Vassilios Vassilikos

Right Atrial and Ventricular Adaptations to Training in Male Caucasian Athletes: An Echocardiographic Study

BACKGROUND The aim of this study was to investigate the systolic and diastolic properties of the right cardiac chambers (the right ventricle and right atrium) among different subsets of athletes to unveil potential variations in right ventricular and right atrial remodeling secondary to different training modes. METHODS A cohort of Caucasian male top-level athletes (n = 108; 80 endurance athletes [EAs], mean age, 31.2 ± 10.4 years; 28 strength-trained athletes [SAs], mean age, 27.4 ± 5.7 years) and untrained controls (n = 26; mean age, 26.6 ± 5.6 years) (P = .327) were prospectively enrolled. Conventional echocardiographic parameters, including transtricuspid inflow, Doppler tissue imaging, and two-dimensionally derived peak systolic longitudinal strain and strain rate indices of the right ventricle and right atrium, were calculated. RESULTS EAs had greater internal right ventricular and right atrial dimensions compared with SAs and controls. There were no significant differences concerning strain between groups (-23.1 ± 3.7% in EAs vs -25.1 ± 3.2% in SAs vs -23.1 ± 3.5% in controls, P = .052), with SAs presenting higher global systolic strain rates (-1.42 ± 0.22 sec(-1) in SAs vs -1.21 ± 0.21 sec(-1) in EAs vs -1.2 ± 0.28 sec(-1) in controls, P = .016), as well as greater right atrial strain rate systolic and diastolic components. Training volume (highly vs moderately trained athletes) did not significantly influence deformation parameters. No significant differences concerning diastolic transtricuspid inflow and Doppler tissue imaging indices were also noted among different athlete groups and controls. CONCLUSIONS Despite the existence of right geometric alterations in athletes participating in different sport disciplines, few meaningful differences in deformation and diastolic function exist.

Novel non-invasive P wave analysis for the prediction of paroxysmal atrial fibrillation recurrences in patients without structural heart disease: A prospective pilot study

OBJECTIVES The pathogenetic mechanisms responsible for the initiation and recurrence of PAF are not fully elucidated and vary among individuals. We evaluated the ability of a novel non-invasive approach based on P wave wavelet analysis to predict symptomatic paroxysmal atrial fibrillation (PAF) recurrences in individuals without structural heart disease. METHODS We studied 50 patients (24 males, mean age 54.9 ± 9.8 years) presented to our emergency department with a symptomatic episode of PAF. The patients were followed-up for 12.1 ± 0.1 months and classified into two groups according to the number of PAF episodes: Group A (<5 PAF, n = 33), Group B (≥ 5 PAF, n = 17). A third Group of 50 healthy individuals without history of PAF was used as control. Study groups underwent echocardiography and orthogonal ECG-based wavelet analyses of P waves at baseline and follow-up. Maximum and mean P wave energies were calculated in each subject at each orthogonal lead using the Morlet wavelet analysis. RESULTS Larger P wave energies at X lead and relatively larger left atrium were independently associated with >5 PAF episodes vs. <5 PAF episodes. No difference in P wave duration was detected between Groups A and B (p > 0.1), whereas Group A and B patients had longer P waves at Z lead compared to Group C (86.4 ± 13 vs. 71.5 ± 15 msec, p < 0.001). CONCLUSIONS P wave wavelet analysis can reliably predict the generation and recurrence of PAF within a year. P wave wavelet analysis could contribute to the early identification of patients at risk for increased number of PAF recurrences.

Can P Wave Wavelet Analysis Predict Atrial Fibrillation After Coronary Artery Bypass Grafting

VASSILIKOS V., et al.: Can P Wave Wavelet Analysis Predict Atrial Fibrillation After Coronary Artery Bypass Grafting? The purpose of this study was the evaluation of Morlet wavelet analysis of the P wave as a means of predicting the development of atrial fibrillation (AF) in patients who undergo coronary artery bypass grafting (CABG). The P wave was analyzed using the Morlet wavelet in 50 patients who underwent successful CABG. Group A consisted of 17 patients, 12 men and 5 women, of mean age 66.9 ± 5.9 years , who developed AF postoperatively. Group B consisted of 33 patients, 29 men and 4 women, mean age 62.4 ± 7.8 years , who remained arrhythmia‐free. Using custom‐designed software, P wave duration and wavelet parameters expressing the mean and maximum energy of the P wave were calculated from 3‐channel digital recordings derived from orthogonal ECG leads (X, Y, and Z), and the vector magnitude (VM) was determined in each of 3 frequency bands (200–160 Hz, 150–100 Hz and 90–50 Hz). Univariate logistic‐regression analysis identified a history of hypertension, the mean and maximum energies in all frequency bands along the Z axis, the mean and maximum energies (expressed by the VM) in the 200–160 Hz frequency band, and the mean energy in the 150–100 Hz frequency band along the Y axis as predictors for post‐CABG AF. Multivariate analysis identified hypertension, ejection fraction, and the maximum energies in the 90–50 Hz frequency band along the Z and composite‐vector axes as independent predictors. This multivariate model had a sensitivity of 91% and a specificity of 65%. We conclude that the Morlet wavelet analysis of the P wave is a very sensitive method of identifying patients who are likely to develop AF after CABG. The occurrence of post‐CABG AF can be explained by a different activation pattern along the Z axis. (PACE 2003; 26[Pt. II]:305–309)

Left ventricular function in elite rowers in relation to training‐induced structural myocardial adaptation

To examine left ventricular (LV) function in elite young athletes in relation to structural adaptation to prolonged intense training. Conventional echocardiography and tissue Doppler imaging (TDI) were performed in 15 elite rowers and 12 sedentary matched controls. Rowers had increased LV mass index, septal (12 vs 10 mm, P<0.005) and posterior wall thicknesses (12 vs 9 mm, P<0.001) and increased relative wall thickness. Septal and lateral systolic velocities were enhanced in rowers (septal Sm=8.5 vs 6.3 cm/s, P<0.001; lateral Sm=11.4 vs 8.0 cm/s, P<0.005), representing a 35% and 42% increase, respectively. Similarly, septal and lateral early diastolic velocities were enhanced (septal Em=12.1 vs 9.5 cm/s, P<0.01; lateral Em=16.6 vs 11.6 cm/s, P<0.001), representing a 27% and 43% increase, respectively. Systolic and early diastolic TDI velocities of the lateral wall showed a positive correlation (r=0.65, P<0.01) in athletes indicating a parallel improvement of systolic and diastolic function, while LV stiffness was decreased [(E/Em)/(LV end‐diastolic diameter)=1.13 vs 1.57, P<0.005). Both systolic and diastolic LV function were improved in elite rowers, despite a pattern of concentric hypertrophy.

Percutaneous Extraction of Transvenous Defibrillator Leads Using the VascoExtor Pacing Lead Removal System

In the implantable cardioverter defibrillator era the necessity for lead removal is not negligible. A specially designed extraction lead system for percutaneous removal of such leads is lacking, in contrast to the existing pacing lead extraction systems. We report the successful percutaneous extraction of four implantable cardioverter defibrillator leads in three patients because of lead malfunction using a novel pacemaker lead extraction system, the VascoExtor (VascoMed) system. Three leads were successfully removed in two patients using traction with special locking stylets from the superior approach. One lead was removed using the systems additional extraction tools through the femoral approach. There were no complications. This preliminary experience shows that the VascoExtor (VascoMed) pacemaker lead extraction system can also be used in implantable cardioverter defibrillator lead extraction safely and effectively. In addition to the locking stylets, adjunct percutaneous extraction tools may be needed in some cases.

Sinus node disease in subjects with type 1 ECG pattern of Brugada syndrome

BACKGROUND The spectrum of phenotypes related to mutations of the SCN5A gene include Brugada syndrome (BS), long QT syndrome, progressive cardiac conduction defect, and sinus node disease (SND). The present study investigated the incidence of SND in subjects with type 1 electrocardiogram (ECG) pattern of BS. METHODS AND RESULTS The study population consisted of 68 individuals (55 males, mean age 44.8±12.8 years) with spontaneous (n=27) or drug-induced (n=41) type 1 ECG pattern of BS. Twenty-eight subjects were symptomatic with a history of syncope (41.2%). SND was observed in 6 symptomatic subjects (8.8%), and was mainly attributed to sino-atrial block with sinus pauses. Two patients were initially diagnosed with SND, and received a pacemaker. Patients with SND displayed an increased P-wave duration in leads II and V2, PR interval in leads II and V2, QRS duration in leads II and V2, and increased QTc interval in lead V2 (p<0.05). AH and HV intervals as well as corrected sinus node recovery time (cSNRT) were significantly prolonged in subjects with SND (p<0.05). During a mean follow-up period of 5.0±3.6 years, five subjects with a history of syncope suffered appropriate implantable cardioverter defibrillator (ICD) discharges due to ventricular arrhythmias (7.4%). None of those diagnosed with SND suffered syncope or ICD therapies. CONCLUSION SND is not an uncommon finding in subjects with type 1 ECG pattern of BS. The occurrence of SND in relatively young patients may deserve meticulous investigation including sodium channel blocking test.

The prognostic significance of atrial arrhythmias recorded early after cardioversion for atrial fibrillation.

MAOUNIS, T., et al.: The Prognostic Significance of Atrial Arrhythmias Recorded Early After Cardioversion for Atrial Fibrillation. In a substantial number of patients, AF recurs after successful electrical cardioversion. The purpose of this study was to investigate if the atrial arrhythmias recorded immediately after cardioversion are associated with the risk of recurrence of the arrhythmia and to compare the prognostic significance of this parameter with that of other established risk factors. In a series of 71 patients, the risk factors for recurrence of AF during the first year after successful electrical cardioversion were analyzed. A new parameter that was investigated was the frequency of atrial premature beats and the presence of runs of supraventricular tachycardia in the Holter recording started immediately after the cardioversion. Age, left atrial size, left ventricular systolic function, duration of the arrhythmia before cardioversion, underlying cardiac disease, or medication taken were not found to be predictive of recurrence of the arrhythmia. However, the natural logarithm of the number of atrial premature complexes per hour of the Holter recording in the 37 patients in whom AF recurred was higher compared to that of the 34 patients who maintained sinus rhythm (P < 0.0005). The same was true if only the first 6 hours of the recording were analyzed (P < 0.0005). There was a trend for more frequent arrhythmia recurrence if runs of supraventricular tachycardia were present. The finding of > 10 atrial premature complexes per hour in the recording had a relative risk of 2.57 (1.51–4.37), a positive predictive accuracy of 76.5%, and a negative predictive accuracy of 70.3% for subsequent arrhythmia recurrence. We can conclude that frequent (> 10/hour) atrial premature complexes in the Holter recording after electrical cardioversion for AF is a significant risk factor for recurrence of the arrhythmia.

Ranolazine as a promising treatment option for atrial fibrillation: electrophysiologic mechanisms, experimental evidence, and clinical implications.

Currently available agents for pharmacologic management of atrial fibrillation (AF) are limited by their suboptimal efficacy and nonnegligible proarrhythmic risk. Ranolazine (RN) is a novel antianginal agent with increasingly appreciated antiarrhythmic properties that can suppress ventricular and supraventricular arrhythmias including AF. In this review, we describe the electrophysiological properties of RN, focusing on atrial‐selective inhibition of a number of ion channels implicated in the development of AF, particularly the sodium current. We further summarize evidence from experimental studies that demonstrate a potent AF‐suppressing effect of RN, alone or in combination with other antiarrhythmic drugs. Of clinical relevance, we present growing evidence from preliminary clinical investigations indicating the safety and efficacy of RN for prevention and treatment of AF in various clinical settings including prevention of AF in patients with acute coronary syndromes, prevention and conversion of postoperative AF after surgical coronary revascularization, sinus rhythm maintenance in drug‐resistant recurrent AF, and facilitating of electrical or pharmacological cardioversion in cardioversion‐resistant patients. While current experimental and clinical evidence points to RN as a potentially promising agent for suppression of AF, well‐designed, large‐scale trials will be required before RN can be considered for pharmacological treatment of AF in clinical practice.

QRS analysis using wavelet transformation for the prediction of response to cardiac resynchronization therapy: a prospective pilot study.

BACKGROUND Wider QRS and left bundle branch block morphology are related to response to cardiac resynchronization therapy (CRT). A novel time-frequency analysis of the QRS complex may provide additional information in predicting response to CRT. METHODS Signal-averaged electrocardiograms were prospectively recorded, before CRT, in orthogonal leads and QRS decomposition in three frequency bands was performed using the Morlet wavelet transformation. RESULTS Thirty eight patients (age 65±10years, 31 males) were studied. CRT responders (n=28) had wider baseline QRS compared to non-responders and lower QRS energies in all frequency bands. The combination of QRS duration and mean energy in the high frequency band had the best predicting ability (AUC 0.833, 95%CI 0.705-0.962, p=0.002) followed by the maximum energy in the high frequency band (AUC 0.811, 95%CI 0.663-0.960, p=0.004). CONCLUSIONS Wavelet transformation of the QRS complex is useful in predicting response to CRT.

Patients with hypertrophic cardiomyopathy at risk for paroxysmal atrial fibrillation: advanced echocardiographic evaluation of the left atrium combined with non-invasive P-wave analysis

AIMS The maintenance of sinus rhythm is crucial for the functional capacity of patients with hypertrophic cardiomyopathy (HCM). Using a multimodality approach, we attempted to identify potential predictors of paroxysmal atrial fibrillation (PAF) in HCM patients. METHODS AND RESULTS Thirty HCM patients (17 males, mean age 57.9 ± 13.6) with at least one documented PAF episode and 32 age- and sex-matched HCM control patients as well as 25 healthy volunteers were studied in sinus rhythm. Study subjects underwent 2D echocardiography including a colour Doppler myocardial imaging evaluation of the left atrium (LA). Additionally, an orthogonal electrocardiogram was acquired; P-wave duration, maximum, and mean energies were calculated for each subject at each orthogonal lead and the composite vector axis using the Morlet wavelet analysis. Compared with HCM controls, in HCM-PAF patients, LA antero-posterior diameter was significantly enlarged (LADAP: 46.1 ± 5.9 vs. 40.0 ± 4.7 mm, P < 0.001), peak strain rate of the LA lateral wall in the reservoir phase was significantly decreased (LAT peak SR-S: 1.93 ± 0.51 vs. 2.55 ± 0.83 s(-1), P < 0.01), and P-wave duration in the Z-lead was significantly prolonged (P-durZ: 106.9 ± 24.6 vs. 86.2 ± 14.3 ms, P < 0.001). Cut-off values and areas under the curve (AUCs) for individual parameters were 42.0 mm, 2.32 s(-1), and 98.8 ms and 0.81, 0.74, and 0.78, respectively. A multivariable model combining LADAP, LAT peak SR-S and P-durZ had an AUC of 0.90, a sensitivity of 0.87, and a specificity of 0.91 for identifying PAF patients. CONCLUSION P-wave duration combined with LA antero-posterior diameter and myocardial deformation indices resulted in a higher power for discriminating HCM-PAF patients, when compared with individual parameters derived from either wavelet analysis or 2D echocardiography.