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.

Ibutilide for the Cardioversion of Paroxysmal Atrial Fibrillation during Radiofrequency Ablation of Supraventricular Tachycardias.

Direct current electrical cardioversion (DC-ECV) is the preferred treatment for the termination of paroxysmal atrial fibrillation (AF) that occurs during radiofrequency ablation (RFA) of supraventricular tachycardias (SVT). Intravenous Ibutilide may be an alternative option in this setting. Thirty-four out of 386 patients who underwent SVT-RFA presented paroxysmal AF during the procedure and were randomized into receiving ibutilide or DC-ECV. Ibutilide infusion successfully cardioverted 16 out of 17 patients (94%) within 17.37 ± 7.87 min. DC-ECV was successful in all patients (100%) within 17.29 ± 3.04 min. Efficacy and total time to cardioversion did not differ between the study groups. No adverse events were observed. RFA was successfully performed in 16 patients (94%) in the ibutilide arm and in all patients (100%) in the DC-ECV arm, p = NS. In conclusion, ibutilide is a safe and effective alternative treatment for restoring sinus rhythm in cases of paroxysmal AF complicating SVT-RFA.

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.

Practice patterns of cardiologists, general practitioners, and internists for managing supraventricular tachycardias in Greece.

OBJECTIVES: Supraventricular tachycardias (SVT) often lead to emergency room and primary care visits. Not only cardiologists, but also general practitioners (GPs) and internists are involved to an increasing extent in the acute and long-term management of SVT. We aimed to explore the differences between practice patterns of cardiologists and noncardiologists with regard to SVT management in Greece. METHODS: A cross-sectional questionnaire survey was conducted among 250 cardiologists and 250 GPs/internists from various areas across Greece. RESULTS: A response rate of 61.8% was obtained. Vagal maneuvers were the initial therapeutic approach for SVT termination; however, 22% of noncardiologists would rather start with an antiarrhythmic drug. Adenosine was the most popular drug for SVT termination, but the GPs/internists would use it less often than the cardiologists (67 vs. 86%, P<0.001). The GPs/internists would keep the patient for at least 24 h or more after SVT termination, while 48% of the cardiologists would discharge the patient within the first 3 h. Noncardiologists would more often suggest a 24-h Holter recording than the cardiologists (73 vs. 55%, P<0.005). With regard to the long-term management of SVT, the GPs/internists would prescribe antiarrhythmic drugs earlier than the cardiologists, and seem to be less familiar with the indications for the electrophysiological testing and ablation. CONCLUSION: Significant differences in practice patterns exist in Greece with regard to SVT management between cardiologists and noncardiologists. The GPs/internists seem to rely more on antiarrhythmic drugs and tend to underestimate the role of ablation therapy for the long-term management of SVT.

Differences in management of atrial fibrillation between cardiologists and non-cardiologists in Greece.

INTRODUCTION: We aimed to assess trends in the management of atrial fibrillation (AF) at various levels of medical care in Greece and to compare the treatment practices of cardiologists to those of non-cardiologists. METHODS: From January to May 2007, 500 questionnaires were mailed to cardiologists, internists and general practitioners, randomly selected from regional medical associations. Questions assessed management practices for paroxysmal, persistent and permanent AF. RESULTS: A total of 309 physicians (194 cardiologists and 115 non-cardiologists) responded. Cardiologists showed no preference regarding the site of cardioversion of paroxysmal AF, whereas non-cardiologists tend to cardiovert paroxysmal AF in the emergency department. Intravenous amiodarone is the most frequently used antiarrhythmic agent for cardioversion by both groups (63% vs. 71%, p=NS). Cardiologists utilise propafenone or ibutilide more frequently than non-cardiologists (24% vs. 11%, p<0.05 and 10% vs. 2%, p<0.01 respectively), while 12% of non-cardiologists would use digitalis for cardioversion (vs. 0.5% of cardiologists, p<0.001). Cardiologists prescribe commonly, but less frequently than non-cardiologists (42% vs. 59%, p<0.01) an antiarrhythmic drug after the first episode of paroxysmal AF, propafenone being the most popular among cardiologists (66%) and amiodarone (33%) or digitalis (23%) among general practitioners/internists. Beta-blockers are considered as first choice agents for rate control among cardiologists, while non-cardiologists would prescribe mainly digitalis. Antiplatelet agents were suggested by most physicians after cardioversion of the first episode of AF in low-risk patients. Cardiologists prefer aspirin, while non-cardiologists would prescribe clopidogrel as first choice antiplatelet agent. Both groups would recommend anticoagulants in high risk patients; nevertheless, in elderly patients without other risk factors, anticoagulants are more often prescribed by cardiologists (79% vs. 50%, p<0.001). CONCLUSIONS: Important differences exist in the management of AF between cardiologists and general practitioners/internists in Greece. Non-cardiologists overuse digitalis, underuse beta-blockers, prefer clopidogrel to aspirin and are reluctant to prescribe anticoagulants in the elderly.

Ceruloplasmin is a better predictor of the long-term prognosis compared with fibrinogen, CRP, and IL-6 in patients with severe unstable angina.

BACKGROUND: We investigated the time course and prognostic value of fibrinogen (Fib), C-reactive protein (CRP), interleukin-6 (IL-6), and ceruloplasmin (CP) in patients with severe unstable angina. METHODS: All 4 substances were measured on admission and after 6, 12, 24, 48, and 72 hours, and after 7 days and 6 months in 40 patients with Braunwald's classification class IIIB unstable angina. RESULTS: All recorded substances increased significantly; 15 patients had cardiovascular events during hospitalization and 11 patients during follow-up. The time course and the mean values of Fib, CRP, and IL-6 were similar in patients with and without complications both during hospitalization and follow-up. However, CP levels from 6 hours until 6 months were significantly higher in patients with complications during follow-up (P < .05). CONCLUSIONS: Fib, CRP, IL-6, and CP levels alter in patients with severe unstable angina. However, only CP levels were related to 12-month follow-up prognosis.

Indications for permanent pacing and pacing mode prescription from 1989 to 2006. Experience of a single academic centre in Northern Greece.

INTRODUCTION: Indications for pacing and pacing mode prescription have changed in the past decades following advances in pacemaker technology. The aim of the present study was to evaluate changes in indications for pacing and pacing modes during the years 1989-2006 in a single academic pacemaker centre in Northern Greece. METHODS: Archives of permanent pacemaker implantation procedures were studied retrospectively and data from all implants, first or replacements, were retrieved. RESULTS: Data from 2078 procedures were found, 78.7% of which were first implantations. Patients were 54% male with mean age 72.5 years. Main indications for pacing were atrioventricular block (AVB, 45.7%), sick sinus syndrome (SSS, 32.8%), and atrial fibrillation (12.1%). Almost half (48.9%) of the AVB cases were complete AVB, while the most common types of SSS were tachy-brady syndrome (44.1%) and asystole (27.1%). Rare indications for pacing were carotid sinus syndrome (5.0%), heart failure (3.3%) and hypertrophic obstructive cardiomyopathy (1.0%). The two most frequently used pacing modes were VVI (38.5%) and DDD (25.8%). However, pacing modes have changed greatly over the years, with a marked increase in dual-chamber pacing after 1997 and a preference for rate responsive units after 2002. Biventricular systems were also used in selected patients with heart failure from 2002 on. CONCLUSIONS: Indications for pacing and pacing mode prescription in our centre are similar to other pacemaker registries and reflect the global trend in pacing for mimicking the physiological activity of the heart and for addressing problems other than symptomatic bradycardia.

Clinical significance of N-terminal-probrain natriuretic peptide in hypertrophic cardiomyopathy.

N-Terminal-probrain natriuretic peptide (NT-proBNP) plasma levels are elevated in patients with congestive heart failure. Published data concerning the utility of NT-proBNP in hypertrophic cardiomyopathy (HCM) are lacking. Our aim was to evaluate the clinical significance of NT-proBNP in patients with HCM. A blood sample was collected for plasma NT-proBNP measurement from 43 consecutive patients with documented HCM. NT-proBNP was measured using a chemiluminescent immunoassay kit (Roche Diagnostics) on an Elecsys 2010 analyzer. Median value of NT-proBNP was 219 pg/ml (range 8-3 045 pg/ml) in NYHA class I patients, 698 pg/ml (125-2 463 pg/ml) in NYHA class II patients, and 2 683 pg/ml (131-11 542 pg/ml) in NYHA class III and IV patients. NT-proBNP plasma levels were significantly higher across the severity of functional limitation (i.e., NYHA class classification) (P = 0.002). NT-proBNP levels were significantly higher in female than male (P = 0.034), in referral vs nonreferral patients (P = 0.004), in symptomatic vs asymptomatic patients (P = 0.020), in patients with basal subaortic gradient >or=30 mmHg (P = 0.001) and in the patients who were on cardioactive medication (P = 0.010). In univariate analysis NT-proBNP was significantly correlated with age (P < 0.001), left ventricular maximum wall thickness (P = 0.001), left atrial size (P = 0.019), and subaortic gradient >or=30 mmHg (P < 0.001). In multivariate regression analysis, age (P < 0.001), maximum wall thickness (P = 0.007), and gradient >or=30 mmHg (P = 0.027) were independently associated with NT-proBNP levels. Our data support the idea that measurement of plasma NT-proBNP levels in HCM patients is useful to assess their clinical status, especially the severity of hypertrophy and the presence of obstruction, although age must be taken into account.

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 arrhythmid-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.