IH-5 Core System for Isolated Rat, Guinea Pig and Rabbit Heart

The IH-5 Langendorff Core System is the starting point for all isolated perfused heart experiments for medium-sized rodents (rat, guinea pig and rabbit) in the Langendorff retrograde perfusion mode.

The Core System contains all the primary equipment to accomplish the basic Langendorff experiment. A fully functional IH-5 Langendorff System requires the addition of core system options and other components including:

• Method of constant pressure perfusion
• Species-specific additions (cannulae, buffer reservoirs and balloons)
• Heart chamber
• Desired data acquisition system

The modular nature of the IH-5 allows the system to evolve along with your research. Our Langendorff System can easily be upgraded to a full working heart system according to Neely, accommodating aortic flows up to 500 ml/min or to a biventricular working heart system where both sides of the heart eject fluid as in vivo. Other options add additional measurement and application capabilities, such as multi-channel ECG and MAP cardiac electrophysiology applications.

Advanced System Design
Features & Benefits
Applications
Measured Signals & Calculated Parameters
Included items
Additional Requirements for a Functional Langendorff Unit
Additional Components
Specialized Applications & Upgrades

Advanced System Design

The IH-5 utilizes the architecture of the ground-breaking IH-SR to set the standard for isolated heart perfusion in rabbits, adult guinea pigs, or adult rats. Engineered for the increased flow produced by these species (up to 500 mL/min), the IH-5 offers ultimate perfusion stability and real physiological conditions for longer, more relevant recordings with fewer artifacts. This compact platform has been optimized to create in situ-like perfusion features, delivering a considerably higher sensitivity for various experimental manipulation while maintaining the advantages of an ex vivo preparation. Like the IH-SR, the IH-5 System does not utilize high water columns but creates a constant pressure perfusion setup using a pressure feedback pump controller, resulting in a compact system fully within your reach.

If the aortic block with the Starling resistor (working heart ready) is used for Langendorff applications, the aortic perfusion pressure is defined by the setting of the membrane pressure in the Starling resistor. By setting a defined threshold pressure at the Starling resistor, the system works under constant pressure. By increasing the threshold pressure to a super-maximal pressure (300 mmHg),the system works under constant flow. The complete aortic block is mounted on acompact acrylic stand.

The IH-5 utilizes convenient switches that allow you to easily change from constant flow to constant pressure perfusion, Langendorff to working heart,and between two different perfusion solutions.

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Features & Benefits

• Compact design, no high water columns—optimized individually for rabbit, rat or guinea pig
• Easily upgraded to a working (ejecting) heart system or biventricular working heart system—special flow resistance and compliance chamber closely mimics the in vivo afterload
• Constant pressure or constant flow perfusion in one unit—easily switch between the two modes
• Suitable for hearts from hypertensive animals—perfusion pressures up to 300 mmHg are possible
• Fast and easy changes of perfusion pressure (within seconds)
• Continuous measurement of heart mechanics (contractility), bioelectrical signals (ECG, MAP) and perfusate characteristics (pCO₂, pO₂, pH) 
• Unique integrated small volume aortic block with built-in bubble trap and Windkessel chamber
• Natural physiological environment for isolated heart with large heated chamber
• Continuous measurement of heart mechanics (contractility), bioelectrical signals (ECG, MAP) and perfusate characteristics (pCO₂, pO₂,pH)
• Unique cannula design, available in different sizes, all metal, no fragile glass cannulae
• Cannula resistance is optimized according to Hagen-Poiseuilles Physical Law
• Proprietary mini holders allow easy and stress-free access to hold electrodes and catheters in position
• Drug injection pathway built directly into aortic perfusate stream

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Applications

• Study of myogene autoregulation with the addition of the Flow Measurement Option 
• Testing with inotropic substances
• Testing of lusitrope substances
• Testing of vasoactive substances
• Cardiac rhythm tests
• Ischemia/hypoxia studies
• Refractory period studies
• Ischemia/reperfusion injury studies
• Cardioplegia studies
• Cardiac preconditioning
• Cardiovascular screening performance
• Electrophysiology studies
• Phenotyping of transgenic animals 
• Drug compound screening
• Toxicology studies
• Biochemical tests

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Measured Signals and Calculated Parameters

 The following signals are recorded as raw data in retrograde Langendorff perfusion:

• Isovolumetric left ventricular pressure (LVP) with balloon
• Aortic (perfusion) pressure
• Coronary flow*

The following parameters are calculated from the raw data (using the ISOHEART data acquisition software):

• dLVP/dt, dLVP/dt Max, dLVP/dt Min, contractility index
• Systolic and diastolic LVP
• Heart rate
• Mean perfusion pressure
• Mean perfusion flow*
• Coronary resistance*

* This parameter is based on indirect flow measurement with the SCP controller or direct ultrasonic flow measurement with the TTFM-2 flowmeter and suitable flow probe.

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Included Items

The IH-5 Base Unit (73-4996) includes:

Plexiglas stand, aortic block with aorta link unit with Windkessel, heat exchanger, jacketed heart chamber, needle valve for adjusting gas flow, holder for transducer for perfusion pressure, tubings. Aortic cannula and buffer reservoir must be ordered separately.

For a functional unit, species-specific core options and pressure controller systems must be added.

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Additional Requirements for a Functional Langendorff Unit

An IH-SR Langendorff basic functional unit requires the addition of core options to the selected core system (either 73-4397 or 73-4398). Specifically, the core system requires the addition of a selection a perfusion pressure controllers (SCP or Starling),a species-specific options, and an application-appropriate heart chamber.

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Additional Components

Please contact our technical team for help.

ISOHEART Data Acquisition Software

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Specialized Applications & Upgrades

IH-5 Core System Options  

Options for required additions to the IH-5 Core System for species-specific Langendorff Only or Langendorff Working Heart-Ready configurations.

Working Heart Upgrade

The IH-5 Langendorff Core System is prepared for upgrade to a working ejecting heart  according to Neely later on. To upgrade an IH-5 Lagendorff Core System to a IH-5 Working Heart System, add the Working Heart Upgrade and one of the species-specific additions. Researchers who know they will be upgrading to working ejecting heart in the future may start with a Langendorff Working Heart-Ready configuration. If you intend to measure coronary flow, you need a TTFM-2 flowmeter and a species suitable flowmeter. (SCP cannot be used for Working Heart.) 

A Langendorff Only configuration can easily be modified to a Langendorff Working Heart-Ready configuration. Please contact our technical team for help!

Coronary Flow Measurement 

Coronary flow measurement can be accomplished in an IH-SR unit using two methods: 

• Indirect measurement by controlling the pump speed of a peristaltic pump (SCP controller)
• Direct measurement with Ultrasound Transit Time Technique (TTFM-2 module)

Coronary Effluent Collection

Pulmonary artery cannulae, preparation dish and effluent funnel for collection of effluent from the coronaries for metabolic studies, further analysis, or for continuous pO₂, pH, or pCO₂, measurements.

Perfusate Oxygenation of Foaming Media

For oxygenation of buffer solution supplemented with albumin, fatty acids, washed erythrocytes, or other foaming additives. 

Perfusate Filtration

For filtration of recirculated perfusate.

Temperature Measurement

Measure perfusate temperature in any isolated perfused organ system. Since the system is well thermostated, temperature measurement is only necessary when specific temperature studies with special temperature protocols, e.g. cooling or transplantation studies, are being performed.

Perfusion Solution Monitoring

Permits precise continuous or intermittent measurement in liquid media or perfusate of three key parameters: pO₂,, pH and pCO₂,.

Drug Addition

For accurate drug addition using a syringe pump. Additional option for flow controlled drug addition, where flow is measured (or calculated) and a drug must be added in a certain ratio. 

Pacing Option

For addition of pacing to functional IH-SR or IH-5 Langendorff and Working HeartSystems. For small rodent hearts (mouse, rat and guinea pig). 

Single-Lead ECG and MAP Measurement

For single-lead ECG and MAP on functional IH-SR or IH-5 systems, one ECG lead can be measured in combination with MAP electrodes.

Multi-Lead ECG and MAP Measurement

For multi-lead ECG and MAP measurements on functional IH-5 Langendorff or working heart systems, up to 12 ECG leads are combined with up to 8 MAP electrodes for measurement on rat, guinea pig or rabbit hearts.

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