Pectus excavatum: uncommon electrical abnormalities caused by extrinsic right ventricular compression.

We report a case of pectus excavatum associated with ventricular tachycardia provoked by exercise in a 19-year-old man. Although this chest deformity has been associated with supraventricular dysrhythmias, documented ventricular tachycardia has only been reported once. Our patient's ventricular dysrhythmia was treated by surgical correction of his pectus excavatum only, and at 3 years follow-up he has had no recurrence of his ventricular tachycardia.

Catheter ablation of ventricular fibrillation storm in a long QT syndrome genotype carrier with normal QT interval.

Patients with long QT syndrome can sometimes present with a ventricular fibrillation (VF) storm. Catheter ablation of culprit premature ventricular complexes responsible for the triggering of the VF episodes may be required in rare cases of electrical storm that do not respond to conventional measures, and this can be life-saving. We describe a case of emergency catheter ablation in a young woman with a normal corrected QT interval, who presented with malignant VF storm for the first time. We also discuss the diagnostic and management challenges involved, as well as the value of genetic testing in refining the diagnosis.

Impact of left ventricular epicardial and biventricular pacing on ventricular repolarization in normal-heart individuals and patients with congestive heart failure.

AIMS: Malignant ventricular arrhythmias can arise in a subset of congestive heart failure (CHF) patients after they undergo cardiac resynchronization therapy (CRT), thus counteracting the haemodynamic benefits typically associated with biventricular pacing. This study seeks to assess whether alteration of the ventricular transmural repolarization and conduction due to reversal of the depolarization sequence during epicardial or biventricular pacing facilitate the development of ventricular arrhythmias. METHODS AND RESULTS: ECGs and monophasic action potential (MAP) were recorded during programmed stimulation from right ventricle (RV) endocardium (RV-Endo), left ventricle (LV) epicardium (LV-Epi), or both (biventricular, Bi-V) in 15 individuals without structural heart diseases. In patients with severe CHF and CRT (n=21), ECGs were collected during RV-Endo, LV-Epi, and Bi-V pacing. MAP duration on intracardiac electrogram, the QT, JT, and T(peak)-T(end) intervals on ECGs at different pacing sites were measured and compared. In subjects with or without structural heart disease, compared with RV-Endo pacing, LV-Epi and Bi-V pacing resulted in a longer JT (341.78+/-61.97 ms with LV-Epi, 325.86+/-59.69 ms with Bi-V vs. 286.14+/-38.68 ms with RV-Endo in CHF individuals, P<0.0001) or T(peak)-T(end) interval (121.55+/-19.88 ms with LV-Epi, 117.71+/-42.63 ms with Bi-V vs. 102.28+/-12.62 ms with RV-Endo in normal-heart subjects, P<0.0001; 199.70+/-62.44 ms with LV-Epi, 184.89+/-74.08 ms with Bi-V vs. 146.41+/-31.06 ms with RV-Endo in CHF patients, P<0.0001), in addition to prolonged myocardial repolarization time and delayed endocardial activation. During follow-up, sudden death and arrhythmia storm occurred in two CHF patients after CRT. CONCLUSION: Epicardial and biventricular pacing prolong the time and increase the dispersion of myocardial repolarization and delay the transmural conduction. All of these should be considered as potential arrhythmogenic factors in CHF patients who receive CRT.

Flutter localized to the anterior left atrium after catheter ablation of atrial fibrillation.

INTRODUCTION: Organized atrial arrhythmias following atrial fibrillation (AF) ablation are typically due to recovered pulmonary vein (PV) conduction or reentry at incomplete ablation lines. We describe the role of nonablated anterior left atrium (LA) in arrhythmias observed after AF ablation. METHODS: A total of 275 consecutive patients with paroxysmal (n = 200) or chronic (n = 75) AF had PV isolation with/without additional linear ablation at the mitral isthmus (n = 106), LA roof (n = 23), or both (n = 88). Organized arrhythmias occurring after ablation were evaluated utilizing activation and entrainment mapping. RESULTS: Fourteen patients (11 female, 65 +/- 13 years, 10 chronic AF, 10 structural heart disease) demonstrated tachycardia localized to the anterior LA, an area not targeted by prior ablation. Eight had ECG features during sinus rhythm suggestive of impaired anterior LA conduction at baseline. These arrhythmias demonstrated a distinctive ECG flutter morphology in 7 of 10 (70%) with discrete -/+ or +/-/+ aspect in inferior leads. Mapping the anterior LA revealed electrograms spanning the entire tachycardia cycle length (325 +/- 125 msec). Entrainment was possible in all with a postpacing interval exceeding the tachycardia cycle length by 9 +/- 10 msec. Electroanatomic mapping in 6 demonstrated small reentrant circuits rotating clockwise in 4 and counterclockwise in 2. Low-amplitude, fractionated mid-diastolic potentials with long duration (200 +/- 80 msec) occupying 63 +/- 22% of the cycle length were targeted for ablation resulting in termination and subsequent noninducibility. CONCLUSION: Organized arrhythmias occurring after AF ablation can be due to reentrant circuits localized to the anterior LA, predominantly in females with chronic AF, structural heart disease, and abnormal atrial conduction. They are characterized by a distinctive surface ECG and highly responsive to RF ablation at the slow conduction area.

Long-term evaluation of atrial fibrillation ablation guided by noninducibility.

BACKGROUND: Pulmonary vein (PV) isolation and linear lesions are effective in eliminating paroxysmal atrial fibrillation (AF), but linear lesions probably are not required in all patients. Noninducibility of AF has been shown to be associated with freedom from arrhythmia in 87% of patients. OBJECTIVES: The purpose of this study was to prospectively evaluate the role of noninducibility in guiding a stepwise approach tailored to the patient. METHODS: In 74 patients (age 53 +/- 8 years) with paroxysmal AF, PV isolation was performed during induced or spontaneous AF. If AF was inducible after PV isolation, one to two additional linear lesions were placed at the mitral isthmus and/or left atrial roof, with the endpoint of noninducibility of AF or atrial flutter. Inducibility (AF/atrial flutter, lasting > or = 10 minutes) was assessed using burst pacing at an output of 20 mA down to refractoriness from the coronary sinus and both atrial appendages. RESULTS: In 42 patients (57%), PV isolation restored sinus rhythm and rendered AF noninducible. In the 32 patients with persistent or inducible AF after PV isolation, a single linear lesion achieved noninducibility in 20, whereas two linear lesions were required in 12 and resulted in conversion to sinus rhythm and noninducibility in 10. Using this stepwise approach, a total of 69 patients (93%) were rendered noninducible. During follow-up of 18 +/- 4 months, 67 patients (91%) were free from arrhythmia without antiarrhythmic drugs. Repeat procedures were performed in 23 patients: repeat ablation was required to consolidate prior targets in 15 patients (20%), and "new" linear lesions, which were not predicted by inducibility during the index procedure, were required in 8 (11%). CONCLUSION: Noninducibility can be used as an endpoint for determining the subset of patients with paroxysmal AF who require additional linear lesions after PV isolation. This tailored approach is effective in 91% of patients while preventing delivery of unnecessary linear lesions.

Reduction of fluoroscopy exposure and procedure duration during ablation of atrial fibrillation using a novel anatomical navigation system.

AIMS: Catheter ablation of atrial fibrillation (AF) is centred on pulmonary vein (PV) ablation with or without additional atrial substrate modification. These procedures may be prolonged with significant fluoroscopy exposure. This study evaluates a new non-fluoroscopic navigation system during ablation of AF. METHODS AND RESULTS: Seventy-two patients undergoing catheter ablation of symptomatic drug refractory AF were prospectively randomized to ablation with (n=35; study group) or without (n=37; control group) non-fluoroscopic navigation. PV isolation was performed in all patients. In patients with persistent or inducible sustained AF after PV isolation linear ablation was performed by joining the superior PVs. PV isolation was achieved in all patients; fluoroscopy (15.4+/-3.4 vs. 21.3+/-6.4 min; P<0.001) and procedural (52+/-12 vs. 61+/-17 min; P=0.02) durations were significantly reduced in the study group. Linear block was achieved in 37 of the 39 patients; with a significant reduction in fluoroscopy (5.6+/-2.2 vs. 9.9+/-4.8 min; P=0.003) and procedural (14.7+/-5.5 vs. 26.6+/-16.9 min; P=0.007) durations in the study group. After a follow-up of 6.9+/-2.9 months (range 3-10), 26 (74%) patients in the non-fluoroscopic navigation group and 29 (78%) patients in the control group were arrhythmia-free after the first procedure. CONCLUSION: This prospectively randomized study demonstrates significant reduction of fluoroscopy exposure and procedural duration using supplementary non-fluoroscopic imaging system for AF ablation.

Fever as a precipitant of idiopathic ventricular fibrillation in patients with normal hearts.

INTRODUCTION: Ventricular fibrillation (VF) is the main mechanism of sudden cardiac death. The clinical precipitants of sudden cardiac death due to idiopathic VF are poorly characterized. Emerging evidence implicates triggers originating predominantly from the distal Purkinje arborization and the right ventricular outflow tract. METHODS AND RESULTS: We report three patients without structural heart disease or repolarization abnormalities in whom a febrile illness was the only concurrent disease associated with unexpected sudden cardiac death due to VF storm. An automated defibrillator was implanted in all three patients. In one patient with persistent recurrent VF episodes, mapping demonstrated the origin of these triggers was from the Purkinje arborization of the anterior wall of the right ventricle. Ablation at a site of earliest activation during ectopy, where pace mapping was concordant and Purkinje potential preceded the onset of ventriculogram, resulted in suppression of all arrhythmias. After follow-up of 22, 9, and 18 months in the three patients, no ventricular arrhythmias have been recorded. CONCLUSION: We present a series of patients in whom an apparently benign febrile illness was associated with malignant ventricular arrhythmias in the absence of cardiac disease or other factors known to precipitate sudden cardiac death. Physicians should be aware of this possible phenomenon in cases of febrile illness associated with syncope.

Transcardiac pericardiocentesis: an emergency life-saving technique for cardiac tamponade.

Life-threatening cardiac tamponade is one of the most serious complications of catheter-based cardiac procedures. Although most cases can be effectively treated by percutaneous pericardiocentesis, urgent surgical drainage is required in unsuccessful cases. Rarely, in collapsed patients, the delay for surgery, however minimal, may be fatal. We describe a technique whereby life-saving pericardial drainage was rapidly achieved via a novel transcardiac approach, using the transseptal puncture kit, after failure of conventional pericardiocentesis in a patient with procedure-related acute tamponade who rapidly deteriorated and developed cardiorespiratory arrest within a few minutes. Although surgical repair for the perforation had to be performed subsequently, the patient survived without sequelae. This transcardiac approach may be an important and potentially life-saving adjunctive technique after failure of conventional pericardiocentesis in rapidly deteriorating or extremely unstable patients.

Mapping and ablation of ventricular fibrillation associated with long-QT and Brugada syndromes.

BACKGROUND: The long-QT and Brugada syndromes are important substrates of malignant ventricular arrhythmia. The feasibility of mapping and ablation of ventricular arrhythmias in these conditions has not been reported. METHODS AND RESULTS: Seven patients (4 men; age, 38+/-7 years; 4 with long-QT and 3 with Brugada syndrome) with episodes of ventricular fibrillation or polymorphic ventricular tachycardia and frequent isolated or repetitive premature beats were studied. These premature beats were observed to trigger ventricular arrhythmias and were localized by mapping the earliest endocardial activity. In 4 patients, premature beats originated from the peripheral right (1 Brugada) or left (3 long-QT) Purkinje conducting system and were associated with variable Purkinje-to-muscle conduction times (30 to 110 ms). In the remaining 3 patients, premature beats originated from the right ventricular outflow tract, being 25 to 40 ms ahead of the QRS. The accuracy of mapping was confirmed by acute elimination of premature beats after 12+/-6 minutes of radiofrequency applications. During a follow-up of 17+/-17 months using ambulatory monitoring and defibrillator memory interrogation, no patients had recurrence of symptomatic ventricular arrhythmia but 1 had persistent premature beats. CONCLUSIONS: Triggers from the Purkinje arborization or the right ventricular outflow tract have a crucial role in initiating ventricular fibrillation associated with the long-QT and Brugada syndromes. These can be eliminated by focal radiofrequency ablation.