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Medical Center Tower I 7950 Floyd Curl Drive Suite 803 San Antonio, TX 78229 tel: 210-615-9500 fax: 210-615-9600 email: office at cecst.com |
Specializing in the compassionate care of people who suffer from abnormalities of the electrical system of the heart |
Current Insurance Plans:
We accept most major commercial insurance plans. Please call for details. Medicare: We have opted out of Medicare, and are happy to care for Medicare beneficiaries on an affordable cash basis. Note: Federal law prohibits signing the Federally-mandated opt-out contract with a Medicare beneficiary who is in an emergency situation. No insurance? No problem! Consider our affordable Fee for service (direct pay). Home of the Original Personalized Medical Office SystemTM released April 5, 2013 |
| Table of Contents |
| Atrioventricular nodal reentrant tachycardia | |
| This is a reentrant supraventricular rhythm whose circuit is located in the region of the atrioventricular node. It is characterized by a QRS morphology that is normal for the patient. P waves may or may not be seen, but they follow closely after the QRS if they are seen. Only about 60% of narrow-complex tachycardias have this mechanism. It is important to note that 20% of narrow-complex tachycardias are atrioventricular reentrant tachycardias, which use a concealed accessory pathway for retrograde conduction. The clinical significance of this rhythm depends on the rate. It stops abruptly with effective treatment. The usual initial treatments are the Valsalva maneuver, then intravenous adenosine. If these are unsuccessful, one can try medication that reduces conduction through the atrioventricular node. Consultation with a Cardiac Electrophysiologist is recommended for follow-up because this rhythm can now be cured by catheter-mediated radiofrequency ablation. | |
| Atrioventricular reentrant tachycardia (AVRT) | |
| This is a reentrant supraventricular rhythm whose circuit includes both the atrium and the ventricle, and that uses an accessory atrioventricular pathway for at least one limb of the circuit. "Orthodromic" AVRT, which is the most common form, proceeds antegrade (from atrium to ventricle) over the AV node, and retrograde over an accessory pathway. "Antedromic" AVRT proceeds in the reverse direction, and has is a wide QRS tachycardia except when the accessory pathway is located in the right anteroseptal location very close to the His bundle. When multiple pathways are present, it is also possible for the circuit to use two pathways as a circuit. P waves may or may not be seen, but they usually do not follow closely after the QRS if they are seen. The clinical significance of this rhythm depends on the rate. It stops abruptly with effective treatment. The usual initial treatments are the Valsalva maneuver, then intravenous adenosine. If these are unsuccessful, one can try medication that reduces conduction through the atrioventricular node, except that verapamil and digitalis SHOULD NOT BE GIVEN. Consultation with a Cardiac Electrophysiologist is recommended for follow-up because this rhythm can now be cured by catheter-mediated radiofrequency ablation. | |
| Bigeminy | |
| An abnormal but usually harmless rhythm characterized by occurrence of one ventricular premature complex (VPC) after each normal QRS complex. This rhythm usually does not progress to dangerous forms of fast ventricular rhythms. Note that in this rhythm, two VPCs never occur one right after the other. | |
| Bundle branch block | |
| This term refers to the QRS morphology seen when either the right bundle branch or the left bundle branch fails to conduct from the His bundle to the ipsilateral ventricle. Right bundle branch block is characterized by an "M" pattern in V1 and wide S waves in the lateral leads (I, V6). Complete left bundle branch block is characterized by negative forces (QS or rS) in V1 and positive forces (monophasic R wave with no Q wave) in V6. Incomplete left bundle branch block can manifest as left anterior hemiblock or left posterior hemiblock. Consultation with Marriott's "Practical Electrocardiology", or the ECG textbook of your choice, is recommended for further information. | |
| Hidden Atrial Activation | |
| Activation of the atrium by the sinus node can be inferred from surrounding sinus P waves. For example, if the P wave following a ventricular premature complex occurs at the time that would have been expected had the premature complex not occurred, then in can be inferred that the atrium was not activated retrogradely by the premature complex and that a hidden, or obscured, P wave did occur. Such an inference can be confirmed during invasive electrophysiologic study. | |
| Idioventricular rhythm | |
| This is diagnosed when only ventricular escape complexes are present, and they occur at 20 to 40 beats per minute. This rhythm is barely consistent with life. If you see this, you should consider initiating Cardiopulmonary Resuscitation immediately, and should move the patient to an intensive care unit as soon as possible. DO NOT give lidocaine or any other antiarrhythmic medication for this rhythm. You could cause asystole and death by inhibiting the only spontaneous rhythm the patient's heart is able to generate. | |
| Junctional escape complex | |
| This is a QRS with normal morphology for the patient that is not preceded by a P wave and occurs later than would be expected from the sinus rate. Like all escape complexes, it can occur only when the normal cardiac pacemaker does not function, as is sinus arrest. | |
| Junctional premature complex | |
| This is a QRS complex that occurs earlier than would be expected from the sinus rate, and that usually has a normal morphology for the patient. It can fail to conduct retrograde through the atrioventricular node, in which case it results in a compensatory pause. That is, the next P wave occurs at the same time as would be expected had the VPC not occurred. More usually, it does conduct through the atrioventricular node, so that the following P wave may occur either sooner or later than would be expected. Junctional premature complexes are relatively uncommon. They can be seen with increased frequency during stress, with ingestion of caffeine, and with sympathomimetic drugs such as some over-the-counter cold remedies. They can also be misdiagnosed when the P wave of an atrial premature complex is obscured by the preceding T wave. | |
| Junctional premature couplet | |
| See junctional premature complex. This is an unusual rhythm, and most likely represents two cycles of one of the supraventricular tachycardias. | |
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