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Dhanunjaya Lakkireddy

Publications and source records attributed to Dhanunjaya Lakkireddy.

9 recordsLinked to original sources
PubMed2006

Pulmonary vein total occlusion following catheter ablation for atrial fibrillation: clinical implications after long-term follow-up.

OBJECTIVES: We present the clinical course and management outcomes of patients with total pulmonary vein occlusion (PVO). BACKGROUND: Pulmonary vein occlusion is a rare complication that can develop after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). The long term follow-up data of patients diagnosed with PVO are minimal. METHODS: Data from 18 patients with complete occlusion of at least one pulmonary vein (PV) were prospectively collected. All patients underwent RFA for AF using different strategies between September 1999 and May 2004. Pulmonary vein occlusion was diagnosed using computed tomography (CT) and later confirmed by angiography when intervention was warranted. Lung perfusion scans were performed on all patients before and after intervention. The percent stenoses of the veins draining each independent lung were added together to yield an average cumulative stenosis of the vascular cross-sectional area draining the affected lung (cumulative stenosis index [CSI]). RESULTS: The patients' symptoms had a positive correlation with the CSI (r = 0.843, p < 0.05) and a negative one with the lung perfusion (r = -0.667, p < 0.05). A CSI > or =75% correlated well with low lung perfusion (<25%; r = -0.854, p < 0.01). Patients with a CSI > or =75% appeared to improve mostly when early (r = -0.497) and repeat dilation/stenting (r = 0.0765) were performed. CONCLUSIONS: Patients with single PVO are mostly asymptomatic and should undergo routine imaging. On the other hand, patients with concomitant ipsilateral PV stenosis/PVO and a CSI > or =75% require early and, when necessary, repeated pulmonary interventions for restoration of pulmonary flow and prevention of associated lung disease.

Atrial Fibrillation↗
PubMed2006

Atrial arrhythmias after surgical maze: findings during catheter ablation.

OBJECTIVES: We describe the clinical and electrophysiologic characteristics and management of post "cut and sew" Maze arrhythmias in symptomatic patients. BACKGROUND: The Cox Maze procedure was developed as a surgical treatment of atrial fibrillation. Until recently, invasive electrophysiologic studies in patients with symptomatic post-operative arrhythmias in this patient population have not been described. METHODS: The management and clinical course of consecutive patients with post-Maze arrhythmias refractory to antiarrhythmic drugs (AADs) between January 2000 and December 2003 are presented. RESULTS: Twenty-three patients (15 men) presented 14 +/- 14 months after Maze surgery for treatment of atrial fibrillation (AF). Eight patients underwent "cut and sew" Maze for lone AF with no other surgical indication. Fifteen patients underwent the "cut and sew" Maze procedure in addition to another surgical procedure: mitral valve surgery (11 patients) and coronary artery bypass graft surgery (4 patients). Eight patients (35%) had recurrent AF secondary to recovered conduction around the lines encircling the pulmonary veins. Five patients were documented to have focal atrial tachycardia, which was mapped to the coronary sinus in 3 patients, to the posterolateral right atrium in 1 patient, and to the left atrial (LA) septum in 1 patient. Four patients had right atrium incisional atrial flutter (AFL), and 6 had LA incisional AFL, which was mapped around the mitral valve annulus in 4 patients and around the right pulmonary veins in 2 patients. Twenty-two of the 23 patients were treated successfully with radiofrequency ablation. At 1-year follow-up, 19 patients were arrhythmia-free and taking no AADs. CONCLUSIONS: After surgical "cut and sew" Maze, approximately one-third of patients experiencing atrial arrhythmias have AF secondary to pulmonary vein-left atrium conduction recovery. Moreover, incisional AFL seems to be a common finding in this group of patients. Catheter-based mapping and ablation of these arrhythmias seems to be feasible and effective.

Aged↗
PubMed2006

Effects of cocaine intoxication on the threshold for stun gun induction of ventricular fibrillation.

OBJECTIVES: This study sought to assess cocaine's effects on Taser-induced ventricular fibrillation (VF) threshold in a pig model. BACKGROUND: Stun guns are increasingly used by law enforcement officials to restrain violent subjects, who are frequently intoxicated with cocaine and other drugs of abuse. The interaction of cocaine and the stun gun on VF induction is unknown. METHODS: We tested five adult pigs using a custom device built to deliver multiples of standard neuromuscular incapacitating (NMI) discharge that matched the waveform of a commercially available electrical stun gun (Taser X-26, Taser International, Scottsdale, Arizona). The NMI discharges were applied in a step-up and step-down fashion at 5 body locations. End points included determination of maximum safe multiple, minimum VF-inducing multiple, and ventricular fibrillation threshold (VFT) before and after cocaine infusion. RESULTS: Standard NMI discharges (x1) did not cause VF at any of the 5 locations before or after cocaine infusion. The maximum safe multiple, minimum VF-inducing multiple, and VFT of NMI application increased with increasing electrode distance from the heart. There was a 1.5- to 2-fold increase in these values at each position after cocaine infusion, suggesting decreased cardiac vulnerability for VF. Cocaine increased the required strength of NMI discharge that caused 2:1 or 3:1 ventricular capture ratios at all of the positions. No significant changes in creatine kinase-MB and troponin-I were seen. CONCLUSIONS: Cocaine increased the VFT of NMI discharges at all dart locations tested and reduced cardiac vulnerability to VF. The application of cocaine increased the safety margin by 50% to 100% above the baseline safety margin.

Animals↗
PubMed2006

Catheter ablation of ventricular fibrillation storm in patients with infiltrative amyloidosis of the heart.

Recent studies have demonstrated that premature ventricular contractions (PVCs) originating from the Purkinje system are responsible for initiation of ventricular fibrillation (VF) in patients with and without structural heart disease. Ablation of the PVCs has been shown to be feasible. We report 2 patients with repetitive VF associated with cardiac amyloidosis. Each episode of ventricular arrhythmia was preceded by monomorphic PVC. The electrical storms were drug resistant. Electrophysiological testing was performed and the sites of earliest activation were localized within the left ventricle in the absence of significant scar tissue. After ablation, PVCs subsided and there were no further VF recurrences.

Amyloidosis↗
PubMed2005

Pacemaker utilization during permanent atrial fibrillation in patients who received pacemaker implantation for sinus node dysfunction.

Patients who have pacemakers and sinus node dysfunction frequently have atrial fibrillation (AF). The need for continued pacemaker therapy after conversion to permanent AF remains uncertain. This study showed that, among 174 patients who received pacemaker implantation for sinus node dysfunction, 38% (n = 62) had the minimum intrinsic ventricular rate of >60 beats/min after conversion to AF. The pacemaker memory showed that 30 patients (18%) never used ventricular pacing during permanent AF. The study results suggest that patients who have a stable intrinsic ventricular rate during permanent AF by serial assessment may no longer need continued pacemaker therapy.

Aged↗
PubMed2005

Safety and efficacy of radiofrequency energy catheter ablation of atrial fibrillation in patients with pacemakers and implantable cardiac defibrillators.

BACKGROUND: Catheter ablation has significantly transformed the clinical management of atrial fibrillation (AF). The safety and efficacy of this procedure are not well understood in patients with pacemakers and defibrillators. OBJECTIVES: The purpose of this study was to study the impact of radiofrequency catheter ablation of AF in patients with pacemakers and implantable cardiac defibrillators. METHODS: We studied 86 patients with pacemakers and defibrillators (group I) and a similar number of age- and gender-matched controls (group II) who underwent AF ablation between 1999 and 2004. Clinical and procedural variables were compared between the two groups. In group I, various generator and lead parameters were compared before and after the procedure. Resurgence of clinical AF after 2 months was considered recurrence. RESULTS: Both groups were similar with regard to age, gender, body mass index, and type of AF. Group I had a higher incidence of diabetes (17% vs 6%, P = .03), coronary artery disease (25% vs 13%, P = .05), less prolonged AF (31 +/- 21 vs 45 +/- 30 months, P <.001), lower left ventricular ejection fraction (49 +/- 13% vs 52 +/- 9%, P = .03), and left ventricular end-diastolic dimensions (4.97 +/- 0.81 vs 4.72 +/- 0.67, P = .03). No changes in the sensing and pacing thresholds, impedance of atrial and ventricular leads, or defibrillator coil impedance after AF ablation were observed in group I. Atrial lead dislodgment was seen in two patients. Transient abnormal but "expected" pulse generator behavior was seen in 25% of patients without permanent malfunction. Stroke (1% vs 1%, P = 1.000), pulmonary vein stenosis (2% vs 1%, P = .77), and AF recurrence rates at 12 months were similar between groups I and II, respectively (19% vs 21%, P = .73). CONCLUSION: AF ablation is safe and efficacious in patients with pacemakers and defibrillators.

Atrial Fibrillation↗
PubMed2005

The impact of povidone-iodine pocket irrigation use on pacemaker and defibrillator infections.

BACKGROUND: Infection is a devastating complication of permanent pacemakers (PMs) implantable cardioverter defibrillators (ICDs). Many implanting physicians commonly use povidone-iodine solution to irrigate the device pocket before implanting the device. We sought to assess if such a measure would alter the rate of infection. METHODS: A total of 2,564 consecutive patients who received implantable PM or ICD devices between 1994 and 2002 were studied. Povidone-iodine was used for pocket irrigation in 53% and saline in 47%. A total of 18 (0.7%) patients developed pocket infections with 0.7% (10/1,359) in povidone-iodine (group I) and 0.6% (8/1,205) in saline (group II) pocket irrigation (p = ns). Groups I and II were studied for various clinical and demographic variables described in the results section. RESULTS: There was no statistical difference in the baseline demographic and clinical characteristics between groups I and II, respectively. ICDs were most frequently infected than PMs (56% vs 44%). Most (83%) of the devices were dual chamber. Reopening of the pocket for either lead or generator replacement had a higher incidence of infection than new implants (61% vs 39%). There was no difference in the use of preimplantation antibiotic prophylaxis. Late (61%) and deep pocket infections (78%) were more common than early (39%) and superficial infections (22%). Blood cultures were positive in 67% and Staphylococcus aureus was the common most pathogen (50%). The mean duration of antibiotics use after the diagnosis of device infection was 35 +/- 23 days with 72% requiring device explantation. The device was reimplanted on the contralateral side in 56% cases. One patient in each group died due to device infection and related complications. No significant allergy to iodine was seen in either group. CONCLUSION: Povidone-iodine irrigation of the subcutaneous pocket did not alter the rates of pocket infection after pacemaker/defibrillator implantation.

Aged↗
PubMed2005

Modified Mid America Heart Institute Coronary Care Unit scoring system--a new comprehensive prognostic index for Coronary Care Unit patients.

BACKGROUND: Prediction of long-term outcomes for patients presenting with cardiac events is important, but few predictive instruments are available. We previously developed an innovative scoring system, the Mid America Heart Institute (MAHI) Coronary Care Unit (CCU) scoring system, for quantifying outcomes of patients admitted to the CCU, using clinical events rather than solely physiologic and laboratory variables. The objective of our study was to validate a refined version of this system (MAHI-2) and to explore its prognostic value, we have postulated that patients with high MAHI scores would have higher mortality and morbidity in 1-year follow-up. MATERIAL/METHODS: 154 patients admitted to the CCU were followed and assigned a MAHI score based on key clinical variables and events. The patients were followed for 1 year and outcomes were analyzed based on MAHI score quartiles. RESULTS: The mean MAHI-2 score was 14+/-8. Over one year, 34 patients died, 13 suffered myocardial infarction, 12 had coronary artery bypass graft, 6 had percutaneous transluminal coronary angiography, 37 had a cardiovascular-related admission, and a total of 48 (31%) suffered >1 major adverse cardiac event (MACE - death/myocardial infarction/revascularization). MACE rates increased progressively by MAHI-2 score quartile (from 21% for those in the lowest quartile, to 42% in the highest quartile; p=0.22). The risk of death was more strongly correlated with MAHI-2 score, with patients in the highest quartile being at 6-fold greater risk for death in 1 year than those in the lowest quartile (p<0.0017). CONCLUSIONS: The MAHI-2 score appears to be a useful tool for predicting 1-year clinical outcomes based on in-hospital events.

Coronary Care Units↗