The Isolated Langendorf Heart

Overview:

The isolated perfused mammalian heart preparation was established by the German physiologist Oskar Langendorff in 1895 as a tool for studying heart biology. Since then it has been one of the most widely adopted models of mammalian cardiophysiology for basic and pre-clinical drug research.

The basic design of the Langendorff technique involves retrograde perfusion of the ascending aorta, which forces the aortic valve closed and shunts the blood flow via the coronary ostia into to the coronary arteries. Once coronary flow is re-established, the perfused heart is amenable to many different types of analyses over the course of several hours, including: contractile function in response to drugs; heart rate; coronary vascular tone; cardiac metabolism; morphology; QT interval length.

The Langendorff technique is well suited to many different models of cardiac disease and dysfunction. Some of the more widely used models include:

  • Ischemia and hypoxia
  • Focal ischemia-reperfusion
  • Ischemic preconditioning
  • Antiarrhythmic drug response (e.g., induced by ischemia)
  • Toxicology (e.g., screening for arrhythmic effects in novel test compounds)
  • Donor-heart transplantation storage techniques
  • Stem-cell therapy for myocardial diseases

Method:

To ensure viability of the Langendorff system, care must be taken to ensure that the heart is well perfused with oxygenated 37° C perfusate.

All media has to be aerated and if a system other than whole blood is used, the media must be buffered, either with the traditional carbonate buffers such as Krebs-Henseleit, Locke’s or Tyrode’s or with variations of these formulas using HEPES or MES buffers. A substrate such as glucose is necessary and, dependent on experimental designs, other energy substrates can be utilized, such as pyruvate, lactate, fatty acids, and amino acids. The ionic components of the media will vary with the species; potassium and calcium are the most variable and critical of the ions. Temperature is also an important factor, can be manipulated depending on the experimental model being used: e.g., 4.5 °C for cryogenic studies; 37.5 °C for physiological studies and > 37.5 °C for heat shock studies.

For adequate perfusion of the heart a suitably sized cannula is required for insertion into the aorta. The technique originally required elevated reservoirs to provide a constant, gravity supplied pressure but has evolved to include both constant pressure and constant flow models in both recirculating (recycling of perfusate) and non-recirculating modes.

In the Langendorff preparation, blood or more commonly crystalloid perfusates, are delivered into the heart through a cannula inserted in the ascending aorta, either at constant pressure or constant flow. Retrograde (reverse) flow in the aorta closes the aortic valve and as a result, the entire perfusate enters the coronary arteries via the ostia at the aortic root. After passing through the coronary circulation the perfusate drains into the right atrium via the coronary sinus.

Once the heart is cannulated and successfully beating, there are several parameters that can be measured and recorded from the Langendorff preparation including:

  • Mechanical parameters (contractile force, volume, ventricular diameter)
  • Coronary perfusate flow
  • Bioelectrical parameters (ECG, monophasic injury potentials)
  • Cardiac cycle rhythm

ADInstruments offer a range of complete systems as well as instruments, transducers and accessories for recording and analyzing numerous parameters of interest:

Perfusion Pressure/Coronary Flow Rate

Langendorff studies are normally carried out in either ‘constant flow’ or ‘constant pressure’ modes. To maintain these different modes of operation, ADInstruments offer the STH Pump Controller which uses a simple feedback system to allow the switching from one to the other with the push of a button. This eliminates the need for elevated reservoirs.

  • Constant Flow Mode - perfusate is pushed through the heart at a constant rate and the perfusion pressure is measured to give a representation of the coronary resistance
  • Constant Pressure Mode - the desired pressure is maintained and the resulting fluctuations in the rate of coronary flow are measured

Left Ventricular Pressure

In the Langendorff system, because the cardiovascular system is no longer a closed loop, the ventricles do not fill with the perfusate and therefore do not perform pressure-volume work. Left ventricular pressure can however still be measured with the use of a fluid-filled balloon-tipped catheter connected to a pressure transducer. Once inserted, the ventricle can contract isovolumetrically against the balloon.

The balloon is placed into the left ventricle and inflated until a resting pressure of approximately 3-10 mmHg is achieved. Balloon-catheters can be supplied by ADInstruments for hearts of rats or larger animals, however they can also be made quite easily using commonplace items (e.g., food wrap and condom tips). For more information, see the Intraventricular Pressure Measurement in a Langendorff Preparation technique note.

Note: Mikro-Tip Catheters can be used for the pressure measurements, but these would need to be placed inside a fluid filled balloon in order to register the pressure changes.

Contractile Force

A simple method that can be used to measure the contractile force of the heart, is to connect the apex to a Force Transducer and Bridge Amp via a pulley system.  Tension is applied to the thread attaching the heart to the transducer and changes in contractile force can be monitored.

Electrical Activity

Cardiac electrical activity can be measured using a Bio Amp and extracellular electrodes. Typically, one electrode is connected to the apex of the heart and one to the atria. The ground electrode can be connected to the aortic cannula. Alternatively, with a suitable electrode, monophasic action potentials can be measured form single cardiac cells.

Temperature

For models involving a normal physiological temperature range, it is very important that a stable temperature of 37.5 °C is maintained. The temperature can be measured with a T-Type Temperature Probe and T-Type Pod. The probe can be inserted into the perfusate flow or into the heart.

Pacing

The heart may be paced using an external Stimulator with a stimulus that exceeds the natural cardiac pacemaker rate, after the sinoatrial node is crushed or the right atrium excised. Pacing voltage is determined as a set percentage (normally 110-150%) above the voltage required to pace the heart and usually should not have to exceed 3-5V with a duration of 0.1 to 1 msec. The PowerLab data acquisition system has an analog output that can be used to control the frequency of the stimulator pulses.

pH & O2 Concentration

It is important to maintain the correct pH and a suitable oxygen concentration of the perfusate solution. These can be measured if required using a suitable pH Electrode and pH Amp and a suitable Oxygen Electrode (dip-type or flow-through). To measure the oxygen consumption, O2 electrodes can be placed in the inflow and in the effluent and the difference in concentration calculated.

Additional hardware information

  • Radnoti Tissue/Organ Bath Principles Technique Note: Information about various techniques and principles related to isolated tissue/organ research applications. Download
  • Glassware Maintenance and Post-Experimental Cleaning Technique Note: Information about maintaining and cleaning glassware and other components manufactured by Radnoti Technology Inc. Download

Software:

The LabChart Advantage:

(May require additonal Modules and Extensions)

  • Units Conversion for easy calibration into appropriate units such as mmHg, °C, pH, mN
  • Comments can be added in real time, viewed or moved at a later stage
  • Online calculations (e.g. heart rate, dP/dt, mean pressure) can be performed using the Arithmetic and Cyclic Measurements features of LabChart software
  • Fast data extraction, analysis and export (e.g. csv. or txt.) to other applications using Timed Add to Data Pad and Multiple Add to Data Pad
  • LabChart software can be used to control stimulation frequency and timing of pulse trains using an external stimulator
  • The Blood Pressure Module allows for the calculation of arterial and ventricular parameters online or offline.
  • The Dose Response Module allows for the calculation of dose response type data from LabChart recordings, automatically or manually, offline or online.
  • The Peak Analysis Module provides automatic detection and analysis of multiple, but not overlapping, signal waveforms from recordings, online or offline. Ideal for analyzing cardiac action potentials.

LabChart

LabChart software (for Windows and Macintosh) together with a PowerLab data acquisition system offers up to 32 channels of real-time data acquisition, data integrity, easy selection of hardware settings, powerful online and offline analysis, procedure automation, seamless extraction of experimental data and flexible display options. Additional acquisition and analysis functionality is provided with the use of specialized LabChart Extensions and LabChart Modules. LabChart Modules are available as part of LabChart Pro and LabChart Extensions are free for download from the website for existing LabChart users.

Blood Pressure Module

The Blood Pressure Module (Windows) automatically detects, analyzes and reports a number of cardiovascular parameters.

The Analysis View displays pressure cycles as beat-by-beat or as the average of a specified number of cycles. These measurements are logged in the Table View for easy exporting. The Settings dialog allows the user to select ventricular pressure for analysis and the Classifier View allows for easy selection of pressure waveforms for further analyses. Pressure cycles that are contaminated by artifacts, have abnormal cycle heights or cycle durations (frequency) can be excluded from analysis using the classifier

Features and benefits include:

  • Suitable for analysis of pressure signals from humans as well as large and small animals
  • Pressure signals can be analyzed in real time during acquisition
  • The BP Classifier makes detection and exclusion of atypical waveforms easy
  • Parameters can be displayed as continuous data on separate channels
  • Values are logged to the Table View
  • Averages any number of pressure waveforms

Calculated ventricular parameters include:

  • EDP
  • Max,min, mean dP/dt
  • Min, max, mean, max-min pressure
  • Systolic and diastolic duration
  • Cycle duration
  • Heart rate
  • Contractility index
  • Tau
  • Pressure time index

Dose Response Module

The Dose Response Module (Windows) provides easy analysis of dose response experiments to a variety of measured variables, such as: muscle contraction, enzyme activity, heart rate, blood pressure, and membrane potential.

  • Muscle contraction
  • Enzyme activity
  • Hormone secretion
  • Heart rate
  • Blood pressure
  • Membrane potential

This module provides:

  • Real-time or offline analysis
  • Automated or manual modes of analysis
  • Fast analysis of raw data to dose response parameters
    • Fast comment detection and conversion to dose response markers
    • Easy options for calculating different response parameters
    • Instant single or multiple dose response curves (Hill-curves) generation
    • Instant calculation of EC50 and Hill slopes  
  • Export options to other software applications for further analysis

Peak Analysis Module

The Peak Analysis Module (Windows) provides automatic detection and analysis of multiple, but not overlapping, signal peaks in acquired waveforms. This is ideal for investigating the morphology of pressure and volume waveforms.

It provides: 

  • Real-time or offline analysis
  • Fast parameter extraction and analysis from single or multiple peaks
  • Automatic peak detection of an entire channel or a selection within a channel
  • Detection of positive or negative peaks
  • Analysis presets suitable for evoked responses and cardiac action potentials
  • Instant tabulation of extracted parameters that can be exported to other applications

GLP and 21 CFR Part 11

For those researchers working within a laboratory requiring GLP and 21 CFR Part 11 compliance the GLP Client and GLP Server are available for use with LabChart (Windows only) and PowerLab data acquisition systems. For more information, visit the Good Laboratory Practice application page or contact your nearest ADInstruments representative.

Hardware:

PowerLab Data Acquisition Systems

The PowerLab is a high-performance data acquisition unit capable of recording at speeds of up to 400,000 samples per second continuously to disk (aggregate). PowerLab units are compatible with instruments, signal conditioners and transducers supplied by ADInstruments, as well as many other third-party companies. In addition to standard single-ended BNC inputs, 4 differential Pod ports are also available for direct connection of Pod signal conditioners and appropriate transducers. Research PowerLab units include:

Research Systems

Compact “All-in-One” Langendorff Isolated Heart Systems

Modular Langendorff Isolated Heart Systems

Signal Conditioners

Pressure and Contractile Force

Temperature

  • ML312 T-type Pod: Suitable for general temperature measurements in the range 0°C to 50°C using standard T-type thermocouples with a 2-pin T-type plug.

pH

  • ML165 pH Amp: Suitable for pH, temperature and ion-selective measurements in solution. Supplied with a RTD Temperature Probe.

Biopotentials

  • FE136 Animal Bio Amp: An isolated, high performance and software-controlled differential amplifier.
  • FE132 Bio Amp: A single channel, differential amplifier that is suitable for recording a range of biopotentials including Lead I, Lead II or Lead III ECG.
  • FE135 Dual Bio Amp: A dual channel, differential amplifier that is suitable for recording 2 independent biopotentials that share a common ground.
  • ML138 Octal Bio Amp: A differential amplifier that consists of eight electrically isolated differential input AC amplifiers.
  • GT201/F 16 Channel Bio Amp: A fully isolated, 16 channel stand-alone biological amplifier that consists of 8 modules, with each module containing two channel amplifiers that share a common ground input.

Instruments

Isolated Heart- Langendorf

Transit-Time Ultrasound Blood/Fluid Flowmeters

Stimulators

(Note: Pacing electrodes not available)

Temperature

Transducers and Accessories

Pressure (fluid-filled) Transducers

Mikro-Tip Pressure Catheters (Small animals)

Contractile Force

(Note: Pulley system not available)

Thermocouple Temperature Probes

pH Sensors

  • MLA060 Redox Electrode: Suitable for operation from 0 to 60°C. The double junction is easily cleaned, making it suitable for biological samples.
  • MLA042 pH Electrode: Operates from 0 to 60°C and for a pH of 0 to 14. The double junction is easily cleaned and therefore the electrode is suitable for biological samples, in particular those of low ionic strength.
  • MI-405 Miniature Glass Electrode for pH: For use in general purpose analyses and in microchemical studies. Requires the use of an external reference electrode such as the MI-409 Miniature Reference Electrode.
  • MI-409 Miniature Reference Electrode: For use with any pH or ion selective electrodes and used with the ML165 pH Amp. Features an internal Ag-AgCl internal reference electrode with KCl filling solution.

Oxygen Electrodes

  • MLT1120 Micro-Oxygen Electrode: Features a 3 mm tip which is best suited for measuring oxygen concentration in small volume samples and is designed for applications that require a fast response time with minimal oxygen consumption. This electrode is supplied with a MLT1121 Membrane Housing Kit. Note: Requires MLT1122 Analog Adapter (supplied separately) to connect the electrode directly to the PowerLab.
  • MLT1123 Micro-oxygen Electrode (Flow-Through): Features low oxygen consumption, fast response (less than 20s) and requires less than a drop of solution. Ideal for monitoring oxygen in a continuous flow such as water, blood, urine, physiological fluids. "T" fitting size is 1/16" (1.5mm). Supplied with an MLT1124 Membrane Housing Kit consisting of six T-membranes and a bottle of electrolyte solution. Note: Requires MLT1122 Analog Adapter (supplied separately) to connect the electrode directly to the PowerLab.
  • MLT1115 Galvanic Oxygen Electrode: Connects directly to the BNC input of any PowerLab.

Biopotentials

Langendorff Accessories

Third-Party Electrodes

Third-party electrodes and meters may be connected to a PowerLab data acquisition system, provided that they have a ± 10 V analog output range. Such electrodes may include:

  • Ion Selective Electrodes and Microelectrodes
  • pH Field Effect Transistor (pHFET) Electrodes
  • Ion Selective Field Effect Transistor (ISFET) Electrodes
  • Fiber Optic Probes

Epoxyeicosatrienoic acid prevents postischemic electrocardiogram abnormalities in an isolated heart model
S.N. Batchu, E. Law, D.R. Brocks, J.R. Falck, J.M. Seubert, Journal of Molecular and Cellular Cardiology, 67–74, 2009

Excessive thyroxine enhances susceptibility to apoptosis and decreases contractility of cardiomyocytes
Yun-Ying Wang, Bo Jiao, Wang-Gang Guo, Hong-Lei Che, Zhi-Bin Yu, Molecular and Cellular Endocrinology, 67-75, 2010

Citations Database


The material on this page is provided in good faith and believed accurate at the time of writing. No responsibility will be taken, or liability accepted, for damages arising from the use of information herein. Readers are urged to check with respective manufacturers the accuracy of all product related information.

Research Solutions
Education Solutions
Pharma Solutions
Citations Database
Top Solutions:
Site Feedback
X

Site Feedback

http://www.adinstruments.com/solutions/research/Langendorff-Heart/

* Denotes a required field
* Name
* E-Mail
* Operating System
* Web Browser

* Comments