Therapy Efficacy of Idiopathic Ventricular Extrasystoles: A Real Life Study.

Background: Ventricular extrasystoles (VESs) are common and often harmless in a healthy heart, but they can significantly affect the quality of life. If changes in lifestyle and antiarrhythmic medication are not enough, invasive and often curative catheter ablation can be considered. Better understanding of the conformation of VESs with a 12-lead ECG, as well as their precise localization, have increased their treatment with catheter ablation. Our goal was to determine whether the anatomical site of VES had an effect on procedure success. We also analyzed the safety of the procedure and patient-related factors affecting the results. Materials and Methods: In this retrospective study, we analyzed the medical records of 63 consecutive patients with multiple idiopathic VESs treated by catheter ablation at Heart Hospital, Tampere University Hospital, during 2017 and 2018. Patients with structural heart disease were excluded. Ablation success was estimated with two endpoints, primary and follow-up success. Results: The majority of the patients received treatment on the right ventricular outflow tract (66.7%), others on the left ventricle (17.5%), or the aortic cusp (9.5%). The site of origin remained unknown in four procedures (6.3% of patients). Primary success was observed in 48 procedures (76.2%). During the follow-up period of three months, the procedure was successful in 70.3% of the cases. The anatomical site of VES had no significant effect on either primary or follow-up success. Those with a successful follow-up result had a lower body mass index (BMI = 26.4) than those who had an unsuccessful result (BMI = 28.7; p=0.069); this did not reach statistical significance, potentially due to the small study population size. Complications were observed in three patients (4.5%). All of them were related to the catheter insertion site. Conclusions: For a symptomatic patient, catheter ablation is an effective and often fully curative treatment. The success rate was similar regardless of the site of VESs. This suggests that catheter ablation should also be assessed early on for other cases besides classic right ventricular outflow tract VESs. A high BMI was the only factor associated with a poor procedure success rate. The procedure itself is safe, and adverse effects are rare. The radiation dose is also low partly due to the current magnetic navigation method.

Triggers of Ventricular Fibrillation in Patients With Inferolateral J-Wave Syndrome.

BACKGROUND: There are few data on ventricular fibrillation (VF) initiation in patients with inferolateral J waves. OBJECTIVES: This multicenter study investigated the characteristics of triggers initiating spontaneous VF in inferolateral J-wave syndrome. METHODS: A total of 31 patients (age 37 ± 14 years, 24 male) with spontaneous VF episodes associated with inferolateral J waves were evaluated to determine the origin and characteristics of triggers. The J-wave pattern was recorded in inferior leads in 11 patients, lateral leads in 3, and inferolateral leads in 17. RESULTS: The VF triggers (n = 37) exhibited varying QRS durations (176 ± 21 milliseconds, range 119-219 milliseconds) and coupling intervals (339 ± 46 milliseconds, range 250-508 milliseconds) with a right (70%) or left (30%) bundle branch block (BBB) pattern. Trigger patterns were associated with J-wave location: left BBB triggers with inferior J waves and right BBB triggers with lateral J waves. Electrophysiologic study was performed for 22 VF triggers in 19 patients. They originated from the left or right Purkinje system in 6 and from the ventricular myocardium in 10 and were undetermined in 6. Purkinje vs myocardial triggers showed distinct electrocardiographic characteristics in coupling interval and QRS-complex duration and morphology. Abnormal epicardial substrate associated with fragmented electrograms was identified in 9 patients, with triggers originating from the same region in 7 patients. Catheter ablation resulted in VF suppression in 15 patients (79%). CONCLUSIONS: VF initiation in inferolateral J-wave syndrome is associated with significant individual heterogeneity in trigger characteristics. Myocardial triggers have electrocardiographic features distinct from Purkinje triggers, and their origin often colocalizes with an abnormal epicardial substrate.

Detection of concurrent atrial ischemia with continuous monitoring of dynamic PR-segment changes in patients with acute myocardial infarction.

Despite its potential prognostic value concurrent atrial ischemia is often overlooked in patients with acute myocardial infarction (AMI). There is no study concerning the relationship between atrial coronary circulation and dynamic PR-segment changes in patients with AMI. We evaluated dynamic PR-segment changes in 37 patients with AMI. The flow in the principal atrial coronary branches was diminished in 14 (38%) patients. Dynamic changes in the PR-segment level [median 47 (inter quartile range 19-55) µV vs. 23 (18-30) µV, P=0.005] and PR-segment area [3.15 (1.75-3.69) nVs vs. 1.62 (1.18-2.04) nVs, P=0.005] were significantly greater in patients with compromised than in those with normal flow in the atrial coronary branches. Our findings support the concept that atrial ischemia produces similar changes in the PR-segment as ventricular ischemia in the ST-segment. Given the possible deleterious consequences of atrial ischemia these data may have important clinical implications in evaluation of patient with AMI.

Sudden cardiac arrest associated with early repolarization.

BACKGROUND: Early repolarization is a common electrocardiographic finding that is generally considered to be benign. Its potential to cause cardiac arrhythmias has been hypothesized from experimental studies, but it is not known whether there is a clinical association with sudden cardiac arrest. METHODS: We reviewed data from 206 case subjects at 22 centers who were resuscitated after cardiac arrest due to idiopathic ventricular fibrillation and assessed the prevalence of electrocardiographic early repolarization. The latter was defined as an elevation of the QRS-ST junction of at least 0.1 mV from baseline in the inferior or lateral lead, manifested as QRS slurring or notching. The control group comprised 412 subjects without heart disease who were matched for age, sex, race, and level of physical activity. Follow-up data that included the results of monitoring with an implantable defibrillator were obtained for all case subjects. RESULTS: Early repolarization was more frequent in case subjects with idiopathic ventricular fibrillation than in control subjects (31% vs. 5%, P<0.001). Among case subjects, those with early repolarization were more likely to be male and to have a history of syncope or sudden cardiac arrest during sleep than those without early repolarization. In eight subjects, the origin of ectopy that initiated ventricular arrhythmias was mapped to sites concordant with the localization of repolarization abnormalities. During a mean (+/-SD) follow-up of 61+/-50 months, defibrillator monitoring showed a higher incidence of recurrent ventricular fibrillation in case subjects with a repolarization abnormality than in those without such an abnormality (hazard ratio, 2.1; 95% confidence interval, 1.2 to 3.5; P=0.008). CONCLUSIONS: Among patients with a history of idiopathic ventricular fibrillation, there is an increased prevalence of early repolarization.

Heart rate turbulence after atrial premature beats before spontaneous onset of atrial fibrillation.

OBJECTIVES: This study was designed to assess the temporal changes in vagal responses to atrial premature beats before spontaneous onset of atrial fibrillation (AF). BACKGROUND: Enhanced vagal activity plays a major role in the onset and perpetuation of experimental AF, but the role of vagal activation in the onset of clinical AF episodes is not so well established. METHODS: We calculated heart rate turbulence after atrial premature impulses occurring 0 to 60 min before the onset of AF ("prior to AF") and compared it with the hourly means of the other hours of the 24-h electrocardiogram recordings ("non-AF hours") in 39 patients with structural heart disease and 29 patients with lone AF. Traditional heart rate variability measurements and approximate entropy (ApEn) were also analyzed. RESULTS: Turbulence onset (TO) was significantly less negative during the 1 h preceding AF than during the non-AF hours (0.71 +/- 1.76 vs. -0.35 +/- 1.46, p < 0.00001). Less negative TO before AF was observed among both the patients with structural heart disease (1.16 +/- 1.73 vs. 0.07 +/- 1.23; p < 0.0001) and those with lone AF (0.17 +/- 1.67 vs. -0.85 +/- 1.56; p < 0.0001). No significant difference was seen in the turbulence slope between the two periods, and none of the traditional frequency and time domain measurements differentiated between the periods; ApEn was significantly lower before AF than during the non-AF hours (p < 0.01). CONCLUSIONS: Altered heart rate dynamics, suggesting transient enhancement of vagal outflow after premature atrial excitation, are temporally related to spontaneous onset of clinical AF.

Role of electrophysiological studies in predicting risk of ventricular arrhythmia in early repolarization syndrome.

BACKGROUND: The early repolarization (ER) pattern is associated with an increased risk of arrhythmogenic sudden death. However, strategies for risk stratification of patients with the ER pattern are not fully defined. OBJECTIVES: This study sought to determine the role of electrophysiology studies (EPS) in risk stratification of patients with ER syndrome. METHODS: In a multicenter study, 81 patients with ER syndrome (age 36 ± 13 years, 60 males) and aborted sudden death due to ventricular fibrillation (VF) were included. EPS were performed following the index VF episode using a standard protocol. Inducibility was defined by the provocation of sustained VF. Patients were followed up by serial implantable cardioverter-defibrillator interrogations. RESULTS: Despite a recent history of aborted sudden death, VF was inducible in only 18 of 81 (22%) patients. During follow-up of 7.0 ± 4.9 years, 6 of 18 (33%) patients with inducible VF during EPS experienced VF recurrences, whereas 21 of 63 (33%) patients who were noninducible experienced recurrent VF (p = 0.93). VF storm occurred in 3 patients from the inducible VF group and in 4 patients in the noninducible group. VF inducibility was not associated with maximum J-wave amplitude (VF inducible vs. VF noninducible; 0.23 ± 0.11 mV vs. 0.21 ± 0.11 mV; p = 0.42) or J-wave distribution (inferior, odds ratio [OR]: 0.96 [95% confidence interval (CI): 0.33 to 2.81]; p = 0.95; lateral, OR: 1.57 [95% CI: 0.35 to 7.04]; p = 0.56; inferior and lateral, OR: 0.83 [95% CI: 0.27 to 2.55]; p = 0.74), which have previously been demonstrated to predict outcome in patients with an ER pattern. CONCLUSIONS: Our findings indicate that current programmed stimulation protocols do not enhance risk stratification in ER syndrome.

Relation of heart rate dynamics to the occurrence of myocardial ischemia after coronary artery bypass grafting.

Postoperative myocardial ischemia is a common finding after coronary artery bypass grafting (CABG) and is associated with an adverse short-term clinical outcome. The reasons and pathophysiologic background for the occurrence of ischemia after CABG are not well established. We tested the hypothesis that altered heart rate (HR) behavior precedes the onset of myocardial ischemic episodes in patients after CABG. Time-domain HR variability measurements, along with analysis of Poincaré plots and fractal scaling analysis were assessed in 40 CABG patients from 48-hour postoperative Holter recordings. Twenty patients experienced 195 ischemic episodes during the postoperative course. In the univariate analysis of HR variability measurements of the first postoperative day (POD), the increased ratio between the short-term (SD1) and long-term (SD2) HR variability analyzed from the Poincaré plot and the decreased short- and intermediate-term fractal scaling exponents alpha(1) and alpha(2) were significantly associated with ischemia during the study period (p <0.01, p <0.05, and p <0.05, respectively). In the multivariate model, the increased SD1/SD2 ratio of the first POD was the most powerful independent predictor of all possible confounding variables for the occurrence of postoperative ischemia (corresponding to a change of 0.15 U; odds ratio 2.2 and 95% confidence interval 1.2 to 5.7; p <0.01). Altered HR dynamics have been associated with myocardial ischemic episodes in patients after CABG, suggesting that the autonomic nervous system has an important role in the pathogenesis of myocardial ischemia in the postoperative phase of CABG.

Characteristics of recurrent ventricular fibrillation associated with inferolateral early repolarization role of drug therapy.

OBJECTIVES: Our purpose was to evaluate the efficacy of antiarrhythmic drugs (AADs) in recurrent ventricular fibrillation (VF) associated with inferolateral early repolarization pattern on the electrocardiogram. BACKGROUND: Although an implantable cardioverter-defibrillator is the treatment of choice, additional AADs may be necessary to prevent frequent episodes of VF and reduce implantable cardioverter-defibrillator shock burden or as a lifesaving therapy in electrical storms. METHODS: From a multicenter cohort of 122 patients (90 male subjects, age 37 +/- 12 years) with idiopathic VF and early repolarization abnormality in the inferolateral leads, we selected all patients with more than 3 episodes of VF (multiple) including those with electrical storms (> or =3 VF in 24 h). The choice of AAD was decided by individual physicians. Follow-up data were obtained for all patients using monitoring with implantable defibrillator. Successful oral AAD was defined as elimination of all recurrences of VF with a minimal follow-up period of 12 months. RESULTS: Multiple episodes of VF were observed in 33 (27%) patients. Electrical storms (34 +/- 47 episodes) occurred in 16 and were unresponsive to beta-blockers (11 of 11), lidocaine/mexiletine (9 of 9), and verapamil (3 of 3), while amiodarone was partially effective (3 of 10). In contrast, isoproterenol infusion immediately suppressed electrical storms in 7 of 7 patients. Over a follow-up of 69 +/- 58 months, oral AADs were poorly effective in preventing recurrent VF: beta-blockers (2 of 16), verapamil (0 of 4), mexiletine (0 of 4), amiodarone (1 of 7), and class 1C AADs (2 of 9). Quinidine was successful in 9 of 9 patients, decreasing recurrent VF from 33 +/- 35 episodes to nil for 25 +/- 18 months. In addition, quinidine restored a normal electrocardiogram. CONCLUSIONS: Multiple recurrences of VF occurred in 27% of patients with early repolarization abnormality and may be life threatening. Isoproterenol in acute cases and quinidine in chronic cases are effective AADs.

No evidence of automatic atrial overdrive pacing efficacy on reduction of paroxysmal atrial fibrillation.

AIMS: Paroxysmal atrial fibrillation (PAF) is frequently encountered in pacemaker patients, most commonly in sick sinus syndrome. The combination of site-specific pacing in conjunction with an overdrive algorithm combined with antiarrhythmic drugs on the incidence of PAF in patients with a conventional indication for pacing is unknown. METHODS AND RESULTS: Patients with pacemaker indication and PAF received a DDDR-pacemaker, which included an automatic atrial overdrive (AO) algorithm. The atrial lead was implanted in either the right atrial appendage (RAA) (n = 83) or the right low-atrial septum (LAS) (n = 94). The algorithm was switched on or off in a 3 month, single blind crossover design and antiarrhythmic drugs were kept stable. A control group of 96 patients (LAS, n = 14; RAA, n = 84) without PAF served as controls to assess any proarrhythmic effect of overdrive pacing. Atrial fibrillation (AF) burden defined as cumulative time in mode switch was not reduced during automatic AO from either the RAA or from the LAS. The reduction was not effective both for AF of short (<24 h) and long (> or =24 h) duration. There was no atrial proarrhythmia induced by the overdrive algorithm in the control group. CONCLUSIONS: We could not demonstrate a reduction of AF burden defined as cumulative time in AF by the AO algorithm, in patients who are paced for standard indications and PAF, neither from the RAA nor from the LAS.

SCN5A mutation associated with cardiac conduction defect and atrial arrhythmias.

INTRODUCTION: We aimed at identifying the molecular defect underlying the clinical phenotype of a Finnish family with a cardiac conduction defect and atrial arrhythmias. METHODS AND RESULTS: A large Finnish family was clinically evaluated (ECG, 24-hour ambulatory ECG, echocardiography). We performed linkage analysis with markers flanking the SCN5A gene and subsequently sequenced the SCN5A gene. Five family members had atrial arrhythmias and intracardiac conduction defects, and due to bradycardia needed a pacemaker when adolescents. No heart failure or sudden cardiac death was observed. Left ventricle dilatation was seen in one individual and three individuals had a slightly enlarged right ventricle. Premature death due to stroke occurred in one subject during the study, and two other members had suffered from stroke at young age. Linkage analysis favored the role of the SCN5A gene in disease pathogenesis, and direct sequencing disclosed D1275N mutation. This alteration was present not only in all six affected individuals, but also in two young individuals lacking clinical symptoms. CONCLUSIONS: Cardiac conduction defect and atrial arrhythmias in a large Finnish family appear to result from the SCN5A D1275N mutation. Although no sudden cardiac death was recorded in the family, at least three affected members had encountered brain infarction at the age of 30 or younger.

Heart rate variability and recurrence of atrial fibrillation after electrical cardioversion.

BACKGROUND: Heart rate (HR) variability has been shown to predict spontaneous onset of atrial fibrillation (AF). This study was designed to test the hypothesis that HR variability after electrical cardioversion (CV) of persistent AF predicts the recurrence of AF. METHODS: Various time and frequency domain measures of HR variability, along with the non-linear measures of HR dynamics, were analyzed from the 24-hour ECG recordings in 78 patients with persistent AF after restoration of sinus rhythm with electrical CV. RESULTS: During the follow-up of one month, 27 patients (35%) had recurrence of AF. The patients with AF recurrence had significantly higher standard deviation of all R-R intervals (SDNN 117 +/- 34 versus 100 +/- 29 P < 0.05), increased high-frequency (InHF 5.7 +/- 0.6 versus 5.3 +/- 0.7 P < 0.05 ), low-frequency (InLF 6.2 +/- 0.8 versus 5.6 +/- 0.9 P < 0.01) and very-low-frequency (InVLF 7.1 +/- 0.8 versus 6.5 +/- 0.8 P < 0.01) power spectral components of HR variability than those who remained in sinus rhythm. Approximate entropy, a measure of complexity of HR dynamics, and the short-term fractal scaling exponent did not differ between the groups, but the long-term power-law slope beta was steeper among the patients who remained in sinus rhythm (P < 0.05). During the first week after the CV, increased HF power (highest tertile) was the most powerful predictor of AF recurrence with odds ratio of 2.8 (95% confidence interval 1.0 to 8.0, P < 0.05). Increased VLF power spectral component at baseline predicted best the late recurrence of AF with odds ratio of 3.3 (95% confidence interval 1.6 to 7.2, P < 0.01). No clinical or echocardiographic variable predicted the recurrence of AF. CONCLUSIONS: Increased HR variability in all major power spectral bands is associated with late recurrence of AF after electrical CV. Enhanced cardiac vagal outflow, reflected as an increased HF power spectral component, seems to predict specifically the early recurrence of AF after the CV.