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.

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.

Respiratory cycle-dependent atrial tachycardia: prevalence, electrocardiographic and electrophysiologic characteristics, and outcome after catheter ablation.

BACKGROUND: Little is known about the tachyarrhythmias relating to respiration. Case reports presented patients with respiratory cycle-dependent atrial tachycardias (RCATs), which cyclically emerge after starting inspiration and cease during expiration. OBJECTIVE: The aim of the present study was to elucidate the prevalence, characteristics, and long-term outcome after radiofrequency catheter ablation (RFCA) of RCATs. METHODS: The electrocardiographic and electrophysiologic properties and results of RFCA were analyzed in 60 patients with a total of 71 focal atrial tachycardias (ATs). RESULTS: Nine RCATs (13%) were observed in 7 patients (12%). RCATs were irregular, with a mean cycle length ranging from 220 to 650 ms, and developed incessantly accounting for 32% ± 14% of the 24-hour heartbeats. The P-wave morphology was positive or biphasic (positive to negative) in V1, and positive in I and II. The electroanatomical mapping demonstrated a centrifugal activation pattern, with the earliest site located at the antrum of the right superior pulmonary vein (RSPV), inside the RSPV, and inside the superior vena cava (SVC) in 4, 2, and 3 RCATs, respectively. Radiofrequency energy delivery at the earliest site or the electrical isolation of the RSPV and SVC suppressed all RCATs. During a follow-up of 25 ± 15 months, 1 RCAT recurred and was eliminated in a second procedure. CONCLUSION: RCATs were observed in 13% of the focal ATs. As presumed from the P-wave morphologies, their foci converged around the RSPV or inside the SVC. RFCA was effective to eliminate RCATs.

The undetermined geometrical factors contributing to the transverse conduction block of the crista terminalis.

BACKGROUND: The crista terminalis (CT) is known to be a functional barrier during typical atrial flutter (AFL). The relationship between the CT structural characteristics and its transverse conduction block, however, has not been understood well. METHODS: This study consisted of AFL (group 1, N = 15) and non-AFL patients (group 2, N = 13). The CT structural characteristics were determined with intracardiac echocardiography. A 20-pole electrode catheter was located along the CT and pacing at progressively faster rates from either low anterolateral right atrium (LRA) or coronary sinus (CS) was applied. RESULTS: The CT height, width, and area were significantly greater in group 1 than in group 2 (P < 0.001). In both groups, at the longest pacing cycle length during CS pacing resulting in CT transverse conduction block at some levels, the width and area were significantly greater at the levels with block than at those without block. During LRA pacing, the area was also significantly larger at the levels with block than at those without in group 1, but not in group 2. The slope angle of CT ridge was significantly steeper at the levels with block than at those without in both groups (P < 0.01), but that was not the case with CS pacing. CT arborization in its inferior portion was more frequently documented in group 1 than group 2 (P < 0.05). CONCLUSIONS: The CT structural characteristics that may influence its transverse conduction differ between LRA and CS pacing. Steep slope and arborization of the CT are implicated as a geometric factor in its transverse conduction block.

Adenosine-sensitive atrial tachycardia originating from the proximal coronary sinus.

BACKGROUND: Atrial tachycardia (AT) can originate from the proximal coronary sinus (CS). However, detailed electrophysiologic characteristics of the tachycardia are not available. OBJECTIVES: We describe the electrophysiologic characteristics, response to adenosine 5'-triphosphate, and results of radiofrequency ablation of AT with the earliest activation in the proximal CS. METHODS: In 7 of 54 patients (age 57 +/- 18 years) with nonmacroreentrant "focal" AT undergoing electrophysiologic study and radiofrequency ablation, the earliest atrial activation site was located in the proximal CS. RESULTS: The earliest activation site was inside the CS 13 +/- 3 mm from the ostium. The AT could be induced and terminated by atrial extrastimuli or burst pacing. In all patients, the AT was also terminated by a very small dose of adenosine 5'-triphosphate (4.2 +/- 1.1 mg). Rapid ventricular pacing during the tachycardia produced ventriculoatrial dissociation. Radiofrequency ablation directed at the earliest atrial activation site was effective in only three patients (group A). In the remaining four patients (group B), after the radiofrequency energy deliveries, the earliest activation site shifted to an adjacent site with a small increase in the cycle length. Three group B patients underwent successful ablation in the slow pathway region. No recurrence was observed over a follow-up period of 22 +/- 5 months. CONCLUSION: AT with earliest activation in the proximal CS is sensitive to a small dose of adenosine 5'-triphosphate. In some patients, radiofrequency applications in the slow pathway region are effective even if the local activation is not early.

Angiotensin-converting enzyme inhibitor therapy inhibits the progression from paroxysmal atrial fibrillation to chronic atrial fibrillation.

BACKGROUND: Atrial fibrillation is a progressive disease, which in the paroxysmal form (PAF) becomes more frequent and finally becomes chronic (CAF). A retrospective analysis of patients with PAF was conducted to examine the hypothesis that angiotensin-converting enzyme inhibitors (ACEI) will prevent the progression to CAF. METHODS AND RESULTS: On the basis of their treatment, 95 patients with PAF were divided into 2 groups: 42 patients treated with ACEI for hypertension throughout the period of treatment and follow-up (ACEI group) and 53 patients not given ACEI (non-ACEI group). Cardiac rhythms were assessed either from the medical records or the electrocardiograms recorded every 2-4 weeks at follow-up visits. The mean follow-up time was 8.3+/-3.5 years. There was no significant difference in the use of antiarrhythmic drugs, left atrial diameter or left ventricular ejection fraction between the 2 groups. The Kaplan-Meier curve for the time to occurrence of CAF showed a lower incidence of CAF in the ACEI group and demonstrated that the 5-year probability for persistence of PAF without progression to CAF was 88.3%, but 47.5% in the non-ACEI group. CONCLUSIONS: These results indicate that ACEI will prevent progression from PAF to CAF.

Unusual petal-like fibromuscular dysplasia as a cause of acute abdomen and circulatory shock.

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory segmental arterial occlusive disorder that involves primarily the renal and carotid arteries, and less often the coronary, iliac, and visceral arteries. We report the case of 78-year-old Japanese woman who presented with acute abdomen complicated by shock. Autopsy revealed hemorrhagic necrosis of the small intestine due to severe narrowing of the mesenteric arteries. Histologically, smooth muscles showed in-bundle hyperplasia surrounding the adventitia together with medial and perimedial fibrodysplasia of these arteries, forming the characteristic petal-like appearance of FMD. No occlusive thrombus was observed. Further, another medial fibrodysplasia type of FMD was also seen in the renal and left circumflex coronary arteries. Unusual proliferation of smooth muscles resulted in the petal-like atypical FMD at the superior mesenteric artery.