Redo Ventricular Tachycardia Ablation in a Frail Patient with Ischemic Cardiomyopathy. Benefit of Survival versus Risk of Complications

We present a case of repeated successful ventricular tachycardia ablation in an elderly frail post-myocardial infarction patient who presented with recurrent and often incessant episodes of slow ventricular tachycardia. An 85-year old thin male was presented with a hemodynamically stable, slow ventricular tachycardia, temporarily terminated after multiple anti-tachycardia pacing attempts. A previous recent ventricular tachycardia ablation procedure due to multiple ICD activations yielded poor result. Identification and elimination of late potentials was accompanied by final non-inducibility and a free from ventricular tachycardia mid-term outcome

Have we Made Any Progress in Preventing Sudden Cardiac Death in the Community? A Review on Automatic External Defibrillators

ABSTRACT:  Automated External Defibrillators (AEDs) have been recognised lately as an important link in the chain of survival of patients experiencing Sudden Cardiac Arrest (SCA) still remaining a major public health problem in the Western countries, being responsible for more than 250,000 out-of-hospital deaths annually. Due to the fact that survival rates following SCA are still unacceptably poor and that in most of the cases the underlying heart rhythm in out-of-hospital SCA is Ventricular Fibrillation/ pulseless Ventricular Tachycardia, introduction of AEDs seems to open a new prospective. Since the early 1990’s, when first launched, significant improvement has been made in AEDs technology and in many countries Public Access Defibrillation programs are now widespread. After minimal training, lay rescuers and first responder who might not be health professionals effectively provide early defibrillation using AEDs, resulting in many cases in improved survival rates. In the present paper we review the status of AEDs in clinical practice in the year of 2010 emphasizing on their key role for the widespread prevention of sudden cardiac death in the community

A Case of Asymptomatic Brugada Electrocardiographic Pattern Incidentally Unmasked During the Recovery Phase of an Exercise Stress Test

The interest about Brugada syndrome, an inherited channelopathy associated with sudden cardiac death in individuals without structural heart disease, is exponentially increasing lately. Similarly to chameleon, the electrocardiographic (ECG) signal of the disease fluctuates over time, it is often concealed, and may be unmasked under certain conditions. Recently, emergence of the characteristic ST-segment elevation during exercise stress test (EST) has been reported, probably resulting from an alteration of the autonomic tone in the different stages of exercise. We present the case of a 43-year-old, otherwise healthy male with an asymptomatic Brugada ECG pattern incidentally unmasked during the recovery phase of an EST

Decreased Deceleration Capacity of Heart Rate Detects Heart Failure Patients at Risk for Malignant Ventricular Arrhythmias

BACKGROUND: Deceleration capacity (DC) of the heart rate has proved an independent predictor of total mortality in post-myocardial infarction (post-MI) patients but it is unknown whether DC predicts the arrhythmic risk as well. OBJECTIVE: Our aim was to investigate whether DC can predict the arrhythmic sudden cardiac death (SCD) surrogate in patients with heart failure (HF). PATIENTS AND METHODS: We prospectively screened 145 HF patients with electrocardiogram (ECG), signal averaged ECG, echocardiography, and 24-hour Holter ECG. After 41.2 months, patients were divided into high (n=43) and low risk (n=102) groups according to three arrhythmic surrogates: clinical ventricular tachyarrhythmia (ventricular tachycardia -VT/ ventricular fibrillation-VF) (n=18), appropriate activation of the implantable cardioverter defibrillator (ICD) device (n=23) and confirmed SCD (n=2). RESULTS: High risk patients had impaired DC with significantly lower values (3.2±1.8 ms vs 4.0±2.1 ms, p=0.025). In the Cox regression analysis model adjusted for age, gender, diabetes, left ventricular ejection fraction (LVEF), filtered QRS, QTc, nonsustained VT episode(s) ≥ 1/24 h, ventricular premature beats ≥240/24 and DC, DC emerged as an important SCD surrogate predictor with a hazard ratio of 0.804, (95% confidence intervals-CI: 0.671- 0.963, p = 0.018). The cutoff point of DC≤3.352 ms (median) presented a hazard ratio of 2.885 (95% CI: 1.342 - 6.199, p=0.007, log rank test: p=0.003) for SCD surrogate. CONCLUSION: Decreased DC was found to be an important and independent SCD surrogate predictor. The cutoff point of DC≤3.352 ms detects HF patients at increased arrhythmic risk.

Effect of Transient Myocardial Ischemia on QT Interval Dispersion Among Patients with Unstable Angina

Objective: Our aim was to examine the effect of transient myocardial ischemia on QT interval and QT interval dispersion in patients presenting with unstable angina.Methods: We studied 31 patients (mean age 64±10, 22 men, 16 with an old myocardial infarction, 6 with previous coronary bypass surgery) admitted with unstable angina manifestations. Patients with a history of complex ventricular ectopy, malignant ventricular arrhythmias, advanced congestive heart failure or antiarrhythmic drug therapy were excluded. The uncorrected and corrected QT interval and QT dispersion were measured during angina as well as after the relief of pain.Results: The RR intervals were not significantly changed by the ischemic event (879±121 ms at rest to 877±173 ms during angina). However, both the uncorrected and corrected QT intervals were significantly increased during angina (from 410±45 ms and 440±41 ms at rest to 425±53 ms and 460±42 ms during angina respectively, p<0.05 for both). Similarly, both the uncorrected (QTd) and the corrected (QTcd) QT dispersion values were significantly prolonged during ischemia (QTd: 58±23 ms at rest to 83±33 ms during ischemia, p<0.001, QTcd: 63±26 ms at rest to 95±36 ms during ischemia, p<0.001). The observed increment in the QTd and QTcd provoked by ischemia was not different among the unstable angina patients with and without old myocardial infarction.Conclusion: Transient myocardial ischemia besides an increase in the QT and QTc intervals provokes an increase in both the corrected and uncorrected QT interval dispersion. Under certain circumstances, this may contribute to the genesis of serious reentry ventricular arrhythmias

Risk stratification for sudden cardiac death in heart failure patients

Sudden Cardiac Death (SCD) threatens survival of Coronary Artery Disease and Dilated Cardiomyopathy patients with Heart Failure. After MADIT II study results were published, the depressed left ventricular systolic function as is quantified by the calculation of the Left Ventricular Ejection Fraction (LVEF) has been emerged as the main risk stratifier for the primary prevention of SCD achived with an Implanted Cardiac Deffibrilator (ICD). This study reported an improvement in survival with 1 life saved for 11 Defibrilators implanted, during a 3 years period of follow up. Guidelines followed in 2006 indicated an Implanted Cardiac Deffibrilator (ICD) for all post infarction patients with LVEF450 ms presenting Odds Ratio for SCD: 3.081. (p=0.003, CI: 1.460-6.499), 2) the decreased standard deviation of wavelet coefficients (σwav)from heart rate variability, with cut off point σwav30% δεν καλύπτεται, παρ’ ότι αυτοί οι ασθενείς παρουσιάζουν συχνά ΑΚΘ. Ταυτόχρονα ενώ αυτή η πρακτική μπορεί να προσφέρει ομπρέλα κάλυψης στους ασθενείς με ΚΕΑΚ450 ms να παρουσιάζουν Σχετικό Λόγο Kινδύνου ΑΚΘ: 3.081 εν συγκρίσει με τους ασθενείς υπό του ορίου,(p=0.003, Δ.Ε.: 1.460-6.499), η μειωμένη σταθερά απόκλιση των συντελεστών κυματιδίων (σwav) από την μεταβλητότητα καρδιακής συχνότητας, με τους ασθενείς υπό του ορίου σwav<181 ms να παρουσιάζουν Σχετικό Κίνδυνο ΑΚΘ 2.526 εν συγκρίσει με τους ασθενείς οι οποίοι είχαν ικανοποιητική μεταβλητότητα και βρίσκονταν πάνω από το όριο (p=0.013, Δ.Ε.:1.213-5.259), η μειωμένη ικανότητα επιβράδυνσης της καρδιακής συχνότητας προσδιορισμένη με την μέθοδο του πρόσημου του κλάσματος (Deceleration Capacity Sign of Fraction) με τους ασθενείς υπό του διαχωριστικού ορίου DCsign≤5.373ms να παρουσιάζουν Σχετικό Κίνδυνο για ΑΚΘ 1.815, (p= 0.024, Δ.Ε.: 1,080-3.049), και η αδυναμία για κιρκάδια επιβράδυνση της καρδιακής συχνότητας κατά την διάρκεια της νύχτας με τους ασθενείς οι οποίοι είχαν υψηλή μέση Νυχτερινή Καρδιακή Συχνότητα (HRn≥74 bpm,75ο εκατοστημόριο) να παρουσιάζουν Σχετικό Κίνδυνο για ΑΚΘ 2.562 έναντι των ασθενών που είχαν χαμηλή μέση Νυχτερινή Καρδιακή Συχνότητα (HRn≤61 bpm, 25ο εκατοστημόριο)

Deceleration Capacity Alterations before Non-Sustained Ventricular Tachycardia Episodes in Post Myocardial Infarction Patients

Abstract While Non-Sustained Ventricular Tachycardia (NSVT) can be characterized as innocent in healthy persons, such arrhythmias in post-infarction patients can be associated with an increased risk for Arrhythmic Sudden Cardiac Death (SCD). The Autonomic Nervous System (ANS) may influence the electrical status before fatal arrhythmias initiations. In this work we study the differences between the behavior of Deceleration Capacity (DC) of heart rate before the onset of NSVT and in the rest of the signal. Twenty (20) patients having presented NSVT episodes are examined. Nine (9) of them have been classified as high risk for SCD after 16 months of follow up, while the rest (11) have been considered as low risk. For each NSVT episode the 30 min period before the episode and the 150 min period exactly before this period were compared. Windowed analysis was performed. Mean values showed that DC is reduced before NSVT episodes in both high and low risk patients. High risk patients presented lower mean values for DC compared to the low risk