Biomedical subjects
Publications and source records attributed to Ranjan K Thakur.
Complications after coronary artery bypass grafting are myriad and are to a certain extent operator dependent. The investigators report 2 unusual cases of inadvertent aortocoronary fistula after coronary artery bypass grafting that escaped routine detection. In conclusion, the development of heart failure led to the detection of this rare complication.
This case report describes a 51-year-old man who presented with syncope. His electrocardiogram showed an abnormally long pause and the electrophysiology study revealed a prolonged H-V interval. This was attributed to the radiation therapy he received to the chest. He was successfully treated with implantation of a permanent pacemaker. This case highlights this rare complication of radiation-induced conduction system disease and management of this potentially life-threatening condition.
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INTRODUCTION: Inappropriate implantable cardioverter defibrillator (ICD) therapy (IT) is a common complication in patients with ICD. IT is commonly triggered by supraventricular tachycardias (SVT). Dual chamber ICDs (D-ICDs) may distinguish SVT from ventricular tachycardia/ventricular fibrillation better than single chamber ICDs (S-ICDs) and may be associated with a smaller incidence of IT. METHODS: We reviewed the charts of 386 patients who had an ICD implanted for an AHA class I indication. Intracardiac electrograms were used to classify shocks as either appropriate or inappropriate. RESULTS: Of 295 patients with an S-ICD, 66 (22.3%) received IT, compared to 5 (5.4%) of 91 patients with a D-ICD. The likelihood of being event-free at 1, 2, 3, and 4 years was 96.1%, 96.1%, 96.1%, and 89% for patients with D-ICD and 80.7%, 72.7%, 69.6%, and 66.4%, respectively, for patients with S-ICD (P < 0.001). Multivariate analysis showed no significant association with age, sex, history of atrial fibrillation, history of hypertension, or ejection fraction. SVTs were the commonest cause of IT in our patients. CONCLUSION: Patients with D-ICD are less likely to receive IT as compared to patients with S-ICD.
BACKGROUND: Atriofascicular accessory pathway (AP), often referred to as Mahaim pathway, is an uncommon form of preexcitation. The usual target for ablation is at the site of a high-frequency potential along the tricuspid annulus (TA). We present our observations in mapping and ablation of 29 patients with atriofascicular APs. METHODS AND RESULTS: Twenty-nine consecutive patients who underwent radiofrequency ablation (RFA) for atriofascicular pathways comprised the series. Demographic factors, clinical features of the tachycardia, ablation site, and results were analyzed. The mean age was 19 +/- 8 years; 15 were men. Three patients had Ebstein's anomaly of the tricuspid valve. Four patients had an additional AP and two patients had concomitant typical atrioventricular nodal reentrant tachycardia. RFA was successful in 28 patients (97%); repeat ablation was required in two patients. The site of successful ablation was on the TA at the site of a sharp, high frequency potential in 15 patients (52%). In the remaining 14 patients, a potential was not found along the TA, and ablation was targeted at the ventricular insertion of the AP into the distal right bundle. At the successful ventricular ablation site, local ventricular activation preceded the surface electrocardiogram by 20 +/- 6 ms. Eight of the 14 patients (57%) undergoing ablation in the ventricle, developed right bundle branch block (RBBB). One patient who underwent successful ablation along the TA also manifested RBBB after ablation; however, this patient had Ebstein's anomaly and preexcitation had completely masked the RBBB. The mean procedure and fluoroscopy time was 150 +/- 32 and 35 +/- 12 minutes, respectively. CONCLUSIONS: In atriofascicular pathways, an AP potential was found along the TA in only 52% of patients. Ablation at the ventricular insertion site often resulted in RBBB (57%), but the AP was also successfully ablated.
We report a case of a 57 year-old man with a minute ventilation rate-response pacemaker and an inappropriate increase in his heart rate during a transthoracic echocardiography study. The increase in heart rate was due to interference between echocardiography and minute ventilation sensor. This was confirmed by a repeat echocardiogram, which reproduced the same effect and turning off the minute ventilation sensor stopped the tachycardia. We suggest that deactivating the minute ventilation sensor would avoid this interaction and electrophysiologists should be aware of this unusual electromagnetic interference phenomenon.
The presence of isolated interrupted inferior vena cava (IVC) is very rare. Though the occurrence of typical atrial flutter in this setting has recently been described, the use of 3-dimensional activation mapping to aid the management of such patients has not yet been described. We report the successful ablation of this arrhythmia in a 63-year-old woman using the superior route through the internal jugular vein with the help of a mapping system.
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BACKGROUND: Mortality benefit from implantable cardioverter defibrillator (ICD) therapy in ischemic cardiomyopathy (ICM) with non-sustained ventricular tachycardia (NS-VT) and inducible VT is well defined. Although NS-VT may suggest an increased risk of sudden cardiac death (SCD) in non-ischemic cardiomyopathy (NICM), the role of ICD therapy is unclear. This retrospective study compares follow-up data in these two groups after ICD implantation. METHODS: 153 consecutive patients with ICD implantation for NS-VT were analyzed. ICM patients received an ICD if they had inducible VT at electrophysiology study (EPS). NICM patients did not routinely undergo EPS before ICD implantation. RESULTS: There were 48 patients (33 males) in NICM group and 105 patients (89 males) in the ICM group. Baseline characteristics including mean ejection fraction (EF), distribution in various New York Heart Association (NYHA) classes, and the mean duration of follow up in the two groups were similar. 50% of the patients in the NICM group and 36% in the ICM group received appropriate therapies (p = 0.106). The mean number of appropriate therapies in the two groups were similar (23.3 +/- 56.7 and 22.5 +/- 59.5 respectively, p = NS). The percentage of patients with inappropriate therapies in the two groups were 27% and 23% respectively (p = NS). Patients in the NICM group received appropriate ICD discharges at a greater rate (p = 0.02). CONCLUSION: Patients undergoing ICD implantation for NICM and NS-VT receive appropriate ICD therapy at a greater rate than those implanted for ICM, NS-VT, and a positive EPS. Although these data do not prove survival benefit in NICM, they suggest a beneficial effect.
Endograft Stenting for contained rupture in descending thoracic aorta has not been reported in the past. We successfully deployed a 28 mm long AneuRx cuff, percutaneously to exclude the descending thoracic aortic pseudoaneurysm in a 62-year-old patient with inoperable retroperitoneal malignant fibrous histiocytoma.
Cardiac disease is the most common cause of death in the United States, and sudden cardiac arrest frequently claims the lives of men and women during their most productive years. It is believed that much better survival rates can be achieved for victims of cardiac arrest through optimizing the "chain of survival" as described by the American Heart Association. The relative and incremental benefit of full prehospital ACLS over basic life support and defibrillation is unproven, however. This is an important issue in this era of cost containment. Some of the ongoing studies including the OPALS study may clarify the cost effectiveness and relative efficacy of rapid defibrillation and full ACLS programs for victims of prehospital cardiac arrest [6].
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VF was observed in four patients (group A) with preexcited AF presenting to the emergency department who had been given 12 mg of adenosine. These patients were resuscitated and underwent electrophysiological study and catheter ablation of the accessory pathway (AP). In a control (group B) of five patients with manifest AP, sustained AF was induced by rapid atrial pacing during electrophysiological study and 12 mg of adenosine was administered. The ECG and electrophysiologic features in the two groups were compared. All patients had a single manifest AP. In group A, three patients had a left free-wall AP and one patient had a posteroseptal AP, while in the control group all had left free-wall APs. The antegrade AP effective refractory period (ERP) in groups A and B was 227 +/- 29 and 289 +/- 37 ms, respectively (P < 0.05). The atrial ERP was 210 +/- 17 versus 219 +/- 21 ms, respectively, in groups A and B (P > 0.05). The shortest R-R interval during AF in group A was 246 +/- 51 ms and 301 +/- 60 ms in group B (P value < 0.05). After adenosine, no patient in group B developed VF. Adenosine may cause VF when administered during preexcited AF. This phenomenon is seen in patients having APs with short refractory periods.
Fascicular VT and RVOT tachycardia are sometimes difficult to induce by programmed electrical stimulation (PES), despite pharmacologic provocation. In such instances, catheter mapping is hampered and efficacy of catheter ablation is difficult to judge. The study included nine patients who presented with incessant idiopathic VT and were directly taken to the electrophysiological laboratory for RF ablation. During the same period, elective ablation was performed on 108 patients with idiopathic VT. The success rate, procedural and fluoroscopy times number of energies, and the peak temperature were evaluated and compared. Of the nine patients, seven had incessant fascicular VT and two had RVOT tachycardia. The mean VT cycle length was 356 +/- 32 ms and the earliest endocardial activation time during VT was 23.6 +/- 6 ms relative to surface QRS complexes. A fascicular potential was not seen in three of the seven patients with fascicular VT. The mean procedural time was 71 +/- 32 minutes and 144 +/- 40 minutes (P = 0.023) while the fluoroscopy time was 14.6 +/- 4.6 minutes and 30 +/- 16 minutes (P < 0.001), respectively, in the primary ablation and elective groups. The total number of RF energies delivered was 2.0 +/- 1.3 versus 7.4 +/- 5.6 (P = 0.07), respectively. The significantly increased procedural time during elective ablation was largely due to time spent in fascicular VT induction. All patients in the primary ablation group were successfully ablated and none had a recurrence. Primary ablation is a safe and effective option in patients with incessant idiopathic VT. Moreover, in fascicular VT, it is superior to elective ablation in terms of success, fluoroscopy and procedural times.
BACKGROUND: Sudden cardiac death in patients on a liquid protein diet has been suggested to be related to repolarization abnormalities. Although increased QT dispersion is also associated with sudden cardiac death, it has not been examined in the setting of weight loss using liquid protein diet. METHODS AND RESULTS: Sixty-three patients (mean age 42 years, 18 men) with a mean initial weight of 116 kg were randomly chosen from patients who had completed 26 weeks of liquid protein diet therapy. QT, corrected QT interval, QT dispersion and corrected QT dispersion were measured blindly along with serum albumin and electrolytes at the beginning and end of 26 weeks of liquid protein diet therapy. In 57 patients (89.5%) (group 1), QT dispersion shortened after weight loss while it was prolonged in 6 patients (10.5%) (group 2). The mean weight loss (group 1: 115+/-21 to 91+/-16 kg; group 2: 122+/-21 to 98+/-13 kg), and serum albumin and electrolyte levels before weight loss were the same in both groups. The decrease in QT dispersion in group 1 was due to increase in the minimum QT interval (350+/-22 v. 375+/-21 mis, p<0.01) after weight loss. However, the QT dispersion increase in group 2 was due to prolongation of the maximum QT interval (402+/-27 v. 441+/-19 ms, p<0.05) after weight loss. This suggests that shortening of the minimum QT interval causes the increased QT dispersion in obesity. Half the patients in group 2 showed a drop in the serum albumin level and 2 patients had an abnormally high phosphorous level at the end of the treatment. CONCLUSIONS: QT dispersion shortens in most patients (89.5%) using liquid protein diet for weight loss. However, increase of QT dispersion is seen in 10.5% of patients. The cause of increased QT dispersion in obesity (before weight loss) differs from that in patients after weight-loss using liquid protein diet. QT dispersion changes observed in this study may explain the risk of sudden cardiac death in these patients.
Catheter ablation for atrial tachycardia is limited by its low success rate and prolonged procedure time because of difficulties in mapping the site of the tachycardia. A new three-dimensional mapping system, the Cardiac Pathways mapping system, using an ultrasound transducer, has recently become available. We report a case of focal atrial tachycardia ablation with this system.
BACKGROUND: Defibrillation testing can be done either via an external cardiac defibrillator or directly via the implanted defibrillator during implantation (device-based testing). The advantage of one testing methodology over the other has not been adequately studied. METHODS AND RESULTS: Seventy-four patients (72% men) were randomized into two groups depending on the defibrillation testing methodology used--external cardiac defibrillation and device-based testing groups. R-wave, pacing threshold, pacing impedance, defibrillation threshold, defibrillation pathway impedance and total procedure time were not significantly different between the two groups. CONCLUSIONS: Device-based testing did not significantly reduce the procedure time. Lead and defibrillation parameters were similar in both the groups; lead repositioning and replacement were required in three patients in the external cardiac defibrillation group.