The role of catheter ablation in the management of patients with implantable cardioverter defibrillators presenting with electrical storm.

OBJECTIVE: Electrical storm (ES) is not uncommon among patients with an implantable cardioverter defibrillator (ICD) in situ. Catheter ablation (CA) may suppress the arrhythmia in the acute setting and prevent ES recurrence. METHODS: Nineteen consecutive patients with an ICD in situ presenting with ES underwent electrophysiologic studies followed by CA. CA outcome was classified as a complete success if both clinical and non-clinical tachycardia were successfully ablated, partial success if ≥1 non-clinical tachycardia episodes were still inducible post-CA, and failure if clinical tachycardia could not be abolished. Patients were followed for a median period (IQR) of 5.6 (1.8-13.7) months. The primary endpoint was event-free survival from ES recurrence. The secondary endpoint was event-free survival from a composite of ES and/or sustained ventricular tachycardia (VT) recurrence. RESULTS: Clinical arrhythmia was successfully ablated in 14 out of 19 (73.7%) cases after a single CA procedure. A completely successful CA outcome was associated with significantly increased ES-free survival compared with a partially successful or failed procedure (Log rank P=0.039). Nevertheless, patients with acute suppression of all tachycardia episodes (n=11), relative to those with a partially successful or a failed CA procedure (n=8), did not differ in incidence of the composite endpoint of sustained VT or ES (Log rank P=0.278). CONCLUSION: A single CA procedure can acutely suppress clinical arrhythmia in three-quarters of cases. A completely successful CA outcome can prolong ES-free survival; however, sporadic ICD therapies cannot be abrogated.

Atrial fibrillation in hypertrophic cardiomyopathy: A turning point towards increased morbidity and mortality.

BACKGROUND: Atrial fibrillation (AF) is the most common arrhythmic event in patients with hypertrophic cardiomyopathy (HCM). The aim of this study was to identify the clinical impact and prognostic significance of AF on a large cohort of patients with HCM. METHODS: Echocardiographic and clinical correlates, risk factors for AF and thromboembolic stroke and the prognostic significance of AF were evaluated in 509 patients with an established diagnosis of HCM. RESULTS: A total of 119 patients (23.4%) were diagnosed with AF during the index evaluation visit. AF patients had a higher prevalence of stroke and presented with worse functional impairment. Left atrial diameter (LA size) was a common independent predictor of the arrhythmia (OR: 2.2, 95% CI 1.6-3.3) and thromboembolic stroke (OR: 1.6, 95% CI 1.01-2.40). AF was an important risk factor for overall mortality (HR=3.4, 95% CI: 1.7-6.5), HCM-related mortality (HR=3.9, 95% CI: 1.8-8.2) and heart failure-related mortality (HR=6.0, 95% CI: 2.0-17.9), even after adjusting for statistically significant clinical and demographic risk factors. However, AF did not affect the risk for sudden death. CONCLUSIONS: LA size is an independent predictor of both AF and thromboembolic stroke. Moreover, patients with AF, regardless of type, have significantly higher mortality rates than patients without AF.

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.

A de novo novel cardiac ryanodine mutation (Ser4155Tyr) associated with catecholaminergic polymorphic ventricular tachycardia.

We describe the case of a 14-year-old girl with a history of syncopal episodes triggered by stress or exercise. Catecholaminergic polymorphic ventricular tachycardia was diagnosed with the aid of an implantable loop recorder. The genetic testing of the patient and her family revealed a de novo novel missense mutation (Ser4155Tyr) in the exon 90 of the ryanodine receptor gene. This mutation affects a highly conserved residue (S4155) and results to replacement of serine (S) with tyrosine (Y) leading to change in physical and chemical properties. The girl was treated with an implantable defibrillator, metoprolol and flecainide. Over 1 year of follow-up she had no recurrence of ventricular tachycardia.

Quinidine: an "endangered species" drug appropriate for management of electrical storm in brugada syndrome.

Brugada syndrome is an inherited channelopathy associated with an increased risk of syncope and sudden cardiac death. In rare cases it can be manifested with electrical storm. We report two cases of Brugada syndrome that presented with electrical storm and were treated successfully with oral quinidine, an "endangered species" drug.

Increased right atrial volume index predicts low Duke activity status index in patients with chronic heart failure.

INTRODUCTION: The aim of the present study was to examine the value of the right atrial volume index (RAVI) as predictor of functional capacity in patients with heart failure. METHODS: A total of 51 patients with stable chronic heart failure of ischaemic or non-ischaemic aetiology were prospectively enrolled. The systolic function of the right ventricle was quantified using the tricuspid annular plane systolic excursion (TAPSE). Right atrial volume was measured in the apical 4-chamber view and was indexed to body surface area. The functional capacity was assessed by the Duke Activity Status Index (DASI). RESULTS: Patients with a low functional capacity (DASI<10) had lower TAPSE (1.4 ± 0.3 cm versus 2.0 ± 0.4 cm, p<0.001), higher RAVI (42 ± 15 ml/m(2) versus 22 ± 9 ml/m(2), p<0.001), higher estimated right ventricular systolic pressure (61 ± 13 mmHg versus 40 ± 16 mmHg, p<0.001), larger right ventricular end-diastolic diameter (4.7 ± 0.8 cm versus 3.6 ± 0.7 cm, p<0.001) and lower left ventricular ejection fraction (26 ± 6% versus 30 ± 7%, p=0.022). Multivariate analysis revealed that TAPSE was the single independent predictor of DASI. In the subgroup of patients with reduced right ventricular systolic function (TAPSE<2 cm), RAVI was the single independent predictor of low DASI. In the overall population RAVI=30.6 ml/m(2) had 75% sensitivity and 83% specificity in predicting DASI<10. Within the subgroup of patients with TAPSE<2 cm, RAVI=30.6 ml/m(2) had better sensitivity and specificity (79% and 90% respectively) in predicting DASI<10. CONCLUSIONS: Increased right atrial volume index predicts low functional capacity quantified by the Duke Activity Status Index in patients with stable chronic heart failure.

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.

Cardiac arrest caused by torsades de pointes tachycardia after successful atrial flutter radiofrequency catheter ablation.

A 66-year-old woman underwent successful radiofrequency catheter ablation for long-lasting, drug refractory fast atrial flutter. Two days later she had a cardiac arrest due to torsades de pointes (TdP) tachycardia attributed to relative sinus bradycardia and QT interval prolongation. After successful resuscitation further episodes of TdP occurred, which were treated with temporary pacing. Because of concomitant systolic dysfunction due to ischemic and valvular heart disease she was finally treated with an implantable defibrillator. In conclusion we strongly advise prolonged monitoring for 2 or more days for patients with structural heart disease following successful catheter ablation for long lasting tachyarrhythmias.

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.

Spontaneous dissection of right coronary artery manifested with acute myocardial infarction.

Spontaneous coronary artery dissection is a rare cause of acute ischemic coronary events and sudden cardiac death. It usually occurs in young women without traditional risk factors for coronary artery disease during pregnancy or postpartum period. However, it has also been reported in patients with atherosclerotic coronary disease. We present a case of spontaneous right coronary artery dissection in a 48-year male with recent myocardial infarction and previous percutaneous coronary intervention.

An interesting case of cardiac amyloidosis initially diagnosed as hypertrophic cardiomyopathy.

Cardiac involvement occurs frequently in primary amyloidosis and is associated with heart failure hospitalizations and poor survival. The initial presentation of the disease may be misleading, resulting in under-diagnosis of cardiac amyloidosis and late initiation of treatment. We present a case of cardiac amyloidosis initially misdiagnosed as hypertrophic cardiomyopathy and we discuss the key findings of the disease along with the latest evidence regarding the management and prognosis of cardiac amyloidosis.

The use of transtelephonic loop recorders for the assessment of symptoms and arrhythmia recurrence after radiofrequency catheter ablation.

Radiofrequency catheter ablation (RFA) is an effective treatment of arrhythmias. However, patients often remain symptomatic after the procedure. We aimed to assess the arrhythmia recurrence after successful RFA in relation to patients' symptoms using transtelephonic loop recorders. Thirty-six consecutive patients (age 50 +/- 14 years, 17 males/19 females) were enrolled after successful RFA for atrioventricular (AV) nodal reentrant tachycardia (n = 21), AV reentrant tachycardia (n = 8), atrial tachycardia (n = 2), atrial fibrillation/flutter (n = 4), and ventricular tachycardia (n = 1). During 23 +/- 6 days of follow-up, 679 events were recorded, 246 of which were true arrhythmic events, mostly (56%) asymptomatic. The vast majority of these true arrhythmic events were due to trivial arrhythmias (extrasystoles or sinus tachycardia), equally distributed among symptomatic and asymptomatic episodes. Arrhythmia relapse was shown in four patients, who had a total of nine episodes, eight of which were symptomatic. No high degree AV block was detected. Overall, symptom recurrence had low sensitivity (44%) and high specificity (95%) for the detection of any arrhythmia, and high sensitivity (89%) but low specificity (58%) for the detection of relapse. In conclusion, transtelephonic monitoring was a useful tool for the assessment of symptoms after RFA and its use may be reserved for the most symptomatic patients to detect a relapse or to reassure them for the benign nature of their symptoms.

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.

Kinetics and prognostic value of inflammatory-sensitive protein, IL-6, and white blood cell levels in patients undergoing coronary stent implantation.

BACKGROUND: The levels of interleukin-6 (IL-6), white blood cells (WBCs), and some inflammatory-sensitive proteins (ISPs), such as fibrinogen (FIB) and C-reactive protein (CRP), have been related to coronary stent restenosis. The aim was to investigate the time course of the levels of IL-6, WBC, and several ISPs, i.e. FIB, CRP, cerruloplasmin (CER), haptoglobin (HPT), alpha-1 antitrypsin (A1AT), and alpha-1 acid glycoprotein (A1GP), after successful coronary stenting in patients with stable angina and to relate them to prognosis. MATERIAL/METHODS: FIB, CRP, IL-6, CER, HPT, A1AT, A1GP, and WBC levels were measured in 40 patients with stable angina before, and 6, 12, 24, 48, and 72 hours and 6 months after successful coronary stenting. The patients were followed up for 12 months. RESULTS: FIB levels increased significantly (p<0.05) 48 hours, CRP and WBC count 24 hours, CER, HPT, A1AT, and A1GP 72 hours, and IL-6 6 hours after stenting. All the levels remained unchanged in 20 control patients undergoing coronary angiography. During follow-up, stent restenosis occurred in 7 patients. Time-course and mean values of all the studied substances did not significantly differ in patients with or without restenosis (p>0.05). CONCLUSIONS: FIB, CRP, IL-6, CER, HPT, A1AT, A1GP, and WBC levels increase significantly after stenting, but they are not related to 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.

Diagnostic value of stored electrograms in pacemaker patients.

OBJECTIVE: Stored electrograms (EGMs) are diagnostic tools in modern pacemakers, providing data concerning arrhythmia occurrence and device function. We sought to validate the impact of stored EGMs on diagnosis and verification of arrhythmias presented after pacemaker implantation. METHODS AND RESULTS: We enrolled 71 consecutive patients (mean age 64 +/- 8 years, 51 men) with a standard indication for pacemaker implantation. The following pacemaker devices were implanted: DDDR = 57, VDDR = 5, VVIR = 9. EGM triggers were atrial tachycardia (AT), non-sustained ventricular tachycardia (NSVT) and ventricular tachycardia (VT). We retrieved and analysed 362 EGMs at 3 and 6 months after implantation. The EGMs were triggered by AT in 260 EGMs (72%), by NSVT in 80 (22%) and by VT in 22 (6%). In total, 243 episodes (67%) confirmed the arrhythmic events, while 119 episodes (33%) were classified as false-positive. They were divided into false-positive AT in 85 EGMs (33%), false-positive NSVT in 28 (35%) and false-positive VT in 6 EGMs (27%). The false-positive AT cases were caused by ventricular far-field sensing from the atrial channel in 34 EGMs (40%) and noise or myopotentials in 51 EGMs (60%). Most of the false-positive VT and NSVT episodes were due to atrial fibrillation or atrial tachycardias in 21 EGMs (62%), while the rest were caused by noise in 11 EGMs (32%) or ventricular T wave oversensing in 2 EGMs (6%). CONCLUSIONS: Stored EGMs in pacemaker patients were diagnostic in two thirds of arrhythmic episodes. They are useful tools to diagnose arrhythmias and identify sensing problems, and they contribute to optimal device programming and patient management.

Primary percutaneous coronary intervention in an acute myocardial infarction due to the occlusion of the left main coronary artery.

A 75-year-old woman with no prior medical history was admitted to the hospital because of retrosternal pain for six hours, presenting in a state of cardiogenic shock, specifically hypotension, dyspnoea and slight confusion. Her admission ECG showed ST-segment elevation in the anterolateral leads. Having been started on aspirin, clopidogrel, heparin and dopamine, the patient was immediately transferred to the catheterisation laboratory. The coronary angiogram showed total occlusion of the bifurcation of the left main (LM) coronary artery and some collateral flow from the right coronary artery (RCA), the latter itself presenting multiple critical stenoses. Percutaneous coronary intervention (PCI) was performed with deployment of stents at the LM bifurcation, which resulted in the relief of the obstruction, the restoration of the flow in the left coronary artery and the immediate clinical improvement of the patient. The patient left the hospital in good general condition after being treated for ten days and underwent a successful second PCI in the RCA two months later.

Improved papillary muscle function attenuates functional mitral regurgitation in patients with dilated cardiomyopathy after cardiac resynchronization therapy.

BACKGROUND: Functional mitral valve regurgitation attenuation after cardiac resynchronization therapy (CRT) in patients with severe heart failure has been attributed to both the increased rate of left ventricular systolic pressure increase and to papillary muscle (PM) recoordinated contraction. We hypothesized that an increase in systolic deformation of the PMs or the adjacent myocardial wall may in part account for this effect, by preventing their outward displacement during systole. METHODS: We studied by echocardiography 22 patients with moderate/severe functional mitral valve regurgitation and a mean ejection fraction of 18 +/- 4% at baseline and after implantation of a CRT system. RESULTS: CRT induced a significant reduction of the effective regurgitant orifice area (0.18 +/- 0.11 vs 0.35 +/- 0.17 mm2, P < .001). Strain improved in both PMs and their adjacent walls, although this improvement was significant only in anterolateral PM (-16 +/- 4.7 vs -11 +/- 4.3%, P = .02) and posteromedial PM adjacent wall (-16 +/- 10 vs -8 +/- 4.6%, P = .01). CONCLUSIONS: CRT acutely reduces the severity of functional mitral valve regurgitation in patients with heart failure and this effect may be in part attributed to improved strain of PM or adjacent wall.

Inappropriate detection and therapy from an implantable cardioverter defibrillator due to atrial undersensing.

We present a case of inappropriate detection and therapy in a patient with an implantable cardioverter defibrillator. The device interpreted a supraventricular tachycardia as ventricular tachycardia due to unsensed P waves as a result of a relatively high level of atrial sensitivity setting. Subsequently, inappropriate therapy was delivered. The problem was resolved by decreasing the atrial sensitivity value.