Pilsicainide-Induced Verapamil Sensitive Idiopathic Left Ventricular Tachycardia

A 20-year-old man was admitted to our hospital for treatment of verapamil sensitive idiopathic left ventricular tachycardia (ILVT). During the electrophysiologic study (EPS), no sustained ventricular tachycardia (VT) could be induced both at baseline and after infusion of isoproterenol. However, sustained clinical VT could be easily induced with single ventricular extrastimulation following intravenous administration of pilsicainide, a class Ic sodium channel blocker. The arrhythmia was ablated with radiofrequency catheter ablation.

Unique electrophysiologic characteristics of atrioventricular nodal reentrant tachycardia with different ventriculoatrial block patterns: effects of slow pathway ablation and insights into the location of the reentrant circuit

BACKGROUND

The electrophysiologic mechanisms of different ventriculoatrial (VA) block patterns during atrioventricular nodal reentrant tachycardia (AVNRT) are poorly understood.

OBJECTIVES

The purpose of this study was to characterize AVNRTs with different VA block patterns and to assess the effects of slow pathway ablation.

METHODS

Electrophysiologic data from six AVNRT patients with different VA block patterns were reviewed.

RESULTS

All AVNRTs were induced after a sudden AH "jump-up" with the earliest retrograde atrial activation at the right superoparaseptum. Different VA block patterns comprised Wenckebach His-atrial (HA) block (n = 4), 2:1 HA block (n = 1), and variable HA conduction times during fixed AVNRT cycle length (CL) (n = 1). Wenckebach HA block during AVNRT was preceded by gradual HA interval prolongation with fixed His-His (HH) interval and unchanged atrial activation sequence. AVNRT with 2:1 HA block was induced after slow pathway ablation for slow-slow AVNRT with 1:1 HA conduction, and earliest atrial activation shifted from right inferoparaseptum to superoparaseptum without change in AVNRT CL. The presence of a lower common pathway was suggested by a longer HA interval during ventricular pacing at AVNRT CL than during AVNRT (n = 5) or Wenckebach HA block during ventricular pacing at AVNRT CL (n = 1). In four patients, HA interval during ventricular pacing at AVNRT CL was unusually long (188 +/- 30 ms). Ablations at the right inferoparaseptum rendered AVNRT noninducible in 5 (83%) of 6 patients.

CONCLUSION

Most AVNRTs with different VA block patterns were amenable to classic slow pathway ablation. The reentrant circuit could be contained within a functionally protected region around the AV node and posterior nodal extensions, and different VA block patterns resulted from variable conduction at tissues extrinsic to the reentrant circuit.

Assessment of ability of activation mapping by duodecapolar catheter to diagnose complete isthmus block utilizing electroanatomical mapping system

Duodecapolar catheters (DPCs) have been widely used to diagnose isthmus block after ablation in patients with atrial flutters. The purpose of this study was to assess the ability of DPC to diagnose isthmus block utilizing electroanatomical mapping system (CARTO).

METHODS

Sixty-two patients with common atrial flutter underwent isthmus ablation during CS pacing while DPC was positioned at lateral wall of RA along tricuspid annulus (TA). When activation sequence of DPC recording changed exclusively counter-clockwise after ablation, or did not even after ablations targeting single potentials on ablation line (Ab-L), only lateral side of Ab-L was remapped using CARTO to assess whether complete block (CB) was established.

RESULTS

After ablation, DPC recording suggested CB and incomplete block (ICB) in 53 (85%) and 9 patients (15%), respectively. In 51/53 patients (96%) with CB suggested by DPC recordings, CARTO remap also demonstrated CB, however, in the remaining two patients (4%), demonstrated ICB with residual isthmus conduction that was slow enough to allow wavefront conducting around TA to arrive at distal dipole of DPC earlier, mimicking CB. In 4/9 patients (44%) with ICB suggested by DPC recordings, CARTO remap also demonstrated ICB, however, in the remaining five patients (56%), demonstrated CB with earlier arrival of wavefront traversing posterior wall at just lateral to Ab-L than that conducting around TA, mimicking ICB. Sensitivity, specificity, positive, and negative predictive values of DPC to diagnose CB were 91, 67, 96, and 44%, respectively.

CONCLUSIONS

Mapping using DPC would not be sufficient for diagnosis of CB and ICB.

Long-Term Follow-up of Transvenous Defibrillation Leads High Incidence of Fracture in Coaxial Polyurethane Lead

BACKGROUND

As a result of longer follow-up after implantation of cardioverter defibrillators (ICD), fatigue of the leads has become a concern. The aim of this study was to determine the incidence and clinical presentation of ICD lead failures.

METHODS AND RESULTS

The study population consisted of 241 patients with 249 ICD leads who underwent implantation of an ICD with a transvenous lead system. After device implantation, the patients were routinely followed up every 4 months. Five lead failures (2.0%) occurred as an oversensing of artifact during the follow-up period (2.6+/-2.1 years); 4 of those 5 patients received inappropriate shocks and 1 case of lead failure was identified in a patient with frequent episodes of non-sustained ventricular fibrillation. In particular, the right ventricular polyurethane transvenous lead in the Medtronic model 6936 failed in 4 (13%) of 31 cases. Percutaneous lead extraction was not available in all cases, so an additional ICD lead was inserted through the same site of the subclavian vein.

CONCLUSIONS

Lead failures may occur 5 years after ICD implantation and polyurethane leads have an especially high incidence of failure. However, there were no follow-up parameters observed that predicted lead failures.

Malignant Entity of Idiopathic Ventricular Fibrillation and Polymorphic Ventricular Tachycardia Initiated by Premature Extrasystoles Originating From the Right Ventricular Outflow Tract

OBJECTIVES

The aim of this study was to assess the clinical characteristics and the efficacy of radiofrequency catheter ablation (RFCA) for idiopathic ventricular fibrillation (VF) and/or polymorphic ventricular tachycardia initiated by ventricular extrasystoles originating from the right ventricular outflow tract (RVOT).

BACKGROUND

Ventricular fibrillation and/or polymorphic ventricular tachycardia are occasionally initiated by ventricular extrasystoles originating from the RVOT in patients without structural heart disease.

METHODS

Among 101 patients without structural heart disease in whom RFCA was conducted for idiopathic ventricular tachyarrhythmias arising from the RVOT, we examined the clinical characteristics and the efficacy of RFCA in 16 patients with spontaneous VF and/or polymorphic ventricular tachycardia initiated by the ventricular extrasystoles originating from the RVOT.

RESULTS

Among 16 patients, spontaneous episodes of VF were documented in 5 patients, and 11 patients had prior episodes of syncope. Holter recordings showed frequent isolated ventricular extrasystoles with the same morphology as that of initiating ventricular extrasystoles, and non-sustained polymorphic ventricular tachycardia with short cycle length (mean of 245 +/- 28 ms) in all 16 patients. Radiofrequency catheter ablation by targeting the initiating ventricular extrasystoles eliminated episodes of syncope, VF, and cardiac arrest in all patients during follow-up periods of 54 +/- 39 months.

CONCLUSIONS

Our data suggest that the malignant entity of idiopathic VF and/or polymorphic ventricular tachycardia was occasionally present in patients with idiopathic ventricular arrhythmias arising from the RVOT. Radiofrequency catheter ablation was effective as a treatment option for this entity.

Coexistence of the permanent form of junctional reciprocating tachycardia and atrial tachycardia

This case report describes a patient with the permanent form of junctional reciprocating tachycardia coexisting with atrial tachycardia. A detailed electrophysiological study established the diagnosis, and radiofrequency catheter ablation abolished both arrythmias.

Diagnostic value of epinephrine test for genotyping LQT1, LQT2, and LQT3 forms of congenital long QT syndrome

OBJECTIVES

The aim of this study was to test the hypothesis that epinephrine test may have diagnostic value for genotyping LQT1, LQT2, and LQT3 forms of congenital long QT syndrome (LQTS).

BACKGROUND

A differential response of dynamic QT interval to epinephrine infusion between LQT1, LQT2, and LQT3 syndromes has been reported, indicating the potential diagnostic value of the epinephrine test for genotyping the three forms.

METHODS

The responses of 12-lead ECG parameters to epinephrine were retrospectively examined in 15 LQT1, 10 LQT2, 8 LQT3, and 10 healthy volunteers to select the best ECG criteria for separating the four groups. The epinephrine test then was prospectively conducted in 42 probands clinically affected with LQTS, their 67 family members, and 10 new volunteers. The best criteria were applied in a blinded fashion to prospectively separate a different group of 31 LQT1, 23 LQT2, 6 LQT3, and 30 Control patients (10 genotype-negative LQT1, 10 genotype-negative LQT2 family members, and 10 volunteers).

RESULTS

The sensitivity (penetrance) by ECG diagnostic criteria was lower in LQT1 (68%) than in LQT2 (83%) or LQT3 (83%) before epinephrine and was improved with steady-state epinephrine in LQT1 (87%) and LQT2 (91%) but not in LQT3 (83%), without the expense of specificity (100%). The sensitivity and specificity to differentiate LQT1 from LQT2 were 97% and 96%, those from LQT3 were 97% and 100%, and those from Control were 97% and 100%, respectively, when Delta mean corrected Q-Tend >/=35 ms at steady state was used. The sensitivity and specificity to differentiate LQT2 from LQT3 or Control were 100% and 100%, respectively, when Delta mean corrected Q-Tend >/=80 ms at peak was used.

CONCLUSIONS

Epinephrine infusion is a powerful test to predict the genotype of LQT1, LQT2, and LQT3 syndromes as well as to improve the clinical diagnosis of genotype-positive patients, especially those with LQT1 syndrome.

Response of beat-by-beat QT variability to sympathetic stimulation in the LQT1 form of congenital long QT syndrome

OBJECTIVES

The purpose of this study was to test the hypothesis that the lability of beat-by-beat QT variability is prominent during sympathetic stimulation in LQT1 patients. We analyzed beat-by-beat QT variability using a newly developed program and applied cross-correlation methods in LQT1 patients before and after epinephrine infusion.

BACKGROUND

Studies suggest that cardiac events associated with sympathetic stimulation are more common in the LQT1 form than the LQT2 and LQT3 forms of congenital long QT syndrome (LQTS). Although beat-by-beat alternation of T-wave morphology is observed in LQTS, its objective estimation is difficult because of complicated T-wave morphology.

METHODS

Twelve-lead ECG was recorded under baseline conditions and during epinephrine infusion (0.1 mug/kg/min) in 14 LQT1 and five control patients. We measured beat-by-beat QT interval by a cross-correlation technique. Mean of successive changes in RR (DeltaRR), QT (DeltaQT), standard deviation of DeltaRR (SD-DeltaRR), DeltaQT (SD-DeltaQT), and QTI (QT/ RR) before and after epinephrine were compared between the two groups.

RESULTS

No significant differences in any parameters were observed between the two groups under baseline conditions. DeltaQT, SD-DeltaQT, and QTI were increased in LQT1 but not in control patients during epinephrine (LQT1: DeltaQT 2.3-4.2 ms, SD-DeltaQT 2.2-4.1, QTI 0.10-0.22, P < .005 vs baseline;

CONTROL

DeltaQT 2.5-2.4 ms, SD-DeltaQT 1.9-2.1, QTI 0.08-0.09: P = NS vs baseline).

CONCLUSIONS

Beat-by-beat QT variability analyzed by the cross-correlation method was greater in LQT1 patients during epinephrine infusion, suggesting sympathetic stimulation accentuates beat-by-beat alternation of repolarization in LQT1 patients.

Diagnostic value of the recovery time-course of st slope on exercise ECG in discriminating false-from true-positive ST-segment depressions

BACKGROUND

Using the exercise ECG for diagnosing coronary artery disease (CAD) is hampered by the occurrence of false-positive (FP) ST-segment depression. Because it is known that the recovery ST-T time-course in CAD differs from that in FP subjects, the ST slope may help discriminate FP from true-positive (TP) results.

METHODS AND RESULTS

Treadmill digitized ECG from patients with significant ST-segment depressions and normal resting ECG were analyzed in 134 patients with CAD on angiography (>50% narrowing) and reversible perfusion defects (TP group), and 64 subjects with normal perfusion (FP group) on exercise single photon emission computed tomography. The ST slope between the J-point and J(80) was measured every minute up to 6-min postexercise. The ST slope was significantly higher in FP than in TP at peak exercise, and at postexercise 1-, 2- and 3-min (p<0.01, all). Thereafter, it gradually increased in TP, while monotonically decreasing in FP. Its decrease from 3- to 6-min could correctly diagnose 88% of FP subjects, whereas it was found in only 19% of TP patients (total accuracy 83%).

CONCLUSIONS

The ST slope change from early to late recovery is a simple yet reliable marker for discriminating FP from TP ST-segment responses in subjects with a normal resting ECG.

Pronounced HR variability after exercise in inferior ischemia: evidence that the cardioinhibitory vagal reflex is invoked by exercise-induced inferior ischemia

Potent cardioinhibitory vagal reflex resulting in bradycardia and hypotension has been observed under particular conditions of transmural inferior ischemia and its reperfusion, such as those observed with acute infarction. However, whether exercise-induced ischemia with ST depressions that is subendocardial and that might be recurrently experienced in daily activities can evoke this reflex remains unknown. In patients with exercise-induced ST depressions due to either inferior [right coronary artery stenosis (RCA), n = 52] or anterior ischemia [left anterior descending artery stenosis (LAD), n = 51], we evaluated post exercise vagal activity (from 0 to 6 min) by the time constant of heart rate (HR) decay and HR variability by 30-s averages of the absolute values of successive RR interval differences (ΔRR). Exercise parameters were similar between groups. The time constant was slightly but significantly shorter in RCA than LAD patients (79 ± 24 vs. 93 ± 29 s, P < 0.01). More significantly, ΔRR early after exercise (0.5–2.5 min) was approximately twofold greater in RCA than LAD patients (from +76 to +118%, P < 0.001), indicating pronounced vagal activity stimulated by inferior ischemia. Revascularization prolonged the time constant ( P < 0.05) and attenuated recovery ΔRR in RCA patients ( P < 0.05, n = 10) but did not change both parameters in LAD patients ( n = 12). As well as acute inferior infarction, exercise-induced inferior subendocardial ischemia, which might recurrently occur in daily activities, activates the cardioinhibitory reflex. These new findings must be taken into account in interpreting vagal activity in patients with coronary artery disease.

Surgical treatment of unruptured cerebral aneurysms in the elderly

We retrospectively analyzed the prevalence and surgical outcomes of unruptured cerebral aneurysms in the elderly for the past five years. Between 1998 and 2002, we collected data from 575 subjects with unruptured aneurysms who had no history of subarachnoid hemorrhage (SAH). One hundred and eighty-two of these patients (31.7%) were aged > or = 70 years and they had 233 aneurysms. The proportion of older patients among all subjects increased significantly from 21.4% in 1998 to 40.3% in 2002. Unruptured aneurysms found in the elderly had a predominance of female, higher frequency of multiple aneurysms, and lower frequency of anterior communicating artery aneurysms when compared with those in the younger patients. The majority of intradural aneurysms detected in the elderly were less than 10 mm in diameter (84.8%). One hundred and eleven out of 224 intradural aneurysms in the elderly were treated (49.6%); most aneurysms were directly clipped, while only 13 aneurysms including six basilar artery aneurysms were coiled endovascularly. Among the 83 elderly subjects who underwent direct surgery, perioperative complication appeared in seven subjects (morbidity 8.4%, mortality 1.2%). No SAH occurred postoperatively and conservatively during 1-5 years of follow-up. Since the rupture rate of small unruptured aneurysms without SAH history is reported to be low, surgical indication should be considered with care particularly in the elderly.

Classification and mechanism of initiation in patients with congenital long QT syndrome

AIMS

To examine the initiating mode of Torsade de Pointes (TdP) in patients with congenital long QT syndrome (LQTS).

METHODS AND RESULTS

We evaluated 111 episodes of TdP recorded on the electrocardiograms of 24 patients with congenital LQTS, and clarified the initiating mode, the three consecutive preceding RR intervals defined as C(2), C(1), and C(0), the timing of initiating premature ventricular contraction (PVC) and the cycle length (CL) of TdP. Three different initiating patterns were observed: (1) a "short-long-short" sequence (SLS) pattern (23 patients, 72 TdP, 65%) defined as one or more short-long cardiac cycles followed by an initiating short-coupled PVC (C(1)>C(2) and C(0)), (2) an "increased sinus rate" (ISR) pattern (8 patients, 28 TdP, 25%) defined as a gradual increase in sinus rate with or without T-wave alternans (C(2)>/=C(1)>/=C(0)), and (3) a "changed depolarization" (CD) pattern (5 patients, 11 TdP, 10%) defined as a sudden long-coupled PVC or fusion beat followed by short-coupled PVC. The C(0) was shorter in ISR than SLS and CD (mean C(0): 488 vs. 587 and 603 ms, respectively; P<0.05). Therefore, the initiating PVC appeared near the T-wave peak of the last beat before onset in ISR, while it occurred after the T-wave peak in SLS and CD. The CL of TdP was shorter in ISR than in SLS (256 vs. 295 ms, P<0.05).

CONCLUSIONS

Our data show the existence of three predominant initiating modes of TdP in patients with congenital LQTS and suggests a differential mechanism of initiation of TdP for each mode.

Excessive Increase in QT Interval and Dispersion of Repolarization Predict Recurrent Ventricular Tachyarrhythmia after Amiodarone

Although chronic amiodarone has been proven to be effective to suppress ventricular tachycardia (VT) and ventricular fibrillation (VF), how we predict the recurrence of VT/VF after chronic amiodarone remains unknown. This study evaluated the predictive value of the QT interval, spatial, and transmural dispersions of repolarization (SDR and TDR) for further arrhythmic events after chronic amiodarone. Eighty-seven leads body surface ECGs were recorded before (pre) and one month after (post) chronic oral amiodarone in 50 patients with sustained monomorphic VT associated with organic heart disease. The Q-Tend (QTe), the Q-Tpeak (QTp), and the interval between Tpeak and Tend (Tp-e) as an index of TDR were measured automatically from 87-lead ECG, corrected Bazett's method (QTce, QTcp, Tcp-e), and averaged among all 87 leads. As an index of SDR, the maximum (max) minus minimum (min) QTce (max-min QTce) and standard deviation of QTce (SD-QTce) was obtained among 87 leads. All patients were prospectively followed (15 +/- 10 months) after starting amiodarone, and 20 patients had arrhythmic events. The univariate analysis revealed that post max QTce, post SD-QTce, post max-min QTce, and post mean Tcp-e from 87-lead but not from 12-lead ECG were the significant predictors for further arrhythmic events. ROC analysis indicated the post max-min QTce > or = 106 ms as the best predictor of events (hazard ratio = 10.4, 95%, CI 2.7 to 40.5, P = 0.0008). Excessive QT prolongation associated with increased spatial and transmural dispersions of repolarization predict the recurrence of VT/VF after amiodarone treatment.

Impact of biochemical failure on long-term clinical outcome after radical prostatectomy for prostate cancer in Japan

Detailed information is needed to understand the impact of biochemical failure (bF) on long-term outcome after definitive therapy for prostate cancer. In all, 223 consecutive men treated with radical retropubic prostatectomy were followed and long-term clinical outcome was investigated. Pathological examination revealed more locally advanced tumors in this study compared with the typical cohorts seen in the Western series. The Cox proportional hazards model indicates pretreatment prostate-specific antigen levels and risk group stratification to be a significant predictors for bF (P<0.05), but not for overall survival. Seminal vesicle involvement was a significant predictor of systemic progression, cancer death and overall survival (P<0.05). Positive surgical margin and bF were also found to be independent predictors of overall survival (P<0.05). In contrast to reports from Western countries, this study found a significant correlation between bF after radical prostatectomy and overall survival. This may reflect years-later detection of prostate cancer in Japan compared with Western series. Biochemical failure may ultimately be translated into decreased overall survival after sufficient follow-up.

Changes in prostate-specific antigen and hormone levels following withdrawal of prolonged androgen ablation for prostate cancer

We conducted a study in order to characterize changes after withdrawal of androgen ablation (AA) for prostate cancer. AA was withdrawn in 38 Japanese patients with prostate cancer who had undergone this therapy for various periods. Patients were stratified into those who had undergone AA for less than 24 months (Group 1, n=12) and those with longer periods of AA (Group 2, n=26). Serial changes in hormones and prostate-specific antigen (PSA) were prospectively monitored following cessation of AA. The median durations of AA in the two groups were 8.5 and 54.5 months, respectively. Levels of total testosterone (T), luteinizing hormone and PSA increased significantly with time. At the end of 2 y, 30/38 patients (78.9%) had T levels above 50 ng/dl and 19/38 (50%) had levels above 320 ng/dl. Patients in Group 2 required significantly longer duration for T recovery. Complete T recovery is not always accompanied by rising PSA. Recovery of T levels is often slow following cessation of prolonged AA. Expression of PSA after AA is often variable and unpredictable. Thus, interpretation of outcomes in clinical trials incorporating AA needs caution and careful consideration.

Ventricular Tachycardia with Figure Eight Pattern Originating From the Right Ventricle in A Patient with Cardiac Sarcoidosis

This case report describes VT with figure eight pattern originating from the right ventricle in a 33-year-old patient with cardiac sarcoidosis. Multiple radiofrequency linear ablation could abolish the VT, and this patient has been clinically free from symptoms of VT during a 6-month follow-up.

Ventricular Tachycardia Associated with Bidirectional Reentrant Circuit Around the Tricuspid Annulus in Arrhythmogenic Right Ventricular Dysplasia

This case report describes two distinct morphological ventricular tachycardias (VTs) associated with bidirectional reentrant circuit around the tricuspid annulus in a 32-year-old patient with arrhythmogenic right ventricular dysplasia. Multiple radiofrequency linear ablation could abolish both VTs, and this patient has been clinically free from symptoms of VTs at 1-year follow-up.

A simple and accurate method to identify early ventricular contraction sites in Wolff-Parkinson-White syndrome using high frame-rate tissue-velocity imaging

The high frame-rate tissue-velocity imaging method may be superior to the conventional M-mode method in accurately localizing accessory pathways without consuming large amounts of time.