Skin burns associated with radiofrequency catheter ablation of cardiac arrhythmias.

Skin burns are a rare complication associated with radiofrequency catheter ablation of cardiac arrhythmias. Burns related to the indifferent electrode patch may be severe and result in significant comorbidity. We describe our experience of skin burns and discuss potential predisposing and possible causative factors.

Successful ablation for atrioventricular nodal reentrant tachycardia in a patient with left atrial isomerism.

Left atrial isomerism (LAI) is characterized by the presence of two morphologically identical atria. It is commonly associated with conduction defects. We report a case of LAI presenting with highly symptomatic atrioventricular nodal reentrant tachycardia, which was cured by ablation.

Cryoballoon ablation for iatrogenic left atrial tachycardia.

Percutaneous and surgical left atrial ablation has been widely used to treat paroxysmal and persistent atrial fibrillation. However, left atrial ablation may result in left atrial tachycardia due to an iatrogenic substrate created by the ablation lesion sets. Ablation of these iatrogenic arrhythmias can be technically challenging, requiring prolonged procedures and the use of three-dimensional electroanatomical mapping systems. In some cases, the atrial tachycardia may terminate during mapping, or may degenerate into atrial fibrillation during the procedure before adequate mapping. Some patients also have several arrhythmia circuits, each requiring separate mapping, which may be time consuming. The present article reports the cases of three patients in whom a large cryoballoon was used to empirically ablate the pulmonary vein antral region, which is important for the initiation and maintenance of these arrhythmias.

Endocardial ablation of ventricular ectopic beats arising from the basal inferoseptal process of the left ventricle.

BACKGROUND: Idiopathic ventricular ectopy (VE) shows predilection to sites within the left ventricular (LV) base such as the outflow tract/aortic sinuses, LV summit, and areas adjacent to the aortomitral continuity. We characterize VE arising from the inferior septum of the LV base that was successfully managed by LV endocardial ablation from the inferoseptal recess of the LV. OBJECTIVE: The purpose of this study was to determine the incidence, electrocardiographic (ECG) findings, electrophysiological findings, and anatomical features associated with VE arising from the basal inferoseptal process of the LV (ISP-LV) ablated using an LV endocardial approach via the inferoseptal recess of the LV. METHODS: A total of 425 consecutive patients undergoing VE ablation between January 1, 2012 and December 31, 2016 at 3 centers were evaluated. Demographic characteristics, ECG findings, and procedural data were analyzed for patients with ISP-LV VEs. RESULTS: Seven (1.5%) had a site of origin from the ISP-LV. Common ECG findings were a right bundle branch block concordant pattern or an atypical left bundle branch block early transition pattern, suggestive of a basal origin with a left superior axis, a biphasic QRS complex in lead aVR, and a small s wave in lead V6. Earliest activation was seen in an area below the outflow tract accessed from the inferoseptal recess inferior to the His bundle. In 3 cases, transient junctional rhythm was seen during ablation. All cases were ablated successfully with no complications. CONCLUSION: VE arising from the ISP-LV represents a distinct subset of idiopathic arrhythmia and can be successfully treated by endocardial catheter ablation from the inferoseptal recess. They share common surface ECG and electrophysiological findings with special anatomical features that need recognition for successful catheter ablation.

Delayed paced ventricular activation in the long QT syndrome is associated with ventricular fibrillation.

BACKGROUND: LQTS may cause sudden cardiac death (SCD), but the mechanisms linking gene mutations to ventricular fibrillation (VF) are unclear. OBJECTIVE: To determine whether ventricular activation delays in congenital long QT syndrome (LQTS) are associated with VF and to describe these delays clinically by measuring activation through ventricular myocardium after a premature extrastimulus. METHODS: Forty-six patients with LQTS, including 16 with VF (LQTS VF) were investigated, and the results were compared with those from 24 patients with hypertrophic cardiomyopathy and VF (HCM VF). Electrograms in response to premature stimuli were analyzed for increases in electrogram duration (DeltaED) and the S1S2 coupling intervals at which electrogram latency starts to increase (S1S2(delay)). Two piecewise continuous straight line segments were fitted to the last electrogram deflection as a function of S1S2 interval in the LQTS and HCM VF populations, and the difference in their gradient (alpha) was taken as an index of the abruptness of the onset of this delay. RESULTS: Thirteen LQTS VF and six LQTS non-VF patients had values of DeltaED and S1S2(delay) comparable to those in HCM VF patients, while the remainder (three LQTS VF and 24 LQTS non-VF) had lower values (P<.001). There was only a weak correlation between delay and the corrected QT interval. The HCM and LQTS VF patients could be separated by the value of alpha (P<.01), with the LQTS patients having a more abrupt onset of delay. CONCLUSIONS: Large delays in ventricular activation after an extrastimulus occur in patients with the LQTS, especially those with VF. The change in delay is abrupt in the LQTS, indicating sudden block to activation creating a dynamic substrate for arrhythmogenesis.

Percutaneous mitral commissurotomy using the metallic valvulotome technique in a critically ill adult.

A 25-year-old man presented with cardiogenic shock secondary to rheumatic mitral stenosis. Despite aggressive medical treatment he continued to deteriorate. This report describes the successful use of the metallic valvulotome technique for mitral commissurotomy in the context of a critically ill patient.

Impact of race in using PSA velocity to predict for prostate cancer.

OBJECTIVE: To assess whether race is a significant factor in the ability of prostate-specific antigen velocity (PSAV) for predicting high-grade prostate cancer (HGPC). METHODS: Records of men who underwent prostate biopsy between January 2003 and December 2007 were retrospectively reviewed to collect demographic data, self-reported race, prostate-specific antigen (PSA) data, and pathology results. PSAV was calculated using linear regression. Subjects were stratified by the presence or absence of HGPC. Median PSA and PSAV values were compared within each racial group using receiver operating characteristic analysis and Student t test. RESULTS: Static PSA was significantly higher in Caucasian men with HGPC (4.81 vs. 8.3 ng/mL, p = 0.0000001) while PSAV was also higher in men with HGPC (0.639 vs. 1.15 ng/mL/yr, p = 0.081). Static PSA in Asians did not perform well in predicting HGPC (5.3 vs. 9.42 ng/mL, p = 0.11), but fared much better than PSAV (0.51 vs. 0.93 ng/mL/yr, p = 0.27). PSA in African Americans did not significantly predict HGPC (6.27 vs. 7.7 ng/mL, p = 0.474), but PSAV showed a stronger trend toward significance (0.615 vs. 1.54 ng/mL/yr, p = 0.068). CONCLUSIONS: PSAV may complement static PSA in African Americans and help identify early stage aggressive cancers.

Why we Should Not Delay Ablation in New Onset Recurrent Atrial Fibrillation.

Recurrent episodes of atrial fibrillation are associated with progressive left atrial substrate remodelling over time. We present an argument for early ablation in the treatment of recurrent paroxysmal atrial fibrillation prior to such deleterious changes in "left atrial electrical health".

Intra-isthmus reentry associated with uncorrected double inlet left ventricle and transposition of the great arteries.

A 62-year-old man with uncorrected cyanotic congenital heart disease involving double inlet left ventricle with visceral and atrial situs solitus, L-looped ventricles, L-transposed great vessels, and pulmonary stenosis, presented with recurrent atrial tachycardia. Entrainment mapping revealed the arrhythmia mechanism to be an uncommon micro-reentrant cavotricuspid isthmus-dependent circuit (intra-isthmus reentry), which was amenable to radiofrequency ablation. This uncommon right atrial arrhythmia is yet to be reported in patients with complex congenital heart disease and was amenable to radiofrequency ablation.

Cardiac arrhythmia management using a noncontact mapping multielectrode array.

BACKGROUND: The multielectrode array (MEA) enables noncontact mapping of cardiac arrhythmias; our experience is reviewed and reported. HYPOTHESIS: The MEA has a role as first line therapy in multiple arrhythmias. METHODS: Retrospective and prospective analysis of all consecutive cases performed using the MEA over a 6 year period. RESULTS: Electrophysiological study and catheter ablation, 46% under general anaesthesia, using radiofrequency (RF), cryothermal and low energy direct current (DC) was performed in 66 procedures on 31 females and 29 males, average age 50.2 yrs (19.3-81.6); 8 patients underwent multiple procedures. 24 patients (36%) had undergone past ablation for the same arrhythmia. A wide variety of arrhythmias from all chambers were treated, majority right atrial (56%) and right ventricular (29%). Procedural success was complete in 77.4% and partial/indeterminate in 11.3%, highest in right atrial tachycardia, right ventricular outflow tract ectopy and typical atrial flutter (79, 82 and 100%). RF energy was most commonly used (67%) and DC carried 100% success. Ablation was delivered at 'early activation' and 'breakout' in focal arrhythmias. In re-entrant circuits linear ablation transecting path of activation extending to regions of functional/anatomic block was performed. Two of 7 complications were attributed to the MEA: groin haematomas. At mean 12.4 mo follow up 56% were arrhythmia free, 15% asymptomatic or minimally symptomatic and 12 patients had new arrhythmias. CONCLUSIONS: The MEA is effective, safe and suitable for first line therapy in multiple cardiac arrhythmias particularly in the right heart. Further study is warranted comparing it to other mapping techniques.

Catheter ablation of premature ventricular contraction-induced cardiomyopathy.

BACKGROUND: A 44-year-old female presented with a long history of chest pain, palpitations and increasing dyspnea. Electrocardiography and 24 h Holter monitoring revealed multiple premature ventricular complexes (PVCs), and echocardiography demonstrated significant left ventricular dilatation and systolic impairment. After further investigation it was concluded that this cardiomyopathy was secondary to the observed multiple PVCs and that these represented a potential target for treatment. INVESTIGATIONS: Electrocardiography, echocardiography, cardiac MRI, 24 h Holter monitoring, coronary angiography, tilt testing and invasive electrophysiological testing using a multielectrode array catheter. DIAGNOSIS: PVC-induced dilated cardiomyopathy. MANAGEMENT: Electrophysiological mapping and cryoablation of the focus of the ventricular ectopy.

Arrhythmic complications of electrical cardioversion: relationship to shock energy.

BACKGROUND: Existing guidelines for electrical cardioversion (ECV) of atrial arrhythmias suggest starting at a low energy setting on the grounds that shocks of high energy might damage the myocardium or trigger more serious arrhythmias. We hypothesised that more powerful shocks would exceed the upper limit of vulnerability for inducing ventricular fibrillation. The initial use of higher energy could therefore reduce arrhythmic complications. METHODS: We collected data on the sequence of shocks delivered and the resulting changes in cardiac rhythm in 1896 patients who underwent transthoracic ECV. Rhythm strips derived from 200 consecutive ECV attempts were studied to verify the accuracy of the synchronisation of the shocks delivered. RESULTS: In 2522 attempts at transthoracic ECV, 6398 shocks were delivered, 1243 in atrial flutter or atrial tachycardia, the others in AF. Ventricular fibrillation was significantly more common after shocks of < 200 J (5 of 2959 vs. 0 of 3439 shocks, p<0.05, Fischer's exact test). Conversion of atrial flutter or atrial tachycardia to AF was also more common at < 200 J (20 of 930 shocks vs. 1 of 313 shocks at > or = 200 J, p<0.05, chi2 test). Sinus bradycardia or sinus arrest complicated 0.95% of cardioversion attempts, but none required emergency pacing. The incidence of bradycardia was not related to the energy used. CONCLUSIONS: Shocks of > 200 J are associated with fewer tachyarrhythmic complications, and do not increase the risk of other serious complications. Bradycardia after cardioversion is very rarely of clinical importance.