, Rosell-Ferrer J. Effect of electrode locations and respiration in the characterization of myocardial tissue using a transcatheter impedance method. Physiol Meas. 2004 Oct;25(5):1095-103. — View Citation

Schwartzman D, Chang I, Michele JJ, Mirotznik MS, Foster KR. Electrical impedance properties of normal and chronically infarcted left ventricular myocardium. J Interv Card Electrophysiol. 1999 Oct;3(3):213-24. — View Citation

Soejima K, Stevenson WG, Sapp JL, Selwyn AP, Couper G, Epstein LM. Endocardial and epicardial radiofrequency ablation of ventricular tachycardia associated with dilated cardiomyopathy: the importance of low-voltage scars. J Am Coll Cardiol. 2004 May 19;43(10):1834-42. — View Citation

Sosa E, Scanavacca M, d'Avila A, Pilleggi F. A new technique to perform epicardial mapping in the electrophysiology laboratory. J Cardiovasc Electrophysiol. 1996 Jun;7(6):531-6. — View Citation

Warren M, Bragós R, Casas O, Rodríguez-Sinovas A, Rosell J, Anivarro I, Cinca J. Percutaneous electrocatheter technique for on-line detection of healed transmural myocardial infarction. Pacing Clin Electrophysiol. 2000 Aug;23(8):1283-7. — View Citation

Wolf T, Gepstein L, Dror U, Hayam G, Shofti R, Zaretzky A, Uretzky G, Oron U, Ben-Haim SA. Detailed endocardial mapping accurately predicts the transmural extent of myocardial infarction. J Am Coll Cardiol. 2001 May;37(6):1590-7. — View Citation

Wolf T, Gepstein L, Hayam G, Zaretzky A, Shofty R, Kirshenbaum D, Uretzky G, Oron U, Ben-Haim SA. Three-dimensional endocardial impedance mapping: a new approach for myocardial infarction assessment. Am J Physiol Heart Circ Physiol. 2001 Jan;280(1):H179-88. — View Citation

Zarowitz BJ, Pilla AM. Bioelectrical impedance in clinical practice. DICP. 1989 Jul-Aug;23(7-8):548-55. Review. — View Citation

Zhu F, Leonard EF, Levin NW. Body composition modeling in the calf using an equivalent circuit model of multi-frequency bioimpedance analysis. Physiol Meas. 2005 Apr;26(2):S133-43. Epub 2005 Mar 29. — View Citation

* Note: There are 17 references in all — Click here to view all references