Torsade de pointes associated with moxifloxacin: a rare but potentially fatal adverse event.

Torsade de pointes occuring due to a long QT interval is a rare but potentially fatal arrhythmia. Acquired long QT develops most commonly because of drugs that prolong ventricular repolarization. It has been reported that fluoroquinolone antimicrobials prolong the corrected QT interval but rarely cause torsade de pointes. A patient with torsade de pointes risk factors (female sex, advanced age, extreme bradycardia and renal failure) who developed the condition on the fourth day of 400 mg/day of oral moxifloxacin treatment is presented. After the moxifloxacin was stopped, the corrected QT interval normalized and a permanent cardiac pacemaker was implanted. During 11 months of follow-up, arrhythmia did not recur.

Glossopharyngeal neuralgia with cardiac syncope treated by glossopharyngeal rhizotomy and microvascular decompression.

A glossopharyngeal neuralgia case with cardiac asystole is presented. The sinus mode dysfunction and subsequent syncope with pain appears to be the most important life-threatening symptom in the late period of the disease. Because of cardiac symptoms induced by intense vagal stimulation, this case was considered to be vagoglossopharyngeal neuralgia. Several medical and surgical alternatives have been proposed for its treatment. In the presented case the cause of disease was compression of lower cranial nerves in the right cerebello-pontine angle (CPA) by the vertebro-basilar arterial system. Carbamazepine and pacing were determined ineffective, so the patient was treated surgically by cutting the glossopharyngeal nerve and by decompression of the vagal nerve at the CPA. The sinus arrest and paroxysmal pain attacks disappeared and the patient's life returned to normal.

Heart rate variability in hypertrophic obstructive cardiomyopathy: association with functional classification and left ventricular outflow gradients.

BACKGROUND: The aim of this study was to investigate cardiac autonomic control in patients with hypertrophic obstructive cardiomyopathy (HOCM) and to assess the indexes of heart rate variability (HRV) in relation to the clinical and echocardiographic features. METHODS AND RESULTS: Twenty-three patients (17 male, six female: mean age 43+/-11) with HOCM and 18 healthy volunteers were included. M-mode and two-dimensional echocardiography, pulsed and continuous-wave Doppler studies were obtained. All patients and volunteers underwent continuous 24-h ambulatory ECG monitoring. Time domain variables considered in this study were standard deviation of mean R-R intervals (SDNN), root mean-squared successive difference (RMSSD) and percentage of cycles differing from the preceding one by more than 50 ms (PNN 50%). Patients were compared to detect associations between indices of heart rate variability, left ventricular outflow tract obstruction and clinical status. Heart rate variability parameters were also correlated with the echocardiographic and clinical characteristics of the patients. Both New York Heart Association (NYHA) functional class I-II patients (group I) and NYHA III-IV patients (group II) had lower values of SDNN, RMSSD and PNN 50% when compared with the control group (P<0.001, P<0.05 and P<0.01, respectively, for group I and P<0.001, P<0.001 and P<0.001, respectively, for group II). Time domain heart rate variability parameters were found to be significantly correlated with the subaortic dynamic obstruction. CONCLUSION: Heart rate variability is reduced in HOCM and well correlated with the degree of subaortic obstruction. Heart rate variability indices are also sensitive markers of the functional status.

Lengthening of intraatrial conduction time in atrial fibrillation and its relation with early recurrence of atrial fibrillation.

Intraatrial conduction delay in atrial fibrillation (AF) that is considered a component of atrial electrical remodeling has been demonstrated previously in experimental models and it is considered an important factor for the induction or stabilization of AF. However, it is not known if this phenomenon exists in human AF. The present study aimed to compare intraatrial conduction time (IACT) in patients with chronic atrial fibrillation who were converted to sinus rhythm and a matched control group, and to investigate its relation with early AF recurrence. Seventeen patients with chronic AF (mean duration of 20.71+/-16.35 months) were enrolled in the study (7 males, 10 females, 63+/-8 years). An age and sex matched control group (n=12) consisted of patients with sinus rhythm who underwent electrophysiological study (EPS). None of the patients were on any antiarrhythmic treatment during the procedures. Cardioversion was performed via external DC cardioversion. Eight patients in the control group were delivered a DC shock because of induced ventricular tachycardia during EPS. IACT was defined as the interval between the onset of P wave surface ECG and the beginning of A wave at high right atrium (IACT 1) and low right atrium (IACT 2). Additionally, the interval between A wave at high right atrium and low right atrium was measured (IACT 3). Patient characteristics such as age, sex and echocardiographic variables were not different between the AF group and the control group. Heart rate after cardioversion was found to be similar between the two groups. Total delivered energy was significantly higher in the AF group than in the control group (464.47+/-165.82 joules vs. 315.00+/-27.77 joules, p<0.001). IACT 1 (15.30+/-7.61 msec vs 8.50+/-5.29 msec, p<0.02 ), IACT 2 (45.25+/-836 msec vs 26.44+/-10.45 msec, p<0.001) and IACT 3 (26.9+/-8.26 msec vs. 18.67+/-10.05, p<0.05) significantly lengthened in the AF group after maintenance of sinus rhythm compared to the control group. There were 6 early AF recurrences during the 1 week follow-up period. Multivariate analysis, revealed IACT 2 and IACT 3 were significantly different between the control group, the patient with recurred AF and the patients with maintained sinus rhythm. Post-hoc analysis revealed that IACT 2 and IACT 3 significantly lengthened in the patients with recurred AF compared to both the control group and patients with maintained sinus rhythm. On the other hand, only IACT 2 patients with maintained sinus rhythm were found to be higher than those of the control group. The present study indicated that intraatrial conduction was disturbed in patients with AF, a finding which is consistent with those of previous experimental studies. Additionally, such a phenomenon may be a risk factor for the early recurrence of AF after cardioversion to sinus rhythm.

Atrial sensing performance of a single-lead VDD pacing system during physical activities.

This study was undertaken to evaluate the atrial sensing performance of a single-lead atrial synchronous-ventricular pacing system during various physical activities on late follow-up. Fourteen patients (mean age 55 +/- 17 years) with a third-degree or high-degree atrioventricular block and normal sinus node function were treated with the single-lead Thera VDD (Medtronic, Inc, Minneapolis, MN) pacemaker system. Mean P-wave amplitude at implantation was 3.2 +/- 1.3 mV. To assess the VDD system performance, P-wave amplitudes during various physical maneuvers (supine, sitting, deep breathing, standing, and exercise; respectively) were measured and atrial sensing was evaluated at a mean follow-up of 11 +/- 4 months. During deep breathing, minimum and maximum P-wave amplitudes (0.8 +/- 0.7, 1.2 +/- 1.0 mV, respectively) were found to be significantly lower than the standing position (minimum, 1.1 +/- 0.9, maximum, 1.4 +/- 1.1 mV P = .02 in both). No significant difference was found during other physical maneuvers. During the testing maneuvers, atrial undersensing was observed in 8 patients (57%) at the nominal atrial sensitivity of 0.5 mV. After increasing the atrial sensitivity (0.25 mV), no sensing failure was observed in these patients. It has been concluded that Medtronic Thera VDD system is a safe and reliable device with an easy implantation technique providing effective atrioventricular synchronization. The sensing problems, which may occur on late follow-up, can be corrected successfully by reprogramming. To achieve an optimal atrial sensing function in patients with a single-lead VDD pacing, we recommend that the atrial sensing capability should be examined in various physical maneuvers.

Left atrial appendage function in patients with different pacing modes.

Many studies suggest that patients who receive a ventricular pacemaker have a higher incidence of systemic thromboembolism compared to patients receiving a physiological pacemaker. However, the exact mechanism regarding the etiology of thromboembolism remains unclear. We evaluated the left atrial appendage (LAA) functions, using multiplane transesophageal echocardiography (TEE), in patients with different pacing modes. In order to evaluate the ejection fraction (EF), peak emptying (V(E)) and filling (V(F)) flow velocities of the LAA by TEE, we studied 31 patients (mean age 63+/-18.5 years) who had been paced for 5.0+/-2.9 years. Patients with atrial fibrillation, left ventricular dysfunction and mitral valve disease were excluded. The pacing indications were complete atrioventricular block (AVB) in 19 patients (9 VVI, 10 VDD or DDD) and sick sinus syndrome (SSS) in 12 patients (5 VVI, 7 DDD). Mean EF, V(E) and V(F) of the LAA were significantly lower in all patients with ventricular pacing (25.5+/-15.6%, 30.4+/-15.6 cm/s and 29. 1+/-19.2 cm/s, respectively) compared to those with physiologic pacing (48.5+/-16.9%, 59.6+/-16.3 cm/s, 57.9+/-18.5 cm/s, respectively) (P<0.01 in all). When patients were further classified with respect to underlying heart disease whether they had SSS or AVB, all measurements of the LAA (EF, V(E) and V(F)) in both subgroup of patients with SSS and AVB were found significantly lower in those with ventricular pacing than in those with physiologic pacing (Tables 3 and 4). This decrease, especially in LAA flow, was much greater in those with SSS (Mean V(E) and V(F) <20 cm/s). In a patient paced with VVI for SSS, a thrombus was detected within the LAA cavity. In conclusion, these results suggest that the pacing modality appeared to influence the LAA functions in paced patients. Patients with asynchronous ventricular pacing modes had a significantly higher incidence of depressed LAA functions than did patients with physiological pacing, especially more marked in patients with sick sinus syndrome. This may be a factor responsible for increased risk of thrombus formation and thromboembolic events in this patient population.

Bronchial hyperreactivity in patients with mitral stenosis before and after successful percutaneous mitral balloon valvulotomy.

OBJECTIVES: We aimed to identify the bronchial response to inhaled methacholine in patients with mitral stenosis (MS) and to clarify whether or not the bronchial hyperreactivity (BHR) is reversible after percutaneous mitral balloon valvulotomy (PBMV). PATIENTS AND SETTING: Thirty patients with MS and 28 age-matched healthy control subjects were prospectively evaluated with pulmonary function tests and methacholine challenge. The productive concentration of methacholine causing 20% decrease in FEV(1) (PC(20)) was calculated and used as a parameter of bronchial responsiveness. BHR was defined as a PC(20) < 8 mg/mL. Mean pulmonary artery pressure (PAP) and mean pulmonary capillary wedge pressure (PCWP) were recorded in all patients through a Swan-Ganz balloon-tipped catheter. Sixteen patients underwent PMBV, and a methacholine test was repeated after each procedure. RESULTS: Bronchial response to methacholine was significantly increased in patients with MS, so that 53% of them had BHR, whereas all control subjects were nonresponders. The PC(20) was closely correlated with the PAP (r = - 0.777; p < 0.001), PCWP (r = - 0.723; p < 0.001), and mitral valve area (MVA; r = 0.676; p < 0. 001). Balloon valvulotomy was successfully performed in all of the 16 patients, and the cardiac parameters (MVA, PAP, and PCWP) significantly improved after the procedure. In contrast, no significant changes were shown in pulmonary function test variables (total lung capacity, vital capacity [VC], FEV(1), and FEV(1)/VC). Although significant improvement was observed in the mean PC(20) values (from 4.97 +/- 5.24 to 7.47 +/- 6.96 mg/mL; p = 0.0006), BHR was completely eliminated in only one patient. CONCLUSIONS: Our data shows that BHR is fairly common among patients with MS, and severity of bronchial responsiveness is significantly correlated with the severity of MS. Moreover, PMBV leads to significant reduction in pulmonary congestion and a consequent improvement in BHR.

Left ventricular filling and ejection fraction after successful percutaneous balloon mitral valvuloplasty.

The effect of percutaneous balloon mitral valvuloplasty (PBMV) on left ventricular (LV) filling and ejection fraction (EF) still remains controversial. We evaluated LV filling and EF in 23 patients (19 women and four men, mean age 35.6+/-9.6, range 17-56 years) with mitral stenosis (MS) and sinus rhythm immediately before and after successful PBMV not complicated with significant mitral regurgitation and arrhythmia during left ventriculography. After PBMV mean mitral valve area increased from 1.4+/-0.2 to 2.2+/-0.3 cm2 (P<0.01), mean mitral valve gradient (MVG) decreased from 18.6+/-5.7 to 6.9+/-3.2 mmHg (P<0.01) and mean left atrial pressure (LAP) decreased from 26.0+/-8.2 to 12.3+/-5.2 mmHg (P<0.01). We did not determine any change in EF (before PBMV 61.8+/-9.3% and after PBMV 61.8+/-7.6% (P>0.05)). Heart rate did not change significantly before and after valvuloplasty (P>0.05). Despite the decrease in LAP and MVG, the early diastolic filling fraction of left ventricle did not change (before PBMV 59.5+/-7.5%, after PBMV 57.8+/-8.9% (P>0.05)). Also, we did not determine any increase in LV end diastolic volume index (before PBMV 89.9+/-27.7 cm3/m2 and after PBMV 84.6+/-20.9 cm3/m2 (P>0.05)). However, LV end diastolic pressure increased significantly after PBMV (from 6.6+/-3.0 to 11.3+/-4.9 mmHg (P<0.01)). We conclude that in patients with MS, LV diastolic performance is impaired and LV EF does not change acutely after PBMV.

Undersensing of the tiny QRS complexes that emerged after the isolation of the right ventricle in a patient with ventricular tachycardia.

This article describes a patient who underwent right ventricular disconnection for medically refractory ventricular tachycardia associated with arrhythmogenic right ventricular dysplasia. After the operation there was no ventricular tachycardia recurrence. Two years after the operation, he received a permanent VVI pacemaker for the symptomatic second-degree AV block. Sensing function of the pacemaker was normal for the normal QRS complexes, but the tiny QRS complexes that appeared after the arrhythmia surgery were not sensed by the pacemaker and therefore caused no problem.

Evaluation of a new rate adaptive ventricular pacemaker controlled by double sensors.

UNLABELLED: The LEGEND-PLUS, a new rate adaptive pacemaker that combines activity and minute ventilation sensing for automatic rate adaptation was implanted in the right ventricle (VVIR) in 11 patients (mean age 62 +/- 9 years). Initial programming was performed using the Programmer Exercise Protocol (a 3-minute walk). This programming was evaluated by treadmill tests, up-stairs and down-stairs walking, and Holter recordings. RESULTS: Following the final programming of LEGEND-PLUS, the mean upper activity rate was 102 +/- 7 beats/min (range 90-120 beats/min), while the mean upper minute ventilation rate was 125 +/- 16 beats/min (range 100-150 beats/min). The mean rate responses during the exercise protocol and the final programming in minute ventilation and activity sensing modes were 5.4 +/- 2.3 (range 1-9), versus 4 +/- 2.4 (range 1-8; P < 0.01) and 7.6 +/- 1.1 (range 5-9), versus 7.5 +/- 0.8 (range 6-9; P = 0.8), respectively. In the combined sensing mode, the acceleration rate was identical to the activity rate response and the deceleration rate mimicked the minute ventilation. CONCLUSION: Dual sensor VVIR pacemakers have the potential to improve rate adaptation to exercise. The rate response to exercise in patients fitted with activity and minute ventilation sensors, VVIR pacemakers closely mimics the physiological rate response.

Severe vascular toxicity associated with cisplatin-based chemotherapy.

A 19-year-old man with a germ cell tumor who experienced hypertension, acute myocardial infarction, and cerebrovascular accident (CVA) associated with hypomagnesemia as late complications of cisplatin-based chemotherapy is presented, and previously reported cases in the literature are reviewed. Different physiopathologic mechanisms are hypothesized for early and late vascular complications of cisplatin.

Is there an effect of amiodarone on the defibrillation threshold?

The interaction between amiodarone and the defibrillation threshold (DFT) is still controversial. We present a case with dilated cardiomyopathy and recurrent sustained monomorphic ventricular tachycardia who received an automatic implantable cardioverter defibrillator (AICD) while under long-term amiodarone treatment. AICD implantation was performed without thoracotomy. The transvenous lead was inserted via a left subclavian vein puncture and the patch was placed on the lateral chest wall, submuscularly. At the time of implantation a 35J shock was not successful in converting ventricular fibrillation to sinus rhythm, but a 40J rescue shock was successful. After discontinuation of amiodarone, DFT measurements were repeated. Sixteen days later DFT was still higher than 34J, but 71 days later it decreased to 20J.