Harish Doppalapudi

Idiopathic ventricular arrhythmias originating from the aortic root prevalence, electrocardiographic and electrophysiologic characteristics, and results of radiofrequency catheter ablation.

OBJECTIVES This study investigated the prevalence and electrocardiographic and electrophysiologic characteristics of aortic root ventricular arrhythmias (VAs). BACKGROUND Idiopathic VAs originating from the ostium of the left ventricle may be ablated at the base of the aortic cusps. METHODS We studied 265 patients with idiopathic VAs with an inferior QRS-axis morphology. RESULTS The successful ablation site was within (or below) the aortic cusps in 44 patients (16.6%). The site of the origin was the left coronary cusp (LCC) in 24 (54.5%), the right coronary cusp (RCC) in 14 (31.8%), the noncoronary cusp (NCC) in 1 (2.3%), and at the junction between the LCC and RCC (L-RCC) in 5 (11.4%) cases. The maximum amplitude of the R-wave in the inferior leads was significantly greater with an LCC than with an RCC origin (p < 0.05). The ratio of the R-wave amplitude in leads II and III was significantly greater with an LCC than with an RCC origin (p < 0.01) and was significantly smaller in the NCC than in the other sites (p < 0.0001). The ventricular deflection in the His bundle electrogram was significantly later relative to the surface QRS with an LCC or L-RCC origin than with an RCC or NCC origin (p < 0.0001). The ratio of the atrial-to-ventricular deflection amplitude was significantly greater in the NCC than in the other sites (p < 0.0001). No other factors predicted the site of origin. CONCLUSIONS Idiopathic VAs are more common in the LCC than in the RCC and rarely arise from the NCC. The electrocardiogram is useful for differentiating the site of origin.

Implantable cardioverter-defibrillator prescription in the elderly

BACKGROUND Because sudden cardiac death increases with age, implantable cardioverter-defibrillators (ICDs) might greatly benefit the elderly. However, elderly patients are underrepresented in clinical trials, and comorbid conditions may attenuate benefit. OBJECTIVE The purpose of this study was to examine ICD prescription in the elderly. METHODS The ages, indications, and implanted ICD type of patients enrolled in the Advancements in ICD Therapy (ACT) Registry were compared to those from the National Cardiovascular Data Registry (NCDR). RESULTS The ACT Registry included 4,566 patients who underwent first ICD or cardiac resynchronization therapy ICD (CRT-D) implantation. Among these patients, 2.6% were 18-39 years old, 8.6% were 40-49 years, 20.1% were 50-59 years, 27.6% were 60-69 years, 29.0% were 70-79 years, and 12.0% were >or=80 years. In the six age groups, 82.5%, 79.4%, 77.3%, 80.1%, 77.7%, and 74.6% received devices for primary prevention, and single-chamber ICDs were implanted in 41.4%, 42.8%, 38.7%, 33.8%, 25.2%, and 28.1%, respectively (P <.0001). Two-year mortality rates increased incrementally from 5.80% to 17.80% in the six groups (P <.05). Noncardiac death was more common in older than in younger patients. Among patients >or=80 years old receiving a CRT-D, 78% had QRS duration and New York Heart Association class that met accepted implantation criteria. Age distribution, indication, and type of device were similar in the ACT Registry and in 74,476 patients in the NCDR. CONCLUSION More than 40% of new ICDs and CRT-Ds are implanted in patients >70 years old and more than 10% in patients >or=80 years old. A significant proportion of those receiving a CRT-D did not fulfill accepted criteria for implantation. Noncardiac death occurred more frequently in older patients, but cardiac death rates were similar.

Idiopathic Ventricular Arrhythmias Originating From the Left Ventricular Summit Anatomic Concepts Relevant to Ablation

Background—The summit of the left ventricle (LV) is the most superior portion of the epicardial LV bounded by an arc from the left anterior descending coronary artery, superior to the first septal perforating branch to the left circumflex coronary artery. Ventricular arrhythmias (VAs) originating from this region may present challenges for catheter ablation. Methods and Results—We studied 27 consecutive patients with VAs originating from the LV summit. The great cardiac vein (GCV) divides this region between an inferior area accessible to ablation and a superior, inaccessible area. Successful ablation was achieved within the GCV in 14 patients and on the epicardial surface in 4. Ventricular prepotentials were recorded at the successful ablation site in 80% of these patients. In 5 patients, ablation was abandoned because of inaccessibility of the catheter to the myocardium or high impedance with radiofrequency application within the GCV. In the remaining 4 patients, epicardial mapping suggested VA origins in a region of low voltage that was located superior to the GCV (inaccessible area), and ablation was abandoned because of close proximity to the coronary arteries or high impedance. A right bundle-branch block, transition zone, R-wave amplitude ratio in leads III to II, Q-wave amplitude ratio in leads aVL to aVR, and S waves in lead V6 accurately predicted the site of origin. Conclusions—LV summit VAs may be ablated within the GCV or inferior to the GCV on the epicardial surface, though sites superior to the GCV are usually inaccessible to ablation.

Ventricular Tachycardia Originating From the Posterior Papillary Muscle in the Left Ventricle A Distinct Clinical Syndrome

Background—Several distinct forms of focal ventricular tachycardia (VT) from the left ventricle (LV) have been described. We report a new syndrome of VT arising from the base of the posterior papillary muscle in the LV. Methods and Results—Among 290 consecutive patients who underwent ablation for VT or symptomatic premature ventricular complexes (PVCs) based on a focal mechanism, 7 patients were found to have an ablation site at the base of the posterior papillary muscle in the LV. All patients had normal LV systolic function and a normal baseline electrocardiogram. The electrocardiogram during VT or PVCs demonstrated a right bundle-branch block and superior-axis QRS morphology in all patients. VT was not inducible by programmed atrial or ventricular stimulation. In 2 patients with sustained VT, overdrive pacing neither terminated VT nor demonstrated any criterion for transient entrainment. Activation mapping localized the earliest site of activation to the base of the posterior papillary muscle in all patients. When Purkinje potentials were recorded at the site of successful ablation, these potentials preceded local ventricular muscle potentials during sinus rhythm. During VT or PVCs, however, the ventricular muscle potential always preceded the Purkinje potentials. After recurrence of VT or PVCs with standard radiofrequency ablation, irrigated ablation was successful in eliminating the arrhythmia in all patients. Over a mean follow-up period of 9 months, all patients have been free of PVCs and VT. Conclusion—We present a distinct syndrome of VT arising from the base of the posterior papillary muscle in the LV by a nonreentrant mechanism. Ablation can be challenging, and irrigated ablation may be necessary for long-term success.

Electrocardiographic and Electrophysiological Characteristics in Idiopathic Ventricular Arrhythmias Originating From the Papillary Muscles in the Left Ventricle Relevance for Catheter Ablation

Background—Idiopathic ventricular arrhythmias (VAs) can originate from the left ventricular papillary muscles (PAMs). This study investigated the electrophysiological characteristics of these VAs and their relevance for the results of catheter ablation. Methods and Results—We studied 19 patients who underwent successful catheter ablation of idiopathic VAs originating from the anterior (n=7) and posterior PAMs (n=12). Although an excellent pace map was obtained at the first ablation site in 17 patients, radiofrequency ablation at that site failed to eliminate the VAs, and radiofrequency lesions in a relatively wide area around that site were required to completely eliminate the VAs in all patients. Radiofrequency current with an irrigated or nonirrigated 8-mm-tip ablation catheter was required to achieve a lasting ablation of the PAM VA origins. During 42% of the PAM VAs, a sharp ventricular prepotential was recorded at the successful ablation site. In 9 (47%) patients, PAM VAs exhibited multiple QRS morphologies, with subtle, but distinguishable differences occurring spontaneously and after the ablation. In 7 (78%) of those patients, radiofrequency lesions on both sides of the PAMs where pacing could reproduce an excellent match to the 2 different QRS morphologies of the VAs were required to completely eliminate the VAs. Conclusions—Radiofrequency catheter ablation of idiopathic PAM VAs is challenging probably because the VA origin is located relatively deep beneath the endocardium of the PAMs. PAM VAs often exhibit multiple QRS morphologies, which may be caused by a single origin with preferential conduction resulting from the complex structure of the PAMs.

Idiopathic focal epicardial ventricular tachycardia originating from the crux of the heart.

BACKGROUND Idiopathic ventricular tachycardia (VT) can arise from the epicardium, usually near the summit of the left ventricle (LV). OBJECTIVE The purpose of this study was to describe a distinct syndrome of epicardial VT that arises from the crux of the heart. METHODS Among 340 patients with idiopathic VT referred for ablation, four were identified with VT that was mapped to the epicardium at the crux. RESULTS VT was sustained in all patients and was associated with syncope or presyncope in three. Rapid VT (mean cycle length 264 ms) was induced with programmed stimulation or burst pacing from the ventricle but required isoproterenol infusion in three. ECG during VT demonstrated a left superior axis QRS morphology with a precordial maximal deflection index >or=0.55 in all patients (mean 0.61). Intracardiac mapping revealed earliest activation in the middle cardiac vein or proximal coronary sinus at the crux in all patients. Irrigated radiofrequency ablation in the middle cardiac vein or proximal coronary sinus was attempted in all patients and successfully abolished VT in one. Percutaneous epicardial radiofrequency ablation was attempted in 2 of 3 remaining patients and successfully abolished VT in both. Simultaneous coronary angiography demonstrated the site of earliest activation within 5 to 10 mm of the proximal posterior descending coronary artery, with no acute narrowing of that artery following ablation. CONCLUSION Idiopathic VT may arise by a focal mechanism from the epicardium at the crux in close proximity to the posterior descending coronary artery. This syndrome can result in rapid, catecholamine-sensitive VT and requires careful attention to the posterior descending coronary artery during ablation.

Ventricular Tachycardia Originating From the Posterior Papillary Muscle in the Left VentricleCLINICAL PERSPECTIVE

Background—Several distinct forms of focal ventricular tachycardia (VT) from the left ventricle (LV) have been described. We report a new syndrome of VT arising from the base of the posterior papillary muscle in the LV. Methods and Results—Among 290 consecutive patients who underwent ablation for VT or symptomatic premature ventricular complexes (PVCs) based on a focal mechanism, 7 patients were found to have an ablation site at the base of the posterior papillary muscle in the LV. All patients had normal LV systolic function and a normal baseline electrocardiogram. The electrocardiogram during VT or PVCs demonstrated a right bundle-branch block and superior-axis QRS morphology in all patients. VT was not inducible by programmed atrial or ventricular stimulation. In 2 patients with sustained VT, overdrive pacing neither terminated VT nor demonstrated any criterion for transient entrainment. Activation mapping localized the earliest site of activation to the base of the posterior papillary muscle in all patients. When Purkinje potentials were recorded at the site of successful ablation, these potentials preceded local ventricular muscle potentials during sinus rhythm. During VT or PVCs, however, the ventricular muscle potential always preceded the Purkinje potentials. After recurrence of VT or PVCs with standard radiofrequency ablation, irrigated ablation was successful in eliminating the arrhythmia in all patients. Over a mean follow-up period of 9 months, all patients have been free of PVCs and VT. Conclusion—We present a distinct syndrome of VT arising from the base of the posterior papillary muscle in the LV by a nonreentrant mechanism. Ablation can be challenging, and irrigated ablation may be necessary for long-term success.

Catheter ablation of ventricular arrhythmias originating in the vicinity of the His bundle: Significance of mapping the aortic sinus cusp

BACKGROUND There is a close anatomical relationship between the right coronary cusp (RCC) and noncoronary aortic cusp (NCC) and sites recording His bundle (HB) activation in the right ventricle (RV). OBJECTIVE The purpose of this study was to examine the electrocardiographic and electrophysiological characteristics of ventricular arrhythmias (VAs) that originate near the HB and their potential as predictors of successful catheter ablation sites. METHODS We studied 147 consecutive patients undergoing successful catheter ablation of idiopathic VAs originating from the ventricular outflow tract of either ventricle or the HB region. RESULTS In 13 (9%) patients with an origin in the RCC (n = 5), NCC (n = 1), or RV HB region (n = 7), the local RV activation in the HB region preceded the QRS onset. In two VAs originating from the RCC or NCC, failed radiofrequency applications near the HB region in the RV delayed the near-field ventricular electrogram and separated the far-field electrograms before the QRS onset in the HB region. The QRS transition in the precordial leads did not discriminate between an RV origin near the HB and an NCC or RCC origin. A QS pattern in lead aVL might be helpful for predicting an RCC origin. CONCLUSIONS VAs originating near the HB have similar electrocardiographic and electrophysiological characteristics, regardless of whether the ablation site is in the RV or aortic sinuses because of the close anatomical relationship of these structures and rapid transseptal conduction. When RV mapping reveals an earliest ventricular activation in the HB region during VAs, mapping in the RCC and NCC should be added to accurately identify the site of origin.

Radiofrequency Catheter Ablation of Idiopathic Ventricular Arrhythmias Originating From Intramural Foci in the Left Ventricular Outflow Tract Efficacy of Sequential Versus Simultaneous Unipolar Catheter Ablation

Backgrounds—Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) sometimes require catheter ablation from the endocardial and epicardial sides for their elimination, suggesting the presence of intramural VA foci. This study investigated the efficacy of sequential and simultaneous unipolar radiofrequency catheter ablation from the endocardial and epicardial sides in treating intramural LVOT VAs. Methods and Results—Fourteen consecutive LVOT VAs, which required sequential or simultaneous irrigated unipolar radiofrequency ablation from the endocardial and epicardial sides for their elimination, were studied. The first ablation was performed at the site with the earliest local ventricular activation and best pace map on the endocardial or epicardial side. When the first ablation was unsuccessful, the second ablation was delivered on the other surface. If this sequential unipolar ablation failed, simultaneous unipolar ablation from both sides was performed. The first ablation was performed on the epicardial side in 9 VAs and endocardial side in 5 VAs. The intramural LVOT VAs were successfully eliminated by the sequential (n=9) or simultaneous (n=5) unipolar catheter ablation. Simultaneous ablation was most likely to be required for the elimination of the VAs when the distance between the endocardial and epicardial ablation sites was >8 mm and the earliest local ventricular activation time relative to the QRS onset during the VAs of <–30 ms was recorded at those ablation sites. Conclusions—LVOT VAs originating from intramural foci could usually be eliminated by sequential unipolar radiofrequency ablation and sometimes required simultaneous ablation from both the endocardial and epicardial sides.

Cardiovascular implantable electronic device implantation with uninterrupted dabigatran: comparison to uninterrupted warfarin.

While continuation of oral anticoagulation (OAC) with warfarin may be preferable to interruption and bridging with heparin for patients undergoing cardiovascular implantable electronic device (CIED) implantation, it is uncertain whether the same strategy can be safely used with dabigatran.