Multiparametric Cardiac Magnetic Resonance and Arrhythmias in Myocarditis.

Myocarditis is an inflammatory disease of the myocardium with a wide range of potential etiological factors, including a variety of infectious agents (mainly viral), systemic diseases, drugs, and toxins.

Retrograde Snaring for Left Ventricular Lead Placement in the Presence of a Persistent Left Superior Vena Cava.

Left ventricular lead positioning is technically demanding in cardiac resynchronization therapy (CRT) device implantation, especially in patients with complex cardiac venous anatomies. We report a case in which retrograde snaring was employed to successfully deliver the left ventricular lead through a persistent left superior vena cava for CRT implantation.

Ventricular Tachycardia Storm After Standard Radiofrequency Pulmonary Vein Isolation.

BACKGROUND The occurrence of ventricular arrhythmias (VAs), particularly premature ventricular complexes, following pulmonary vein isolation (PVI) is a documented phenomenon, but monomorphic scar-related ventricular tachycardia (VT) following PVI is an unusual phenomenon. In this case report, we present a case of new-onset VA after radiofrequency PVI in a patient with no prior history of sustained VTs. CASE REPORT Our patient was a 69-year-old man with a history of symptomatic persistent atrial fibrillation, with an apparently structurally normal heart with subtle regional wall motion abnormalities. He underwent radiofrequency directed pulmonary vein isolation ablation. On the night of an uneventful procedure, the patient for the first time experienced a sustained ventricular tachycardia that exacerbated into a VT storm. Each arrhythmia was terminated by cardioversion due to hemodynamic instability. Antiarrhythmic treatment with lidocaine was initiated immediately. The patient settled from sustained ventricular arrhythmia and received further ablation to monomorphic ventricular tachycardia. CONCLUSIONS The incidence of ventricular ectopics after PVI ablation has been previously described, but a sustained monomorphic ventricular storm has not been reported before with RF ablation. We attribute the pathophysiology to an increase in myocardial excitability and/or ventricular autonomic modulation. This is a very rare phenomenon, but any subtle imaging abnormality before planning RF-PVI should be taken into consideration.

Ventricular substrate identification using close-coupled paced electrogram feature analysis.

AIMS: Substrate based catheter ablation strategies are widely employed for treatment of scar-related ventricular tachycardia (VT). We analysed intracardiac electrograms (EGMs) from close-coupled paced extrastimuli extracted from the EnSite Precision mapping system. We sought to characterize EGM responses of ventricular myocardium to varying coupling intervals from the right ventricular apex (RVA) in both healthy individuals and patients presenting with VT for catheter ablation. METHODS AND RESULTS: Extrastimuli were delivered from the RVA after estimation of the ventricular effective refractory period. Electrograms were recorded from high-density mapping catheters in the left ventricle and exported for analysis to MATLAB. Observational data were collected from 14 patients with ischaemic VT (mean age 72.4 ± 6.3 years, one female) and five controls (mean age 59.4 ± 7.4 years, one female). These derived data were used to inform an interventional strategy on a further 10 patients (mean age 64.7 ± 10.0 years; two female). Significant differences were observed in EGM duration (ED) and latency (LT) at all coupling intervals between VT patients and controls. Significant increases in ED and LT with decreased RVA coupling interval were observed at VT isthmuses. Abnormal responses derived from control subject data were used to classify four types of ventricular EGM response. Targeting sites with abnormal LT and ED significantly reduced VT inducibility (5/14 derivation patients to 0/10 intervention patients; P = 0.03). CONCLUSION: Paced electrogram feature analysis is a novel tool to characterize the ischaemic substrate. Association with VT isthmuses and early ablation results suggest a possible role in substrate ablation for ischaemic VT.

Contact-Force Guided Pulmonary Vein Isolation does not Improve Success Rate in Persistent Atrial Fibrillation Patients and Severe Left Atrial Enlargement: A 12-month Follow-Up Study.

BACKGROUND: Catheter ablation is a cornerstone treatment strategy in atrial fibrillation (AF). Left atrial (LA) size is one of the contributors in development of AF recurrences. The impact of contact-forced (CF) guided catheter ablation on the success rate of persistent AF patients with severe enlarged LA has not been investigated yet. METHODS: Sixty-six patients with diagnosis of longstanding persistent AF undergoing catheter ablation were enrolled. All patients underwent a standard transthoracic echocardiography according to the guidelines. LA size was considered severely enlarged when LA diameter was ≥ 50 mm. CF catheter ablation with a Tacticath Quartz catheter (St Jude Medical, St. Paul, MN, USA) was used in all patients. RESULTS: The mean age was 61.9 ± 9.9 years, and LAD 47.8 ± 11.6 mm. Among 66 patients with persistent AF, 32 (48%) patients were diagnosed with AF recurrences. Twenty-eight (42%) patients had severely enlarged LA. The recurrence of AF was comparable in patients with and without severe enlarged LA (47% vs. 42%, p=0.79). The recurrence of AF was lower in patients who underwent CF-guided ablation with a normal LA dimension (36 %, p=0.54). Procedure duration was longer in patients with severely enlarged LA. LA dimension was not significantly different between patients with and without AF recurrence (49.8 ± 7.9 mm vs. 45.9 ± 7.5 mm, p=0.15). LAD and was significantly correlated with the time to recurrence of AF (r:-0.60, p=0.02). CONCLUSION: Our preliminary findings have demonstrated that CF guided ablation does not improve the success rate in longstanding persistent AF patients with severe LA enlargement.

Ineffective Shock Deliveries in a Patient with Ischemic Cardiomyopathy: Shock Vector Matters.

A 56-year-old male who had previously received an implantable cardioverter-defibrillator for primary prevention was admitted to the hospital with frequent shocks. Device interrogation revealed ineffective shock deliveries. Possible explanations for failed treatment are discussed herein.

High Voltage Guided Pulmonary Vein Isolation in Paroxysmal Atrial Fibrillation.

BACKGROUND: Ablation of the pulmonary vein (PV) antrum using an electroanatomic mapping system is standard of care for point-by-point pulmonary vein isolation (PVI). Focused ablation at critical areas is more likely to achieve intra-procedural PV isolation and decrease the likelihood for reconnection and recurrence of atrial fibrillation (AF). Therefore this prospective pilot study is to investigate the short-term outcome of a voltage-guided circumferential PV ablation (CPVA) strategy. METHODS: We recruited patients with a history of paroxysmal atrial fibrillation (AF). The EnSite NavX system (St. Jude Medical, St Paul, Minnesota, USA) was employed to construct a three-dimensional geometry of the left atrium (LA) and voltage map. CPVA was performed; with radiofrequency (RF) targeting sites of highest voltage first in a sequential clockwise fashion then followed by complete the gaps in circumferential ablation. Acute and short-term outcomes were compared to a control group undergoing conventional standard CPVA using the same 3D system. Follow-up was scheduled at 3, 6 and 12 months. RESULTS: Thirty-four paroxysmal AF patients with a mean age of 40 years were included. Fourteen patients (8 male) underwent voltage mapping and 20 patients underwent empirical, non-voltage guided standard CPVA. A mean of 54 ± 12 points per PV antrum were recorded. Mean voltage for right and left PVs antra were 1.7±0.1 mV and 1.9±0.2 mV, respectively. There was a trend towards reduced radiofrequency time (40.9±17.4 vs. 48.1±15.5 mins; p=0.22). CONCLUSION: Voltage-guided CPVA is a promising strategy in targeting critical points for PV isolation with a lower trend of AF recurrence compared with a standard CPVA in short-term period. Extended studies to confirm these findings are warranted.

Lesion Size Index in Maximum Voltage-Guided Cavotricuspid Ablation for Atrial Flutter.

The application of optimum contact force (CF) can be used to improve ablation procedure success and safety. The lesion size index (LSI) is a novel dimensionless contact force parameter that allows for an accurate estimation of lesion volume in real time by integrating contact force (grams), duration (seconds) and power (watts). The aim was to correlate LSI values with current contact force parameters to achieve successful and safe bidirectional block of the cavotricuspid isthmus (CTI) using a maximum voltage-guided (MVG) ablation strategy. Fifteen consecutive patients (age 69 ± 7.9 years, nine males) with symptomatic atrial flutter (AFL) were evaluated and compared with 23 control (age 66.3 ± 10.4 years, 16 males) non-contact force-guided ablation cases. Irrigated-tip force-sensing ablation catheters (TactiCath Quartz™, St. Jude Medical, St. Paul, MN, USA) were used in the CF group to achieve the primary endpoint of complete bidirectional block of the isthmus. In the CF group, a total of 233 radiofrequency (RF) applications were examined. A mean LSI of 6.4 ±1.0 correlated with a force-time integral (FTI) of 581.2 ±230.9 g/s and an average CF of 13.9 ±4.9 g concurrently. Intraprocedural, fluoroscopy time and RF time demonstrated lower trends in the CF group, but no significance with respect to these trends was observed. The secondary endpoint of no reconnection within 20 min after the procedure was equally attained in both groups, and, likewise, the level of safety was comparable. An LSI value of >5 represents a new effective parameter in MVG ablation for the cavotricuspid region that demonstrates a safe profile. Guidance of CTI ablation using LSI and other contact force parameters of CF 13.9 ±4.9 g and FTI 581.2 ±230.9 g/s demonstrated highly effective and safe outcomes.

A Guide to Transseptal Access.

Transseptal access is commonly performed for any procedure that requires access to the left side of the heart such as catheter ablation of atrial fibrillation, left atrial tachycardia, left-sided accessory pathways, ventricular tachycardia, left atrial appendage closure, percutaneous mitral valvuloplasty, and mitral valve repair. To perform this in a safe and effective manner it is important that the operator has a detailed knowledge of the relevant anatomy, the technique required, and the ability to deal with difficult cases and complications. The aim of this article is to provide a detailed description of the anatomy, techniques, potential complications, and difficulties associated with performing this procedure.

Interatrial block and interatrial septal thickness in patients with paroxysmal atrial fibrillation undergoing catheter ablation: Long-term follow-up study.

BACKGROUND: Interatrial block (IAB) is a strong predictor of recurrence of atrial fibrillation (AF). IAB is a conduction delay through the Bachman region, which is located in the upper region of the interatrial space. During IAB, the impulse travels from the right atrium to the interatrial septum (IAS) and coronary sinus to finally reach the left atrium in a caudocranial direction. No relation between the presence of IAB and IAS thickness has been established yet. OBJECTIVE: To determine whether a correlation exists between the degree of IAB and the thickness of the IAS and to determine whether IAS thickness predicts AF recurrence. METHODS: Sixty-two patients with diagnosis of paroxysmal AF undergoing catheter ablation were enrolled. IAB was defined as P-wave duration ≥120 ms. IAS thickness was measured by cardiac computed tomography. RESULTS: Among 62 patients with paroxysmal AF, 45 patients (72%) were diagnosed with IAB. Advanced IAB was diagnosed in 24 patients (39%). Forty-seven patients were male. During a mean follow-up period of 49.8 ± 22 months (range 12-60 months), 32 patients (51%) developed AF recurrence. IAS thickness was similar in patients with and without IAB (4.5 ± 2.0 mm vs. 4.0 ± 1.4 mm; p = .45) and did not predict AF. Left atrial size was significantly enlarged in patients with IAB (40.9 ± 5.7 mm vs. 37.2 ± 4.0 mm; p = .03). Advanced IAB predicted AF recurrence after the ablation (OR: 3.34, CI: 1.12-9.93; p = .03). CONCLUSIONS: IAS thickness was not significantly correlated to IAB and did not predict AF recurrence. IAB as previously demonstrated was an independent predictor of AF recurrence.

"Spontaneous Twiddler's" Syndrome: The Importance of the Device Shape.

Twiddler's syndrome is caused by patient manipulation of the cardiac implantable device (CID) around its central axis within the pocket, resulting in retraction and dislocation of the electrodes. There are, however, some reports that Twiddler's syndrome may occur spontaneously without the patient's manipulation. This remains contentious as it may be argued that patients may not want to admit to manipulating the CID or may have been unaware of their actions. Recently, we have observed three very similar cases with a "spontaneous" Twiddler's syndrome resulting in lead displacement. All of the three patients denied device manipulation and were not prone to somnambulism or repetitive involuntary motor behaviors. It, therefore, seems highly unlikely that all patients could have manipulated the device in exactly the same way to result in the same postrotational position within the implant pocket. The fact is that the same device was implicated in all these cases in a relatively similar time sequence from implant to recognition of the implantable cardiac defibrillator rotation. We postulate that the unique elongated decision of the Fortify Assura (St. Jude Medical, Minneapolis, MN, USA) ICD makes this device prone to spontaneous rotation as is exemplified by our case series.

Renal Drug Dosage Adjustment According to Estimated Creatinine Clearance in Hospitalized Patients With Heart Failure.

It is of clinical importance to determine creatinine clearance and adjust doses of prescribed drugs accordingly in patients with heart failure to prevent untoward effects. There is a scarcity of studies in the literature investigating this issue particularly in patients with heart failure, in whom many have impaired kidney function. The purpose of this study was to determine the degree of awareness of medication prescription as to creatinine clearance in patients hospitalized with heart failure. Patients hospitalized with a diagnosis of heart failure were retrospectively evaluated. Among screened charts, patients with left ventricular ejection fraction <40% and an estimated glomerular filtration rate (eGFR) of ≤50 mL/min were included in the analysis. The medications and respective doses prescribed at discharge were recorded. Medications requiring renal dose adjustment were determined and evaluated for appropriate dosing according to eGFR. A total of 388 patients with concomitant heart failure and renal dysfunction were included in the study. The total number of prescribed medications was 2808 and 48.3% (1357 medications) required renal dose adjustment. Of the 1357 medications, 12.6% (171 medications) were found to be inappropriately prescribed according to eGFR. The most common inappropriately prescribed medications were famotidine, metformin, perindopril, and ramipril. A significant portion of medications used in heart failure requires dose adjustment. Our results showed that in a typical cohort of patients with heart failure, many drugs are prescribed at inappropriately high doses according to creatinine clearance. Awareness should be increased among physicians caring for patients with heart failure to prevent adverse events related to medications.

Assessment of atrioventricular conduction following cryoablation of atrioventricular nodal reentrant tachycardia in children.

BACKGROUND: Early-onset transient atrioventricular block (AVB) is a rare occurrence following cryoablation of atrioventricular nodal reentrant tachycardia (AVNRT), despite lack of any AVB at the end of the procedure. The purpose of this prospective study was to assess AVB shortly after successful cryoablation of AVNRT in children. METHODS: A 6-mm-tip cryocatheter was used in 39 procedures. An 8-mm-tip catheter was used in 11 procedures. Twelve-lead electrocardiograms (ECGs) and 24-hour ambulatory ECGs were performed 24 hours prior to the procedure and immediately following the procedure. All procedures were done using the EnSite system (St. Jude Medical, St. Paul, MN, USA) without fluoroscopy. RESULTS: Although nine (18%) patients developed variable degrees of transient AVB during the procedure, all of them had normal atrioventricular (AV) conduction at the end of the procedure and did not require any intervention. Four of these patients had variable degrees of transient AVB following the procedure despite having normal AV conduction at the end of the procedure. One developed Mobitz type I AVB, which lasted for 11.5 hours, and the other three experienced 2:1 AVB, which lasted for 2, 8, and 24 hours, respectively. All patients had complete resolution of the AVB, which was also documented with the 24-hour ambulatory ECGs after the procedure. CONCLUSION: Early transient AVB can develop following AVNRT cryoablation even if AV conduction is normal at the end of the procedure. Despite the transient AVB in the initial 24 hours after the procedure in some cases, there is no evidence for ongoing AV nodal dysfunction.

"The end of good luck''--long-term survival without anticoagulation: a case report and review of the literature.

Long-term anticoagulation in patients with metallic prosthetic valve disease is required according to current guidelines. We describe a patient with a functioning mitral mechanical valve without anticoagulation for 27 years. A 46-year-old man admitted to the emergency department with complains of palpitation. The patient had a mitral valve replacement because of severe mitral stenosis. He discontinued warfarin treatment 1 month after surgery because of the unavailability of this drug in Turkey. Transthoracic echocardiography revealed functioning metalic mitral valve with a mean gradient of 9 mm Hg. Fluoroscopy showed normal excursions of the mechanical mitral valve. Transesophageal echocardiography was performed and revealed fresh thrombus formation in the left atrial appendix. Admission international normalized ration (INR) level was 1.79. Due to the higher INR level and long-term survival, genetic analysis of warfarin polymorphism was performed. There was a homozygous mutation in the vitamin K epoxide reductase complex 1 (VKORC1) 1173C>T and 1639G>A genotypes. The possible explanations of long-term survival and baseline higher INR level were linked to the mutation in warfarin metabolism. We also briefly review the literature.

Dilemma in predicting the infarct-related artery in acute inferior myocardial infarction: a case report and review of the literature.

The electrocardiogram (ECG) has being used for decades as a reliable and inexpensive tool to diagnose acute myocardial infarction (AMI). ECG diagnosis of an occluded coronary artery is of the utmost importance. We present the case of a 46 year-old man admitted to our hospital for inferior AMI. The ECG findings suggested right coronary artery occlusion. Coronary angiography showed left circumflex artery occlusion. We also briefly review the literature.

An unusual presentation of left anterior descending artery occlusion: significance of lead aVR and T-wave direction.

Acute occlusion of the left anterior descending coronary artery (LAD) is frequently encountered in acute ST-elevation myocardial infarction. Early detection of the clinical entity by the presenting electrocardiogram (ECG) should result in immediate aggressive clinical management. Although the typical ECG pattern of LAD occlusion is ST elevation, also atypical presentations, like ST depression, may occur. We describe a case with an unusual ECG pattern that suggested acute anterior myocardial infarction due to LAD occlusion.