Microvolt T-wave alternans predicts cardiac events after acute myocardial infarction in patients treated with primary percutaneous coronary intervention.

BACKGROUND: Current risk stratification after acute myocardial infarction (MI) depends on left ventricular ejection fraction. Microvolt T-wave alternans (MTWA) is one of promising markers to predict cardiac events in patients after acute MI treated according to current guidelines. METHODS: In this single center study, 112 consecutive patients with the first anterior ST-elevation MI undergoing PCI <12 hours from symptom onset, were enrolled prospectively. Demographics, established risk factors, myocardial contrast echocardiography (MCE) perfusion, index event data and MTWA were assessed. Composite cardiac events (CCE) defined as: death, recurrent MI, sustained ventricular tachycardia (sVT) or readmission for acute heart failure (HF) were recorded during follow-up. RESULTS: MTWA test was negative in 76, positive in 18 and undetermined in 7 patients. MTWA negative patients had significantly higher LVEF at 30 days. At 4 years, 26 patients experienced CCE (10 died, 2 reinfarcted and 14 HF events). In multivariate Cox proportional hazard model maximum CKMB, non-negative MTWA and reduced LVEF made the best model to predict CCE. Four year CCE free survival was 77% and was significantly lower for non-negative MTWA (94% vs 50%, p<0.003). CONCLUSIONS: Non-negative MTWA with infarct size index and reduced LVEF could predict cardiac events in patients with anterior STEMI treated with primary PCI. MTWA non-negative patients have significantly worse outcome.

Comparison of pulmonary veins anatomy in patients with and without atrial fibrillation: analysis by multislice tomography.

UNLABELLED: A possible role of anomalies in number and insertion of pulmonary veins (PV) in initiating atrial fibrillation (AF) has been suggested. It has been shown as well that changes in anatomy of PVs such as enlargement may have an effect on arrhythmogenesis. The aim of the study was to compare anatomy of the left atrium (LA) and PVs in patients with AF and control subjects. METHODS: Eighty two patients were evaluated with 64-slice computed tomography (MSCT). Fifty one of them were referred to catheter ablation with history of highly symptomatic AF--AF(+) group. Thirty one control subjects had no history of AF and were referred to MSCT for noninvasive evaluation of different pathologies which finally were excluded--AF(-) group. Study groups did not differ in regard to age, sex, presence of hypertension and left ventricular systolic function. Diameters of PV ostia were measured in anterior-posterior (AP) and superior-inferior (SI) directions. Venous ostium index was calculated as a ratio between these measurements. RESULTS: The diameter of LA was higher in AF(+) patients than in the AF(-) patients (39±6 mm vs. 35±4 mm, p<0.005). In 68.6% of AF(+) patients and in 83.9% of AF(-) patients the anatomical pattern was typical with two right and two left PVs. Additional PVs were detected in 6 patients, only in AF(+) group (p<0.05). Common ostia were more frequently found in AF(+) subjects (37.2% vs. 19.3, p=0,08), mainly left-sided. In AF(+) group mean SI diameters of both-sided superior PVs and left inferior veins were larger. All AP diameters except for right inferior PVs were also larger in AF(+) group than in control cases. CONCLUSIONS: Variations in the PVs anatomy are more common and diameters of ostial portions of the veins are larger in AF patients than in control subjects. These findings suggest that further studies on the role of structural abnormalities of PVs in arrhythmogenesis are needed.

Bleeding complications after pacemaker or cardioverter-defibrillator implantation in patients receiving dual antiplatelet therapy: Results of a prospective, two-centre registry.

Introduction. The aim of the study was to define the prevalence of bleeding events in patients treated with dual antiplatelet therapy (DAT) in comparison with patients receiving only acetylsalicylic acid (ASA).Methods. Prospective two-centre registry of all first implantations of pacemakers, cardioverter-defibrillators and cardiac resynchronisation therapy units in patients receiving ASA (n=194) or DAT (n=53).Results. Bleeding complications were detected in 27 (16.2%) patients in the ASA group and in 13 (24.5%) in the DAT group. There was no significant difference in the overall number of complications between the patients receiving ASA or DAT, although there was a trend towards a higher incidence of overall complication rates in the DAT group (p=0.0637). The incidence of major complications (requiring blood transfusion or surgical intervention or prolonging hospital stay) was low (3.6%), and similar in both groups (3.6 and 3.8% respectively, ns). The rate of minor complications (subcutaneous haematomas) was greater in the DAT group (p=0.015).Conclusions. Treatment with DAT does not increase the risk of major bleeding complications as a result of device implantation; however, minor complications are significantly more frequent. Our results suggest that DAT could be continued in patients undergoing device implantation with a moderate risk of bleeding complications. (Neth Heart J 2010;18:230-5.).

The implications of genetic mutations in the sodium channel gene (SCN5A).

Mutations in sodium channel alpha-subunit gene (SCN5A) result in multiple arrhythmic syndromes, including long QT3 (LQT3), Brugada syndrome (BS), an inherited cardiac conduction defect, sudden unexpected nocturnal death syndrome (SUNDS) and sudden infant death syndrome (SIDS), constituting a spectrum of disease entities termed Na+ channelopathies. These diseases are allelic disorders, if not the same disease with variable penetrance and variable modifiers worldwide. Interestingly, death occurs during sleep in all of these disorders, suggesting a common mechanism. To date, mutational analyses have revealed about 103 distinct mutations in SCN5A, of which at least more than 30 mutations are associated with LQT3, whereas the rest of the mutations are affiliated with the remaining sodium channel disorders. The majority of these mutations are missense. However, other types such as deletions, insertions, frameshifts, nonsense and splice-donor errors have also been reported.

Task Force on Sudden Cardiac Death, European Society of Cardiology.

The European Society of Cardiology has convened a Task Force on Sudden Cardiac Death in order to provide a comprehensive, educational document on this important topic. The main document has been published in the European Heart Journal in August 2001. The Task Force has now summarized the most important clinical issues on sudden cardiac death and provided tables with recommendations for risk stratification and for prophylaxis of sudden cardiac death. The present recommendations are specifically intended to encourage the development and revision of national guidelines on prevention of sudden cardiac death. The common challenge for cardiologists, physicians of other medical specialties and health professionals throughout Europe is to realize the potential for sudden cardiac death prevention and to contribute to public health efforts to reduce its burden.

Correlation of heart rate variability parameters and QT interval in patients after PTCA of infarct related coronary artery as an indicator of improved autonomic regulation.

UNLABELLED: The purpose of this study was to determine if PTCA of the infarct related coronary artery (IRA) in the late phase of myocardial infarction (MI) can improve autonomic regulation of sinus rhythm and electrical stability of the myocardium measured by heart rate variability (HRV), QT, QTc, and its dispersion (QTd) and if any correlation exists among these measures. The study was performed in 25 patients (21 male, age: 50 +/- 9 years, EF: 52% +/- 11%) in the late phase of MI (2.5 +/- 1.5 months). HRV parameters were calculated automatically. QT, QTc, and QTd were measured manually from a 12-lead surface ECG (50 mm/s). All measurements were made before and 3-5 days after PTCA. Day and night parameters of HRV were sampled over two periods: 2 pm to 10 pm (day) and 10 pm to 6 am (night). Parameters of HRV measured from whole recordings were significantly higher after successful PTCA: SDRR (116 +/- 31 vs 128 +/- 38 ms), SD (55 +/- 17 vs 62 +/- 22 ms), rMSSD (30 +/- 13 vs 36 +/- 14 ms) and HF (246 +/- 103 vs 417 +/- 224 ms2). Significant differences were found during daytime for SD, rMSSD, and HF, and during nighttime for SDRR, SDANN. QT interval duration, QT corrected to the heart rate, and QT dispersion were significantly lower after PTCA (QTd: 54 +/- 15 vs 39 +/- 12 ms). There was no correlation between HRV and QT values before PTCA. High correlations were found after the procedure, particularly between QTd and nighttime HRV. CONCLUSIONS: PTCA of IRA in the late phase of MI enhances sympathovagal regulation of the cardiac rhythm and the electrical stability of the heart, which may be prognostically important.

Value of heart rate variability parameters for prediction of serious arrhythmic events in patients with malignant ventricular arrhythmias.

Heart rate variability (HRV) assesses the electrical stability of the heart and can identify patients at risk of sudden cardiac death (SCD). The value of 10 HRV parameters from 24 hour ECG (in both time and frequency domain) to predict serious arrhythmic events (SAE) in a group of 56 patients with ventricular tachycardia and/or ventricular fibrillation of different etiologies not due to acute myocardial infarction was explored. Eighteen patients had low left ventricular ejection fractions (LVEF). During follow-up (6-46 months, mean = 24) 8 SCD and 12 recurrences of malignant ventricular arrhythmias or ICD discharges were recorded. Proportional hazard analysis (Cox model) for SAE revealed that the mean of all 5 minute standard deviation of RR intervals (SD) and the amplitude of low frequency spectrum (L) were independent risk factors of SAE (P < 0.05). The best models were: SD+EF and L+EF where predictive values were high (sensitivity approximately 60%, specificity over 95%, positive predictive value over 90% and negative predictive value approximately 80%). Event-free survival curves revealed a significantly shorter survival in patients with EF < 40%: 47% vs. 92%, SD < 43 ms; 56% vs. 92% and L < 16 ms; 56% vs. 89% (all P < 0.001) after 2 years. The subgroup with low EF and SD < 43 ms revealed a significantly shortened survival (27% vs 83% at 2 years, P < 0.01). Some HRV parameters, SD from the time and L from the frequency domain, were predictive of a fatal outcome in VT/VF patients. Combined SD+EF and L+EF values are powerful predictors of serious arrhythmic events.

Heart rate variability: its association with hemodynamic function of the left ventricle in patients with coronary heart disease.

Patients with heart failure secondary to coronary heart disease (CHD) are characterized by an imbalance of the autonomic nervous system, which can be assessed by analysis of the heart rate variability (HRV). However it is still unclear whether all patients with CHD reveal suppression of HRV and if it is related to hemodynamic function and contractile disturbances of the left ventricle. To answer these questions data from 105 consecutive patients were analyzed and compared with 17 healthy subjects. All study participants underwent 24-hour ambulatory ECG recordings with calculation of HRV parameters and angiographic examination after collection of clinical data and other noninvasive evaluations. Time- (SDRR, SDANN, SD, pNN50) and frequency- (LF, HF) domain parameters of HRV were assessed. All ventriculographic and hemodynamic measurements were used in the analysis. Highly significant correlations were found between all HRV parameters, and left ventricular ejection fraction (LVEF) and left ventricular end-diastolic pressure (P < 0.001). Patients with LVEF < 40% were characterized by significantly lower values of HRV and impairment or lack (LVEF < 20%) of diurnal variation of frequency-domain measurements of HRV. Patients with segmental akinesis or dyskinesis also had lower values of HRV. The group with dyskinesis was characterized by significantly lower diurnal rhythms of LF and HF, independent of LVEF.

Dispersion of the QT interval as a predictor of cardiac death in patients with coronary heart disease.

Abnormal dispersion of the QT interval (QTd), measured as interlead variability of QT, may reflect a regional variation in duration of ventricular action potential and, hence, of cardiac electrical instability. In this retrospective study, we analyzed the effect of QTd on survival and its relation to other known predictors of subsequent cardiac death (CD) and sudden cardiac death (SCD) in 162 patients with coronary heart disease (CHD). QTd was calculated as the difference between the highest and lowest values measured in each of the 12 ECG leads (Qtmax - QTmin). Seventeen CDs occurred, including nine SCDs, during a 25 +/- 11 month follow-up. There were significant differences in CD (P < 0.001 in log-rank test) and in SCD (P < 0.01). The 1- and 3-year survivals were 87.5% and 76.5% in patients with QTd > 0.060 seconds versus 98% and 93.5% in patients with QTd < 0.060 seconds, respectively. Additionally, a stepwise Cox regression analysis revealed that increased QTd was an independent risk factor of CD and SCD. A cut-off value of 60 ms for QTd had a 53% sensitivity and 79% specificity in discriminating patients who are at risk of CD. The positive and negative prognostic values were 23% and 93%, respectively. Our findings support the hypothesis that increased QTd has a prognostic value in the stratification of patients with CHD independent of other known risk factors.

[Intravenous ablation of the atrio-ventricular junction in patients with supraventricular tachyarrhythmias]. / Przezzylna ablacja lacza przedsionkowo-komorowego u chorych z szybkimi arytmiami nadkomorowymi.

Since the first successful therapeutic DC ablation of the AV junction in 1986, we have treated 20 symptomatic patients with drug-refractory supraventricular tachyarrhythmias (average of 6 antiarrhythmic drugs prior to the ablation attempt). The primary rhythm disturbances necessitating ablation were: AV nodal reentrant tachycardia (50% of pts), atrial flutter or fibrillation, with an uncontrolled rapid ventricular response (40%), atrioventricular reentrant tachycardia using an accessory pathway (20%), atrial tachycardia (10%), and junctional reciprocating tachycardia (5%). Percutaneous catheter ablation of the AV junction was made by Gallagher's method. The USCI 4-polar catheter (7F) was used in 40% of pts, and bipolar Cordis catheter (5F) in the remaining 60%. 70% of pts received either one or two shocks, usually of 200 or 300 J during one session. Another 25% received stored cumulative energy from 800 to 1200 J (in two sessions), and one patient--1800 J (during three sessions). In 85% of pts, the immediate post-ablation conduction was third-degree AV block with the escape pacemaker, ranging from 20 to 50 beats/min., which was infra-His in 57%, and supra-His in 43% of pts. In 15% of pts were either first-degree AV block (10%) or normal AV conduction (5%). A His bundle deflection more than 0.2 mV was predictive of successful production of third-degree AV block. Except a mild and transient increase of indicating enzymes (CPK and CPK-MB) we did not observe any other serious complications directly related to the ablalation procedure. Follow-up study included 19 pts (time range from 2 to 56 months, mean 28).(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term antiarrhythmic pharmaco-therapy guided by Holter monitoring in patients with malignant ventricular arrhythmias and ischemic heart disease.

In 126 patients with clinical ventricular tachycardia and/or fibrillation, ischemic heart disease and repetitive and/or frequent ventricular ectopic beats long-term therapy guided by Holter ecg was assessed. Criteria for efficacy of antiarrhythmic drugs were following: 1) > 75% decrease in ectopic beats, 2) elimination of salvos, 3) > 90% reduction of couples and R/T and 4) reduction of multiformity up to 2 forms. They were fulfilled in 71% of patients (responders). During follow-up 1-49 months, mean 20, rate of sudden death was lower in responders as compared with nonresponders (p < 0.05). However, suppression of ventricular ectopic beats was not predictive for a favorable outcome, because the incidence of arrhythmic events and total cardiac death was similar in the two groups.

[Does the appearance of pro-arrhythmic response to anti-arrhythmic drugs have prognostic significance?]. / Czy wystapienie reakcji proarytmicznej na lek przeciwarytmiczny ma znaczenie prognostyczne?

Study was undertaken to assess whether proarrhythmic response to antiarrhythmic drug is a risk factor for cardiac death in patients (pts) with ischaemic heart disease (IHD). In 782 pts with IHD and frequent and/or complex ventricular ectopic beats (VEB) 1041 drug tests guided by 24 hour Holter monitoring were conducted. The following drugs were assessed: propranolol, disopyramide, mexiletine, amiodarone. Pro-arrhythmia was defined according to Velebit: 1/greater than or equal to 4-fold increase in VEBs, 2/greater than or equal to 10-fold increase in repetitive forms of 3/new occurrence of ventricular tachycardia or ventricular fibrillation (VT/VF). Proarrhythmic effect was observed in 8.4% of pts and in 7.9% of drug tests. The frequency with individual drugs ranged from 5.7% to 9%. No drug was completely free of this type of reaction. Antiarrhythmic drugs inducing arrhythmogenic response were eliminated. Pts were followed-up for a mean of 22 months (range 1-49). Chronic antiarrhythmic treatment was conducted. Pts were discharged taking the agent deemed most effective for suppression of arrhythmia. Follow-up visits were made every 6-12 months. All cases of death were verified. In long-term observation cardiac death and sudden death occurred in 53 and 32 pts. With actuarial analysis (Kaplan-Meler method, log rank test) there was significant difference in cardiac death (p less than 0.05) of pro-arrhythmia (+) compared with ++pro-arrhythmia (-) pts at yr (11% v 4%, 7% v 3%) and 3 yr (24% x 11%, 16% v 7%). The relative importance of baseline clinical variables in predicting survival was assessed with a stepwise Cox regression.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of beta adrenergic blocking drugs on the prognostic value of ST-segment depression during exercise electrocardiogram testing]. / Wplyw leków beta adrenolitycznych na wartosc prognostyczna obnizonego odcinka ST w elektrokardiogramie wysilkowym.

Exercise testing has been shown to be predictive for future cardiac events in patients with established diagnosis of coronary heart disease. Exercise test parameters associated with poor prognosis may be unreliable if patient is receiving beta adrenergic agents. The purpose of this study was: 1) to compare the results of exercise testing performed before and during beta blocking therapy, and 2) to determine the role of beta blockers in the prognostic significance of the ST-segment response recorded during exercise testing. The study population consisted of 518 patients (mean age 52 +/- 7 years) with coronary heart disease. The diagnosis was based on the presence of one of the following three criteria: 1) typical history and significant ST-segment depression on resting or exercise electrocardiogram, 2) history of myocardial infarction, 3) significant coronary angiographic abnormalities. In all patients symptom-limited exercise test was performed before and two weeks after the onset of beta blocker therapy. The data from the first and second tests were estimated for significance of differences between the mean values with following results: maximal heart rate--135 +/- 21 and 123 +/- 19 bpm (p less than 0.001), maximal work load achieved--98 +/- 43 and 109 +/- 44 W (p less than 0.001), maximal systolic blood pressure--171 +/- 28 and 163 +/- 26 mmHg (p less than 0.001). Occurrence of characteristic ST-segment depression was more frequent during the first than during the second test (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Proarrhythmic response to antiarrhythmic drug as a risk factor for sudden cardiac death in patients with ischemic heart disease.

The prognostic significance of arrhythmogenic response to an antiarrhythmic drug was studied. In 782 patients with ischemic heart disease (IHD) and frequent and/or complex ventricular premature beats (VPBs), 1,041 drug tests guided by 24-hour Holter monitoring were conducted. The following drugs were assessed: beta blockers, disopyramide, mexiletine, amiodarone. Proarrhythmia was defined as: (1) greater than 4-fold increase in VPBs, (2) greater than 10-fold increase in repetitive forms, or (3) new occurrence of ventricular tachycardia or ventricular fibrillation (VT/VF). During a follow-up of 1-49 months (mean 22) patients were treated with antiarrhythmic drugs found to be safe in control Holter monitoring. Proarrhythmic effects were observed in 8.4% of patients. No drug was completely free of this type of reaction. In long-term observation, cardiac death and sudden death occurred in 53 and 32 patients, respectively. With actuarial analysis (Kaplan-Meier method, log-rank test) there was a significant difference in cardiac death (P less than 0.01) and sudden death rate (P less than 0.05) of proarrhythmia (+) compared with proarrhythmia (-) patients at 1 year (11% vs 4%, 7% vs 3%) and 3 years (24% vs 11%, 16% vs 7%). Proarrhythmic response was an independent risk factor apart from myocardial infarction, VT/VF, ejection fraction less than 40% and QTc greater than 440 msec. Arrhythmogenic response to antiarrhythmic drugs seems to be an additional predictor of sudden death in IHD.

[The importance of the autonomic nervous system for sinus and atrioventricular node function in patients with sick sinus syndrome]. / Znaczenie ukladu wegetatywnego dla czynnosci wezlów zatokowego i przedsionkowo-komorowego, u chorych z zespolem chorego wezla zatokowego.

Autonomous nervous system (ANS) influence on sinus (SN) and atrioventricular (A-V N) nodes is still under investigation, especially in pathological states. We analysed role of ANS for SN and A-VN function in patients with different forms of sick sinus syndrome (SSS). From 310 patients (pts) after electrophysiological examinations before and after pharmacological denervation of the heart we selected 206 pts with SSS (group S) for further investigation. In group S were 124 men and 82 women from 17 years old (mean 46 +/- 16). Coronary heart disease was present in 102 pts (myocardial infarction in 7), mitral valve prolapse in 10, hypertrophic cardiomyopathy in 2. SSS was the only pathological finding in 75 pts. In 92 cases pacemaker was implanted (45%) of whole group S. Only sinus bradycardia was observed in 118 cases, tachycardia-bradycardia syndrome in 34 and sinus arrest or/and sinoatrial block in 53 cases. Electrophysiological examinations were performed using transesophageal stimulation of the left atrium before and after denervation of the heart. Pharmacological denervation of the heart was obtained by propranolol (i.v. 0.2 mg/kg body weight) and than atropine (i.v. 0.04 mg/kg body weight). We analysed sinus cycle length in basic state, after propranolol injection and after full denervation, maximal sinus nodes recovery time, maximal corrected sinus node recovery time, secondary pause, sino-atrial conduction time, Wenckebach point before and after full denervation. The whole group with SSS (group S) was divided: pts with normal (S1) and abnormal (S2) intrinsic properties of SN (104 and 102 pts respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Predictors of ventricular tachycardia inducibility in programmed electrical stimulation and the effectiveness of serial drug testing: Polish multicenter study.

In 100 patients with IHD and complex ventricular arrhythmias, programmed electrical stimulation was performed using up to three extrastimuli at sinus rhythm, and paced 100, 120 and 140 beats/min delivered from the RV apex, outflow tract or the LV with ventricular mapping to evaluate late potentials (LP) in 41 patients. Sustained monomorphic VT (SMVT) was provoked in 91% of 42 patients with a history of VT/VF, P less than 0.001, all five patients had SMVT in 24-hour ECG, P less than 0.005, and 91% of 21 patients with LV dyskinesis, P less than 0.01. After depolarizations were found in 62% of 21 patients with a history of VT, in 58% of 31 patients with inducible VT, P less than 0.01 and in five of six patients with LV dyskinesis. In patients with inducible VT, LP had a higher amplitude (105 +/- 35 vs 60 +/- 47 microV) and were more delayed (202 +/- 96 vs 133 +/- 75 msec) than in noninducible patients. In 17 patients, serial drug testing was performed after oral administration using mexilitene, disopyramide, chinidine, propafenone, sotalol, and amiodarone. If one drug was tested, the therapy efficacy was 25%, if two drugs-60%, and if three drugs-75%. In eight patients, VT was inducible in all tests, but in only one of these patients chronic antiarrhythmic therapy was not effective. We conclude that the most important predictors of VT inducibility are a history of VT or 24-hour ECG, and LV dyskinesis. Serial drug testing is efficient only when many drugs are tested, but even if VT is inducible, it does not exclude the possibility of a good clinical outcome in chronic therapy.