MULTI-MODAL FLUORESCENCE IMAGING FOR CONTRACTING...

MULTI-MODAL FLUORESCENCE IMAGING OF

CONTRACTING INTACT HEARTS2nd BE-OPTICAL School: 2-5 May 2017, Torun

Vineesh Kappadan

Research Group Biomedical Physics

Max Planck Institute for Dynamics and Self-Organization

Project Supervisors

Prof. Ulrich Parlitz & Dr. Jan Christoph

Research Group Biomedical Physics

Max Planck Institute for Dynamics and Self-Organization

Introduction

Heart and Diseases

Sudden Cardiac Arrest (SCA) is a leading cause of death in Europe affecting0.35-0.7 million people every year.

About 25-30 % SCA victims have ventricular fibrillation (VF), a heartrhythm disorder [1].

1. European Resuscitation Council Guidelines for Resuscitation 2010, Rudolph W. Koster, Michael A Baubin

Heart Rhythm Disorders (Cardiac Arrhythmias)

Occurs due to malfunctioning of electrical activity of heart

Sinus Rhythm TachycardiaVentricular

Fibrillation[Numerical simulation by P. Bittihn,

Biomedical Physics Group, 2012]

ECG of heart

Cardiac Arrhythmias

Presence of spiral waves

Electrical Conduction System of Heart

Electrical impulses are responsible for mechanical contraction

Electrical Signal: SA Node AV node Bundle branches Purkinje Fibres

Atrial contraction Ventricular contraction

1. https://ceufast.com/course/ecg-interpretation

2. https://en.wikipedia.org/wiki/Electrical_conduction_system_of_the_heart

[1] [2]

Excitation-Contraction Coupling in Cardiomyocytes

Excitation

Contraction

Coupling

Coupling

t

Cardiomyocyte

contraction

[1] [2]

Goal : To study simultaneous electro-mechanical activity

of heart

1. PhD thesis, Jan Christoph, Biomedical Physics

2. Virtualheart.org F. Fenton

Experimental Methods and Results

Multiparametric Optical Mapping by Fluorescent Imaging

Left

Ventricle

10mm

Langendorff-

perfused

Rabbit Heart

2 x 250fps

Excitation

550nm

Excitation

650nm

Voltage-

sensitive

Calcium-

sensitive

10mm

2 channels:

interleaved

illumination +

exposure

scheme

dual-bandpass

filter

2ms

t

camera

Lee et al, 2011 [1]

fast-switching diode

drivers

Di-4-ANBDQPQRhod-2AM

250fps

500fps

1. P. Lee, P. Kohl; Heart Rhythm, 2011

2 I. Uzelac, J. Christoph, S. Luther, F. Fenton 2014

250fps

10mm

Dye 1Dye 2

[2]

Experimental Setup-Dual Imaging

Fast switching LED driver box

Intact heart in a

perfusion system

Sinus Rhythm with motion

Voltage Calcium

Motion Artifact

[B.Stender et al.]

Sinus Rhythm without motion[After adding Blebbistatin]

Voltage Calcium

Calcium signal and Activation Map

5 mm

Sinus rhythm

Calcium wave propagationActivation time

ms

5 mm5 mm

Voltage Calcium

Ventricular Tachycardia

Ventricular Fibrillation

voltage calcium

Cell culture studies-Rat heart

0.5 mm

Calcium waves

cell culture

stand

light sourcecamera

APPLICATIONS AND WORK PLAN

Electrical Restitution Curve

time (ms)

Voltage(mV)

APD: Action Potential DurationDI: Diastolic IntervalCL: Cycle Length

With electro mechanical un-

couplers

Figure: Electrical restitution curve during

ventricular fibrillation

Slope of the restitution curve is important in deciding the arrhythmic nature of heart

1. Sebastian Berg, Biomedical Physics

2. Marcus L. Koller, Mark L. Riccio, and Robert F. Gilmour, Am. J. Physiol. 275

[1]

[2]

Mechano Electric Feedback

Stability affected by

mechanics:

1. A. Panfilov et. al., Drift and break-up od spiral waves in reaction-diffusion-mechanics system, PNAS 2007

[1]

Shows how electrical activity of heart is affected by mechanics: Stretch activated

Channel.

Shortening of APD, reduction in AP amplitude and spiral wave break up closely

follows stretch in several studies.

THANK YOU FOR YOUR ATTENTION!