Natasja M.S. de Groot

Long‐Term Follow‐Up After Radiofrequency Catheter Ablation of Ventricular Tachycardia: A Successful Approach?

RF Catheter Ablation of VT. Introduction: Radiofrequency ablation (RFCA) of ventricular tachycardia (VT) is a potential curative treatment modality. We evaluated the results of RFCA in patients with VT.

Voltage and activation mapping: how the recording technique affects the outcome of catheter ablation procedures in patients with congenital heart disease.

Background—Endocardial mapping is mandatory before radiofrequency catheter ablation (RFCA). Mapping can be performed with either unipolar or bipolar recordings. Impact of the recording technique used was studied in patients with and without structural heart disease using the 3D electroanatomic CARTO mapping system. Methods and Results—Patients (n=44; 16 males; age 43±16 years) referred for RFCA of atrial flutter (AFL, n=18), focal atrial tachycardia (FAT, n=4), AV nodal reentrant tachycardia (AVNRT, n=5), or scar-related atrial reentrant tachycardia (IART, n=17) were studied. Voltage and activation maps were constructed. Unipolar and bipolar voltage distribution in the different groups was studied to establish a cutoff voltage value to facilitate delineation of scar tissue. Electrograms were recorded during tachycardia (FAT: n=246, cycle length [CL]=449±35 ms; AVNRT: n=182, CL=359±47 ms; AFL: n=1164, CL=255±56 ms; IART: n=2431, CL=280±74 ms). Unipolar voltages were greater than bipolar voltages (P <0.001). Unipolar voltages ≤1.0 mV were equally distributed in both AFL and IART patients. Bipolar voltages ≤0.1 mV were only found in patients with IART, and subsequently 0.1 mV was used as the cutoff value to delineate scar tissue. No unipolar cutoff value could be established. Timing of unipolar and bipolar local activation was correlated in all patient groups. Conclusions—The recording technique used has considerable impact on reconstruction of reentrant pathways and on the outcome of RFCA. In general, unipolar and bipolar recordings provide complementary information; however, only bipolar recordings allow voltage-based scar tissue delineation in patients with congenital heart disease.

Long-Term Outcome After Ablative Therapy of Postoperative Atrial Tachyarrhythmia in Patients With Congenital Heart Disease and Characteristics of Atrial Tachyarrhythmia Recurrences

Background—Catheter ablation has evolved as a possible curative treatment modality for atrial tachyarrhythmia (AT) in patients with congenital heart defects (CHD). However, data on long-term outcome are scarce. We examined characteristics of recurrent AT after ablation of postoperative AT during long-term follow-up in CHD patients. Methods and Results—CHD patients (n=53; 27 men; age, 38±15 years) referred for catheter ablation of AT were studied during a follow-up period of 5±3 years. After ablative therapy of the first AT (n=53, 27 atrial flutter, cycle length=288±81 ms; 22 intra-atrial reentrant tachycardia, cycle length=309±81 ms; 5 focal atrial tachycardia, cycle length=380±147 ms; success rate, 65%), AT recurred (59% within the first year) in 29 patients; 15 underwent repetitive ablative therapy. Mechanisms underlying recurrent AT were similar in 7 patients (intra-atrial reentrant tachycardia, 2; atrial flutter, 5). The location of arrhythmogenic substrates of recurrent AT (intra-atrial reentrant tachycardia, focal atrial tachycardia) was different for all but 1 patient. After 5±3 years, 5 patients died of heart failure, 3 were lost to follow-up, and the remaining patients had sinus rhythm (n=31), AT (n=5), or atrial flutter (n=14). Antiarrhythmic drugs were used by 18 (57%) sinus rhythm patients. Conclusions—Successive postoperative AT in CHD patients developing over time may be caused by different mechanisms, including focal and reentrant mechanisms. Recurrent AT originated from different locations, suggesting that these new AT were not caused by arrhythmogenicity of previous ablative lesions. Long-term outcome is often complicated by development of atrial fibrillation. Despite frequent need for repeat ablative therapy, most patients are in sinus rhythm.

Fragmented, long-duration, low-amplitude electrograms characterize the origin of focal atrial tachycardia.

Background: Focal atrial tachycardias (FAT) originate from areas with poor cell‐to‐cell coupling. Due to cellular uncoupling extracellular potentials become fractionated. The degree of fragmentation may be used to identify the site of origin of FAT prior to catheter ablation. We studied electrical fragmentation in relation to the distance to the site of earliest activity during FAT.

Three‐Dimensional Distribution of Bipolar Atrial Electrogram Voltages in Patients with Congenital Heart Disease

DE GROOT, N.M.S., et al.: Three‐Dimensional Distribution of Bipolar Atrial Electrogram Voltages in Pa‐tients with Congenital Heart Disease. Voltage differences might be used to distinguish normal atrial tissue from abnormal atrial tissue. This study was aimed at identifying lowest voltage areas in patients with atrial tachycardia after surgical correction of congenital heart disease and to evaluate if identification of these areas in diseased hearts facilitates selection of critical conduction pathways in reentrant circuits as target sites for catheter ablation. Ten patients (four men, age 39 ± 15 years) with normal sized atria and atrioventricular reciprocating tachycardia (control group) and ten patients (5 men, 32 ± 7 years) with congenital heart disease and postoperative atrial tachycardia (CL 281 ± 79 ms) referred for radiofrequency catheter ablation were studied. Mapping and ablation was guided by a three‐dimensional electroanatomic mapping system (CARTO) in all patients. In the control group, voltage maps were constructed during sinus rhythm and during tachycardia to evaluate the voltage distribution. The amplitude of bipolar signals was 1.90 ± 1.45 mV (0.11–8.12 mV, n = 660) during sinus rhythm and 1.45 ± 1.66 mV (0.12–5.83 mV, n = 440, P < 0.05) during atrioventricular reciprocating tachycardia. In the study group, the amplitude of 1,962 bipolar signals during tachycardia was 1.01 ± 1.19 mV (0.04–9.40 mV), which differed significantly from the control group during tachycardia (P < 0.0001). No significant difference in the tachycardia cycle length was found (P < 0.05) between the control and study groups. As the lowest voltage measured in normal hearts was 0.1 mV, this value was used as the upper limit of the lowest voltage areas in the patients with congenital heart disease. These areas were identified by detailed voltage mapping and represented by a gray color. Activation and propagation maps were then used to select critical conduction pathways as target sites for ablation. These sites were characterized by fragmented signals in all patients. Ablation resulted in termination of the tachycardia in eight (80%) of ten patients. Complications were not observed. Identification of the lowest voltage areas using a cut‐off value of 0.1 mV in congenital heart disease patients with postoperative atrial reentrant tachycardia facilitated the selection of critical conduction pathways as target sites for ablation.

Fusion of Electroanatomical Activation Maps and Multislice Computed Tomography to Guide Ablation of a Focal Atrial Tachycardia in a Fontan Patient

Introduction: Ablation of atrial tachycardia (AT) occurring late after cardiac surgery for congenital heart disease can be challenging due to the complexity of the arrhythmogenic substrate.

Different mechanisms underlying consecutive, postoperative atrial tachyarrhythmias in a Fontan patient.

Introduction: Atrial tachyarrhythmias (AT) frequently develop later after a Fontan operation and can be successfully treated by ablative therapy. However, new arrhythmias often develop.

Foetal echocardiography: tool to predict the future of patients with congenital heart defects?

Antepartum obstetrical ultrasonic evaluation is nowadays commonly used in order to detect congenital anomalies.1,2 As congenital heart disease is the most frequently encountered congenital anomaly, cardiac examination is of paramount importance to identify defects on time.nnThe advantage of foetal echocardiography is that ultrasound energy can be applied safely in an evolving fetus and that cardiac structures can be studied early in pregnancy (from 10 to 12 weeks by the vaginal approach, and from 16 to 18 weeks using the transabdominal approach).nnFailures to diagnose congenital heart defects correctly are caused by multiple variables including ultrasound technology, sonographer experience, and mother- or foetal-related factors such as gestational age, foetal intrauterine position, or polyhydramnios. As congenital heart malformations are often associated with other cardiovascular and/or extracardiac malformations, extensive ultrasonic evaluation of the fetus is mandatory in case of a congenital heart defect.nnIn their … nn*Corresponding author. Tel: +31 71 5262020, Fax: +31 71 5226567, Email: n.m.s.de_groot{at}LUMC.NL or M.J.Schalij{at}LUMC.NL

Do Not Put Money Where Your Mouth Is

A 60-year-old woman presented with repolarization disorders on the electrocardiogram after a generalized seizure, which immediately disappeared after vomiting up a 20-eurocent coin. We did not find any evidence of coronary artery disease. Multislice computed tomography demonstrated no coronary atherosclerotic stenosis but a close relationship of the esophagus with the coronary arteries. This relation was further studied in detail in a human cadaver. From our findings, it is most likely that the electrocardiogram alterations were due to compression of the ramus descendens posterior of the right coronary artery and/or the ramus circumflexus of the left coronary artery by the coin.