Year of Publication

2014

Degree Name

Master of Science in Biomedical Engineering

Document Type

Master's Thesis

College

Engineering

Department

Biomedical Engineering

First Advisor

Dr. Abhijit Patwardhan

Abstract

Individuals with cardiomyopathy are at higher risk to die from sudden cardiac arrest than those with non-failing (NF) hearts. This study examined the differences in electrical properties of failing and NF human hearts in terms of cardiac memory through explicit control of diastolic intervals in a sinusoidal fashion, restitution of action potential duration (APD) through standard and dynamic pacing protocols, maximum rate of depolarization and APD alternans. Recordings of transmembrane potentials were made in tissues extracted from patients with heart failure and one donor NF heart. Computational simulations were performed using the O’Hara Rudy model for generating surrogates of control data. Significant differences were seen between left ventricular (LV) tissue and NF LV tissue in tilt, and measures of memory in terms of area and thickness during the sinusoidal 400ms protocol. Minimum delay was also significantly higher in the failing LV during the sinusoidal 150ms protocol. Failing tissues showed a higher restitution slope and prolonged AP which is consistent with previous studies and is hypothesized to contribute to the increased susceptibility to unstable alternans. This study further explored how disease alters the electrical functioning of the heart and why these patients are at a higher risk of ventricular arrhythmia.

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