The Mitral Annulus Disjunction Arrhythmic Syndrome

BACKGROUND

Mitral annulus disjunction (MAD) is an abnormal atrial displacement of the mitral valve leaflet hinge point. MAD has been associated with mitral valve prolapse (MVP) and sudden cardiac death.

OBJECTIVES

The purpose of this study was to describe the clinical presentation, MAD morphology, association with MVP, and ventricular arrhythmias in patients with MAD.

METHODS

The authors clinically examined patients with MAD. By echocardiography, the authors assessed the presence of MVP and measured MAD distance in parasternal long axis. Using cardiac magnetic resonance (CMR), the authors assessed circumferential MAD in the annular plane, longitudinal MAD distance, and myocardial fibrosis. Aborted cardiac arrest and sustained ventricular tachycardia were defined as severe arrhythmic events.

RESULTS

The authors included 116 patients with MAD (age 49 ± 15 years; 60% female). Palpitations were the most common symptom (71%). Severe arrhythmic events occurred in 14 (12%) patients. Longitudinal MAD distance measured by CMR was 3.0 mm (interquartile range [IQR]: 0 to 7.0 mm) and circumferential MAD was 150° (IQR: 90° to 210°). Patients with severe arrhythmic events were younger (age 37 ± 13 years vs. 51 ± 14 years; p = 0.001), had lower ejection fraction (51 ± 5% vs. 57 ± 7%; p = 0.002) and had more frequently papillary muscle fibrosis (4 [36%] vs. 6 [9%]; p = 0.03). MVP was evident in 90 (78%) patients and was not associated with ventricular arrhythmia.

CONCLUSIONS

Ventricular arrhythmias were frequent in patients with MAD. A total of 26 (22%) patients with MAD did not have MVP, and MVP was not associated with arrhythmic events, indicating MAD itself as an arrhythmogenic entity. MAD was detected around a large part of the mitral annulus circumference and was interspersed with normal tissue.

Strain echocardiographic assessment of left atrial function predicts recurrence of atrial fibrillation

AIMS

We evaluated if a dispersed left atrial (LA) contraction pattern was related to atrial fibrillation (AF) in patients with normal left ventricular (LV) function, and normal or mildly enlarged left atrium.

METHODS AND RESULTS

We included 61 patients with paroxysmal AF (PAF). Of these, 30 had not while 31 had recurrence of AF after radiofrequency ablation (RFA). Twenty healthy individuals were included for comparison. Echocardiography was performed in patients in sinus rhythm the day before RFA. LA volume was calculated. Peak negative longitudinal strain was assessed in 18 LA segments during atrial systole. Contraction duration in 18 LA segments was measured as the time from peak of the P wave on electrocardiogram to maximum myocardial shortening in each segment. The standard deviation of contraction durations was defined as LA mechanical dispersion (LA MD). LA size was rather preserved in patients with PAF (LA volume 25 ± 10 mL/m(2)). LA MD was more pronounced in patients with recurrence of AF after RFA compared with those without recurrence and controls (38 ± 14 ms vs. 30 ± 12 ms vs. 16 ± 8 ms, both P < 0.001). LA MD was a predictor of PAF [OR 7.84 (95%CI 2.15-28.7), P < 0.01, per 10 ms increase] adjusted for age, LA volume, e', and LA function. LA function by strain was reduced in both patients with and without recurrent AF after RFA compared with controls (-14 ± 4% vs. -16 ± 3% vs. -19 ± 2%, both P < 0.05).

CONCLUSION

LA MD was pronounced, and LA deformation was reduced in patients with PAF with apparently normal LV structure and function, and normal or mildly enlarged LA. LA MD may be useful as a predictor of AF recurrence after RFA.

Effects of short-term exercise training on symptoms and quality of life in patients with chronic atrial fibrillation

BACKGROUND

A randomised study was conducted to determine if short-term exercise training in patients with chronic atrial fibrillation (AF) might improve symptoms and health-related quality of life (HRQoL).

METHODS

AF patients (64+/-7 years) were randomised to exercise training (n=15) or a 2-month control period (n=15) followed by an exercise training program (ETP). The ETP consisted of 24 training sessions with aerobic exercise and muscle strengthening. A cycle ergometer test, with recording of perceived exertion on the Borg scale, was performed. The participants completed HRQoL questionnaires, the Short-Form 36 (SF-36) and Symptom and Severity Checklist (SSCL), before and after training. Because there were no changes after two months in the control group, pooled data for all patients are presented before and after training.

RESULTS

Four of the eight SF-36 scales improved significantly (p<0.05) following training: physical functioning (82+/-14 pre-ETP, 86+/-10 post-ETP), bodily pain (82+/-17 pre-ETP, 92+/-14 post-ETP), vitality (61+/-14 pre-ETP, 68+/-13 post-ETP) and role-emotional (85+/-28 pre-ETP, 94+/-20 post-ETP). The SF-36 physical component summary scale also increased from 49+/-6 pre-ETP to 52+/-6 post-ETP (p<0.05). Significant improvements were also observed for summary and specific symptom scores of the SSCL. Exercise capacity improved by 41+/-20% and perceived exertion during testing by 1.4 points after training (p<0.05 for both).

CONCLUSIONS

The study demonstrates a significant improvement in HRQoL, symptoms during exercise testing and exercise capacity after a short-term exercise training program in patients with chronic AF.

Short-term Exercise Training in Patients With Chronic Atrial Fibrillation

PURPOSE

A randomized study was conducted to determine whether short-term exercise training in patients with chronic atrial fibrillation (AF) might improve exercise capacity and quality of life (QOL), and influence atrioventricular conduction.

METHODS

Atrial fibrillation patients (age 64 +/- 7 years) were randomized to exercise training (n = 15) or a 2-month control period (n = 15) followed by the training program. Twenty-four training sessions consisted of aerobic exercise and muscle strengthening. A cycle ergometer test and a 15-minute resting high-frequency spectral electrocardiogram analysis were performed and a QOL questionnaire (SF-36) was completed before and after training. Because there were no changes after 2 months in the control group, pooled data for all patients are presented before and after training.

RESULTS

Cumulated work at Borg scale 17 increased by 41% +/- 36%. Heart rate at rest and after 10 minutes of exercise decreased from 75 +/- 14 to 68 +/- 14 bpm and 145 +/- 19 to 137 +/- 21 bpm, respectively. HF increased from 81 +/- 17 to 91 +/- 22 milliseconds. Four of the 8 scales and 1 of the 2 summary scales of the Short-Form-36 improved. P <.05 for all results.

CONCLUSIONS

Exercise capacity, heart rate variability, and QOL improved after 2 months of exercise training in patients with chronic AF. Heart rates at rest and during exercise decreased.

Ventricular arrhythmias in arrhythmic mitral valve syndrome-a prospective continuous long-term cardiac monitoring study

AIMS

Arrhythmic mitral valve syndrome is linked to life-threatening ventricular arrhythmias. The incidence, morphology and methods for risk stratification are not well known. This prospective study aimed to describe the incidence and the morphology of ventricular arrhythmia and propose risk stratification in patients with arrhythmic mitral valve syndrome.

METHODS

Arrhythmic mitral valve syndrome patients were monitored for ventricular tachyarrhythmias by implantable loop recorders (ILR) and secondary preventive implantable cardioverter-defibrillators (ICD). Severe ventricular arrhythmias included ventricular fibrillation, appropriate or aborted ICD therapy, sustained ventricular tachycardia and non-sustained ventricular tachycardia with symptoms of hemodynamic instability.

RESULTS

During 3.1 years of follow-up, severe ventricular arrhythmia was recorded in seven (12%) of 60 patients implanted with ILR [first event incidence rate 4% per person-year, 95% confidence interval (CI) 2-9] and in four (20%) of 20 patients with ICD (re-event incidence rate 8% per person-year, 95% CI 3-21). In the ILR group, severe ventricular arrhythmia was associated with frequent premature ventricular complexes, more non-sustained ventricular tachycardias, greater left ventricular diameter and greater posterolateral mitral annular disjunction distance (all P < 0.02).

CONCLUSIONS

The yearly incidence of ventricular arrhythmia was high in arrhythmic mitral valve syndrome patients without previous severe arrhythmias using continuous heart rhythm monitoring. The incidence was even higher in patients with secondary preventive ICD. Frequent premature ventricular complexes, non-sustained ventricular tachycardias, greater left ventricular diameter and greater posterolateral mitral annular disjunction distance were predictors of first severe arrhythmic event.

Misoprostol treatment exacerbates abdominal discomfort in patients with non-ulcer dyspepsia and erosive prepyloric changes. A double-blind, placebo-controlled, multicentre study

One hundred and thirty-seven consecutive outpatients with non-ulcer dyspepsia (NUD) and erosive prepyloric changes (EPC) were randomly allocated to double-blind treatment with 400-micrograms misoprostol tablets twice daily or placebo for 4 weeks. Misoprostol had a significant worsening effect on epigastric pain, nausea, meteorism, lower abdominal pain, and diarrhoea, as compared with placebo. The fact that symptoms in patients with NUD and EPC were exacerbated by an antisecretory dose of misoprostol indicates that the symptoms are largely unrelated to gastric acid.

A New Era in Epicardial Access for the Ablation of Ventricular Arrhythmias: The Epi-Co2 Registry

OBJECTIVES

This multicenter registry aimed to assess the reproducibility and safety of intentional coronary vein exit and carbon dioxide insufflation to facilitate subxiphoid epicardial access in the setting of ventricular tachycardia ablation.

BACKGROUND

Epicardial ablation for ventricular tachycardia is not a widespread technique due to the significant potential complications associated with subxiphoid puncture. The first experience in 12 patients showed that intentional coronary vein exit and carbon dioxide insufflation was technically feasible.

METHODS

A branch of the coronary sinus was cannulated by means of a diagnostic JR4 coronary catheter. Intentional perforation at the distal portion of that branch was performed with a high tip load 0.014-inch angioplasty wire. A microcatheter was advanced over the wire into the pericardial space. Carbon dioxide was then insufflated into the pericardial space, allowing direct visualization of the anterior pericardial space to facilitate subxiphoid puncture.

RESULTS

Intentional coronary vein exit was attempted in 102 consecutive patients in 16 different centers and successfully completed in 101 patients. Significant pericardial adhesions were confirmed in 3 patients, preventing carbon dioxide insufflation and epicardial ablation. None of the punctures were complicated with inadvertent right ventricular puncture or damage to a coronary artery. Significant bleeding (>80 ml) due to coronary vein exit occurred in 5 patients, without hemodynamic compromise. None of the patients required surgery.

CONCLUSIONS

Coronary vein exit and carbon dioxide insufflation can be safely and reproducibly achieved to facilitate subxiphoid pericardial access in the setting of ventricular tachycardia ablation.

Lower than expected burden of premature ventricular contractions impairs myocardial function

Aims

We aimed to explore the burden of frequent premature ventricular contractions (PVCs) associated with myocardial dysfunction in patients with outflow tract arrhythmia (OTA). We hypothesized that this threshold is lower than the previously suggested threshold of 24 000 PVCs/24 h (24%PVC) when systolic function is assessed by strain echocardiography. Furthermore, we aimed to characterize OTA patients with malignant arrhythmic events.

Methods and results

We included 52 patients referred for OTA ablation (46 ± 12 years, 58% female). Left ventricular global longitudinal strain (GLS) and mechanical dispersion were assessed by speckle tracking echocardiography. A subset underwent cardiac magnetic resonance imaging. PVC burden (%PVC) was assessed by Holter recording. Sinus rhythm QRS duration and PVC QRS duration were recorded from electrocardiogram, and the ratio was calculated (PVC QRS duration / sinus rhythm QRS duration). Median %PVC was 7.2 (0.2–60.0%). %PVC correlated with GLS (R = 0.44, P = 0.002) and with mechanical dispersion (R = 0.48, P < 0.001), but not with ejection fraction (R = 0.22, P = 0.12). %PVC was higher in patients with impaired systolic function by GLS (worse than −18%) compared with patients with normal function (22% vs. 5%, P = 0.001). Greater than 8%PVC optimally identified patients with abnormal GLS (area under the curve 0.79). Serious arrhythmic events occurred in 11/52 (21%) patients characterized by high QRS ratios (1.56 vs. 1.91, P < 0.001).

Conclusions

More than 8%PVC was associated with impaired systolic function by GLS, which is a lower threshold than previously reported. Patients with serious arrhythmic events had higher QRS ratios, which may represent a more malignant phenotype of OTA.

RV function in stable and unstable VT: is there a need for hemodynamic monitoring in future defibrillators?

During electrophysiological investigation of 22 patients with VT or aborted sudden cardiac death, arterial and RV pressures were measured. The time courses of mean arterial pressure (MAP), RV pulse pressure (RVPP), RV pulse pressure integral (RVPPI), and maximum right ventricular dP/dt (RV dP/dtmax) were followed during the first 15 seconds after VT induction. Compared to basal (preinduction) conditions, the RVPPI decreased by 41+/-10% (mean +/- SD) after 10-15 seconds of VT in 11 patients with stable VT and by 75+/-8% in 11 patients with unstable VT (MAP < 60 mmHg 15 s after VT onset). RVPP decreased by 13+/-11% after 10-15 seconds of VT in the stable VT group and by 50+/-16% in the unstable VT group. For RV dP/dtmax, these decreases were 4+/-22% in the stable VT group and 37+/-24% in the unstable VT group. There was a good correlation between percent decrease in MAP and percent decrease in RVPPI, RVPP, and RV dP/dtmax at 5-10 seconds (r = 0.86, 0.81, and 0.73, respectively) and 10-15 seconds (r = 0.84, 0.82, and 0.69, respectively) after VT onset. There was hardly any overlap of distributions of the individual values with the RVPPI parameter between the two VT groups. Comparing and correlating the percent decrease in mean arterial pressure with the RVPPI, RVPP, and RV dP/dtmax during induced VT, RVPPI demonstrated the most significant and specific changes in discriminating stable from unstable rhythms. However, by comparing RVPPI and RVPP using the area under the receiver operating characteristic curves, there was no significant statistical difference between the two parameters. By integrating rate criteria, electrogram signal analysis, and RVPPI or RVPP as a hemodynamic criterion, detection and treatment algorithms could improve the performance of future implantable defibrillators and avoiding shocks in VTs that can be terminated by antitachycardia pacing.

Effects of Ablation, Digitalis, and Beta‐Blocker on Dual Atrioventricular Nodal Pathways and Conduction During Atrial Fibrillation

INTRODUCTION

Modification of AV nodal conduction by radiofrequency ablation (RFA) results in a variable reduction in heart rate during atrial fibrillation (AF). Using AF induced in patients with dual AV nodal pathways as a model, we tested the effect of additional treatment with digitalis (ouabain) and beta-blocker (esmolol).

METHODS AND RESULTS

Ten patients were randomized to control (group I) and studied only before ablation. AF was induced in 30 patients before and after slow pathway ablation (group II). Mean ventricular cycle lengths (AF CLmean) were recorded. Slow pathway conduction was eliminated after ablation in 10 patients (group IIA), whereas slow pathway conduction was still present in 20 patients (group IIB). Compared to pre-RFA there was a 10% increase in AF CLmean post-RFA (P < 0.01). During isoproterenol infusion the increase was 8% (P = NS). Adding digitalis and beta-blocker during isoproterenol infusion increased AF CLmean by 75% (95% in group IIA) compared to 36% in group I (P < 0.001 II vs I).

CONCLUSION

Slow pathway ablation reduces ventricular rate during AF. Addition of digitalis and beta-blocker during isoproterenol infusion significantly decreases ventricular rate after ablation compared to the control group. The finding suggests that beta-blocker has significant effects on fast AV nodal pathway conduction during induced AF with isoproterenol infusion.

Dual AV nodal pathways and conduction during atrial fibrillation

OBJECTIVE

AV node modification reduces ventricular rate during atrial fibrillation (AF). We induced AF in patients with dual AV nodal pathways before and after radiofrequency ablation (RFA) of AV nodal reentry tachycardia (AVNRT) and examined the role of the two pathways in the transmission of impulses during AF.

DESIGN AND RESULTS

AF was induced in 30 patients before and after slow pathway ablation. Before RFA mean (AF CLmean) and shortest (AF CLshort) ventricular cycle lengths correlated significantly to ERPf, ERPs, and antegrade Wenckebach block (r = 0.53-0.67). Ablation eliminated slow pathway conduction completely in 10 patients (group A), whereas in 20 patients some slow pathway conduction was still present (group B). After RFA there was a 10% increase in AF CLmean (20%, p < 0.05 in A and 5%, p = NS in B) and 7% in AF CLshort (11%, p = NS in A and 6%, p = NS in B). During isoproterenol infusion after RFA AF CLmean increased 8% (p < 0.05) (14% in A and 6% in B; p < 0.05 in both groups). The effects of RFA were mainly confined to patients with ERPs less than the median value (13% vs 3% in those above median, respectively; p < 0.05).

CONCLUSION

The refractory periods of the AV nodal pathways are the main determinants of ventricular rate during induced AF. Slow pathway ablation reduces ventricular rate during AF. This effect was greatest when slow pathway conduction was completely eliminated. A short ERPs predicted a greater reduction in ventricular rate.

The utility of 24-h electrocardiogram recordings for the prediction of a sufficient number of premature ventricular complexes and mapping strategy during catheter ablation

Background and aims

An insufficient number of premature ventricular complexes (PVCs) during catheter ablation (CA) may prohibit adequate mapping of the site of origin. Parameters to predict this situation have not been established. Our objective was to quantify the association between preprocedural information and the probability of a sufficient number of PVCs for adequate mapping and successful CA.

Methods

Clinical characteristics and results from examinations and procedural data were collected retrospectively from health journals for patients admitted for CA of PVCs from 2011 to 2020.

Results

In total, 46 of 332 patients (14%) had an insufficient number of PVCs to enable adequate electroanatomical mapping. Patients with a sufficient number of PVCs had nominally more PVCs in the 24-h electrocardiogram (ECG), with a strong statistical trend [16,007 (6,509-26,205) vs. 8,332 (3,066-20,974), p = 0.055]. The receiver operator curve for a sufficient number of PVCs in 24-h ECGs had an area under the curve of 0.610 (95% CI 0.498-0.722, p = 0.055). The best predictive values were found at >10,000 PVCs per 24-h, with a positive predictive value of 67% and a negative predictive value of 57%. Patients for whom activation mapping was used as the sole mapping method had more PVCs in the 24-h ECG than did patients for whom pace mapping was added or used as an alternative [19,769 (10,564-30,526) vs. 15,237 (6,000-25,033), p = 0.022]. Neither acute outcome nor procedure time depended on the mapping strategy.

Conclusion

The number of PVCs in a 24-h ECG was moderately associated with the presence of a sufficient number of PVCs to perform electroanatomical mapping during CA. The presence of more PVCs in the preprocedural 24-h ECG was associated with the use of activation mapping as the sole mapping strategy.

[Sudden cardiac death]

Sudden cardiac death is instant unexpected death that occurs within one hour of an abrupt change in a person's stable clinical state. The mechanism is generally a ventricular tachyarrhythmia. The underlying pathology is usually coronary heart disease. In 1990, 18 patients who survived sudden cardiac death, excluding those with acute myocardial infarction, were evaluated and treated in our institution. 15 patients had coronary heart disease, one had hypertrophic cardiomyopathy, one had dilated cardiomyopathy and one had a replaced aortic valve. Evaluation included heart catheterization and electrophysiological examination. Treatment was specifically tailored to each patient according to etiology, results of all tests and the patient's prognostic factors. Treatment included a permanent pacemaker-cardioverter-defibrillator, antiarrhythmic drug therapy, aortocoronary bypass and betablocker therapy.

[Treatment of ventricular tachyarrhythmias with an implantable pacemaker-cardioverter-defibrillator]

During the period from November 1989 to January 1992, 17 patients with ventricular tachyarrhythmias received an implantable pacemaker-cardioverter-defibrillator. The material consists of three female and 14 male patients with an age range of 13-66 years, mean 50.8 +/- 16.6 years. 13 patients had coronary artery disease, one cardiomyopathy, one a myocarditis sequela and two primary rhythm disorder. Four patients received epicardial and 13 endocardial electrode systems. The observation period varied from 4-30 months (april 1992), mean 15.2 +/- 8.8 months. 11 out of 17 patients (65%) experienced one or more episodes of tachyarrhythmias which was treated successfully with overdrive pacing (ramp or burst), cardioversion or defibrillation. One patient died of heart failure after an observation period of 13 months. His pacemaker-cardioverter-defibrillator had been activated more than 100 times. Two children, 13 and 15 years, were treated successfully for ventricular fibrillation four and five months after implantation of the device. The actual one year survival is 100%. Assuming that therapy with a device had not taken place, and that the six patients who experienced episodes of ventricular fibrillation died, the hypothetical probability of survival would have been 62.1 +/- 12.3%.

[Adult patients with atrial septal defect]

Our material included patients older than 30 years who were diagnosed as having atrial septal defect during the period 1980-1993. A questionnaire was used during follow-up. 39 of a total of 42 patients were operated on. The mean follow-up time was 5.5 years. There was no operative mortality. Five patients had died by the time of follow-up. The three patients who had not been operated on had all died. The available literature gives no conclusive answer to the question of whether all patients with an atrial septal defect should be offered surgery or not.

A typical P-wave morphology in incessant atrial tachycardia originating from the right upper pulmonary vein

Automatic atrial tachycardias often originate from the ostia of the pulmonary veins. P-wave morphology during tachycardia may indicate from which pulmonary vein the tachycardia originates. Two patients with pulmonary vein tachycardias demonstrating atypical P-wave morphology were investigated. One of the patients had a tachycardia with two different cycle lengths. P-wave morphology was evaluated in 12-lead ECGs from two patients with incessant atrial tachycardia, during tachycardia and sinus rhythm. Their tachycardias were successfully ablated at the mouth of the right upper pulmonary vein. Previous studies have demonstrated a positive or negative P-wave configuration in lead aVL originating from this area and a change from a biphasic P-wave in V1 during sinus rhythm to a positive P-wave configuration during tachycardia. Neither of our two patients had such a change in lead V1. One our patients had two tachycardias with different cycle lengths originating from the same area. It is concluded that if an atrial tachycardia with P-wave morphology resembling that of sinus rhythm cannot be located to the right atrium, its origin may be the right upper pulmonary vein.