What we Offer at Heart Rhythm Specialists of Southern California

Heart Rhythm Specialists of Southern California offers a comprehensive approach to managing patients with cardiac arrhythmias.  In addition to providing both inpatient and outpatient consultation, we have several active clinics following pacemaker and defibrillator patients.  Our physicians perform an entire range of inpatient and outpatient diagnostic and therapeutic procedures.

Consultation and Second Opinion

Our board-certified Cardiac Electrophysiologists are available for an initial consultation and for a second opinion consultation regarding any aspect of arrhythmias management.  We understand that many patients have invested a significant amount of their time, energy, and even money in setting up and coming in for a consultation.  We further realize that for most patients, the purpose of their consultation is to "get some answers."  Therefore, our philosophy on office consultation is very simple; we "tell it as it is."  We will analyze your complex medical history and distill it down to simple and understandable terms relevant to your arrhythmia.  We are committed to giving you an honest and straight-forward opinion about your condition and lay out all reasonable treatment options. 

A question that frequently comes up is whether a patient needs a "referral" to see a specialist.  The general rule is that consultations do require the referral from your primary physician, but patients may also initiate the request for a second opinion consultation.  Please keep in mind that for certain insurances, especially an HMO, a "referral" is mandatory for any type of specialist visit.  If unsure, please check with your insurance before making the appointment.


In order for your visit to be most productive and worthwhile, having your medical records available at the time of your first visit is critically important.  Please refer to the section on "preparing for your first visit."

Pacemaker Clinic

pacemaker is a complicated electronic medical device that requires close follow-up.  For optimal performance of the device, fine-tuning on a long-term and on-going basis is mandatory.  In general, a pacemaker should be checked in the office at least once or twice a year, and more frequently immediately after initial implantation or toward the end of its battery life. 

At each pacemaker clinic visit, the pacemaker is "interrogated" by the programmer (see picture below).   The programmer uses a "wand" that communicates with your pacemaker over radiofrequency signals.  This can be done without you undressing, as long as the wand is within a few inches of the pacemaker.  Newer generations of defibrillator (see next section) but not pacemakers can be "interrogated" using wireless technology, without the wand.

With each interrogation, the information from the pacemaker is downloaded into the programmer for your physician to review.  The status of the pacemaker battery is evaluated, as well as the integrity of the electrodes (the "wires").  Pacing and sensing thresholds, or the ability for the pacemaker to "capture" the heart and to "see" the underlying heartbeats, are carefully evaluated at each follow-up.  The output of the pacemaker and the "sensing" level are then "adjusted" in order to provide the best combination of patient safety and battery longevity.

One needs to keep in mind that these "thresholds" for a given pacemaker or a given patient can be dynamic and may change over time, thus the need for continued long-term follow-up.  For some patients whose pacing threshold had increased above and beyond the setting of the pacemaker may experience symptoms due to pacemaker pacing ineffectively, or not at all.  Many patients who never been enrolled in a pacemaker clinic may still have their pacemakers programmed at the "out-of-the-box" setting (the original manufacturer default setting), which can lead to premature battery depletion and additional unnecessary surgery.

Modern pacemakers also have a great deal of diagnostic features which can help your physician detect potential pacemaker or arrhythmia problems.  Examples of problems that can be identified during such visits include malfunction of the electrodes, premature depletion of the batteries, unexpected irregular heartbeats, or worsening congestive heart failure.  These information are usually recorded in the memory of the pacemaker which can then be "downloaded" by your physician in the office follow-up.  These data can give your physician important insights into the integrity of the pacemaker and the health of your heart, helping him or her render timely treatment for your heart as needed.

Another important reason for following up in pacemaker clinic is that from time to time, there may be unexpected malfunction of pacemakers that lead to "recall" of the affected units by the manufacturer.  Information on such  issues can be quickly disseminated to patients who maintain regular contact with the pacemaker clinic.  Those that are lost to follow-up may not receive these critical information.

There are pacemaker clinics that are attended by nurse practitioners and physician assistants, many of whom are very well trained and perfectly capable of handling all pacemaker related issues.  At Heart Rhythm Specialists of Southern California, however, we believe that physicians should be present at the time of the visit in order to give the best services to our patients.  Our pacemaker clinic is always attended by our physicians in conjunction with other ancillary service personnel (except in the case of unscheduled or emergency visits).  There are several advantages to our system.  The first is that any problem that is identified during the follow-up visit will have the immediate attention of our physicians, who can then make immediate decision and make any necessary changes to the setting of the pacemaker.  Second, our physicians can evaluate the patient for medical issues that requires immediate attention, above and beyond those associated with the pacemaker, without the need to make another consultation appointment.

Defibrillator Clinic

Just like a pacemaker, a defibrillator is a very complex electronic machinery that requires regular follow-up evaluation.  The follow-up requirement for a defibrillator is even more vigorous than that of a pacemaker because of its more complex functions and the fact that patients who need a defibrillator are in general much sicker and have more medical problems.  The result is that more potential problems can occur and can be readily picked up at the time of follow-up.

A defibrillator follow-up is usually twice a year to four times a year.  At each visit, the defibrillator is "interrogated" by the programmer (see picture below) through a wand or via wireless technology.  Battery status, electrode integrity, pacing and sensing thresholds, along with the entire range of  diagnostic information are determined just like those for a pacemaker (please refer to the section on pacemaker clinic for details on these).  In addition, specific attention is given to the recording of potentially life-threatening arrhythmias and the presence or absence of a defibrillator intervention for such arrhythmias.


The diagnostic and recording capabilities of a defibrillator is even more comprehensive and complicated than those of a pacemaker.  The defibrillator memory can give a precise date and time of nearly every arrhythmia events that have occurred since the last clinic visit, and can provide long-term trends of many parameters pertaining to the functionality of the defibrillator and even the well-being of the patient.  These important data are downloaded at each office visit to help your physician better manage your arrhythmia and heart failure.

Like the pacemaker, a defibrillator should not be programmed to the "out-of-the-box" setting in the long term, as this can lead to premature battery depletion.  Instead, careful fine-tuning is necessary for each individual patient, in order to achieve the optimal performances of the device.  Inadequate defibrillator programming can lead not only to premature battery depletion, but also inappropriate defibrillator shocks and sometimes even failure of the defibrillator to perform some of its most important function, i.e., resuscitation of the heart.  It is important to note that programming of the defibrillator should only be done under the direct supervision of a physician.

Just like the pacemaker clinic, a defibrillator clinic can help inform patients of critical updates about their devices, including the issue manufacturer "recall."

At Heart Rhythm Specialists of Southern California, the defibrillator clinic is attended by our Electrophysiologists, just like the pacemaker clinic.  At each visit, not only do we check the mechanical function of the defibrillator, we also provide medical evaluation for the patient as a whole.  Any medical decision about the care of the defibrillator or the treatment of of the patient can be made at that visit without the need for a return consultation visit.

Home Monitoring

Certain models of pacemaker and defibrillator are capable of so-called "remote monitoring," or "home monitoring."  This service generally utilizes some type of wireless technology to download the information from the pacemaker or defibrillator and transmit it over a phone line or even wirelessly to a remote secure website run by the manufacturer.  This information can be downloaded and viewed by you physician.  This type of remote monitoring may be ideal for patients with transportation difficulties.  However, one should keep in mind that home-monitoring is for diagnostic purposes only.  Any intervention (changes to the setting of the device) still requires a visit to the office. 

We at Heart Rhythm Specialists of Southern California provide home monitoring clinic for patients wishing to enroll this type of service.  Downloaded information is reviewed by the physician and steps are taken to have patient evaluated as the need arises.

Coumadin Clinic

Coumadin (or Warfarin) is an important anti-coagulant (blood-thinner) that helps prevent the formation of blood clot in certain types of condition that predispose the patient to thrombosis (blood clot).  The most common indications for Coumadin are atrial fibrillation and valve replacement.

Long-term monitoring of the status of anti-coagulation is of paramount importance because levels that are too high or too low can both be dangerous.  Furthermore, level of anti-coagulation (how thin or thick the blood is) can vary from day to day and from week to week, even though a patient may be taking the exact same dosage of coumadin.  This is because many factors can influence the level of anti-coagulation, including variation in the diet, differences in the absorption of coumadin, and potential drug-to-drug interaction from other concurrent medications.  Therefore, close monitoring is mandatory.

Monitoring of the level of anti-coagulation is done through a test called Pro-Thrombin time, or "Pro-Time" or "PT" for short.  Most people today refer to the test as INR (International Ratio).  An INR that is too high indicates that the blood is "too thinned" and can patient may bleed.  On the other hand, an INR that is too low means the blood is "too thick" and this can be accompanied by blood clot formation.

Heart Rhythm Specialists of Southern California provides the service of INR evaluation in our Coumadin Clinic for the benefit of patients with atrial fibrillation or other conditions that require anti-coagulation.  While many other offices utilize the laboratory to perform INR, which requires a phlebotomy (blood draw through a needle in the vein) and has a turn-around time of up to 1 day, we perform INR with a finger prick and the results are available within 5 minutes. The decision on whether to change the dosage of Coumadin or to stay the same can be made in one setting without the need for repeated messaging and "phone-tagging."

Office Procedures:  Heart Rhythm Specialists of Southern California offers a comprehensive array of office-based diagnostic procedures for the evaluation and treatment of patients with arrhythmias. The following are brief descriptions of the tests we offer.  Please click on the links to see detailed descriptions of each procedure.

Electrocardiogram (EKG): a simple recording of your heart rhythm, usually with 12 electrodes.

Holter monitor: a 24-hour continuous recording of your heart rhythm, usually with 3 electrodes.

Event monitor: a 30-day long-term, patient-activated monitor.

Tilt table study a non-invasive test for the diagnosis of fainting.

Exercise Treadmill Test a treadmill test to assess for underlying coronary heart disease.

Stress Echocardiogram: an exercise treadmill which involves additional imaging with echocardiogram.

Echocardiogram a non-invasive ultrasonic imaging study of the heart.

Hospital Procedures:  Our physicians are affiliated with most area hospitals and can perform a wide range of procedures for all kinds of arrhythmias.  The following are brief descriptions of the procedures we routinely perform.  Please click on the links to see detailed descriptions of each procedure.

Cardioversion an outpatient treatment to "shock" and restore normal rhythm of the heart.

Pacemaker (PM): an implantable electronic device that helps regulate heartbeat.

Implantable Cardioverter-Defibrillator (ICD or AICD): an implantable pacemaker with defibrillation capability.

Implantable Loop Recorder: an implantable long-term event monitor.

Electrophysiology Study (EPS): an invasive diagnostic test for arrhythmias.

Radiofrequency Ablation (RFA): an invasive, curative procedure for arrhythmias.

3-D Mapping (Electro-Anatomic Mapping): a new computerized mapping technique used to help localize complex arrhythmias.

Atrial Fibrillation Ablation: a curative procedure for atrial fibrillation.

For Frequently Asked Questions (FAQ) about these procedures, follow this link.

Electronic Medical Records (EMR)

Heart Rhythm Specialists of Southern California utilizes paperless Computerized Electronic Medical Records.  This improves efficiency in the running of the office and drastically reduces the chance of human error in appointments, record keeping, patient communication, and medication prescription. 

Pediatric Neurology

Dr. Tseng-Ong is a board-certified Pediatric Neurologist with an active Pediatric Neurology practice at this office.  She sees children with all forms of neurological disorders.  She is the Vice President of Heart Rhythm Specialists of Southern California.

Click here  for an appointment to see Dr. Tseng-Ong for neurology consultation.