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Biomedical subjects

J P Bourke

Publications and source records attributed to J P Bourke.

At least 37 records · Page 2Linked to original sources
PubMed1997

Right ventricular disarticulation procedures: the role of late potentials in the genesis of postoperative ventricular arrhythmias.

Arrhythmogenic right ventricular disease may be associated with life-threatening and drug refractory ventricular arrhythmias. Right ventricular disarticulation procedures are effective antiarrhythmic surgical approaches in selected patients. This study examined the role of late potentials in the postoperative development of new ventricular arrhythmias, and showed that right ventricular isolation is effective, probably because it destroys the tissue giving rise to late potentials. Total disarticulation is associated with fewer postoperative arrhythmias than partial isolation procedures. Total disarticulation may be the surgical approach of choice in such patients.

Adult↗
PubMed1997

Florid psychopathology in patients receiving shocks from implanted cardioverter-defibrillators.

OBJECTIVES: To increase awareness of the potential for disabling anxiety and depression in patients receiving shocks from implanted cardioverter-defibrillators (ICDs). PATIENTS AND METHODS: ICDs are implanted in patients at this hospital for control of serious ventricular tachyarrhythmias inadequately controlled by drug treatment, who are unsuitable for map guided antiarrhythmic surgery. All are reviewed regularly at a dedicated ICD clinic and are advised to make contact between visits if they experience shocks. Symptoms of anxiety or depression were not actively sought, nor was a patient support group operating at the time of this data collection. When overt psychopathology was identified, patients were referred to a designated psychiatrist for management. RESULTS: Over a six year period, six (17%) of 35 patients with ICDs developed florid psychiatric problems after experiencing shocks. None had premorbid psychiatric predisposition. Of the six patients suffering severe psychiatric problems, four were men, their age range was 30-63 years, and left ventricular ejection fraction was 18-40%. All shocks were appropriate for clinical arrhythmias and ranged in frequency from two in six months to 111 in 24 hours. All six patients manifested severe anxiety, focused on fear of future shocks. Depression was also evident in three patients and two had become housebound. All responded within weeks to anxiolytic or antidepressant drugs, combined with relaxation and cognitive therapies. Ongoing psychiatric therapy was refused by one patient, and was required for between three and 18 months in the remainder. One patient died and one received a cardiac transplant during the follow up period (median 27.5 months, range 8-43). CONCLUSIONS: Because ICD implantation occurs against a complex medical background with inevitable psychological stress, all such patients should be considered at high risk for developing psychopathology.

Adult↗
PubMed1996

Long-term thresholds of nonsteroidal permanent pacing leads: a 5-year study.

The present commercial market supports many nonsteroidal endocardial pacing leads of differing construction. In order to compare the performance of these configurations, we studied the long-term pacing properties of three representative lead types by randomized clinical trial in 99 patients undergoing a first elective VVI implant. Thirty-one patients received sintered platinum leads, 36 activated pyrolytic carbon leads, and 32 vitreous carbon leads. All received generators capable of noninvasive threshold testing. Acute sensing parameters were R wave amplitude and ST segment elevation measured from the endocardial electrogram. Noninvasive voltage thresholds were measured at implantation, 2 days, 1, 3, and 6 months, and yearly thereafter for 5 years. There were no significant differences between leads in pacing or sensing capabilities at implantation. All three demonstrated similar increases in thresholds, peaking at 1 month, then falling to a plateau by 6 months and did not vary significantly thereafter. There were no significant differences in thresholds between leads during 5 years of follow-up. The lowest mean threshold at 5 years was 0.93 V at 0.5 ms. This study suggests that: (1) although these lead types all perform well, none offers any particular clinical advantage over another; (2) the degree of early threshold peaking precludes immediate postimplant output reduction, but later thresholds are sufficiently low to enable reductions in pacing output; (3) safe low energy pacing requires greater attention to the lead-generator combinations; (4) data obtained at subsequent annual follow-up provided no additional useful clinical information to that obtained at 1 year; and (5) in the absence of other differences, cost can be the deciding factor in lead selection.

Aged↗
PubMed1995

Does the induction of ventricular flutter or fibrillation at electrophysiologic testing after myocardial infarction have any prognostic significance?

This study examines the significance of inducing sustained ventricular fibrillation (VF) or ventricular flutter by programmed stimulation after infarction. Programmed ventricular stimulation was performed for prognostic reasons from the right ventricular apex at twice diastolic threshold using a protocol containing 4 extrastimuli. Of 502 patients tested 11 +/- 4 days after acute infarction, VF was induced in 164 (33%), ventricular flutter in 134 (27%), ventricular tachycardia (VT) in 44 (9%), and no arrhythmia in 160 (32%). All groups were similar in age, sex distribution, and sites of index infarction. Those with inducible VT had a higher incidence of multiple infarctions and a lower mean left ventricular ejection fraction at the time of testing. Without antiarrhythmic drug therapy, 8 patients (18%) with inducible VT experienced spontaneous VT or died instantaneously during the first year of follow-up. By contrast, only 1 (0.6%) patient with inducible VF, 1 (0.7%) with ventricular flutter, and 1 (0.6%) without any inducible arrhythmias experienced similar events in the same period (p < 0.001). By relating the cycle length of the induced monomorphic arrhythmia to later spontaneous electrical events, induced arrhythmias with cycle length as low as 230 ms still identified patients at high risk for spontaneous arrhythmias. Only the induction of sustained monomorphic VT with a cycle length > 230 ms indicates patients with ventricular electrical instability after infarction. The induction of VF or ventricular flutter is a negative test result with no adverse long-term prognostic significance.

Arrhythmias, Cardiac↗
PubMed1994

Electrophysiologic and histologic effects of dissection of the connections between the atrium and posterior part of the atrioventricular node.

OBJECTIVES: This study was designed to examine the effects of destroying the posterior approaches to the atrioventricular (AV) node. BACKGROUND: Surgical and catheter ablation procedures have been developed for the cure of AV junctional reentrant tachycardia. Some of these destroy the posterior approaches to the AV node. METHODS: Atrioventricular node function and electrical excitation of Koch's triangle and the proximal coronary sinus were examined in 18 dogs. Dissection of the posterior atrionodal connections was performed in 10 dogs and a sham procedure in 8. After 28 to 35 days, repeat electrophysiologic and mapping studies were performed to assess changes in AV node function and the routes of AV and ventriculoatrial (VA) conduction. The AV junction was then examined with light microscopy. RESULTS: The compact AV node was undamaged in eight cases (80%). In two cases minor fibrosis occurred at the posterior limit of the compact node. The right-sided posterior atrionodal connections lying between the coronary sinus orifice and the tricuspid annulus were replaced by scar tissue in all cases, but the left-sided posterior connections and the anterior connections remained intact. Atrioventricular and VA conduction intervals and refractory periods were not altered. Atrioventricular junctional echoes were present in 10 dogs before and in 7 dogs after dissection (p = 0.06). Posterior (slow pathway) retrograde exists from the AV node were present in seven dogs before and in seven dogs after dissection. However, retrograde atrial excitation was altered in four of these seven dogs, so that the site of exit from the AV node was more leftward than it had been preoperatively. The node remained responsive to autonomic blocking drugs postoperatively. Double atrial electrograms similar to slow pathway potentials were found in all dogs. CONCLUSIONS: This procedure ablates the posterior atrionodal connections but rarely damages the compact AV node. Atrioventricular node function is not impaired and the node is not denervated. The mechanism of cure of AV junctional reentrant tachycardia is probably damage to the perinodal atrium. This suggests that part of the slow AV node pathway may lie outside the compact AV node. Dual AV node exits and double atrial electrograms are present in the normal canine heart.

Animals↗
PubMed1994

Surgical procedure for the cure of atrioventricular junctional ("AV node") reentrant tachycardia: anatomic and electrophysiologic effects of dissection of the anterior atrionodal connections in a canine model.

OBJECTIVES: This study was undertaken to examine the electrophysiologic and anatomic effects of a surgical procedure that cures the anterior (common) type of atrioventricular (AV) junctional reentrant tachycardia. BACKGROUND: The procedure was designed to interrupt the reentrant circuit at the point of earliest atrial activation during AV junctional reentrant tachycardia, the anterior atrionodal connections. METHODS: Atrioventricular node function and the sequence of electrical excitation of Koch's triangle were examined in 18 dogs. Excitation of Koch's triangle was mapped using a 60-channel mapping system. Surgical dissection was performed in 10 dogs and a sham procedure in 8. After 28 to 35 days, AV node function and the atrial excitation pattern were reassessed. The AV junction was examined using light microscopy. RESULTS: Some degree of AV node damage was visible in all dogs in the dissection group, but it was minor in 40% of cases. The anterior part of the AV node was disconnected from the anterior atrionodal connections in all cases. Anterograde AV node function was mildly impaired. The median AH interval was increased (62 vs. 76 ms [interquartile ranges 48 to 72 and 64 to 104, respectively], p = 0.05), and the AV Wenckebach cycle length was increased (210 vs. 245 ms [interquartile ranges 200 to 230 and 210 to 260, respectively], p = 0.02). The degree of impairment of conduction was directly proportional to the length of dissection (p < 0.05) but not to the degree of damage to the AV node. Ventriculoatrial (VA) conduction was destroyed in 50% of dogs undergoing dissection but in none of those with a sham operation (p < 0.04). The AV node remained responsive to autonomic blocking drugs, and atrial mapping during ventricular pacing revealed that the site of exit from the AV node had been altered. CONCLUSIONS: The atrionodal connections closest to the His bundle are the preferred route of conduction through the AV node during normal AV or VA conduction. Destruction of these connections modifies AV node conduction. The surgical procedure selectively interrupts these connections, and this interruption is likely to be the mechanism of cure.

Animals↗
PubMed1994

Errors in manual measurement of QT intervals.

OBJECTIVE: To quantify the errors associated with manual measurement of QT intervals and to determine the source of the errors. DESIGN: A randomised study of QT measurement by four cardiologists of electrocardiograms plotted on paper in presentations with different noise levels, paper speeds, amplifier gains, and with and without a second QRST complex to indicate the RR interval. SUBJECTS: Four electrocardiograph leads (I, aVR, V1, V5) recorded in eight healthy people relaxing in a semirecumbent position. MAIN OUTCOME MEASURES: Manual measurement of QT interval in 512 electrocardiograms (eight subjects x four leads x eight presentations x two repeats) by each of four cardiologists. RESULTS: QT intervals measured were significantly longer with greater amplifier gain: by 8 ms for a doubling of gain (p < 0.005), equivalent to a doubling of T wave height. QT intervals measured were significantly longer at slower paper speeds: by 11 ms when paper speed was reduced from 100 to 50 mm/s (p < 0.001) and by 16 ms when speed was further reduced from 50 to 25 mm/s (p < 0.001). Neither the presence of noise nor the presence of a second QRST complex altered the mean QT measurements. There were consistent differences in the measurements between cardiologists, amounting to a maximum mean difference of 20 ms. CONCLUSIONS: Manual measurement of QT interval is significantly affected by the paper speed used to plot the electrocardiogram and by electrocardiogram gain, and hence also T wave amplitude. Manual QT measurement also differed consistently with different cardiologists.

Diagnostic Errors↗
PubMed1994

Is ventricular ectopy a legitimate target for ablation?

Radiofrequency ablation has an established role in the treatment of non-ischaemic ventricular tachycardia. A few patients present with symptomatic but benign ventricular ectopy that can be mapped to the right ventricular outflow tract. The successful use of radiofrequency ablation in a patient with drug resistant, symptomatic ventricular ectopy is reported. Radiofrequency ablation may have a useful role in more benign arrhythmias.

Catheter Ablation↗
PubMed1993

High resolution mapping of Koch's triangle using sixty electrodes in humans with atrioventricular junctional (AV nodal) reentrant tachycardia.

BACKGROUND: Recent evidence suggests that atrioventricular junctional reentrant tachycardia (AVJRT) uses a reentrant circuit that involves the atrioventricular (AV) node, the atrionodal connections, and perinodal atrial tissue. Electrogram morphology has been used to target the delivery of radiofrequency energy to the site of the "slow pathway," a component of this reentrant circuit. The aim of this study was to localize precisely the sites of atrionodal connections involved in AVJRT and to examine atrial electrogram morphologies and their spatial distribution over Koch's triangle. METHODS AND RESULTS: Electrical activation of Koch's triangle and the proximal coronary sinus was examined in 13 patients using a 60-point plaque electrode and computerized mapping system. Recordings were made during sinus rhythm (n = 12), left atrial pacing (n = 8), ventricular pacing (n = 12), and AVJRT (n = 12). During sinus rhythm electrical activation approached Koch's triangle and the AV node from the direction of the anterior limbus, activating the anterior part of the triangle before the posterior part. A zone of slow conduction during sinus rhythm was found within Koch's triangle in 64% of patients. The pattern of atrial activation in Koch's triangle during anterograde fast pathway conduction was similar to that seen during anterograde slow pathway conduction. Retrograde fast pathway conduction during ventricular pacing and during anterior (typical) AVJRT caused earliest atrial activation at the apex of Koch's triangle near the AV node-His bundle junction. In individual patients the site of earliest atrial activation was similar for both anterior AVJRT and retrograde fast pathway conduction during ventricular pacing. Retrograde slow pathway conduction during ventricular pacing and during posterior (uncommon or atypical) AVJRT caused earliest atrial activation posterior to the AV node near the orifice of the coronary sinus. This posterior or "slow pathway" exit site was 15 +/- 4 mm from the His bundle. In individual patients the site of earliest atrial activation was similar for both posterior AVJRT and retrograde slow pathway conduction during ventricular pacing. In one patient anterograde and retrograde conduction occurred via separate slow pathways during AVJRT: Complex atrial electrograms with two or more components were observed near the coronary sinus orifice and in the posterior part of Koch's triangle in all cases. These were categorized as either low or high frequency potentials according to the rapidity of the second component of the electrogram. Low frequency potentials were present at the site of earliest atrial excitation during retrograde slow pathway conduction in 5 of 5 cases (100%) and high frequency potentials in 4 of 5 cases (80%). However, both slow and high frequency potentials could be found at sites up to 16 mm from the site of earliest atrial excitation. CONCLUSIONS: At least two distinct groups of atrionodal connections exist. The site of earliest atrial activation during anterior AVJRT is similar to that of fast pathway conduction during ventricular pacing. This site is close to the His bundle-AV node junction. The site of earliest atrial activation during posterior AVJRT is similar to that of slow pathway conduction during ventricular pacing. This site is near the coronary sinus orifice, approximately 15 mm from the His bundle. The anterograde slow pathway appears to be different from the retrograde slow pathway in some patients. Double atrial electrograms are an imprecise guide to the site of earliest atrial excitation during retrograde slow pathway conduction.

Adolescent↗
PubMed1992

The management and outcome of late post-infarct ventricular tachycardia presenting to a district general hospital.

A review was undertaken of late post-infarct ventricular tachycardia in a district hospital cardiac care unit in order to study the clinical course of a total population of such patients from initial presentation to ultimate outcome. Thirty-six patients with this diagnosis were identified over a 3 1/2-yr period. Twelve were treated by empirically chosen antiarrhythmic drugs. Twenty-four were referred for electrophysiologically guided treatment, of whom 16 were treated by antiarrhythmic drugs, 3 by anti-ischaemic measures alone, and 5 by non-pharmacological antiarrhythmic treatments (antiarrhythmic surgery, percutaneous ablation, defibrillator implantation, cardiac transplantation). Of those treated empirically, 4 died in hospital of their arrhythmia, 1 died suddenly at home, and 2 suffered non-fatal arrhythmia recurrences during mean follow-up of 20 months. There were no arrhythmic deaths in those whose treatment was guided by serial electrophysiology studies, although 4 patients died of cardiac failure or reinfarction, and 3 were hospitalised with a recurrence of ventricular tachycardia during mean follow-up of 16 months. Age, concomitant medical problems and the apparent response to initial antiarrhythmic therapy were the main factors influencing management decisions. The apparent superiority of more intensive management strategies based on electrophysiology studies must be interpreted in the context of the selection processes applied to the total population initially presenting.

Aged↗
PubMed1992

Surgery for ventricular tachycardia associated with right ventricular dysplasia: disarticulation of right ventricle in 9 of 10 cases.

Ten patients (nine men, one woman; mean age 39 years) with arrhythmogenic right ventricular dysplasia underwent surgery to control life-threatening drug refractory ventricular arrhythmias. All had ventricular tachycardia causing syncope and six had a history of cardiac arrest. In all a minimum of three antiarrhythmic drugs (mean five) had been ineffective. At operation, the right ventricle was grossly diseased in all patients. Ventricular tachycardias were induced and mapped intraoperatively in all patients. The surgical plan was to ablate the arrhythmogenic focus if it was less than 4 cm2; one patient was so managed. Of the remaining nine, four underwent partial (approximately 40% of the right ventricular free wall) and five underwent total right ventricular disarticulation. All survived the operation and are alive at a mean follow-up interval of 24 months (range 5 to 67). Two patients developed new sustained ventricular tachycardias. These were well tolerated and, unlike the original arrhythmias, were easily controlled by drug treatment. All patients who underwent right ventricular disarticulation manifested signs of right heart failure in the early postoperative period, but these lessened progressively with the development of systolic septal movement into the right ventricular cavity. All 10 patients are in New York Heart Association class I or II at last review. In selected patients with arrhythmogenic right ventricular dysplasia, surgery offers a curative treatment for ventricular tachycardia and should be considered for patients whose arrhythmias are life-threatening and refractory to drug treatment.

Adolescent↗
PubMed1991

Routine programmed electrical stimulation in survivors of acute myocardial infarction for prediction of spontaneous ventricular tachyarrhythmias during follow-up: results, optimal stimulation protocol and cost-effective screening.

Of 3,286 consecutive patients treated for acute myocardial infarction, electrophysiologic testing was performed in 1,209 survivors (37%) free of significant complications at the time of hospital discharge to determine their risk of spontaneous ventricular tachyarrhythmias during follow-up. Sustained monomorphic ventricular tachycardia was inducible by programmed electrical stimulation in 75 (6.2%). Antiarrhythmic therapy was not routinely prescribed regardless of the test results. During the 1st year of follow-up, 14 infarct survivors (19%) with inducible ventricular tachycardia experienced spontaneous ventricular tachycardia or fibrillation in the absence of new ischemia compared with 34 (2.9%) of those without inducible ventricular tachycardia (p less than 0.0005). During the extended follow-up period (median 28 months) of those with inducible ventricular tachycardia, 19 (25%) had a spontaneous electrical event; 37% of these first events were fatal. These results suggest that the most cost-effective strategy for predicting arrhythmia will be obtained by restricting electrophysiologic testing to infarct survivors whose left ventricular ejection fraction is less than 40% and using a stimulation protocol containing four extrastimuli. Electrophysiologic testing is the single best predictor of spontaneous ventricular tachyarrhythmias during follow-up in infarct survivors. The majority (94%) with a negative test benefit from the more reliable reassurance that all is well, whereas the 25% risk of electrical events in those with inducible ventricular tachycardia justifies a prospective trial of effective prophylactic antiarrhythmic interventions.

Anti-Arrhythmia Agents↗
PubMed1991

Acute and chronic hemodynamic impact of total right ventricular disarticulation.

Right ventricular disarticulation is a radical operation to control ventricular arrhythmias in patients with arrhythmogenic right ventricular dysplasia. This report describes the acute and chronic hemodynamic impact of the procedure based on our experience of five patients with life-threatening arrhythmias unresponsive to medical therapy who have undergone total disarticulation of the right ventricle. Although all patients suffered acute postoperative hemodynamic problems, all survived and returned to an excellent functional class. Right ventricular disarticulation should be considered in patients with drug refractory ventricular tachycardias due to arrhythmogenic right ventricular dysplasia when the arrhythmia either poses a life threat or results in chronic morbidity.

Adult↗
PubMed1990

Valvar stenosis: a comparison of clinical assessment, echocardiography, Doppler ultrasound and catheterisation.

The relative merits of noninvasive techniques in the assessment of valve stenosis were examined by comparing the results of clinical assessment by two independent clinicians, the cross-sectional echocardiogram and Doppler ultrasound using the results of cardiac catheterisation as reference in 58 patients with a total of 60 stenotic valve lesions. Doppler ultrasound was the most reliable technique; it was correct in 57 (95%) of the 60 lesions. Clinical assessment and cross sectional echocardiography were correct in 48 (80%), and 46 (77%) of the 60 lesions, respectively. In 7 instances 2 noninvasive assessments were wrong in the same patient but on no occasion were all 3 techniques misleading in the same patient. In 17 patients with severe mitral stenosis, clinical assessment Doppler ultrasound and cross-sectional echocardiography were correct in 14 (82%), 16 (94%) and 17 (100%) patients, respectively, whilst in the 4 patients with moderate mitral stenosis the corresponding figures were 3 (75%), 4 (100%) and 2 (50%). In mild mitral stenosis (3 patients), the clinical assessment was correct in 2 (67%) patients, Doppler ultrasound in 3 (100%) patients and cross-sectional echocardiography in 2 (67%) patients. In 22 patients with severe aortic stenosis, the clinical assessment and Doppler ultrasound were correct in every patient (100%), whilst the cross-sectional echocardiogram was correct in 18 (82%) patients. In 11 patients with moderate aortic stenosis, the clinical assessment was correct in only 5 (45%) patients, the cross-sectional echocardiogram in 5 (45%) patients and Doppler assessment in 9 (82%) patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Reduction in incidence of inducible ventricular tachycardia after myocardial infarction by treatment with streptokinase during infarct evolution.

The aim of this study was to determine whether intravenous streptokinase administered with or without oral aspirin to patients with evolving myocardial infarction reduces the inducibility of ventricular tachycardia at electrophysiologic study and thus the risk of sudden death in infarct survivors. Of 159 patients randomized at Westmead Hospital to the multicenter Second International Study of Infarct Survival (ISIS-2) after streptokinase and aspirin in acute myocardial infarction, 87 underwent electrophysiologic testing 6 to 28 days after infarction to determine their risk of subsequent ventricular arrhythmias (streptokinase 20 patients; aspirin 25 patients; streptokinase and aspirin 21 patients; both placebos 21 patients). Patients who underwent electrophysiologic testing had similar clinical characteristics to those of patients who did not. The stimulation protocol comprised up to and including four extrastimuli applied to the right ventricular apex at twice diastolic threshold. An abnormal result was defined as ventricular tachycardia with a cycle length greater than or equal to 230 ms lasting greater than or equal to 10 s. Ventricular tachycardia was inducible at electrophysiologic study in 8 patients who received placebo streptokinase, but in no patient who received active streptokinase (8 of 46 versus 0 of 41; p = 0.005, Fischer's exact test). Ventricular tachycardia was inducible in 4 patients who received aspirin therapy and 4 who did not (4 of 41 versus 4 of 46; p = NS). During a mean follow-up period of 39 +/- 9 months, there were no spontaneous episodes of ventricular tachycardia, ventricular fibrillation or witnessed sudden death in the streptokinase-treated group compared with three such events in the placebo-treated group (p = 0.13). When compared with placebo therapy, intravenous streptokinase substantially reduced the incidence of inducible ventricular tachycardia in infarct survivors. No similar benefit was attributable to aspirin therapy.

Aspirin↗
PubMed1990

Surgery for control of recurrent life-threatening ventricular tachyarrhythmias within 2 months of myocardial infarction.

Twenty-seven patients (mean age 57 +/- 7 years) underwent surgery for control of recurrent drug-refractory ventricular tachyarrhythmias (uniform ventricular tachycardia alone in 9 patients, ventricular tachycardia and ventricular fibrillation in 15 and ventricular fibrillation alone in 3) within 2 months of acute myocardial infarction. The mean number of major arrhythmic episodes per patient was 15 (range 2 to 200) and of drug failures 4 +/- 2. Left ventricular function was severely impaired in the majority (ejection fraction 29%; range 14% to 47%) and 18 patients (66%) had a left ventricular aneurysm. Endocardial resection guided by a combination of endocardial activation mapping during tachycardia and fragmentation mapping during sinus rhythm was performed in all patients. All electrically abnormal left ventricular endocardium was excised. Eight patients (29.6%) died within 30 days of surgery. Death was not related to age, time of surgery after infarction, ventricular function, bypass time or type of arrhythmia. Patients requiring emergency surgery had a higher early postoperative mortality rate than did those undergoing planned surgery (43% versus 15%). During a follow-up period of 32 +/- 20 months, there have been no arrhythmic deaths and only three patients (16%) have required antiarrhythmic drug therapy. When required in the early weeks after infarction, surgery for ventricular arrhythmias offers a high cure rate at a risk related to the patient's preoperative arrhythmia frequency, which in turn relates to the risk of arrhythmic death.

Adult↗
PubMed1990

Left posterior fascicular tachycardia due to localized microreentry.

Fascicular tachycardia in young patients without overt heart disease constitutes a rare but electrophysiologically distinct arrhythmia entity. Microreentry within the left posterior fascicle has been proposed as its mechanism, but evidence for this is inconclusive. This report details a patient with incessant fascicular tachycardia. The electrophysiological features, in particular the pattern of resetting response, provided strong evidence for reentry as the tachycardia mechanism. Satisfactory long-term arrhythmia control was achieved with flecainide.

Adult↗