Potential benefit of optimizing atrioventricular & interventricular delays in patients with cardiac resynchronization therapy.

BACKGROUND & OBJECTIVES: The clinical benefit of optimization (OPT) of atrioventricular delay (AVD) and interventricular delay (VVD) in cardiac resynchronization therapy (CRT) remains debatable. This study was aimed to determine the influence of AVD and VVD OPT on selected parameters in patients early after CRT implantation and at mid-term follow up (FU). METHODS: Fifty two patients (61±10 yr, 23 males) with left bundle branch block, left ventricular ejection fraction (LVEF) ≤35 per cent and heart failure were selected for CRT implantation. Early on the second day (2DFU) after CRT implantation, the patients were assigned to the OPT or the factory setting (FS) group. Haemodynamic and electrical parameters were evaluated at baseline, on 2DFU after CRT and mid-term FU [three-month FU (3MFU)]. Echocardiographic measures were assessed before implantation and at 3MFU. The AVD/VVD was deemed optimal for the highest cardiac output (CO) with impedance cardiography (ICG) monitoring. RESULTS: On 2DFU, the AVD was shorter in the OPT group, LV was paced earlier than in FS group and CO was insignificantly higher in OPT group. At 3MFU, improvement of CO was observed only in OPT patients, but the intergroup difference was not significant. At 3MFU in OPT group, reduction of LV in terms of LV end-diastolic diameter (LVeDD), LV end-systolic diameter, LV end-diastolic and systolic volume with the improvement in LVEF was observed. In FS group, only a reduction in LVeDD was present. In OPT group, the paced QRS duration was shorter than in FS group patients. INTERPRETATION & CONCLUSIONS: CRT OPT of AVD and VVD with ICG was associated with a higher CO and better reverse LV remodelling. CO monitoring with ICG is a simple, non-invasive tool to optimize CRT devices.

Relationship Between Changes in Pulse Pressure and Frequency Domain Components of Heart Rate Variability During Short-Term Left Ventricular Pacing in Patients with Cardiac Resynchronization Therapy.

BACKGROUND The aim of the study was to explore the relationship between changes in pulse pressure (PP) and frequency domain heart rate variability (HRV) components caused by left ventricular pacing in patients with implanted cardiac resynchronization therapy (CRT). MATERIAL AND METHODS Forty patients (mean age 63±8.5 years) with chronic heart failure (CHF) and implanted CRT were enrolled in the study. The simultaneous 5-minute recording of beat-to-beat arterial systolic and diastolic blood pressure (SBP and DBP) by Finometer and standard electrocardiogram with CRT switched off (CRT/0) and left ventricular pacing (CRT/LV) was performed. PP (PP=SBP-DBP) and low- and high-frequency (LF and HF) HRV components were calculated, and the relationship between these parameters was analyzed. RESULTS Short-term CRT/LV in comparison to CRT/0 caused a statistically significant increase in the values of PP (P<0.05), LF (P<0.05), and HF (P<0.05). A statistically significant correlation between ΔPP and ΔHF (R=0.7384, P<0.05) was observed. The ΔHF of 6 ms2 during short-term CRT/LV predicted a PP increase of ≥10% with 84.21% sensitivity and 85.71% specificity. CONCLUSIONS During short-term left ventricular pacing in patients with CRT, a significant correlation between ΔPP and ΔHF was observed. ΔHF ≥6 ms2 may serve as a tool in the selection of a suitable site for placement of a left ventricular lead.

[Comparison of basic electrical features of ICD defibrillating leads implanted to right ventricular apex or right ventricular outflow track and septum]. / Porównanee podstawowych parametrów elektrycznych elektrod defibrylujacych wszczepianych do wierzcholka oraz do okolic drogi odplywu prawej komory serca.

UNLABELLED: Automatic implantable cardioverter-defibrillators (ICDs) are nowadays an essential tool for reducing mortality due to sudden cardiac death. Technological advances in the miniaturization of devices and lead fixation, and the development of surgical techniques has led to more frequent implantation of the defibrillation leads outside the right ventricular apex (RVA), especially in those patients requiring cardiac pacing, as data from large clinical trials showed that chronic RVA pacing is harmful, especially in heart failure subjects, who are an important target for the ICD. Very few studies have been published comparing the electrical characteristics of leads placed in the RVA versus those implanted outside the RVA, mainly to right ventricular outflow tract of the heart (RVA), hence any subsequent analysis of this issue seems to be a valuable addition to the available information in this topic. The aim of this study was to compare the electrical parameters of ICD leads implanted into the right ventricular apex (RVA), to those placed in one of the alternative sites: the right ventricular outflow tract (RVOT), or the area of the interventricular septum (RVS). MATERIAL AND METHODS: Retrospective analysis of medical data from a single centre (teaching hospital), which included 132 patients with ICD implanted in 2010-2011, both in primary and secondary prevention of sudden cardiac death. We compared the most important electrical parameters of the ICD system, as the resistance of the pacing system, resistance of high-voltage coil, the amplitude of the sensed beats and pacing threshold. In addition, we compared the time of implantation, X-ray fluoroscopy time and X-ray exposure. RESULTS: There were no statistically significant differences between the two analysed groups in terms of pacing-system resistance (601.012 vs. 602.7omega, p = 0,499), high-energy coil resistance (63.7omega vs. 67.22, p = 0,201), amplitude of sensed R-waves (14,6mV vs. 15.3mV, p = 0, 710) and the pacing threshold energy (0,368 microJ vs. 0.259 microJ, p = 0,803). Also the duration of implantation (123, 3 min vs. 123, 9 min, p = 0,940), fluoroscopy time (11,0 minutes vs. 8,6 minutes, p = 0,06) and dose exposure (1594, 5cGy/cm2 vs. 2094, 4cGy/cm2, p = 0,069) were comparable in both groups. CONCLUSIONS: Implantation of ICD leads to the RVOT/RVS is a safe procedure, and the basic electrical parameters of such systems are comparable to ICDs with lead implanted to the RVA.

A new type of dual atrioventricular nodal nonreentrant tachycardia.

Dual atrioventricular nodal nonreentrant tachycardia (DAVNNT) is very rarely observed clinically. The first review of this arrhythmia was published in 2011 by Wang, where four types of DAVNNT were described. Our case report presents a phenomenon that has never been published before. We revealed a very specific sequence of double fire phenomenon, 1:1 atrioventricular (AV) conduction and AV block.

[Abnormal filter setting or Brugada syndrome?]. / Nieprawidlowe ustawienie filtrów czy zespól Brugadów?

26-year old patient was admitted to our department with suspected Brugada syndrome (BrS). He complained of recurrent dizziness due to which he was taken by a team of rescuers to the district hospital, where the recorded ECG demonstrated isolated 3­7 mm ST segment elevation in leads V1­V3. Coronary angiography performed in this hospital was normal. Then patient was transferred to our department for consideration of ICD implantation. ECG registration in our hospital with 0.05 Hz (3.2 s) filter showed sinus bradycardia with 1­2 mm ST segment elevation in precordial leads. A detailed analysis of all ECG's proved that the district hospital ECG was performed in manual mode with the application of 1.5 Hz (0.1 s) low frequency high-pass filter. To confirm the effect of incorrect filter as the cause of misdiagnosis we repeated ECG recording using the recorder which allows to apply the same settings 1.5 Hz (0.1 s) as in district hospital and reconstructed ECG with repolarisation abnormalities. Negative ajmaline test (1 mg/kg) additionally reaffirmed an exclusion of dynamic form of BrS.

Noninvasive assessment of autonomic cardiovascular activity in patients with inappropriate sinus tachycardia.

Inappropriate sinus tachycardia (IST) is a clinical syndrome characterized by excessive resting heart rate (HR) or disproportional HR increase during exercise. The etiology of IST has not been fully elucidated and remains controversial. The aim of the present study was to assess autonomic function by means of noninvasive tests and commonly available electrocardiographic methods in a series of consecutive patients with symptomatic IST. Twenty-four patients (37 ± 12 years; 20 women) with IST were enrolled. Six cardiovascular reflex tests were performed: (1) HR variation during slow deep breathing, (2) 30-to-15 ratio during active standing, (3) blood pressure response to standing, (4) cold face test, (5) Valsalva maneuver, and (6) blood pressure response to sustained handgrip. Intrinsic HR was calculated and compared with HR after pharmacologic denervation. Additionally, spontaneous baroreflex sensitivity and 24-hour HR variability indices were analyzed. In IST patients, intrinsic HR was significantly higher compared with control subjects. Most cardiovascular autonomic tests revealed abnormal or borderline results, particularly those reflecting mainly parasympathetic function. The spontaneous baroreflex gain was significantly reduced in IST patients. After controlled orthostatic stress and during Valsalva maneuver, impaired baroreflex function was observed. The sympathovagal balance from HR variability was preserved, but altered activity in both bands of frequency domain analysis was recorded. In conclusion, IST is a heterogenic syndrome with enhanced sinus node automaticity modulated by complex alterations of autonomic tone.

[Complete atrio-ventricular block as a first symptom of borreliosis: antibiotic treatment instead of pacemaker implantation]. / Calkowity blok przedsionkowo-komorowy jako pierwszy objaw boreliozy: antybiotykoterapia zamiast wszczepienia rozrusznika serca.

We present a 46-year-old male patient with complete atrio-ventricular block. A inflammatory etiology was suspected and finally lyme carditis was diagnosed. The conduction abnormalities disappeared with antibiotic treatment and a pacemaker implantation was not needed. Further follow-up of two years was uneventful.

Ivabradine in combination with metoprolol succinate in the treatment of inappropriate sinus tachycardia.

BACKGROUND: Inappropriate sinus tachycardia (IST) is a clinical syndrome characterized by excessive resting heart rate (HR) or a disproportional increase in HR during exercise. ß-blocker or calcium channel-blocker therapy is often noneffective or not well tolerated. The HR reduction on ivabradine is similar to ß-blockers but in some patients its efficacy to resolve all IST-related symptoms is limited. The aim of the study was to assess the efficacy and safety of combining ivabradine with metoprolol succinate in patients with refractory highly symptomatic IST. METHODS: Twenty patients (36 ± 10 years; 16 women) with IST were enrolled. All patients received metoprolol succinate 95 mg single dose during the first month of the study. After 4 weeks of treatment with metoprolol, ivabradine was administered as adjuvant therapy up to 7.5 mg twice daily. Holter monitoring and treadmill stress test were performed at baseline, after 4, and 8 weeks of the study, respectively. RESULTS: We observed significant and similar reduction in resting HR both for metoprolol and for combined therapy compared to the baseline. The mean HR during daily activity was significantly lower on ivabradine and metoprolol compared to monotherapy with ß-blocker. The combined treatment yielded a significant increase in exercise capacity as assessed by treadmill stress test. After 4 weeks of combined therapy a significant reduction in IST-related symptoms, measured by means of the European Heart Rhythm Association score, was observed. CONCLUSION: Combining ivabradine with metoprolol is an effective and well-tolerated treatment option for IST in patients with refractory to monotherapy.

Metoprolol succinate vs. ivabradine in the treatment of inappropriate sinus tachycardia in patients unresponsive to previous pharmacological therapy.

AIMS: Inappropriate sinus tachycardia (IST) is a clinical syndrome characterized by excessive resting heart rate (HR) or disproportional increasing HR during exercise. The treatment of IST symptoms using beta-blockers or calcium channel-blockers is often non-effective or not well tolerated. Ivabradine is a new agent inhibiting sinus node I(f) current, resulting in a decrease of HR without haemodynamic compromise. METHODS AND RESULTS: We enrolled 20 patients (36 ± 10 years; 14 women) affected by IST and resistant to previous administered therapy by using beta-blockers or verapamil. After 4 weeks of treatment with metoprolol succinate (up to 190 mg once a day) the therapy was switched to ivabradine up to 7.5 mg twice daily. Holter monitoring and treadmill stress test were performed after 1 and 2 months following start of the study. We observed a significant reduction of resting HR both for metoprolol and for ivabradine compared with baseline (92.8 vs. 90.2 vs. 114.3 b.p.m.; P< 0.001). During daily activity there was an even larger decrease of HR on ivabradine (mean daytime HR 94.6 vs. 87.1 vs. 107.3 b.p.m.; P< 0.001). Ivabradine was very well tolerated whereas in 10 patients on metoprolol we observed hypotension or bradycardia requiring dose reduction. Significantly lower incidence of IST-related symptoms were registered on ivabradine therapy than on metoprolol. Fourteen patients (70%) treated with I(f) blocker were free of IST-related complaints. CONCLUSIONS: Metoprolol and ivabradine exert a similar effect on resting HR in patients with IST. Ivabradine seems to be more effective to relieve symptoms during exercise or daily activity.

Ivabradine in the treatment of inappropriate sinus tachycardia in patients after successful radiofrequency catheter ablation of atrioventricular node slow pathway.

BACKGROUND: Inappropriate sinus tachycardia (IST) occurs relatively common after catheter ablation of slow pathway in patients with atrioventricular nodal reentrant tachycardia. The treatment of IST symptoms using ß-blockers or calcium channel-blockers are often noneffective or not well tolerated. Ivabradine is a new heart rate (HR)-decreasing agent inhibiting sinus node If current. The purpose of the study was to evaluate the efficacy and safety of ivabradine in patients with persistent and ß-blocker-resistant IST after successful radiofrequency (RF) ablation of atrioventricular node slow pathway. METHODS: We enrolled 14 patients (42 ± 11 years; 10 women) affected by IST after RF ablation. Holter monitoring, treadmill stress test, and IST symptoms assessment were performed at baseline and after first, and second month of the study. RESULTS: We observed significant reduction of mean resting HR after 30 and 60 days of ivabradine treatment compared to baseline (P < 0.001). 24-hour Holter monitoring showed a significant reduction of mean HR and mean HR during daily activity (P < 0.001). The study revealed significant improvement in exercise capacity during treadmill exercise test on ivabradine therapy (P < 0.001). Significantly lower incidence of IST-related symptoms were registered after administration of If current inhibitor. After 2 months of treatment no patients reported severe complaints assessed by means of European Heart Rhythm Association score. We did not observe severe side effects during therapy. CONCLUSION: Ivabradine is an effective treatment option to reduce HR and symptoms in patients with IST after RF ablation of atrioventricular node slow pathway. The therapy with ivabradine is well tolerated even with maximum daily dose.

Computer software tool for heart rate variability (HRV), T-wave alternans (TWA) and heart rate turbulence (HRT) analysis from ECGs.

BACKGROUND: This paper presents a software package for quantitative evaluation of heart rate variability (HRV), heart rate turbulence (HRT), and T-wave alternans (TWA) from ECG recordings. The software has been developed for the purpose of scientific research rather than clinical diagnosis. MATERIAL/METHODS: The software is written in Matlab Mathematical Language. Procedures for evaluation of HRV, HRT and TWA were implemented. HRV analysis was carried out by applying statistical and spectral parametric and nonparametric methods. HRT parameters were derived using the Schmidt algorithm. TWA analysis was performed both in spectral and in time domain by applying Poincare mapping. A flexibility of choosing from a number of classical modelling approaches and their modifications was foreseen and implemented. The software underwent preliminary verification tests both on ECGs from the Physionet online ECG signal repository and recordings taken at the Department of Electrocardiology of the Medical University Hospital in Lodz. RESULTS: The result of the research is a program enabling simultaneous analysis of a number of parameters computed from ECG recordings with the use of the indicated analysis methods. The program offers options to preview the intermediate results and to alter the preprocessing steps. CONCLUSIONS: By offering the possibility to cross-validate the results of analyses obtained by several methods and to preview the intermediate analysis steps, the program can serve as a helpful aid for clinicians in comprehensive research studies. The software tool can also be utilized in training programs for students and medical personnel.

Clinical and electrocardiographic covariates of deceleration capacity in patients with ST-segment elevation myocardial infarction.

BACKGROUND: Deceleration capacity (DC) is a novel electrocardiography (ECG) parameter characterizing the overall capacity of slowing down the heart rate. The aim of this study was to evaluate clinical and ECG covariates of DC in patients with the first episode of ST-segment elevation myocardial infarction (STEMI) treated with primary angioplasty. METHODS: Deceleration capacity, heart rate variability (HRV) and heart rate turbulence (HRT) were assessed from 24-hour ECG Holter recordings in 70 patients (66 male, mean age 57 years) with STEMI. Deceleration capacity was evaluated as continuous or dichotomized (< or = 4.5 vs. > 4.5 ms) variable. RESULTS: The median value of DC was 5.12 ms. Thirty patients (43%) had abnormal DC ( < or = 4.5 ms). The abnormal DC was more common in female, older and hypertensive patients. Although DC was not associated with either STEMI localization or left ventricular ejection fraction, it was significantly correlated with mean heart rate, standard HRV indices and HRT slope. Multivariate logistic regression showed that hypertension (OR = 3.23, 95% CI = 1.1-9.9, p = 0.039) and mean heart rate > 70 beats/minute (OR = 6.05, 95% CI = 2.0-18.4, p = 0.001) were independently associated with abnormal DC. CONCLUSIONS: Deceleration capacity in patients with the first STEMI treated with primary angioplasty is influenced by age, gender, hypertension and heart rate, but not the location of myocardial infarction or left ventricular ejection fraction. Correlation between DC and HRV indices suggests that DC is related to autonomic modulation of heart rate.

[Effect of chronic therapy with low dose of angiotensin converting enzyme inhibitors on mortality in patients with left ventricular dysfunction after acute myocardial infarction]. / Wplyw przewleklego leczenia malymi dawkami inhibitorów konwertazy angiotensyny na smiertelnosc chorych z dysfunkcja lewej komory po ostrym zawale serca.

UNLABELLED: Angiotensin converting enzyme inhibitors (ACE-I) used in patients with postinfarction left ventricular dysfunction reduce the risk of death. Some patients do not tolerate high dose of medications which benefit was well documented in multicentre trials. THE AIM OF THIS STUDY: was to evaluate the effect of low doses of ACE-I on mortality rate in patients with ejection fraction (EF) below < or = 35% after acute myocardial infarction (MI) in long-term observation. MATERIAL AND METHODS: Study population consisted of 84 patients (pts) (67 men and 17 women) aged 38-79 (mean age 61 +/- 11) years with post-MI left ventricular dysfunction (EF < or = 35%). Patients were divided into 2 groups according to applied treatment: the group ACE-I (+) - 50 pts who received captopril, enalapril, trandolapril, perindopril or quinapril at doses not exceeding half of target dose in chronic heart failure and the group ACE-I (-) - 34 pts not treated with ACE-I. The end point of this observation was total mortality during 48 month follow-up. RESULTS: During long-term observation 33 from 84 patients died (39%). Mortality from all causes in the group ACE-I (+) was non significantly reduced as compared with the group ACE-I (-) (36% vs. 44%). CONCLUSION: In patients with left ventricular dysfunction (EF < or = 35%) after acute myocardial infarction chronic treatment with low doses of ACE-I do not reduce total mortality rate.

[Effect of spironolactone on mortality in patients with severe left ventricular dysfunction after acute myocardial infarction]. / Wplyw spironolaktonu na smiertelnosc chorych z przebytym swieziym zawalem serca i istotna dysfunkcja lewej komory.

BACKGROUND: Spironolactone--non-selective mineralocroticoid receptor blocker in patients with chronic heart failure reduces the risk of death. Its efficacy was not assessed in patients with postinfarction (post-MI) left ventricular dysfunction. The purpose of this study was to evaluate the effect of spironolactone on mortality in survivors of acute myocardial infarction with depressed ejection fraction < 30% (EF%) during a 24-month, long-term observation. METHODS: Study population consisted of 47 patients, 38 men and 9 women aged 41-79 years, mean age 62 +/- 10 years with severe post-MI left ventricular dysfunction (EF% < 30%). Patients were divided into 2 groups according to applied treatment: the group spironolactone (+) - 22 pts who received spironolactone at daily dose 25-50 mg and the group spironolacton (-) - 25 pts not treated with spironolactone. The end point of this observation was mortality from all causes during a 24-month follow-up. RESULTS: During long-term observation - 19 of 47 patients died (40%). Mortality from all causes in the group spironolactone (+) - 11/22 (50%) was non significantly higher as compared to the group spironolactone (-) - 8/25 (32%). CONCLUSION: In patients with severe left ventricular dysfunction (EF < 30%) after acute myocardial infarction long-term treatment with spironolactone at daily dose 25-50 mg does not reduce mortality rate in long-term follow-up.

[Effect of low doses of metoprolol, bisoprolol and carvedilol on mortality in patients with left ventricular dysfunction after acute myocardial infarction]. / Wplyw malych dawek Metoprololu, bisoprololu i karwedilolu na smiertelnosc chorych z dysfunkcja lewej komory po swiezym zawale serca.

UNLABELLED: Beta-blocking agents (B-A) in patients with postinfarction left ventricular dysfunction or heart failure reduce the risk of death. Some patients do not tolerate high doses of medications which benefit was well documented in multicentre trials. The purpose of this study was to evaluate the effect of low dose of metoprolol, bisoprolol and carvediolol on mortality in postinfarction (post-MI) patients (pts) with depressed < or =35% left ventricular ejection fraction (EF) in 24-month observation. MATERIAL AND METHODS: Study population consisted of 74 pts, (59 men and 15 women) aged 38-79 years (mean age 62 +/- 11 years) with post-MI left ventricular dysfunction (EF < or = 35%). Patients were divided into 2 groups according to applied treatment: the group B-A(+) included 55 pts who received during hospitalization and ambulatory observation beta-blockers in low doses: metoprolol in the dose of 25-75 mg/day (mean 56 +/- 20 mg/day), bisoprolol in the dose of 2,5-5 mg/day (mean 3.1 +/- 1.2 mg/day) or carvedilol in the dose of 6.25-12.5 mg/day (mean 9.1 +/- 3.3 mg/day) and the group B-A(-) - 19 pts not treated with beta-blocking agents. RESULTS: During long-term observation 24 from 44 patients died (32%). All causes mortality in the group B-A(+) - 18/55 (33%) did not differ from mortality in the group B-A(-) - 6/19 (32%). CONCLUSION: In patients with depressed < or =35% ejection fraction after acute myocardial infarction treatment with low doses of metoprolol, bisoprolol and cardvediolol did not reduce mortality rate in 24-month observation.

Usefulness of prolonged P-wave duration on signal averaged ECG in predicting atrial fibrillation in acute myocardial infarction patients.

BACKGROUND: Atrial fibrillation (AF) is a frequent complication of acute myocardial infarction (AMI), with a reported incidence of 7-18%. The incidence of congestive heart failure, in-hospital mortality, and long-term mortality is higher in AMI patients with AF than in those without. P-wave duration (PWD) on Signal-Averaged ECG is a non-invasive marker of intra-atrial conduction disturbances, which are believed to be the main electrophysiological cause of AF. MATERIAL/METHODS: In the present study we investigated whether PWD can predict development of AF in 130 AMI patients (100 men and 30 women, aged 56.9+/-12). PWD was recorded, along with clinical and hemodynamic characteristics. RESULTS: During the observation period (up to 21 days) 22 patients (16.9%) developed AF. In univariate analysis the variables associated with development of AF were age>65, Killip class III-IV, and PWD>125 ms. Stepwise logistic regression analysis showed that age>65 and PWD>125 ms were independently associated with AF. CONCLUSIONS: PWD measured in a very early period of AMI is a useful tool in predicting AF.

Most ventricular depolarization and repolarization abnormalities are not predictors of arrhythmic events in postinfarction patients with normal intraventricular conduction.

BACKGROUND: Survivors of acute myocardial infarction (AMI) are at increased risk for arrhythmic events (AE), which include sudden death (SD) or sustained ventricular tachycardia (sVT). In the prethrombolytic era, abnormal parameters of depolarization and repolarization were considered to be markers of susceptibility to these events. The purpose of the present study was to assess whether these variables should still be considered predictors of AE in postinfarction patients with normal intraventricular conduction. MATERIAL/METHODS: The study population consisted of 236 survivors of AMI, in whom the parameters of depolarization on SAECG (QRSd, LAS, RMS, LPs) and repolarization on ECG (QTc-max, QTd) were assessed before hospital discharge. The patients were followed for 18 months, and all episodes of SD and sVT were recorded. RESULTS: During long-term observation, 3 patients died from SD, and sVT occurred in 1 patient. Univariate Cox regression analysis showed that among the SA-ECG and ECG variables, only QRSd was significantly related to the incidence of AE (p<0.04). A comparison of event-free survival curves by the Kaplan-Meier method at the dichotomy limit of 119ms showed significantly worse prognosis in patients with QRSd> or =119ms (p<0.01). CONCLUSIONS: In postinfarction patients with normal intraventricular conduction treated in the acute and chronic phase of MI according to recent management strategies, QRSd> or =119ms on SAECG is associated with arrhythmic events. Other parameters of depolarization, such as LAS, RMS, and positive LPs, and also repolarization, such as prolonged QTc-max and QTd, seem to be of little use in predicting these events.

P wave dispersion and P wave duration on SAECG in predicting atrial fibrillation in patients with acute myocardial infarction.

BACKGROUND: Atrial fibrillation (AF) is a frequent complication of acute myocardial infarction (AMI), with reported incidence of 7% to 18%. The incidence of congestive heart failure, in-hospital mortality, and long-term mortality is higher in AMI patients with AF than in AMI patients without AF. P wave duration on signal-averaged ECG (PWD) and P wave dispersion on standard ECG (Pd) are noninvasive markers of intra-atrial conduction disturbances, which are believed to be the main electrophysiological cause of AF. METHODS: In the present study we investigated prospectively whether P wave duration on SAECG and P wave dispersion on standard ECG can predict development of AF in a group of patients with AMI. One hundred and thirty patients (100 men and 30 women, aged 56.9 +/- 12) with AMI were investigated. PWD, Pd, their clinical and hemodynamic characteristics were collected. RESULTS: During the observation up to 14 days, 22 patients (16.9%) developed AF. Univariate analysis variables associated with development of AF: age > 65 years, Killip class III-IV, PWD > 125 ms, and Pd > 25 ms. Stepwise logistic regression analysis showed that age > 65 years, PWD > 125 ms, and Pd > 25 ms were independently associated with AF. CONCLUSIONS: PWD and Pd both measured in a very early period of AMI are useful in predicting AF.

The impact of very late revascularization of occluded infarct-related artery on cardiac mortality and the incidence of sudden death in survivors of acute myocardial infarction - long-term observation.

BACKGROUND: In survivors of acute myocardial infarction (AMI), an occluded infarct-related artery (IRA) is an important predictor of cardiac death (CD) and sudden death (SD). Early reperfusion of the IRA was associated with improved survival rate. The purpose of the present study was to assess if late IRA revascularization, performed 10-30 days after AMI, also has a beneficial effect on the incidence of CD and SD during an 18-month follow-up. MATERIAL/METHODS: The study population consisted of 93 post-MI patients with occluded IRA on coronary angiography. The patients were divided into 2 groups according to IRA status at discharge -- revascularized (47 patients) or occluded (46 patients) -- and followed. Before revascularization, the two groups of patients did not differ in the prevalence of clinical and angiographic variables, or in the incidence of risk factors for SD. In patients who underwent angioplasty or bypass graft surgery of closed IRA, the markers of electrical instability demonstrated no significant improvement after revascularization. RESULTS: During the 18-month follow-up a significantly lower incidence of CD (0% vs 15%, p<0.01) and SD (0% vs 11%, p<0.03) was observed in the group of patients with revascularized IRA than in the group of patients with occluded IRA. CONCLUSIONS: In survivors of AMI, late reperfusion of occluded IRA is associated with reduced 18-month cardiac mortality. The beneficial effect of this procedure on the incidence of sudden death, not associated with improvement in myocardial electrical stability, suggests that ischemia can be considered an important factor modulating the arrhythmogenic substrate.