Radiofrequency catheter ablation of persistent atrial fibrillation by pulmonary vein isolation with or without left atrial posterior wall isolation: long-term outcomes of the CAPLA trial.

BACKGROUND AND AIMS: Posterior wall isolation (PWI) is commonly incorporated into catheter ablation (CA) strategies for persistent atrial fibrillation (AF) in an attempt to improve outcomes. In the CAPLA randomized study, adjunctive PWI did not improve freedom from atrial arrhythmia at 12 months compared with pulmonary vein isolation (PVI) alone. Whether additional PWI reduces arrhythmia recurrence over the longer term remains unknown. METHODS: In this multicenter, international, randomized study patients with persistent AF undergoing index CA using radiofrequency (RF) were randomized to PVI+PWI versus PVI alone. Patients underwent regular follow-up including rhythm monitoring for a minimum of 3 years post CA. AF burden at 3 years post-ablation was evaluated with either 28-day continuous ambulatory ECG monitoring, twice daily single-lead ECG or from cardiac implanted device. Evaluated endpoints included freedom from any documented atrial arrhythmia recurrence after a single procedure, AF burden, need for redo catheter ablation, rhythm at last clinical follow-up, healthcare utilisation metrics and AF-related quality of life. RESULTS: 333 of 338 (98.5%) patients (mean age 64.3±9.4 years, 23% female) completed 3-year follow-up, with 169 patients randomized to PVI+PWI and 164 patients to PVI alone. At a median of 3.62 years post-index ablation, freedom from recurrent atrial arrhythmia occurred in 59 patients (35.5%) randomized to PVI+PWI vs 68 patients (42.1%) randomized to PVI alone (HR 1.15, 95% CI 0.88-1.51, p=0.55). Median time to recurrent atrial arrhythmia was 0.53 years (IQR 0.34-1.01 years). Redo ablation was performed in 54 patients (32.0%) in the PVI+PWI group vs 49 patients (29.9%, p=0.68) in the PVI alone group. Pulmonary vein reconnection was present in 54.5% (mean number of reconnected PVs 2.2±0.9) and posterior wall reconnection in 75%. Median AF burden at 3 years was 0% in both groups (IQR 0-0.85% PVI+PWI vs 0-1.43% PVI alone, p=0.49). Sinus rhythm at final clinical follow-up was present in 85.1% with PVI+PWI vs 87.1% with PVI alone (p=0.60). Mean AF Effect On Quality-Of-Life (AFEQT) score at 3 years post-ablation was 88.0±14.8 with PVI+PWI vs 88.9±15.4 with PVI alone (p=0.63). CONCLUSIONS: In patients with persistent AF, the addition of PWI to PVI alone at index RF catheter ablation did not significantly improve freedom from atrial arrhythmia recurrence at long-term follow-up. Median AF burden remains low and AF quality of life high at 3 years with either ablation strategy.

Cesium chloride induced ventricular arrhythmias in dogs: three-dimensional activation patterns and their relation to the cesium dose applied.

INTRODUCTION: Cesium chloride has widely been used in experimental models to produce various ventricular arrhythmias. The study was designed to evaluate whether type and mechanism of these arrhythmias are dose-dependent. METHODS: In 7 dogs with acute AV-block, 60 pins containing 4 bipolar electrodes each were inserted into both ventricles to provide 240 endo-, epi- and midmyocardial recording sites. A computerized mapping system was used to determine three-dimensional activation patterns of ventricular arrhythmias induced by three injections of 1 mmol/kg cesium chloride at 20 minute intervals. RESULTS: Out of all arrhythmias induced, 25 ventricular extrasystoles, 31 monomorphic and 47 polymorphic ventricular tachycardias were mapped. Nonsustained ventricular tachycardias were readily inducible by a single bolus of cesium chloride, whereas sustained episodes required repetitive injections (1.45 +/- 0.61 vs. 2.61 +/- 0.57 doses, p < 0.05). Polymorphic tachycardias were observed more commonly than monomorphic tachycardias (87 vs. 31). Initiation and maintenance of cesium induced arrhythmias were exclusively based on focal mechanisms originating from the subendocardium, irrespective of morphology and dosage. All monomorphic arrhythmias were caused by repetitive firing of single immobile foci located in either the right or the left ventricle. Bi- and multifocal mechanisms, however, were found to underlie the polymorphic episodes. CONCLUSIONS: Although there is a dose-dependence as to the sustenance of mono- or polymorphic tachycardias, this does not reflect on the three-dimensional activation pattern of cesium induced arrhythmias, which are due to mono- or multifocal activation originating from the subendocardium.

New ICD-technologies: first clinical experience with dual-chamber sensing for differentiation of supraventricular tachyarrhythmias.

Inappropriate ICD therapy for supraventricular arrhythmias remains an unsolved problem and may lead to serious clinical situations. Current algorithms for differentiation of supraventricular and ventricular arrhythmias are based on ventricular sensing solely and, therefore, lack sensitivity and specificity. This preliminary analysis from a multicenter trial comprises data from the first 26 patients who received a Res-Q Micron active-can ICD (Sulzer Intermedics) with a ventricular defibrillation lead and an additional bipolar lead for atrial sensing. Digitized atrial and ventricular waveform storage as well as interval charts from 102 induced and 30 spontaneous arrhythmia episodes were prospectively collected and analyzed with regard to appropriateness of ICD therapy. From all 132 arrhythmia episodes, high-quality stored dual-chamber intracardiac electrograms (IEGM) could be retrieved for further analysis: in 40 (30%) episodes, atrial fibrillation (AF with rapid ventricular response 22, AF with VT 9, AF with VF 9) was identified as the underlying intrinsic rhythm, and inappropriate ICD therapy was delivered in 4/22 (18%) episodes of AF with rapid ventricular response. In the remaining 92 (70%) episodes, sinus rhythm was the underlying atrial rhythm (SR with VT 13, SR with VF 79), and no inappropriate therapy was observed. Three of 22 (15%) high-energy shocks delivered for ventricular arrhythmias (VT 9, VF 9, rapid AF 4) terminated AF at the same time. In total, there were 3 complications (2 atrial lead dislodgments, 1 revision for bleeding). Both atrial lead dislodgments occurred in the 2 patients with passive-fixation leads compared to none in the 24 patients with active-fixation leads (p = 0.003). In conclusion, dual-chamber sensing and waveform storage of the new Res-Q Micron offer very helpful diagnostic tools for the detection of inappropriate ICD-therapy. Placement of an additional atrial lead is safe and does not interfere with proper ICD function. However, for avoidance of atrial lead dislodgment, active fixation leads are recommended. With the tested active-can lead configuration, the efficacy of successful atrial cardioversion by high-energy shocks delivered for ventricular arrhythmias seems to be low.

Echocardiographic Fourier phase and amplitude imaging for quantification of ischemic regional wall asynergy: an experimental study using coronary microembolization in dogs.

OBJECTIVES: This study investigated whether echocardiographic Fourier phase and amplitude imaging can be used to evaluate ischemia-related regional wall asynergy. BACKGROUND: Because myocardial ischemia delays the onset and peak of endocardial inward motion and reduces its magnitude, Fourier phase and amplitude analysis of two-dimensional echocardiograms may be used to evaluate regional wall motion abnormalities objectively by analyzing temporal sequence and magnitude of endocardial motion. METHODS: Digital cine loops of left ventricular long- and short-axis views were obtained in six anesthetized dogs at baseline and 1 to 30 min after coronary microembolization and were mathematically transformed using a first-harmonic Fourier algorithm to obtain phase angles and amplitudes of endocardial segments. Mean phase angles and amplitudes were compared with visual wall motion analysis based on a scoring system and quantitative analysis based on segmental fractional area shortening derived from planimetry. RESULTS: Microembolization delayed segmental phase angles by 47 +/- 44 degrees in mild to moderate hypokinesia (fractional shortening [mean +/- SD] 41 +/- 13%) and by 77 +/- 63 degrees in severe hypokinesia (fractional shortening 13 +/- 5%) and reduced segmental amplitudes from 80 +/- 36 gray level intensity at baseline to 53 +/- 34 in segments developing mild to moderate hypokinesia, and from 93 +/- 36 to 35 +/- 28 gray level intensity in segments developing severe hypokinesia. Shifts in segmental phase angles correlated better with dynamic shifts in segmental fractional area shortening than did changes in wall motion score (r = -0.65 vs. r = 0.52, p < 0.001). CONCLUSIONS: Echocardiographic Fourier phase imaging can be used to evaluate ischemia-related regional wall asynergy, displaying contraction sequence and magnitude in a simple, objective format.

[The implantable cardioverter/defibrillator (ICD). Developments up to the present time and future perspectives]. / Der implantierbare Kardioverter/Defibrillator (ICD). Entwicklung bis heute und Zukunftsperspektiven.

The implantable cardioverter/defibrillator is gaining increasing significance in the therapy of life-threatening ventricular arrhythmias. Independently, the team of Mirowski and the team of Schuder started to develop experimental automatic implantable defibrillators in the seventies. In 1980, the first human implant of an automatic defibrillator was done by Levi Watkins together with the team of Mirowski in Baltimore, USA. Since 1989 implantable cardioverter/defibrillators exhibit multiple functions among which are high energy defibrillation therapy, low energy cardioversion, antitachycardia pacing, permanent and post therapy antibradycardia pacing, diagnostic counters, and device status parameters. This offers a markedly improved technical device to the patients. Evaluation of the patient's diagnostic counters provide a detailed overview about the patient's arrhythmia history and information for optimizing antitachycardia pacing therapy and additional antiarrhythmic drug therapy. The availability of non-thoractomy transvenous lead systems and biphasic shock forms allows the insertion of the device without open chest surgery and even without subcutaneous leads resulting in low mortality rates and an exclusively transvenous system. Single-lead unipolar devices are currently investigated in clinical trials. Future development of atrial sensing lead systems may further reduce inappropriate shock therapy triggered by sinus tachycardia or atrial tachyarrhythmias, e.g. atrial fibrillation, and may be used for dual chamber stimulation. Hemodynamic sensors for determining the severity of the arrhythmia are currently under experimental evaluation. Possible prognostic indications of ICD therapy in patients without a history of malignant arrhythmias are currently studied in several prospective trials. All new directions hold promise to expand and improve the use of ICDs in patients at risk for sudden cardiac death.

Advances in follow-up techniques for implantable defibrillators.

The complexity of newer implantable defibrillators has made device follow-up increasingly more intricate. Extensive data-logging capacity provides specific information on recorded events, which facilitates more accurate determination of patient arrhythmias. This helps the clinician judge whether the device is detecting and treating arrhythmias appropriately, or whether false sensing of external signals or supraventricular rhythms is occurring. There is also a record of the efficacy of delivered therapy from the device that helps in optimizing subsequent programming. Programming itself has become much more complicated, with multiple independently programmable therapy zones, each with numerous available therapeutic modalities. In addition, defibrillator status information has been improved. Accurate battery voltage measurements give a reasonable estimate of remaining device life, and pace/sense and shock lead impedances can be measured to provide information on total system integrity. Together, these advances allow more specific programming of the device to the individual patient's condition but require increasing experience and expertise of the physician.

Acute efficacy and chronic follow-up of patients with non-thoracotomy third generation implantable defibrillators.

Non-thoracotomy implantation of implantable cardioverter defibrillators (ICDs) has simplified the process of device insertion, promising to decrease associated procedural complications while providing sudden death protection at least equal to epicardial systems. This study presents the acute and chronic results of 110 patients who underwent attempted non-thoracotomy ICD implantation with the Medtronic Transvene lead system and PCD model 7217 or 7219. Of the 110 patients attempted, 100 (91%) had the system successfully implanted without the need for an epicardial patch. One patient died 1 week postoperatively of septic shock related to the implantation (0.9% perioperative mortality). During follow-up of 16 +/- 11 months, 45% of the patients had an event detected as ventricular tachycardia; 26% of these detections were felt clinically to be due to supraventricular rhythms. Of the remainder, 87% were successfully treated with the first VT therapy, and 98% were terminated by the final therapy; 66% of the patients had at least one episode of ventricular fibrillation, of which 5% were felt to be inappropriate detections; 85% of the appropriate episodes were successfully treated with the first VF therapy, and all were converted by the final therapy. Total mortality at 6, 12, and 24 months was 3%, 11%, and 19% respectively. Only one patient had sudden cardiac death, occurring at 13 months postimplant. Overall, the non-thoracotomy lead system for this ICD displayed infrequent implant complications and proved to be reliable at terminating arrhythmias and maintaining a low rate of sudden cardiac death in this high risk population.

Dobutamine stress echocardiography: initial experience of a Canadian centre.

OBJECTIVE: To investigate the diagnostic accuracy, electrocardiogram and hemodynamic effects and safety of dobutamine stress echocardiography. SUBJECTS: Sixty-one patients with suspected coronary artery disease. All patients underwent coronary arteriography. MAIN RESULTS: The sensitivity of dobutamine stress echocardiography in diagnosis of coronary artery disease in the whole group was 91%. In patients with left anterior descending it was 97%; right 85%; circumflex 76%; three vessel 100%; two vessel 95%; single vessel 77%. Specificity, positive predictive value and accuracy of dobutamine stress echocardiography in diagnosis of coronary disease (whole group) was 57, 94 and 87%, respectively. ST depression of more than 1 mm occurred in 11 patients, ST elevation of more than 1 mm in three patients, T wave inversion in one and T normalization in nine. Significant differences of the effects of beta-blockers were noted on the peak effects of dobutamine as follows: heart rate increase of 46 +/- 22 versus 20 +/- 13 beats/min (P less than 0.0001); systolic pressure increase of 4 +/- 26 versus 22 +/- 19 mmHg (P less than 0.01); diastolic pressure decrease of 18 +/- 16 versus 10 +/- 12 mmHg (P less than 0.03) for patients without or with beta-blockers, respectively. Unifocal ventricular premature beats were noted in 10 patients, atrial premature beats in five and ventricular couplets in one. Angina occurred in 11 patients. Atypical chest pain occurred in seven patients, tingling in 11 and nausea in four. Thirty-six patients were totally asymptomatic. CONCLUSIONS: In this population with high prevalence (85%) of coronary artery disease, dobutamine stress echocardiography had high sensitivity and positive predictive value for coronary disease detection particularly in patients with left anterior descending or three vessel disease. The specificity and accuracy were not as good, but this may reflect the small number of normal patients. Dobutamine was well tolerated and conveniently administered.

Antimicrobial prophylaxis for open heart operations.

Between 1986 and 1988, 450 adults undergoing coronary artery bypass, cardiac valve replacement, or both were enrolled into a prospective, randomized, comparative trial of cephalothin versus cefamandole as perioperative prophylaxis. They were assessed during their hospitalization and at 6 weeks and 6 months after discharge for postoperative infectious complications. Eleven patients had major postoperative infections including 5 with sternal wound infections (three bacteremic), 6 with bacteremia, 1 with prosthetic valve endocarditis, and 3 with severe venous donor graft site infections. Eight major infections occurred in patients receiving cephalothin prophylaxis and three in patients receiving cefamandole, with all five sternal wound infections occurring in the cephalothin group. Postoperative pathogens responsible for the major infections included gram-negative aerobes in 5 patients, Staphylococcus aureus in 4, and Staphylococcus epidermidis in 2. Preoperative colonizing staphylococcal isolates were not predictive of postoperative staphylococcal pathogens. Although there was no statistically significant difference in rate of major postoperative infectious complications using either cephalothin or cefamandole prophylaxis, there was a trend in favor of cefamandole. Gram-negative aerobes are becoming increasingly important pathogens in this setting.

Incessant ventricular tachycardia complicating acute myocardial infarction: treatment by map-guided infarctectomy.

A 58-year-old man developed incessant ventricular tachycardia on the fourth and fifth days following acute anterior myocardial infarction. The tachycardia was resistant to antiarrhythmic drugs, cardioversion and pacing. Preoperative and intraoperative mapping suggested a subendocardial origin, and successful infarctectomy was performed on the fifth day of the infarction.

Extended aortic bypass.

At the University of Alberta Hospital, six patients recently underwent placement of Dacron bypass grafts from the ascending aorta to the infrarenal abdominal aorta or femoral arteries for a variety of vascular problems. The operations were performed in patients with (1) multiple aortic coarctations, (2) congenital aortic arch interruption and congenital mitral stenosis, (3) recoarctation of the thoracic aorta after previous coaractation repair (two patients), (4) aortoiliac occlusive disease in a patient with multiple previous abdominal operations including an abdominal-perineal resection and left lower quadrant colostomy, and (5) idiopathic retroperitoneal fibrosis and multiple previous operations on the abdominal aorta. Surgical access was through midline sternotomy and laparotomy incisions, and groin incisions were used as required. Careful attention was paid to placing as much graft as possible in an extraperitoneal position. All patients survived the operation and had essentially uneventful postoperative courses with good results. This technique has previously been described. However, attention is drawn to it once again as an excellent means of bypassing the thoracic and abdominal aorta in selected patients with complex vascular problems.

Surgical treatment of Ebstein's anomaly.

Neither the role of surgery in Ebstein's anaomaly nor the surgical procedure of choice for its correction are clearly defined. Whether or not the artrialized right ventricle, which plays a major role in the functional abnormalities, should be obliterated in all cases remains unresolved. Of the 26 patients with Ebstein's anomaly seen at the University Hospital between 1953 and 1975, four were treated surgically at this center. All had closure of the atrial septal defect, reconstruction of a tricuspid annulus in the normal position, and insertion of a tricuspid prosthesis and an epicardial ventricular pacemaker. The two patients who also had the atrialized chamber obliterated improved dramatically. Thus, obliteration of the atrialized right ventricle appears to be associated with a better operative result.

False left ventricular aneurysm as a complication of open heart surgery.

A false aneurysm developed at the site of left ventricular venting in an 8-year-old boy who had undergone aortic valve commissurotomy under cardiopulmonary bypass. The diagnosis was made by clinical examination and chest radiography and confirmed by left ventricular cineangiography. The aneurysm was successfully resected.

An unusual case of recurrent left atrial myxoma.

In a patient who had a calcified left atrial myxoma resected, recurrence developed 31 months later. Although complete radical resection of the recurrent tumour presented a special problem, the patient survived the second operation. The tumour recurred again and the patient had two episodes of cerebral embolism 1 1/2 and 2 years later, respectively, and died 3 1/2 years after the second operation. The erythrocyte sedimentation rate correlated with the size of the tumor, and the recurrent tumour seemed to grow more rapidly than the primary tumour. Experience with this case and a review of the nine reported cases of recurrent left atrial myxoma suggest that a radical approach is necessary at the primary operation.