Quality of life is not improved after mitral valve surgery combined with epicardial left atrial cryoablation as compared with mitral valve surgery alone: a substudy of the double blind randomized SWEDish Multicentre Atrial Fibrillation study (SWEDMAF).

Aims: Concomitant surgical ablation of atrial fibrillation (AF) in patients undergoing mitral valve surgery (MVS) has almost become routine despite lack of convincing information about improved quality-of-life (QOL) and clinical benefit. Quality-of-life was therefore assessed after MVS with or without epicardial left atrial cryoablation. Methods and results: Sixty-five patients with permanent AF randomized to MVS with or without left atrial cryoablation, in the double-blinded multicentre SWEDMAF trial, replied to the Short Form 36 QOL survey at 6 and 12 months follow-up. The QOL scores at 12 month follow-up did not differ significantly between patients undergoing MVS combined with cryoablation vs. those undergoing MVS alone regarding Physical Component Summary mean 42.8 (95% confidence interval 38.3-47.3) vs. mean 44.0 (40.1-47.7), P = 0.700 or Mental Component Summary mean 53.1 (49.7-56.4) vs. mean 48.4 (44.6-52.2), P = 0.075. All patients, irrespective of allocated procedure, reached the same QOL after surgery as an age-matched Swedish general population. The Physical Component Summary in patients with sinus rhythm did also not differ from those in AF at 12 months; mean 45.4 (42.0-48.7) vs. mean 40.5 (35.5-45.6), P = 0.096) nor was there a difference in Mental Component Summary; mean 51.0 (48.0-54.1) vs. mean 49.6 (44.6-54.5), P = 0.581). Conclusion: Left atrial cryoablation added to MVS does not improve health-related QOL in patients with permanent AF, a finding that raises concerns regarding recommendations made for this combined procedure.

Left atrial function after epicardial pulmonary vein isolation in patients with atrial fibrillation.

PURPOSE: Epicardial pulmonary vein isolation has become an increasingly used therapy for medically resistant atrial fibrillation. The purpose of the present study was therefore to evaluate if epicardial pulmonary vein isolation combined with ganglionated plexi ablation affects the size and mechanical function of the left atrium, and whether the effects are dependent on the extensiveness of the ablation applications. METHODS: A total of 42 patients underwent an echocardiographic examination prior to and 6 months after a minimal invasive epicardial pulmonary vein isolation procedure for the assessment of the effects on left atrial size and function. In 27 patients, who had sinus rhythm both at baseline and follow-up, was a comparison of atrial size and function possible at these time intervals. Fractional area changes were obtained from the left atrial end-systolic and end-diastolic areas in the apical four-chamber view. Pulsed-Doppler was used to assess the transmitral flow velocities to evaluate mechanical function. RESULTS: Left atrial size and function at 6-month follow-up had not changed significantly from those at baseline as indicated by left atrial maximal area (17.1 ± 4.6 vs. 18.7 ± 5.3, p = 0.118), minimal area (12.5 ± 3.8 vs. 13.4 ± 4.7, p = 0.248), fractional area change (27.4 ± 8.2 vs. 28.7 ± 10.6, p = 0.670), and E/A ratio (1.49 ± 0.47 vs. 1.54 ± 0.67, p = 0.855). CONCLUSIONS: Radiofrequency ablation for epicardial pulmonary vein isolation combined with ganglionated plexi ablation has no major effects on atrial function or size. A preserved atrial function for those maintaining sinus rhythm may have important implications for thromboembolic risk after surgery, but warrants confirmation in larger trials.

Thoracoscopic epicardial left atrial ablation in symptomatic patients with atrial fibrillation.

AIMS: The low efficacy rates reported for conventional catheter ablation of longstanding persistent atrial fibrillation (LPAF) have led to the development of alternative techniques such as minimal invasive surgical ablation, aiming for durable and contiguous transmural lesions. The aim was to evaluate the efficacy and safety of total thoracoscopic epicardial left atrial ablation (TELA-AF) procedures in a prospective study of severely symptomatic patients with either drug-resistant AF and/or failed attempts of catheter ablation. METHODS AND RESULTS: The TELA-AF surgical technique includes pulmonary vein isolation, left atrial (LA) 'box lesion', and partial vagal denervation. The LA appendage was excluded if deemed safe. Patients were followed with clinical evaluations and 12-lead electrocardiograms at 3, 6, and 12 months after the surgical intervention, complemented with a 7-day Holter monitoring after 6 and 12 months. Sixty patients, of whom 38 (63%) suffered from LPAF, underwent TELA-AF between November 2008 and December 2010. One patient with LPAF was lost to follow-up. At 12-month follow-up, 55/59 patients (93%) were free from atrial fibrillation (AF), while 7/59 patients (12%) suffered from recurrent LA tachycardia. Among patients with LPAF, 32/37 (86%) maintained sinus rhythm after 12 months. Adverse events included four perioperative bleedings requiring conversion to sternotomy in three cases, two ischaemic strokes and one transient ischaemic attack. CONCLUSION: The total thoracoscopic surgical ablation procedure is highly effective even in patients with LPAF, and it seems safe. The high rate of iatrogenic LA re-entrant tachycardia, however, warrants further improvement of the technique.

Ablation of atrial fibrillation with cryoballoon or duty-cycled radiofrequency pulmonary vein ablation catheter: a randomized controlled study comparing the clinical outcome and safety; the AF-COR study.

AIMS: The urge to facilitate the atrial fibrillation (AF) ablation procedure has led to the development of new ablation catheters specifically designed as 'one-shot tools' for pulmonary vein isolation (PVI). The purpose of this study was to compare the efficacy, safety, and procedure times for two such catheters using different energy sources. METHODS AND RESULTS: One hundred and ten patients, referred for ablation of paroxysmal or persistent AF, were randomized to treatment with either the cryoballoon or the circular multipolar duty-cycled radiofrequency-based pulmonary vein ablation catheter (PVAC). Complete PVI was achieved in 98 vs. 93% patients in the cryoballoon and PVAC group, respectively, with complication rates of 8 vs. 2% (P = 0.2). Complete freedom from AF, without antiarrhythmic drugs, after one single ablation procedure was seen in 46% in the cryoballoon vs. 34% after 12 months (P = 0.2). Procedure times were comparable, but fluoroscopy time was shorter for the cryoballoon (32 ± 16 min) than for the PVAC procedures (47 ± 17 min) (P < 0.001). A significant improvement of quality of life (QoL) and arrhythmia-related symptoms was seen in both groups after ablation. CONCLUSION: Both catheters proved comparably effective and safe in achieving acute PVI, apart from the shorter fluoroscopy times achieved with the cryoballoon. At follow-up, there was no statistically significant difference between the groups regarding freedom from AF and clinical success. The QoL increased to the same levels as for the general Swedish population in both groups.

Safety and efficacy of pharmacological cardioversion of atrial fibrillation using intravenous vernakalant, a new antiarrhythmic drug with atrial selectivity.

INTRODUCTION: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia that due to its frequent hospitalizations and increased complication rates imposes a significant health economic burden. Many patients with recurrent AF are admitted to the hospital for cardioversion to restore sinus rhythm. Given this knowledge, it is clearly important to identify a feasible and effective approach for cardioversion of these patients. Cardioversion always requires careful assessment of potential complications, which apart from thromboembolic risks, include proarrhythmias and those related to the deep sedation required for electrical cardioversion. Even though electrical cardioversion is proven to be safe and effective, the need for anesthesia makes alternative strategies more attractive. AREAS COVERED: The research discussed is the alternative strategies for cardioversion, including electrical cardioversion and the new relatively atrial-selective antiarrhythmic drug, vernakalant. The literature search methodology undertaken included search in PubMed (cardioversion, vernakalant, conversion as key words). EXPERT OPINION: Vernakalant is shown to have good conversion rates, an apparently safe antiarrhythmic profile and is well tolerated in patients with a history of ischemic heart disease. In most cases of recent-onset AF, pharmacological cardioversion can provide a probably more cost-effective and safer alternative to electrical cardioversion, which can then be used as a second option for those who failed the first attempt of cardioversion.

Atrial function after left atrial epicardial cryoablation for atrial fibrillation in patients undergoing mitral valve surgery.

PURPOSE: To explore the effects on atrial and ventricular function of restoring sinus rhythm (SR) after epicardial cryoablation and closure of the left atrial appendage (LAA) in patients with mitral valve disease and atrial fibrillation (AF) undergoing surgery. METHODS: Sixty-five patients with permanent AF were randomized to mitral valve surgery combined with left atrial epicardial cryoablation and LAA closure (ABL group, n = 30) or to mitral valve surgery alone (control group, n = 35). Two-dimensional and Doppler echocardiography were performed before and 6 months after surgery. RESULTS: At 6 months, 73% of the patients in the ABL group and 46% of the controls were in SR. Patients in SR at 6 months had a reduction in their left ventricular diastolic diameter while the left ventricular ejection fraction was unchanged. In patients remaining in AF, the left ventricular ejection fraction was lower than at baseline. The left atrial diastolic volume was reduced after surgery, more in patients with SR than AF. In patients in SR, the peak velocity during the atrial contraction and the reservoir function were lower in the ABL group than in the control group. CONCLUSIONS: In patients in SR, signs of atrial dysfunction were observed in the ABL but not the control group. Atrial dysfunction may have existed before surgery, but the difference between the groups implies that the cryoablation procedure and/or closure of the LAA might have contributed.

Dronedarone in high-risk permanent atrial fibrillation.

BACKGROUND: Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events in high-risk permanent atrial fibrillation. METHODS: We assigned patients who were at least 65 years of age with at least a 6-month history of permanent atrial fibrillation and risk factors for major vascular events to receive dronedarone or placebo. The first coprimary outcome was stroke, myocardial infarction, systemic embolism, or death from cardiovascular causes. The second coprimary outcome was unplanned hospitalization for a cardiovascular cause or death. RESULTS: After the enrollment of 3236 patients, the study was stopped for safety reasons. The first coprimary outcome occurred in 43 patients receiving dronedarone and 19 receiving placebo (hazard ratio, 2.29; 95% confidence interval [CI], 1.34 to 3.94; P=0.002). There were 21 deaths from cardiovascular causes in the dronedarone group and 10 in the placebo group (hazard ratio, 2.11; 95% CI, 1.00 to 4.49; P=0.046), including death from arrhythmia in 13 patients and 4 patients, respectively (hazard ratio, 3.26; 95% CI, 1.06 to 10.00; P=0.03). Stroke occurred in 23 patients in the dronedarone group and 10 in the placebo group (hazard ratio, 2.32; 95% CI, 1.11 to 4.88; P=0.02). Hospitalization for heart failure occurred in 43 patients in the dronedarone group and 24 in the placebo group (hazard ratio, 1.81; 95% CI, 1.10 to 2.99; P=0.02). CONCLUSIONS: Dronedarone increased rates of heart failure, stroke, and death from cardiovascular causes in patients with permanent atrial fibrillation who were at risk for major vascular events. Our data show that this drug should not be used in such patients. (Funded by Sanofi-Aventis; PALLAS ClinicalTrials.gov number, NCT01151137.).

Right ventricular contractility as a measure of optimal interventricular pacing setting in cardiac resynchronization therapy.

AIMS: The aim of the present study was to assess whether right ventricular (RV) contractility can be used for optimization of the interventricular (VV) interval and to study the acute hemodynamic effect of different VV intervals on right and left ventricular (LV) contractility in patients referred for cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Intracardiac LV and RV dP/dt were measured with a 0.014-in. sensor-tipped pressure guidewire during pacing at nine different VV intervals ranging from +80 ms (LV pre-excitation) to -80 ms (RV pre-excitation) in 26 patients who received a biventricular pacemaker. No correlation was found between the optimal VV intervals identified by maximum LV dP/dt and RV dP/dt, which were identical in only seven cases (27%). Only when testing slightly broader intervals (+/-20 ms) was there a statistically significant correlation (P= 0.037) between the optimized VV intervals. In the majority of patients (58%) either LV or RV pre-excitation was superior to simultaneous pacing according to LV dP/dt(max) measurements. CONCLUSION: RV dP/dt(max) failed to identify the optimal VV interval when compared with LV dP/dt(max) and can therefore not be recommended for VV optimization in CRT patients.

A high quality of life is maintained late after Maze III surgery for atrial fibrillation.

BACKGROUND: Cox Maze surgery for atrial fibrillation (AF) has been found to have high efficacy in maintaining sinus rhythm and has been shown to improve quality of life early after surgery, but reports on long-term effects in this respect are lacking. This study was therefore undertaken to evaluate the effect of the Maze procedure on health-related quality of life in the long term. METHODS: Patients with drug-refractory AF undergoing the 'cut and sew' Maze III procedure without any modification were assessed with the SF-36 Health Survey regarding quality of life at baseline and late after surgery. Totally 61 patients, mean age 55 years (range: 29-74 years), were evaluated. At the time of surgery, 34 patients (56%) had paroxysmal or persistent AF and the remainder had permanent AF. RESULTS: At late follow-up, at a mean of 55+/-12 months, 54 patients (89%) were free from AF recurrences and another five patients (8%) had experienced only one or a few AF episodes. All eight scales on the SF-36 Health Survey were significantly improved at long-term follow-up compared to baseline. The quality-of-life improvement was seen both in patients with paroxysmal/persistent AF and in those with permanent AF. At long-term follow-up, the quality-of-life scores were comparable with those of the general population. CONCLUSIONS: The Cox Maze III procedure has good long-term efficacy for rhythm control in patients with medically refractory AF, resulting in a quality-of-life improvement, which is maintained late after surgery.

Epicardial off-pump pulmonary vein isolation and vagal denervation improve long-term outcome and quality of life in patients with atrial fibrillation.

OBJECTIVES: The limited information available on thoracoscopic pulmonary vein isolation combined with ganglionated plexi ablation and the lack of studies regarding its effect on quality of life and physical capacity urged us to study its acute and long-term results in patients with atrial fibrillation. METHODS: Forty-three patients (mean age 57.1 years) with symptomatic atrial fibrillation referred for thoracoscopic off-pump epicardial pulmonary vein isolation and ganglionated plexi ablation using radiofrequency energy were included. RESULTS: The physical capacity improved significantly at 6-month follow-up compared with baseline (mean +/- standard deviation, 165.2 +/- 65 Watt versus 155.9 +/- 57 Watt, P = .02). Quality of life (Short Form-36 health survey) significantly improved 12 months after surgery compared with baseline in all subscales except for bodily pain. The symptom severity questionnaire score decreased significantly from mean 15.2 +/- 4.0 points to 10.7 +/- 4.8 points (P = .02). Overall, 25 of 33 patients (76%) followed up for 12 months had no symptomatic atrial fibrillation recurrences or atrial fibrillation episodes on 24-hour Holter recordings. The corresponding figures were 79% (19/24) for patients with paroxysmal atrial fibrillation, 100% (2/2) for persistent atrial fibrillation, and 57% (4/7) for permanent atrial fibrillation. The most common complication was bleeding events (9%) during pulmonary vein dissection. CONCLUSIONS: Epicardial off-pump pulmonary vein isolation combined with ganglionated plexi ablation improved quality of life, symptoms, and exercise capacity and therefore may be considered for patients with atrial fibrillation who fail endocardial pulmonary vein ablation or as a first-line procedure if left atrial appendage exclusion is warranted.

The use of impedance cardiography for optimizing the interventricular stimulation interval in cardiac resynchronization therapy-a comparison with left ventricular contractility.

The present study aimed to assess whether impedance cardiography (IC) can correctly identify the optimal interventricular (VV) pacing interval in cardiac resynchronization therapy (CRT). Twenty four patients received a biventricular pacemaker and underwent IC for cardiac output (CO) measurements to identify the optimal VV interval. Invasive measurements of left ventricular (LV) dP/dt(max) were used as a reference. During optimization the VV interval was changed with 20 ms steps from +80 (LV pre-excitation) to-80 ms (RV pre-excitation). The optimal VV interval was defined as the one that resulted in the highest LV dP/dt(max) value and the highest CO obtained by IC, respectively. During simultaneous biventricular pacing both LV dP/dt(max) and CO increased (mean 16.6% and 16.2%, respectively) as compared to baseline. Biventricular pacing with optimized VV intervals resulted in a further absolute increase of LV dP/dt (max) and CO (5.6% and 41.3%, respectively). The average decrease in LV dP/dt(max) was 79.6 +/- 51.6 mmHg/s when the optimal VV interval was programmed according to the IC measurements. Cross spectral analysis showed no correlation between the optimal VV intervals identified by the two methods (p > 0.05) and identical optimal VV intervals were identified in only six of the 24 patients. When broader VV time intervals were compared the correlation between the two methods was statistically significant (p = 0,0166). In conclusion, the use of IC for VV interval optimization is questionable since these optimized time intervals do not seem to correlate well with those obtained by measuring LV dP/dt.

The effects of aetiology on outcome in patients treated with cardiac resynchronization therapy in the CARE-HF trial.

AIMS: Cardiac dyssynchrony is common in patients with heart failure, whether or not they have ischaemic heart disease (IHD). The effect of the underlying cause of cardiac dysfunction on the response to cardiac resynchronization therapy (CRT) is unknown. This issue was addressed using data from the CARE-HF trial. METHODS AND RESULTS: Patients (n = 813) were grouped by heart failure aetiology (IHD n = 339 vs. non-IHD n = 473), and the primary composite (all-cause mortality or unplanned hospitalization for a major cardiovascular event) and principal secondary (all-cause mortality) endpoints analysed. Heart failure severity and the degree of dyssynchrony were compared between the groups by analysing baseline clinical and echocardiographic variables. Patients with IHD were more likely to be in NYHA class IV (7.5 vs. 4.0%; P = 0.03) and to have higher NT-proBNP levels (2182 vs. 1725 pg/L), indicating more advanced heart failure. The degree of dyssynchrony was more pronounced in patients without IHD (assessed using mean QRS duration, interventricular mechanical delay, and aorta-pulmonary pre-ejection time). Left ventricular ejection fraction and left ventricular end-systolic volume improved to a lesser extent in the IHD group (4.53 vs. 8.50% and -35.68 vs. -58.52 cm(3)). Despite these differences, CRT improved all-cause mortality, NYHA class, and hospitalization rates to a similar extent in patients with or without IHD. CONCLUSION: The benefits of CRT in patients with or without IHD were similar in relative terms in the CARE-HF study but as patients with IHD had a worse prognosis, the benefit in absolute terms may be greater.

Long-term effects of the maze procedure on atrial size and mechanical function.

BACKGROUND: The Maze procedure is effective in restoring sinus rhythm, but the extensive procedure may have negative effects on atrial mechanical function. Decreased atrial contractility has been observed early after the Maze procedure. The purpose of this study was to determine the long-term effect of the Maze procedure on atrial size and mechanical function. METHODS: Fifty-two patients with symptomatic atrial fibrillation, without structural heart or valvular disease, underwent the Cox Maze III procedure. Atrial size and mechanical function were assessed by echocardiographic examination at baseline and postoperatively at a mean +/- SD of 6 +/- 1 and 56 +/- 12 months. RESULTS: The left atrial area was decreased 6 months after the procedure compared with baseline (mean, 15.4 +/- 3.3 vs 17.6 +/- 3.2 cm2, p < 0.01). By 56 months, however, the left atrial area had increased compared with the 6-month follow-up (19.5 +/- 3.9 vs 15.4 +/- 3.3 cm2, p < 0.001), resulting in no difference in left atrial size compared with the baseline values. The left atrial contractility, measured as fractional area change, was significantly reduced at 6 and 56 months of follow-up (0.20 +/- 0.09 and 0.19 +/- 0.07 vs baseline 0.36 +/- 0.09), as was the transmitral A-wave velocity (30 +/- 12 and 28 +/- 8 cm/s vs baseline 40 +/- 15). The same pattern was seen for the right atrium. CONCLUSIONS: This study shows that the Maze procedure results in a sustained decrease in atrial contractility. The initial reduction in atrial size is later reversed. These findings contradict late improvements in atrial mechanical function after Maze surgery and may have important implications for the risk of thromboembolic complications.

A randomized double-blind study of epicardial left atrial cryoablation for permanent atrial fibrillation in patients undergoing mitral valve surgery: the SWEDish Multicentre Atrial Fibrillation study (SWEDMAF).

AIMS: The efficacy of epicardial left atrial (LA) cryoablation in eliminating atrial fibrillation (AF) in patients undergoing mitral valve surgery (MVS) is unknown. We hypothesized that MVS combined with LA cryoablation is superior to MVS alone. METHODS AND RESULTS: Sixty-nine patients with permanent AF, included at four centres, underwent MVS with or without epicardial LA cryoablation. The primary endpoint was regained sinus rhythm. Risk factors for failed AF cryoablation were elucidated. Sixty-five out of 69 patients reached the primary endpoint. At 6 and 12 months follow-up, 73.3% of patients who underwent cryoablation had regained sinus rhythm at both follow-ups, compared with 45.7 and 42.9% of patients, respectively, who underwent MVS alone (group differences, at 6 months P = 0.024, after 12 months P = 0.013). The in-hospital complication rate was 11.4% in the MVS group and 26.5% in the cryoablation group (P = 0.110). Risk factors for failed elimination of AF by cryoablation were duration of permanent AF (P = 0.012) and presence of coronary artery disease (P = 0.047), according to multiple logistic regression analysis. CONCLUSION: This first prospective randomized study showed that combining MVS with epicardial LA cryoablation is significantly better in eliminating pre-operative permanent AF than MVS alone.

Effect of right atrial overdrive pacing in the prevention of symptomatic paroxysmal atrial fibrillation: a multicenter randomized study, the PAF-PACE study.

The aim of this study was to assess if right atrial overdrive pacing can suppress symptomatic episodes of paroxysmal atrial fibrillation (PAF) in patients without bradyarrhythmias. Forty-two patients with frequent and symptomatic PAF without other pacing indication had a pacemaker implanted after a 4-week run-in period, during which the frequency of symptomatic PAF episodes and the mean heart rate were objectively documented. Depending on the mean heart rate recorded during run-in, the pacemaker was programmed in random order to right atrial AAI pacing at 10-19 beats/min > mean heart rate (medium overdrive [MO]), at 20-29 beats/min > mean heart rate (high overdrive [HO]) and to no pacing (OAO mode) for 4-12 weeks each using a crossover design. In the 35 patients who completed the protocol, the number of symptomatic episodes of PAF (>30-second duration) per week was significantly lower during MO pacing (median 0.88, P = 0.001, n = 35) and during HO pacing (median 0.75, P = 0.002, n = 20) than during OAO (median 2.02 and 2.04, respectively). There was no difference between MO and HO pacing in the 20 patients paced at both rates (0.97 vs 0.75, P = 0.33). Seven patients did not complete the protocol due to persistent atrial fibrillation (n = 4), angina pectoris requiring surgery (n = 1), and unwillingness to continue the study due to improvement (n = 1) or worsening (n = 1) of symptoms during the study periods. Right atrial overdrive pacing can reduce the number of symptomatic PAF episodes in patients with frequent and drug refractory PAF but without bradyarrhythmias.

Autonomic denervation after the Maze procedure.

The Maze III procedure is a surgical operation for curative treatment of AF. The procedure is extensive, however, with multiple incisions in both atria, and its effects on autonomic regulation of the heart rhythm are not known. This study comprises 17 patients, 10 with paroxysmal AF and 7 with chronic AF, who had no concurrent cardiac disease known to affect heart rate variability (HRV). A 24-hour Holter recording was performed preoperatively and 2 months (early) and 7 months (late) after surgery, for analysis of HRV in the time and frequency domains. Early after the Maze procedure all HRV components were markedly reduced compared to baseline (mean +/- 1 SD): SDNN 73 +/- 13 versus 148 +/- 50 (ms), total power 168 +/- 126 versus 560 +/- 1567 (ms2), low frequency (LF) power 47 +/- 67 versus 826 +/- 677 (ms2), high frequency (HF) power 47 +/- 40 versus 678 +/- 666 (ms2), and LF:HF 1.22 +/- 0.9 versus 2.55 +/- 1.4. Late after the Maze procedure all variables were still reduced. Only total power increased significantly between early and late follow-up (168 +/- 126 vs 496 +/- 435 ms2). Late after Maze surgery, values of the different HRV components did not differ between the patients with paroxysmal AF and chronic AF. Early after the Maze procedure there is a marked decrease of all HRV components, which is maintained 7 months after surgery, a pattern consistent with denervation of the heart.

QRS aberration during atrial fibrillation at rest and during exercise. Effect of a selective potassium channel blocking agent.

This study assesses the occurrence of and identifies clinical characteristics associated with the development of aberrant conduction during infusion of the I(kr)-blocker almokalant. Class III drugs may induce aberrant conduction by prolongation of cardiac repolarization, especially during atrial fibrillation (AF). Ninety-two patients with AF received a 6-hour almokalant infusion, aiming at conversion to sinus rhythm (SR). Fiftyfive of the patients received an identical infusion during SR. During almokalant infusion, the number of patients with intermittent QRS aberration during AF increased, from 21% to 80% at rest, and was further increased to 89% during exercise, with predominantly left, and sequential bilateral, bundle branch aberrancy. Patients with aberrant conduction showed signs of more advanced myocardial disease. Predictors of the development of QRS aberration were female gender, arrhythmia duration, and decreased left ventricular ejection fraction, while use of calcium antagonists decreased the probability. No patient showed aberration during regular SR. Twenty-one patients experienced aberrantly conducted supraventricular premature beats. In conclusion, aberrant conduction is common during infusion of the I(kr)-blocker almokalant during AF, and seems to be more frequent in females and in patients with more advanced myocardial disease.

Atrial size and transport function after the Maze III procedure for paroxysmal atrial fibrillation.

BACKGROUND: The Maze procedure is a curative surgical therapy for atrial fibrillation, restoring sinus rhythm and improving quality of life. Because the procedure results in tissue scarring, the atrial transport function is most likely affected. METHODS: Seventeen patients with paroxysmal atrial fibrillation underwent the Maze III procedure without any concomitant valve operation. Atrial size and transport function were measured before and at 2, 6, and 24 months after operations with two-dimensional echocardiography and pulsed-wave Doppler. RESULTS: Fifteen patients (88%) had signs of left atrial contractions as shown by the presence of a transmitral atrial filling wave on Doppler echocardiography at 6 months follow-up. The transmitral early filling wave and atrial filling wave were measured to calculate the early filling/atrial filling wave ratio, which increased from 1.2 before to 1.9 at 2 months after the Maze procedure (nonsignificant), and further to 2.8 at 24 months (p = 0.02). A decrease in the right and left atrial size was seen at 2 months after an operation, but no further decrease occurred. CONCLUSIONS: In patients with paroxysmal atrial fibrillation, there is a progressive increase in the transmitral early filling/atrial filling wave ratio after the Maze procedure, consistent with a gradual decrease in the left atrial transport function.

Improvement of Echocardiographic M-Mode Detection of Ventricular Precontraction in the Wolff-Parkinson-White Syndrome by Transesophageal Atrial Pacing.

BACKGROUND: The purpose of this study was to evaluate the accuracy of conventional M-mode echocardiography in localizing the site of the accessory pathway in 21 patients with overt Wolff-Parkinson-White (W-P-W) syndrome during sinus rhythm (SR) and during transesophageal atrial stimulation (TAS). METHODS: The invasive electrophysiological study was used as a reference, and the results were compared with the pathway localization obtained through algorithmic interpretation of the 12-lead electrocardiogram during SR. Echocardiographic left parasternal short-axis recordings were performed during SR and TAS (100-120 beats/min). The shortest electromechanical interval measured at six different sites of the atrioventricular valve plane from the onset of the delta wave to the peak of the precontraction defined the pathway localization. RESULTS: Correct localization of the accessory pathway with echocardiography could be attained in 14 patients during SR (14 of 21, or 66%). With the aid of TAS, correct pathway localization was achieved for an additional 2 patients, making a total of 16 patients (76%). During TAS, precontraction was enhanced in 63% of the patients. With the algorithmic electrocardiographic interpretation, the localization of the accessory pathway was correct in 13 of the 21 patients (62%). The differences were not significant. CONCLUSION: M-mode echocardiography is a simple and readily available method for the identification of precontraction. The method is comparable to pathway localization through algorithmic ECG interpretation during SR. Transesophageal left atrial pacing during echocardiography can amplify the precontraction and thereby facilitate the interpretation of the wall motions.