Ippei Tsuboi

Recovery of atrioventricular block following steroid therapy in patients with cardiac sarcoidosis

BACKGROUND Atrioventricular (AV) block is one of the main clinical manifestations in patients with cardiac sarcoidosis (CS). Although steroid therapy is considered to be effective for AV block, the efficacy has not been demonstrated in detail. METHODS AND RESULTS Fifteen CS patients presenting with advanced or complete AV block were retrospectively investigated. All patients were treated with 30mg/day of prednisone after device implantation, which was tapered to a maintenance dosage of 5-10mg/day. During a mean follow-up of 7.1 years, AV block resolved to normal conduction or first-degree AV block in 7 patients (recovery group). The improvement was driven within the first week of steroid therapy in 4 patients, while 3 patients showed late recovery of AV conduction. The remaining 8 patients were classified as the non-recovery group. The recovery group showed a higher left ventricular ejection fraction (69.4±8.9% versus 44.1±19.3%, p=0.029) and higher prevalence of advanced AV block (87.5% versus 28.6%, p=0.040) compared with those of the non-recovery group. In patients with the recovery group, there was no late recurrence of AV block during the follow-up period. CONCLUSIONS Early initiation of steroid therapy may be effective for AV block, and steroid therapy before device implantation is a possible therapeutic strategy for some selected patients.

A case of streptococcal toxic shock syndrome due to Group G streptococci identified as Streptococcus dysgalactiae subsp. equisimilis

A 79-year-old man with a 3-month history of lymphedema of the lower limbs, and diabetes mellitus, was admitted to our hospital for suspected deep venous thrombosis. Several hours after admission, leg pain and purpura-like skin color appeared. On the 2nd hospital day, he was referred to our department for possible acute occlusive peripheral artery disease (PAD) and skin necrosis with blisters; however, computed tomography with contrast showed no occlusive lesions. He had already developed shock and necrotizing deep soft-tissue infections of the left lower leg. Laboratory findings revealed renal dysfunction and coagulation system collapse. Soon after PAD was ruled out, clinical findings suggested necrotizing deep soft-tissue infections, shock state, disseminated intravascular coagulation, and multiple organ failure. These symptoms led to a high suspicion of the well-recognized streptococcal toxic shock syndrome (STSS). With a high suspicion of STSS, we detected Group G β-hemolytic streptococci (GGS) from samples aspirated from the leg bullae, and the species was identified as Streptococcus dysgalactiae subsp. equisimilis (SDSE) by 16S-ribosomal RNA sequencing. However, unfortunately, surgical debridement was impossible due to the broad area of skin change. Despite adequate antimicrobial therapy and intensive care, the patient died on the 3rd hospital day. The M-protein gene (emm) typing of the isolated SDSE was revealed to be stG6792. This type of SDSE is the most frequent cause of STSS due to GGS in Japan. We consider it to be crucial to rapidly distinguish STSS from acute occlusive PAD to achieve life-saving interventions in patients with severe soft-tissue infections.

Urgent catheter ablation for sustained ventricular tachyarrhythmias in patients with acute heart failure decompensation

AIMS Ventricular tachycardia (VT) and ventricular fibrillation (VF) are not uncommon in patients hospitalized with acute heart failure (AHF). We sought to evaluate the efficacy of urgent radiofrequency catheter ablation (RFCA) for recurrent VT/VF during AHF decompensations. METHODS AND RESULTS The present study retrospectively analysed the data of 15 consecutive patients (69 ± 9 years, ischaemic heart disease in 10), who underwent urgent RFCA for frequent drug-refractory VT/VF episodes during an AHF decompensation with pulmonary congestion. The target arrhythmias were clinically documented monomorphic VTs in 10 patients, frequent premature ventricular contractions (PVCs) triggering VF in 4, and both in 1. The mean left ventricular ejection fraction was 26 ± 8%. The maximum number of arrhythmia episodes over 24 h was 9.1 ± 11.7. All RFCA sessions were completed without any major complications except for a temporary deterioration of pulmonary congestion in three patients (20%). Elimination and non-inducibility of the target arrhythmias were achieved in 13 patients (87%). Successful ablation site electrograms showed Purkinje potentials for all 5 PVCs triggering VF and 4 of 14 clinically documented monomorphic VTs (29%). Five patients (33%) underwent second sessions 10 ± 4 days after the first session for acute recurrences. Sustained VT/VF was completely suppressed during admission in 12 patients (80%), and the AHF ameliorated in 13 patients (93%). Twelve patients (80%) were discharged alive. CONCLUSION Urgent RFCA for drug-resistant sustained ventricular tachyarrhythmias during AHF decompensations would be an appropriate therapeutic option. Purkinje fibres can be ablation targets not only in those with PVCs triggering VF, but also in those with monomorphic VT.

Efficacy and safety of flecainide for ventricular arrhythmias in patients with Andersen-Tawil syndrome with KCNJ2 mutations

BACKGROUND Andersen-Tawil syndrome (ATS) is an autosomal dominant genetic or sporadic disorder characterized by ventricular arrhythmias (VAs), periodic paralyses, and dysmorphic features. The optimal pharmacological treatment of VAs in patients with ATS remains unknown. OBJECTIVE We evaluated the efficacy and safety of flecainide for VAs in patients with ATS with KCNJ2 mutations. METHODS Ten ATS probands (7 females; mean age 27 ± 11 years) were enrolled from 6 institutions. All of them had bidirectional VAs in spite of treatment with β-blockers (n = 6), but none of them had either aborted cardiac arrest or family history of sudden cardiac death. Twenty-four-hour Holter recording and treadmill exercise test (TMT) were performed before (baseline) and after oral flecainide therapy (150 ± 46 mg/d). RESULTS Twenty-four-hour Holter recordings demonstrated that oral flecainide treatment significantly reduced the total number of VAs (from 38,407 ± 19,956 to 11,196 ± 14,773 per day; P = .003) and the number of the longest ventricular salvos (23 ± 19 to 5 ± 5; P = .01). At baseline, TMT induced nonsustained ventricular tachycardia (n = 7) or couplets of premature ventricular complex (n = 2); treatment with flecainide completely (n = 7) or partially (n = 2) suppressed these exercise-induced VAs (P = .008). In contrast, the QRS duration, QT interval, and U-wave amplitude of the electrocardiogram were not altered by flecainide therapy. During a mean follow-up of 23 ± 11 months, no patients developed syncope or cardiac arrest after oral flecainide treatment. CONCLUSION This multicenter study suggests that oral flecainide therapy is an effective and safe means of suppressing VAs in patients with ATS with KCNJ2 mutations, though the U-wave amplitude remained unchanged by flecainide.

Three-month lower-dose flecainide after catheter ablation of atrial fibrillation

AIMS Atrial tachyarrhythmias (AT) commonly recur within the first 3 months after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF), and the influence of antiarrhythmic drugs (AADs) on the recurrences has not been fully elucidated. We sought to evaluate the efficacy of a 3-month lower-dose flecainide regime on early and late recurrences of ATs. METHODS AND RESULTS We randomly assigned 126 patients, who underwent RFCA for AF, to the flecainide group (150 or 100 mg/day according to their body weight) or to the control group receiving no AADs. The primary endpoint was any AT lasting for ≥30 s during the first 3 months and the secondary endpoint was a composite of ATs lasting for ≥24 h or requiring cardioversion or hospitalization during the same period. All AADs were stopped after the first 3 months and the late arrhythmia recurrences were also evaluated. The primary endpoint rates were 37 and 41% in the flecainide (143 ± 19 mg/day) and control groups, respectively (log-rank P = 0.76), and those of the secondary endpoint were 10 and 14%, respectively (log-rank P = 0.45). The estimated rates of maintaining sinus rhythm at 12 months after the first 3 months were 78 and 72%, in the flecainide and control groups, respectively (log-rank P = 0.68), and the rates were 51 and 90% in those with and without the primary endpoint, respectively (log-rank P < 0.001). CONCLUSION The 3-month lower-dose flecainide therapy after AF ablation did not reduce the early and late arrhythmia recurrences. The clinically significant ATs were also not prevented.

Clinical and Electrocardiographic Characteristics of Electrical Storms Due to Monomorphic Ventricular Tachycardia Refractory to Intravenous Amiodarone.

BACKGROUND Few reports are available on the characteristics of electrical storms of ventricular tachycardia (VT storm) refractory to intravenous (IV) amiodarone. METHODSANDRESULTS IV-amiodarone was administered to 60 patients with ventricular tachyarrhythmia between 2007 and 2012. VT storms, defined as 3 or more episodes of VT within 24 h, occurred in 30 patients (68±12 years, 7 female), with 12 having ischemic and 18 non-ischemic heart disease. We compared the clinical and electrocardiographic characteristics of the patients with VT storms suppressed by IV-amiodarone (Effective group) to those of patients not affected by the treatment (Refractory group). IV-amiodarone could not control recurrence of VT in 9 patients (30%). The Refractory group comprised 5 patients with acute myocardial infarctions. Although there was no difference in the VT cycle length, the QRS duration of both the VT and premature ventricular contractions (PVCs) followed by VT was narrower in the Refractory group than in the Effective group (140±30 vs. 178±25 ms, P<0.01; 121±14 vs. 179±22 ms, P<0.01). In the Refractory group, additional administration of IV-mexiletine and/or Purkinje potential-guided catheter ablation was effective. CONCLUSIONS IV-amiodarone-refractory VT exhibited a relatively narrow QRS tachycardia. The narrow triggering PVCs, suggesting a Purkinje fiber origin, may be treated by additional IV-mexiletine and endocardial catheter ablation.

Mechanisms of postoperative atrial tachycardia following biatrial surgical ablation of atrial fibrillation in relation to the surgical lesion sets

BACKGROUND Atrial tachycardia (AT) may develop after biatrial surgical ablation of atrial fibrillation. However, the mechanism has not been determined in detail. OBJECTIVE We aimed to determine the mechanism and treatment of postoperative AT following biatrial surgical ablation in relation to the design and durability of the surgical lesion sets. METHODS An electrophysiologic study and radiofrequency ablation were performed in 34 consecutive patients (23 male, mean age of 63 ± 9.4 years) who were referred for AT that developed late after biatrial surgical ablation. RESULTS The mechanism of a total of 53 ATs was macroreentry in 30, a focal mechanism in 20, and localized reentry in 1, and could not be determined in 2. The cause of the macroreentrant AT was residual conduction across a surgical lesion, most of which was located at the annular end of the mitral (n = 18) or tricuspid isthmus incision (n = 7), where cryoablation was applied during the surgery. We did not find any gaps across the cut-and-sew lesions. Radiofrequency (RF) applications to the gap, or an alternative site to transect the circuit, or the earliest activation site of the focus was effective for 48 ATs (91%). After a total of 1.3 ± 0.6 RF sessions, 27 patients (79%) were free of AT (n = 2) or AF (n = 5) during a follow-up period of 50 ± 49 months. CONCLUSIONS Macroreentry due to a gap in a surgical lesion and focal AT were the major mechanisms of AT in patients after biatrial surgical ablation. Radiofrequency ablation of those ATs is feasible.

Frequency analysis of surface electrocardiograms (ECGs) in patients with persistent atrial fibrillation: Correlation with the intracardiac ECGs and implications for radiofrequency catheter ablation

The nature and significance of the frequency characteristics of the surface electrocardiogram (ECG) in patients with persistent atrial fibrillation (AF) undergoing radiofrequency ablation are unclear.

Detection and Evaluation of Pulmonary Hypertension by a Synthesized Right-Sided Chest Electrocardiogram.

BACKGROUND Current standard 12-lead electrocardiogram (ECG) criteria for diagnosing pulmonary hypertension (PH) have a low sensitivity. Although the right-sided chest ECG (V3R-V5R) increases the diagnostic accuracy, these additional leads are not routinely recorded. The aim of the present study was to assess the usefulness of the synthesized right-sided chest ECG (Syn-ECG), generated from 12-lead ECG information, in the detection and evaluation of PH. PATIENTS AND METHODS The Syn-ECG waveforms in 30 patients with PH, defined as an estimated pulmonary arterial systolic pressure (PASP) >35 mmHg, were compared to those in 30 age- and gender-matched normal subjects. RESULTS The R wave amplitude and R/S ratio in the Syn-ECGs were significantly (P<0.01) greater in patients with PH than in the controls. The R wave amplitude in the Syn-ECGs exhibited a significant and better correlation (correlation coefficient 0.513-0.596, P<0.001) with the PASP than lead V1 (correlation coefficient 0.375, P=0.02). A receiver-operating characteristic curve analysis showed that the R wave amplitude (AUC 0.802, P<0.001) and R/S ratio (AUC 0.823, P<0.001) in the synthesized V5R was a good predictor of PH. New criteria, including 1) an R in V5R>0.12 mV, and 2) R/S ratio in V5R>0.42, had an improved sensitivity (0.63 and 0.73, respectively) and comparable specificity (0.93 and 0.87, respectively) to the conventional criteria (sensitivity 0.10-0.43, specificity 0.90-1.00). CONCLUSION The diagnostic criteria derived from the Syn-ECG provided better diagnostic accuracy than the known conventional criteria from the standard 12-lead ECG. This technique described in the present study may be useful for diagnosing and evaluating PH.

Urgent Catheter Ablation in Octogenarians with Serious Tachyarrhythmias

BACKGROUND Urgent catheter ablation is often required for various tachyarrhythmias; however, its efficacy and safety in elderly patients have not been fully elucidated. METHODS This study included consecutive octogenarians who underwent urgent radiofrequency catheter ablation (RFCA) for various serious tachyarrhythmias (urgent group, n=28) that were life-threatening, hemodynamically deleterious, or provoking ischemia, and consecutive octogenarians who underwent elective RFCA (control group, n=36). The rate of a successful RFCA, complications, later arrhythmia recurrences, and mortality were compared between the groups. RESULTS There was no significant difference in the breakdown of the targeted arrhythmias between the groups, and common-type atrial flutter was most often targeted in both the urgent group (57%) and the elective group (56%). Compared with the control group patients, the patients of the urgent group were older (84±3 vs. 82±2 years P=0.001), with a higher frequency of baseline heart disease (68% vs. 17%, P<0.001) and lower left ventricular ejection fraction (45%±15% vs. 68%±10%, P<0.001). The rates of acute success (100% vs. 100%, P=1.00) and later arrhythmia recurrences (4% vs. 14%, P=0.22) were comparable between the groups. Two patients in the urgent group and 2 in the elective group had procedure-related nonlethal complications (7% vs. 6%, P=1.00): groin hematoma in 2, pressure ulcer in 1, and CO2 narcosis in 1. There were no in-hospital deaths, and mortality during follow-up did not differ between the urgent and elective groups (6.0% vs. 3.9% per year, log-rank P=0.38). CONCLUSION Even in octogenarian patients, urgent catheter ablation for serious tachyarrhythmias can be safely performed with a high success rate and acceptable prognosis.