Physician Detail

Mark Marieb, MD, FHRS

System Director, Electrophysiology Labs, Hartford HealthCare Heart & Vascular Institute

5.0 /5
114 surveys


Hartford HealthCare Medical Group


Cardiac Electrophysiology, Board Certified < Accepting new patients for this specialty
Cardiovascular Medicine, Board Certified < Not accepting new patients for this specialty
Internal Medicine, Board Certified < Not accepting new patients for this specialty

Areas of Interest

Antiarrhythmic Medications, Atrial Fibrillation, Atrial Fibrillation Ablation, Atrial Flutter, Brugada Syndrome, Cardiac Arrest, Cardiac Arrhythmias, Cardiac Device Infections, Cardiac Pacing, Cardiac Resynchronization Therapy (CRT), Cardiomyopathy, Catheter Ablation, Congestive Heart Failure (CHF), Cryoablation, Hypertrophic Cardiomyopathy, Implantable Cardiac Defibrillators (ICDs), Implantable Loop Recorders, Lead Extraction, Long QT Syndromes, Pacemakers, Palpitations, Postural Orthostatic Tachycardia Syndrome (POTS), Premature Ventricular Complexes (PVCs), Right Ventricular Cardiomyopathy, Sudden Cardiac Death, Supraventricular Tachycardia (SVT), Syncope, Tilt Table Testing, Ventricular Fibrillation (VF), Ventricular Tachycardia (VT)

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Marieb, Mark, MD, FHRS

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Office Locations

  • Hartford HealthCare Heart & Vascular Institute

    Cardiac Electrophysiology II

    863 North Main Street Extension
    Suite 101
    Wallingford, CT 06492
    Get Directions >>

    Phone: 203.678.1050

  • Hartford HealthCare Heart & Vascular Institute at Hartford Hospital

    85 Jefferson Street
    Suite 701
    Hartford, CT 06106
    Get Directions >>

    Phone: 860.972.1506
    Fax: 860.545.3999

  • Hartford HealthCare Heart & Vascular Institute at Hartford Hospital

    Cardiac Electrophysiology

    85 Jefferson Street
    Suite 726
    Hartford, CT 06106
    Get Directions >>

    Phone: 860.972.1506
    Fax: 860.545.3999

  • Hartford HealthCare Heart & Vascular Institute

    Cardiac Electrophysiology

    455 Chase Parkway
    Waterbury, CT 06708
    Get Directions >>

    Phone: 203.678.1050
    Fax: 203.648.4779

  • Hartford HealthCare Heart & Vascular Institute at MidState Medical Center

    Vascular Surgery

    455 Lewis Avenue
    Suite 203
    Meriden, CT 06451
    Get Directions >>

    Phone: 203.634.1900
    Fax: 203.237.8441

  • Hartford HealthCare Heart & Vascular Institute

    251 West Main Street
    Suite 6
    Branford, CT 06405
    Get Directions >>

    Phone: 203.678.1050
    Fax: 203.648.4779

  • Hartford HealthCare Heart & Vascular Institute

    Cardiac Electrophysiology

    130 Division Street
    1st Floor
    Derby, CT 06418
    Get Directions >>

    Phone: 203.732.7455


Over the years, there have been advancements made in the evaluation and treatment of heart rhythm disturbances, otherwise known as cardiac arrhythmia's.

Physicians who specialize in the evaluation and treatment of these electrical disturbances of the heart are known as cardiac electrophysiologists.

Dr. Mark Marieb, System Director of Electrophysiology Labs for the Hartford HealthCare Heart & Vascular Institute.

Q. Can you start out by giving us a brief overview of the types of heart rhythm problems you deal with?

A. These electrical disturbances of cardiac rhythm or arrhythmia's are numerous. We evaluate and treat extra heart beats known as premature beats. We deal with slow heart rhythms also known as bradycardia. Fast heart rhythms are also called tachycardia. They can come from the upper chambers or atria and this is called supra-ventricular tachycardia. An irregular and usually rapid rhythm coming from the atria known as atrial fibrillation is extremely important as it is very common, can cause debilitating symptoms, and is an important cause of stroke. Finally, rapid rhythms coming from the lower chambers of the heart known as ventricular tachycardia and fibrillation can be very serious and can lead to cardiac arrest and sudden cardiac death.

Q. Tell us about pacemakers and defibrillators. What are these devices used for? Are there recent advances in these devices?

A. Yes, definitely. Pacemakers were first introduced in the late 1950’s and defibrillators in the early 1980’s. Since then, they have become smaller, last longer, and have more features. They are now able to be wirelessly monitored remotely from the patient’s home, checking things such as the battery, leads, and they can also detect arrhythmia's. Newer pacemakers and defibrillators are MRI conditional, meaning patients with these devices can now safely undergo MRI scans.

In terms of pacemakers, we are now also using them not only for slow beats, but to synchronize the beating of both sides of the heart by placing a lead to the left side of the heart and pacing the right and left ventricles simultaneously. This re-synchronization can strengthen the heart in certain patients. We are now also using a technique known as HIS bundle pacing, where a pacing lead is placed to capture the normal electrical or bundle system of the heart. It has been shown that this can preserve normal pumping function of the heart. Finally, we are now implanting lead-less pacemakers, known as a Micra device; this tiny pacemaker looks like a small bullet and is implanted through a vein directly into the heart, and there are no leads or surgery needed.

In terms of defibrillators, they are now implanted in a similar fashion to pacemakers. However, as opposed to pacemakers which are mostly used to treat slow rhythms, these devices do the opposite; they are used to treat dangerous fast rhythms originating in the lower pumping chambers or ventricles of the heart. These arrhythmia's known as ventricular tachycardia and ventricular fibrillation can be very dangerous and can lead to sudden death and cardiac arrest. The defibrillator automatically detects these fast rhythms and delivers a shock to the heart reversing the dangerous rhythm disturbance. These devices also contain a pacemaker as patients often need both functions. One other newer device known as a subcutaneous defibrillator is implanted only under the skin. There are no wires or leads placed within the heart.

Q. Tell us about catheter ablation of cardiac arrhythmia's.

A. I would start by saying that although we have a variety of medications to treat arrhythmia's and use them on a daily basis, they are often ineffective and can have side effects. Therefore, ablation has become very popular. This procedure can effectively treat the arrhythmia's we have been discussing, including supra-ventricular tachycardia, atrial fibrillation, and ventricular tachycardia. The technique uses catheters that have electrodes on them placed through veins into the heart. Next, mapping is performed, which utilizes specialized computer systems and the electrode catheters to localize the area of heart tissue causing the arrhythmia. Finally, a special catheter is moved to the area of the heart and radio-frequency energy is delivered which heats and cauterizes the abnormal heart tissue destroying it. In some instances, the tissue is destroyed by freezing or cryoablation as opposed to heating. Typically patients are discharged on the following day.

Q. What do you feel sets the Hartford HealthCare Electrophysiology service apart?

A. Several factors. We have expanded to a third state-of-the-art electrophysiology lab at Hartford Hospital, and are planning a state of the art facility at MidState Medical Center, where we already implant pacemakers and defibrillators. We have a newly renovated pre and post procedure area just around the corner from the labs, leading to excellent continuity of care and patient comfort. All patients are sedated and kept comfortable by our excellent anesthesia staff. To accommodate our increasing patient volume we have recently expanded to a total of 6 other very well trained and talented electrophysiology physicians in our group. Our nurses and technicians are specialized in the care of patients with arrhythmia's and in running our complex equipment. Finally, our Hartford HealthCare Heart and Vascular Institute Administration have been extremely supportive in all respects. For example, we have four different types of mapping systems to guide us in our ablation procedures.

If you would like more information about the Heart and Vascular Institute call 1-833-444-0014.



Medical School

  • Boston University School of Medicine MD


  • Yale New Haven Hospital, Internal Medicine


  • Yale New Haven Hospital


  • University of Virginia Health Sciences Center, Cardiology
  • Yale University School of Medicine, Cardiac Electrophysiology


  • Boston University BA

Faculty Appointments

Yale University School of Medicine, Associate Professor
Yale University School of Medicine, Associate Clinical Professor

Professional Organizations

Heart Rhythm Society, Fellow


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Insurance Accepted*

Aetna, Anthem, BCBS Medicare, CarePartners of Connecticut, Cigna Healthcare, Colonial Cooperative Care, Community Health Network of Connecticut, Inc., Connecticare, Connecticare Commercial, Connecticare Medicare, Corvel, Coventry, Essence Healthcare, Evercare, First Health Group Corp., Focus, Harvard Pilgrim, Health Connecticut, Health Direct, Health New England, Healthy Connecticut, HMC/ Northeast Healthcare, Medspan Commercial, Medspan Medicare, Multiplan, Northeast Health Direct, One Health Plan/ Great-West Healthcare, Oxford Health Plans, Prime Health Services, Private Health Care Systems, Inc., Senior Whole Health, United Healthcare, WellCare of Connecticut, Inc.

*This information is subject to change at any time. Please check with your insurance provider before scheduling your appointment or receiving services to confirm they are a participating member of the Hartford HealthCare network.

Hartford HealthCare

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