Huagui Li

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.

Transesophageal echocardiography before cardioversion of recurrent atrial fibrillation: Does absence of previous atrial thrombi preclude the need of a repeat test?

BACKGROUND Atrial fibrillation (AF) is a recurrent problem that frequently requires repeat cardioversion. Transesophageal echocardiography (TEE) is indicated before cardioversion in patients who are underanticoagulated (warfarin therapy <3 weeks or international normalized ratio [INR] <2.0). It remains uncertain if TEE should be repeated in underanticoagulated patients who had no atrial thrombi detected by previous TEE. Methods and results From January 1996 to June 2001, 76 patients (43 men, 33 women; mean age, 68.8 +/- 10.4 years) who were underanticoagulated and had no atrial thrombi in previous TEE underwent repeat TEE before cardioversion of recurrent AF. The duration of recurrent AF at the time of the second TEE was 5.1 +/- 9.3 months (1 day to 4 years). The underlying diseases included coronary artery disease (n = 30), hypertension (n = 22), valvular heart diseases (n = 8), dilated cardiomyopathy (n = 4), hypertrophic cardiomyopathy (n = 2), and others (n = 10). Eight (10.5%) patients (2 men, 6 women; mean age, 68.6 +/- 6.6 years) were found to have intra-atrial thrombi on the second TEE. Of these 8 patients, 3 had coronary artery disease, 1 had hypertension, 2 had dilated cardiomyopathy, 1 had hypertrophic cardiomyopathy, and 1 had AF of unknown cause. The duration of recurrent AF in patients with and without thrombi was not significantly different (3.6 +/- 4.7 versus 5.3 +/- 9.7 months, P =.22). Of the 8 patients with intra-atrial thrombi on the second TEE, 5 had been taking warfarin for 3 to 4 weeks but had subtherapeutic INR and 3 were taking aspirin only. Compared with patients without intra-atrial thrombi, patients with intra-atrial thrombi had lower ejection fraction (32.5% +/- 18.1% versus 49.9% +/- 14.1%, P =.015), slower left atrial appendage empty velocity (0.22 +/- 0.08 versus 0.41 +/- 0.17 m/s, P <.01), and higher prevalence of spontaneous echo contrast (87.5%) than in patients without intra-atrial thrombi (19.1%, P <.05) but similar left atrial size (49.5 +/- 5.3 versus 47.3 +/- 7.1 mm, P =.15). Cardioversion was cancelled in all patients with atrial thrombi. CONCLUSIONS In underanticoagulated patients, repeat TEE is necessary before cardioversion of recurrent AF even if the previous TEE showed no atrial thrombi.

Thromboembolism in Patients With Atrial Fibrillation With and Without Left Atrial Thrombus Documented by Transesophageal Echocardiography

The incidence of cerebrovascular events (CVEs) was investigated in 95 consecutive patients with atrial fibrillation (AF) with left atrial thrombus (LAT) diagnosed by transesophageal echocardiography (TEE) and in 131 age- and sex-matched AF patients without LAT. Compared with patients without LAT, patients with LAT had a larger left atrial diameter (49 versus 44 mm, P < 0.0001), a lower left ventricular ejection fraction (40% versus 50%, P < 0.0001), a higher prevalence of spontaneous echocardiographic contrast (88% versus 25%, P < 0.001), a reduced left atrial appendage emptying velocity (0.25 versus 0.41 cm/s, P < 0.0001), and less use of antiarrhythmic drugs (61% versus 76%, P = 0.03). Before TEE, the prevalence of prior CVE was higher in LAT patients (20%) compared with patients without LAT (8%) (P = 0.01). Fifty-four of 95 LAT patients (57%) and 81 of 131 non-LAT patients (62%) were on warfarin before TEE. The incidence of prior CVE in LAT patients without warfarin (32%) was higher than that in non-LAT patients without warfarin (10%) (P = 0.02). The mortality rate in LAT patients with an international normalized ratio (INR) ≥ 2.0 (42%) was higher than that in patients without LAT and an INR ≥ 2.0 (11%) (P < 0.001). Fifty-one of 95 LAT patients (54%) underwent repeat TEE before cardioversion (48 patients received warfarin therapy). The thrombus resolved in 40 of 51 patients (78%) after the first TEE. There was no significant difference in INR between the patients with persistent and resolved LAT. AF patients with persistent LAT had a higher incidence of CVE (45%) than the patients with resolved LAT (5%) (P = 0.003). We suggest that patients with LAT be treated with warfarin to maintain an INR between 2.5 and 3.5 rather than between 2.0 and 3.0 because they are at a high risk for new thromboembolism.

Warfarin Therapy Initiated before Is More Beneficial Than after Transesophageal Echocardiography Detected Left Atrial Thrombus

Objective: Warfarin anticoagulation significantly reduces the risk of thromboembolism in patients with atrial fibrillation (AF). However, there are many patients with AF who begin anticoagulation only after left atrial thrombus (LAT) is detected by transesophageal echocardiography (TEE). The impact of anticoagulation in these patients has not been clearly described. The purpose of this study was to investigate the incidence of cerebrovascular accident (CVA) among AF patients who began warfarin before LAT was detected by TEE compared to those who began warfarin only after TEE demonstrated LAT and those did not receive warfarin at any point. Method: Of the 90 consecutive AF patients with LAT (male 48, female 42, age 71.5 ± 10.1 years), 49 began warfarin more than 3 weeks before TEE (Group I); 29 began warfarin after TEE (Group II); and 12 did not receive warfarin at all (Group III). Results: The incidence of CVA in Group I (14%, 7/49, prior CVA 5, new CVA after TEE 2) was significantly lower than Group II (45%, 13/29, prior CVA 10, new CVA after TEE 3, P = 0.006) and III (42%, 5/12, prior CVA 3, new CVA after TEE 2, P = 0.047). Patients with persistent LAT had significantly higher incidence (64% vs 23%, P = 0.024) of CVA and lower CVA free survival than those with resolved LAT. Conclusion: The incidence of CVA among AF patients, who began warfarin before LAT detection, is significantly lower than those who began warfarin after LAT detection as well as those who did not receive warfarin at all.

Cardiac resynchronization therapy in patients with intrinsic and right ventricular pacing-induced left bundle branch block pattern

We studied 95 consecutive patients, mean age 70 years, who received cardiac resynchronization therapy (CRT) for class III or IV heart failure with a left ventricular (LV) ejection fraction ≤35% and a QRS duration ≥120 ms. Sixty-seven patients had intrinsic left bundle branch block (LBBB) (group 1), and 28 patients had right ventricular pacing-induced LBBB (group 2). The time difference (TPW-TDI) between onset of QRS to the end of LV ejection by pulsed wave Doppler and onset of QRS to the end of systolic wave in the basal segment with greatest delay by tissue Doppler imaging was measured before CRT and at the last follow-up after CRT. TPW-TDI >50 ms was defined as left ventricular mechanical dyssynchrony. A positive response to CRT was defined as LV volume at end-systole decreasing ≥15% after CRT. The percentage of CRT responders in group 2 was significantly greater than that in group 1 (68% versus 42%, P = 0.04) during follow-up of 16 months. After adjusting for age, gender, and clinical features, this pattern of CRT response persisted (P = 0.008). Similarly, there was a greater reduction in QRS duration in group 2 (178 ms) after CRT versus 154 ms for group 1, P = 0.01. There was no significant difference in TPW-TDI between the 2 groups at baseline or at follow-up. There was no significant difference in mortality (15% versus 14%) and Kaplan-Meier survival plot during follow-up. Patients with heart failure and right ventricular pacing-induced LBBB have a better response rate to CRT than patients with intrinsic LBBB. The change in left ventricular mechanical dyssynchrony after CRT was similar in these 2 groups of patients.

Incessant right ventricular outflow tract ventricular tachycardia due to subacute postpartum thyroiditis

A previously healthy 26-year-old, 4-month postpartum primipara presented with palpitations and pre-syncope and Holter monitoring shows frequent monomorphic ventricular tachycardia (VT). She denies any other symptoms. On admission she was haemodynamically stable and ECG in emergency room showed sustained monomorphic VT (cycle length, 240 ms; left bundle branch abnormality-inferior axis morphology, and right axis deviation) consistent with a right ventricular outflow tract (RVOT) origin. The VT responded initially to intravenous esmolol and diltiazem only to recur. Physical examination, echocardiography, and cardiac MRI were within normal limits. No other arrhythmia was recorded. The patient underwent an electrophysiology (EP) study and attempted ablation on the next day. The mapping/ablation catheter was positioned in the RVOT and mechanical pressure of the catheter on the endocardium led to immediate suppression of the tachycardia and …

Effect of medical therapy on left ventricular ejection fraction in patients with systolic heart failure and narrow QRS duration with and without ischemic heart disease and left ventricular mechanical dyssynchrony.

We studied 99 consecutive patients with class III-IV systolic heart failure with a left ventricular ejection fraction (LVEF) ≤35% and a QRS duration <120 milliseconds. Patients with cardiac resynchronization therapy were excluded. Echocardiography was performed in all patients before and after optimal standard heart failure therapy. The septal-to-posterior wall motion delay (SPWMD) ≥130 milliseconds on echocardiogram was defined as left ventricular mechanical dyssynchrony (LVMD). Sixty-nine of 99 patients (70%) had ischemic heart disease. During follow-up of 15.2 ± 9.8 months, LVEF improvement ≥15% was greater patients in nonischemic group (50%, 15/30) than in ischemic group (9%, 6/69; P < 0.001). After adjustment for age, gender, and clinical and echocardiographic characteristics, ischemic heart disease and grade of coronary disease were persistently related to LVEF improvement ≥15% (P = 0.03 and 0.02, respectively). Twenty of 99 patients (20%) had SPWMD ≥130 milliseconds (LVMD group), and 79 of 99 patients (80%) had SPWMD <130 milliseconds (non-LVMD group). LVEF increased in both groups (P = 0.005) during follow-up, but the percentage of patients with LVEF improvement ≥15% in LVMD was greater compared with patients without LVMD (40% versus 16%, respectively, P = 0.03). In conclusion, the improvement of LVEF in patients with systolic heart failure and narrow QRS was greater in patients with nonischemic heart disease and LVMD compared with patients with ischemic heart disease and absence of LVMD during medical therapy without cardiac resynchronization therapy.

A Wide QRS Tachycardia Inducible Only by Atrial Pacing and Terminable Only by Ventricular Pacing

A 72-year-old, white female with a history of idiopathic dilated cardiomyopathy (left ventricular ejection fraction 30%) was referred for electrophysiological study because of multiple shocks from an implantable cardioverter defibrillator (ICD). She received the ICD for recurrent wide QRS tachycardia associated with syncope, 4 years ago. Before the ICD implantation, she had no inducible tachycardia during the electrophysiological study. She has been on amiodarone therapy (400 mg/day) for recurrent tachycardia for the past 3 years. She has no history of spontaneous polymorphic ventricular tachycardia (VT) or ventricular fibrillation. The patient’s baseline rhythm was sinus, with complete right bundle branch block and an AH interval of 100 ms and HV interval of 58 ms. During the baseline electrophysiological study, no tachyarrhythmias could be induced by different atrial or ventricular stimulation protocols, including standard extrastimulation, short-longshort coupling,1 and burst pacing. Programmed stimulation was then repeated with isoproterenol infusion at 1 μg/minute. A wide QRS tachycardia was then induced reproducibly but only by atrial pacing at a cycle length of 300 ms (Fig. 1A and 1B). One to one atrioventricular activation ratio was observed at the beginning of the induced tachycardia (Fig. 1A). The induced tachycardia could be terminated only by ventricular burst pacing. During the tachycardia, recording from the right ventricular outflow tract showed local activation time ≥ 25 ms after QRS onset. The earliest ventricular activation was found at a site just inferior to the tip of the His bundle catheter and was simultaneous with QRS onset. Radiofrequency current application to that site terminated the tachycardia in about 2 seconds (Fig. 2). The termination was preceded by ventriculoatrial conduction block. After tachycardia termination and during radiofrequency application, the first sinus beat had QRS morphology of typical right bundle branch block, with AH and