Electrophysiology treatment of cardiac arrhythmia

Cardiac electrophysiology, which deals with the diagnosis and therapy of cardiac arrhythmia, is a special focus of the Cardiovascular Center.

At rest our heart normally beats at a regular sequence of 50 to 80 times per minute, i.e. around 100,000 times a day. Under physical or mental stress the heart rate can increase considerably in order to satisfy the higher oxygen requirement of our organs, in particular the muscles being exerted. This increase is regarded as “normal” as we have known this phenomenon for our whole lives. However, things are different if unanticipated irregular heartbeats occur, “skipped beats” are noticed or a sudden acceleration of the pulse occurs without a specific cause. Most people consider these situations to be unusual, and frequently also as threatening. This is particularly the case if the feeling of a racing heart is accompanied by dizziness or a severe feeling of weakness.

However, too slow a pulse also has a negative effect on our well-being and resilience. In this case people complain of feelings of dizziness through to impaired consciousness and also the feeling that the heart cannot “keep up” when under strain.
Both functional impairments as well as a racing heart (tachycardia) as well as too slow a heartbeat (bradycardia) usually require evaluation and treatment in order to prevent risks to the patient’s own life and that of others. However, the symptoms of arrhythmia alone say little about how dangerous it is, despite the fact that lasting symptoms, especially those linked to dizziness, shortness of breath or clouding of consciousness, should result in an immediate evaluation with admission to hospital by the emergency response doctor. Many cardiac arrhythmias, in particular recurrent racing of the heart lasting a few minutes to hours in young, otherwise healthy people, require evaluation even if these are not usually life-threatening and can be overcome using what are known as vagal maneuvres (such as compressions, drinking cold water etc.).

Phases of irregular pulse or short episodes of irregular heartbeat should also be taken seriously as these are often due to what is known as atrial fibrillation. This arrhythmia does not usually pose a direct risk to the heart (many people have ongoing atrial fibrillation). If blood-thinning medication is not taken, there is a risk of the formation of blood clots in the heart with the dangerous consequence of a stroke. Therefore, if this arrhythmia is identified, the patient’s physician, internal specialist or cardiologist should advise on and discuss the necessity of blood-thinning treatment.

Important

In all cases it is advisable for the arrhythmia to be documented via an ECG. This can be done in the nearest hospital or practice or, if the symptoms are occurring for the first time or are accompanied by weakness, dizziness, heart pain, by the emergency response doctor who should be alerted immediately.

In the Kempten-Oberallgäu hospitals patients with acute cases of arrhythmia can always be admitted to the emergency admission for internal medicine or, in less urgent cases, may be asked to attend an electrophysiological appointment to evaluate the necessity of an inpatient evaluation (direct registration for private patients, patients with statutory health insurance can be referred by their physician. LINK to the appointment if possible). A cardiologist is on hand in the Kempten and Immenstadt hospitals around the clock to interpret the ECG and define the treatment strategy for an arrhythmia.

If an inpatient evaluation is required in the view of your treating physician or cardiologist, or in our view, a specialist team of doctors and care staff is on hand at the Kempten hospital headed by head physician Associate Professor Dr. med. Martin R. Karch. In order to perform what are known as electrophysiological investigations and catheter ablation treatments (see below), a cardiac catheterization laboratory with state-of-the-art technology was set up in the Memmingerstrasse hospital.

How an arrhythmia be identified and diagnosed?

1. Rest ECG

A rest ECG that was recorded during the arrhythmia is usually very helpful in doing so.
In many cases this enables a decision to be made as to whether there are grounds for performing a further evaluation via an electrophysiological investigation (see below) and whether the arrhythmia in question can be ablated.

2. Long-term ECG

A long-term ECG is performed if it has not so far been possible to record the arrhythmia in question in a rest ECG or to investigate the frequency of an arrhythmia e.g. extra beats. These devices record the ECG continuously for 24 or 48 hours, and in exceptional cases even for up to seven days. During the duration of the recording it is helpful if symptoms that indicate an arrhythmia are noted in a small diary with the exact time. This enables subjective symptoms and ECG data to be compared during the assessment.

SPECIAL FORM: 12 channel long-term ECG
This special ECG is not only able to record an ECG for 24 hours, but rather it stores twelve ECG channels for the entire recording period. This is very important for the planning and assessment of the prospects of success of an ablation treatment.

3. Exercise ECG

An exercise ECG is always performed if arrhythmias could be provoked by physical activity or if there is a suspicion that circulatory disorders of the heart could be a joint cause.

4. Event recorder

This is a small device about the size of a USB sticks that can be implanted under the skin in the chest region under local anesthetic. An implantation is considered if previous investigations were not able to identify any arrhythmias although is a high probability that these are responsible for the patient’s symptoms. An event recorder can record an ECG over three years that can then be retrieved in the cardiological practice or the hospital.

5. EPS (electro physiology study)

An EPS is an invasive investigation in which, under local anesthetic, small catheters are fed - pain-free - through the groin to the heart via a blood vessel in order to evaluate the source or precise mechanisms of an arrhythmia there. This is done by stimulating the heart like a pacemaker via these catheters, which can be perceived as an irregular heartbeat. Before making a diagnosis it is necessary to trigger the clinical arrhythmia in order to understand the precise mechanism. The duration of an EPS is very variable and depends on how quickly the arrhythmia can be induced and its source found. Generally light sedatives can be prescribed to make the investigation easier for the patient.

When is an EPS indicated?
An EPS is always recommended if…

the investigations named above can demonstrate arrhythmias whose origin can most likely be ablated and thus permanently remedied
arrhythmias could not be documented on an ECG but these are most likely responsible for a patient’s symptoms (potentially event recorder implantation first, see point 4)
losses of consciousness cannot be explained by other causes and there is a high probability that arrhythmias are the cause

Which therapy procedures are available for the treatment of arrhythmias?

1. Medicinal therapy

After a precise diagnosis the possible therapy options are explained in an individual consultation. If a medicinal therapy appears promising for treating the arrhythmia, this will be prescribed after an explanation of the characteristics and possible side effects.

If, on the other hand, it is likely that an arrhythmia can be permanently cured with a catheter ablation treatment, the risk of lifelong medication is compared with the risk of invasive surgery in order for a decision to be reached.

2. Catheter ablation treatment

If the source of the arrhythmia has been located, in most cases this can be treated in the same session by means of a catheter ablation. This ablation involves ablating the cells responsible for the arrhythmia via a slight warming of the catheter tip. This procedure is either completely pain-free or may cause a slight burning in the heart or shoulder region during the ablation. In many cases this ablation can completely remove the arrhythmia. This frequently enables the dose of the arrhythmia medication previously needed to be reduced or stopped completely.

For the treatment of complex arrhythmias such as atrial fibrillation, state-of-the-art , radiation-free three-dimensional mapping (localization) systems are used (EnSite NavX). These enable a catheter to be navigated in the heart with millimeter precision and thus enable the sources of an arrhythmia to be identified. They therefore enable an ablation with a high precision with only a minimum of X-ray exposure.

3. Combination of medicinal therapy and catheter ablation treatment

In some cases an adequate therapy strategy can also contain a combination of ablation and special medicinal therapy.

Pacemakers, internal defibrillators (ICD) and cardiac resynchronization systems (CRT)

Both pacemakers and internal defibrillators as well as cardiac resynchronization systems are implanted at both hospital sites by a team with many years’ experience.
All of these device types are inserted subcutaneously under local anesthetic on the right or left under the collarbone. If the patient so requires, sedatives can be prescribed so that the patient sleeps during the procedure.

4a. Pacemakers
The implantation of a pacemaker is indicated if the heart suddenly starts beating too slowly or pauses of several seconds occur.
A further frequent indication exists in patients with what is known as a bradycardia (heartbeat is too slow; tachycardia if the heartbeat is too fast) syndrome is present. In this case the phases where the pulse is too fast need to be slowed down using medication, whereby the heart rate drops even further in the phases where the pulse is too slow. Here a pacemaker is needed that can guarantee an adjustable minimum heart rate.

4b. Internal defibrillator (ICD)
An ICD implantation is justified if life-threatening arrhythmias from the main chambers of the heart have occurred that cannot be safely eliminated using medicinal therapy or catheter ablation treatment (secondary prophylaxis). These arrhythmias generally occur in patients with hearts that have prior damage (heart attack, high blood pressure, heart valve disorders, myocarditis etc.) and can lead to sudden cardiac death. An ICD can safely prevent this as it monitors the heart’s rhythm for 24 hours a day, 365 days a year. If the above arrhythmias occur, it can bring them to an end by means of pain-free overstimulation or a life-saving electric shock.
A second indication for ICD implantation exists in the event of highly weakened heart muscle as a consequence of various cardiac disorders (heart attack, high blood pressure, heart valve disorders, myocarditis etc.) even without life-threatening arrhythmias having occurred (primary prophylaxis) as in these cases an increased probability of the incidence of these arrhythmias is anticipated.

4c. Cardiac resynchronization systems CRT
In the event of substantial heart weakness and defect of a conductor in the heart (left bundle branch block) special pacemakers or defibrillators are used that are able to replace the abovementioned capabilities of the defective conductor in the heart and to achieve an improvement cardiac performance.