Atrial Tachycardia Mapping Techniques

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Questions and Answers

What does a PPI-TCL difference of ⱕ50 ms at the proximal CS suggest?

A left atrial tachycardia

LA tachycardia is likely

AT involving the right pulmonary vein region (correct)

Common RA flutter

What is the specificity of the algorithm for identifying LA origin compared to RA origin in group I?

94%

88%

100% (correct)

86%

When is a PPI-TCL difference greater than 50 ms at the high RA significant?

It likely identifies AT from the lateral RA

It indicates RA tachycardia

It suggests LA tachycardia (correct)

It indicates LA tachycardia is likely

What was the positive predictive value of the algorithm for predicting the correct ablation region?

98% Signup and view all the answers

Which of the following indicates involvement of the atria adjacent to the mitral annulus?

PPI-TCL difference ⱕ50 ms at the distal CS Signup and view all the answers

What does the abbreviation TCL stand for in the context of atrial tachycardias?

Tachycardia cycle length Signup and view all the answers

Which area of the heart is specifically associated with lateral atrial tachycardia?

Right atrial lateral wall Signup and view all the answers

What is the significance of the postpacing interval (PPI) compared to the tachycardia cycle length (TCL)?

PPI is shorter during AT compared to TCL Signup and view all the answers

Which of the following ATs is defined by a circuit adjacent to the right pulmonary veins?

RPV AT Signup and view all the answers

Which statistic indicates the accuracy of the developed algorithm for identifying the successful ablation region?

93% Signup and view all the answers

What does the term 'mitral AT' refer to?

AT involving the isthmus between the mitral annulus and left pulmonary veins Signup and view all the answers

What were the postpacing interval measurements for AT involving the mitral isthmus compared to the left pulmonary vein region?

Higher for the mitral isthmus Signup and view all the answers

In which group was the algorithm for identifying the ablation region developed?

Group I Signup and view all the answers

What percentage of patients underwent closure for an atrial septal defect in group II?

1% Signup and view all the answers

Which procedure had the highest percentage of patients undergoing atrial fibrillation ablation?

Concomitant atrial fibrillation ablation Signup and view all the answers

What was the left ventricular ejection fraction in group I?

0.65 ⫾ 0.16 Signup and view all the answers

What percentage of patients in group I had prior catheter ablation for atrial flutter?

7% Signup and view all the answers

How many ATs were examined in total in group I?

104 Signup and view all the answers

What is the tachycardia cycle length (TCL) reported for the last tracing?

240 to 250 ms Signup and view all the answers

Which region had 15 ATs noted from the study?

Left pulmonary vein Signup and view all the answers

What is the primary purpose of the algorithm developed in the study?

To predict the location of macroreentrant atrial tachycardia circuits. Signup and view all the answers

What was the PPI-TCL difference when entrainment was performed from high RA?

140 ms Signup and view all the answers

How was the difference between postpacing interval (PPI) and tachycardia cycle length (TCL) utilized in this study?

To distinguish between left and right atrial reentrant circuits. Signup and view all the answers

What was the sensitivity and specificity of the algorithm in the validation cohort?

94% sensitivity and 88% specificity. Signup and view all the answers

What was a significant finding regarding PPI-TCL difference at the proximal coronary sinus (CS)?

It distinguished common flutter from lateral right atrial circuits. Signup and view all the answers

Which group had the algorithm developed and later validated in this study?

Group I for 90 patients and Group II for 90 patients. Signup and view all the answers

What was the impact of limited entrainment mapping in the study's conclusions?

It provided a quicker way to suggest atrial tachycardia locations. Signup and view all the answers

What aspect of tachycardia circuits was primarily focused on in this study?

The distinction between left and right atrial tachycardia. Signup and view all the answers

Which specific patient population was evaluated in this research?

Patients with organized reentrant atrial tachycardia. Signup and view all the answers

What was the mean age of the patients included in the study?

56 years Signup and view all the answers

How many patients had atrial tachycardia (AT) not due to reentry through the subeustachian isthmus?

84 Signup and view all the answers

What procedure did systemic anticoagulation aim to achieve during LA mapping and ablation?

An activated clotting time of 250 to 350 seconds Signup and view all the answers

Which mapping system was used for activation sequence mapping?

CARTO Signup and view all the answers

What was the primary outcome of successful ablation in the study?

Termination and suppression of tachycardia reinitiation Signup and view all the answers

What type of catheterization was performed for left atrial (LA) mapping?

Transseptal catheterization Signup and view all the answers

How many consecutive patients were included in the study?

180 patients Signup and view all the answers

What was calculated from the conduction time between the last stimulus that entrained tachycardia and the second beat after the stimulus?

PPI-TCL difference Signup and view all the answers

What indication suggests that entrainment may be misleading in diagnosing automatic tachycardias?

Entrainment does not alter the tachycardia. Signup and view all the answers

How is the post-pacing interval (PPI) affected in cases where the pacing site is close to the reentrant circuit?

PPI will be shorter. Signup and view all the answers

What challenge might arise when distinguishing between focal and macroreentrant atrial tachycardias?

Extensive mapping may be required for accurate identification. Signup and view all the answers

What effect do antiarrhythmic drugs have on conduction delay and diagnostic accuracy?

They may increase conduction delay, reducing diagnostic accuracy. Signup and view all the answers

What assumption can be made about overdrive suppression with repeated pacing at the same rate?

The return cycle increases as the distance from the site increases. Signup and view all the answers

What is the relevance of isolated channels between scars in reentrant atrial tachycardia?

They can permit focal ablation in cases of macro-reentrant circuits. Signup and view all the answers

What characterizes the post-pacing intervals observed in the focus site compared to distant sites?

PPI is shorter at the focus site. Signup and view all the answers

What consideration might affect the success of pacing techniques in entrainment mapping?

Potential changes in tachycardia with pacing. Signup and view all the answers

Study Notes

Entrainment Mapping for Rapid Distinction of Left and Right Atrial Tachycardias

Background: Distinguishing left from right atrial tachycardia is crucial for ablation procedures.
Objective: Develop and validate a simple algorithm to predict reentrant atrial tachycardia (AT) circuit location based on limited entrainment mapping in the right atrium (RA) and coronary sinus (CS).
Methods: 180 patients with organized reentrant AT underwent entrainment mapping at the high RA, proximal CS, and distal CS. The difference between post-pacing interval (PPI) and tachycardia cycle length (TCL) was calculated. AT circuit location was determined by mapping and ablation. An algorithm was developed from 104 ATs in a first group (90 patients) and validated in a second group (90 new patients).
Results: A 50ms PPI-TCL difference at the high RA differentiate RA reentrant circuits from left atrial (LA)reentrant circuits. Analyzing PPI-TCL at proximal CS differentiated common flutter from lateral RA circuits and perimitral from right pulmonary vein/septal reentry circuits in LA circuits. An algorithm with 94% sensitivity, 88% specificity, and 93% predictive accuracy for successful ablation site localization was established.
Conclusion: Limited entrainment from sites within the RA can help rapidly identify the AT location, guiding further mapping and potentially avoiding unnecessary transseptal procedures.

Study Population and Methods

Patient Inclusion Criteria: Organized reentrant AT (<20ms A-A interval variability) with a macroreentrant circuit (activation sequence and entrainment mapping showing widely separated sites).
Total Patients: 180 consecutive patients (135 male).
Patient Age: Mean age 56 ± 11 years (range 20-85).
Entrainment Sites: High RA, proximal CS, and distal CS.
Mapping: 7Fr quadripolar catheters with a 4-mm distal electrode (electroanatomic mapping system). Cardiac electrogram (ECG) electrodes used.
Anticoagulation: Systemic anticoagulation (heparin) maintained activated clotting times (250-350 seconds) during LA mapping and ablation.
Ablation: Radiofrequency catheter ablation to transect reentrant circuit using energy input (20-30W to 50W, temperatures 50°C-60°C), aiming to eliminate or interrupt conduction areas.

Mapping and Catheter Ablation Procedure Details

Electrode Placement: High RA, proximal, and distal Coronary sinus placement (within 1cm for proximal and >3cm for distal).
Stimulation: Train of atrial stimuli (10mA, 2ms) 10-30ms shorter than TCL for sufficient duration.
PPI Measurement: Measured from the last stimulus to the first peak of the next electrogram at the pacing site or adjacent proximal recording electrodes.
ECG/Electrogram Analysis: used to assess activation sequences for AT circuit localization
Activation sequence mapping: Electroanatomic mapping aided by use of Electroanatomic mapping systems to locate reentrant circuits.

Additional Details

AT classification: Based on interruption site during ablation.
Data Analysis: Generalized estimating equations to accommodate multiple observations in patients. Chi-square analysis for categorical variables. Statistical significance considered at P <0.05.

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Description

This quiz focuses on the methods and algorithms used for distinguishing between left and right atrial tachycardia through entrainment mapping. It covers the significance of the PPI-TCL difference in determining reentrant atrial tachycardia circuit locations. Test your understanding of this crucial procedure for effective ablation interventions.