Eraldo Occhetta

Risk stratification of the patients with Brugada type electrocardiogram: a community-based prospective study

AIMS Risk stratification of patients with Brugada electrocardiogram (ECG) is being strongly debated. Conflicting results have been suggested from international registries, which enrolled non-consecutive cases, studied with different programmed electrical stimulation (PES) protocols. The aim of this study was to prospectively evaluate the incidence of arrhythmic events and the prognostic role of clinical presentation, ECG, and of a standardized PES protocol in consecutive cases from a community-based population. METHODS AND RESULTS A total of 166 consecutive patients (45 +/- 14 years) with Brugada ECG were enrolled. Type 1 ECG was observed spontaneously in 72 (43%) and after pharmacological testing in 94 (57%). One hundred and three (62%) were asymptomatic, 58 (35%) had syncope, and five (3%) had a prior cardiac arrest. One hundred and thirty-five (81%) underwent PES with two extra stimuli up to ventricular refractoriness and 34% had ventricular fibrillation (VF) induced. Arrhythmic events occurred in nine patients at a mean follow-up of 30 +/- 21 months (2.2 events per 100 person-year): in three (60%) patients with aborted sudden death (aSD), five (8.6%) of those with syncope, and one (1%) of the asymptomatic. The only predictors of events were a history of syncope or aSD (P = 0.02) and induction at PES (P = 0.004). CONCLUSION Clinical presentation is the most important parameter in the risk stratification of patients with Brugada ECG. Programmed electrical stimulation seems valuable, particularly in patients with previous syncope.

Respiration-dependent ventricular pacing compared with fixed ventricular and atrial-ventricular synchronous pacing: Aerobic and hemodynamic variables

A pacemaker that adapts heart rate in response to the patients metabolic requirements has been developed. The pacemaker uses breathing frequency and tidal volume as the indicators of physiologic demand. Maximal physical work capacity, anaerobic threshold, oxygen uptake (16 patients) and hemodynamic variables (9 patients) were assessed with fixed rate (VVI), atrial synchronous (VDT/I) and respiration-dependent ventricular (VVI-RD) pacing. All subjects attained their anaerobic threshold in stress tests with VVI pacing. The maximal physical capacity (p less than 0.001), work time to attain the anaerobic threshold (p less than 0.01) and oxygen uptake (p less than 0.001) were significantly greater with VVI-RD than with VVI pacing. The transition from the supine to the standing position was characterized by a significant increase of cardiac index at rest with both VDT/I and VVI-RD pacing as compared with VVI pacing. Progressive increments in the cardiac index and average left ventricular stroke work index were significantly different at submaximal and maximal exercise when VVI and VVI-RD were compared. At maximal exercise, mean cardiac output was also significantly different: 10.21 +/- 2.5 (SD) liters/min with VVI, 11.2 +/- 0.8 liters/min with VDT/I (p less than 0.05) and 12.65 +/- 3.1 liters/min with VVI-RD (p less than 0.05) pacing. Maximal oxygen extraction values were greater with VVI and VVI-RD pacing than with VDT/I pacing. Pulmonary artery end-diastolic pressures at maximal exercise were within the normal range with the three different modes of pacing. In conclusion, there is a significant (25%) improvement in exercise performance with VVI-RD pacing as compared with VVI pacing.(ABSTRACT TRUNCATED AT 250 WORDS)

Implantable Cardioverter Defibrillators and Cellular Telephones: Is There Any Interference?

The aim of our study was to consider cellular telephone interference using different cellular telephones and implantable cardioverter defibrillator (ICD) models. Thirty (26 men, 4 women) patients with ICDs were considered during follow‐up. The ICD models were: Telectronics (7), CPI (7), Medtronic (7), Ventritex (5), and Ela Medical (4). All patients were monitored with surface ECG; permanent telemetric endo‐ECG monitoring was activated. Then, the effect of two different European telephone systems were tested: TACS system (Sony CM‐R111, 2 W power) and GSM system (Motorola MG1–4A11, 2 W power). For both systems, the effect during call, reception, active conversation (dialogue), and passive conversation (listening) were observed. Cellular telephones were located first in contact with the programming head, then near the leads system, and lastly, in the hands of the patient. At the end of the evaluations, memories were interrogated again to check for false arrhythmia detections. In five of these patients during arrhythmia induction at device implant (first implant or ICD replacement), we also evaluated possible interference between cellular telephones in the reception phase and the ventricular fibrillation detection phase of the ICD. All evaluated models showed significant noise in the telemetric transmission when the cellular telephone (both TACS and GSM) was located near the ICD and the programming head; noise was particularly significant during call and reception, in most cases leading to loss of telemetry. No false arrhythmia detections have been observed during tests with cellular telephones located on the ICDs. During tests performed with cellular telephones located near the leads or in the hands of patients, no telemetric noises or false arrhythmia detections were observed. During induced ventricular fibrillation and cellular telephones in reception mode near the device, the arrhythmia recognition was always correct and not delayed. In conclusion, present ICD models seem to be well protected from electromagnetic interference caused by European cellular telephones (TACS and GSM), without under‐/oversensing of ventricular arrhythmias. However, cellular telephones disturb telemetry when located near the programming head. ICD patients should not be advised against the use of cellular telephones, but it has to be avoided during ICD interrogation and programming.

Combined use of morphology discrimination, sudden onset, and stability as discriminating algorithms in single chamber cardioverter defibrillators.

BORIANI, G., et al.: Combined Use of Morphology Discrimination, Sudden Onset, and Stability as Discriminating Algorithms in Single Chamber Cardioverter Defibrillators. Morphology Discrimination (MD) is a rhythm discriminator based on QRS morphology analysis that can be combined with other discriminators like Stability, with or without Sinus Interval History (SIH) and Sudden Onset. Thirty‐five patients implanted with a St. Jude Medical single chamber ICD were evaluated during exercise testing, during induced AF, and during follow‐up for 14 ± 5 months. At exercise testing (60 episodes detected) MD had a specificity (SP) of 96.7% and Sudden Onset a SP of 91.7%; during induced AF (25 episodes) both MD and Stability had a SP of 96.0%. The diagnostic performance on spontaneous arrhythmias was as follows: for ventricular tachycardia (126 episodes) a sensitivity (SE) of 94.4% for MD, 92.1% for Sudden Onset, 89.7% for Stability without SIH and 79.4% for Stability + SIH; for sinus tachycardia (44 episodes) a SP of 86.4% for MD, 97.7% for Sudden Onset, 2.3% for Stability and of 95.5% for Stability + SIH. For AF (165 cases) a SP of 67.9% for MD, 69.1% for Stability and 90.3% for Stability + SIH, 44.8% for Sudden Onset. Use of MD alone provided a SE of 94.4% and a SP of 71.4% for spontaneous arrhythmias and combined use of the discriminators in a “2 of 3” diagnostic logic implied a SP of 90.9% with maintenance of 96.0% of SE. In single chamber ICDs a wide range of SE/SP ratios may be obtained by use of multiple discriminators, but use of the algorithm in a 2 of 3 diagnostic logic may achieve a SP of 90.9% and a SE of 96.0%.

DDDR pacing driven by contractility versus DDI pacing in vasovagal syncope: a multicenter, randomized study.

DEHARO, J.‐C., et al .: DDDR Pacing Driven by Contractility Versus DDI Pacing in Vasovagal Syncope: A Multicenter, Randomized Study. Recent clinical trials have shown that selected patients with recurrent vasovagal syncope (VVS) may benefit from permanent cardiac pacing. In a previous study using head‐up tilt testing (HUT) the authors demonstrated that the increase in sympathetic activity preceding syncope could be sensed by a microaccelerometer located in the tip of a ventricular pacing lead and used to drive a rate adaptive pacer. They compared in a single blind randomized crossover study, DDDR pacing driven by this system, with conventional DDI pacing in patients with recurrent VVS. Twenty‐three patients (age 61.8 ± 15.2  years , 19 men) with recurrent VVS were enrolled at seven European centers and underwent implantation of a “MiniLivingD/Best” pacing system. Inclusion criteria were (1) >6 cumulative syncopal episodes or ≥1 syncope within 6 months of a positive HUT, and (2) a positive HUT with bradycardia. Using a crossover study design, the pacemakers were randomly programmed for two successive periods of 6 months to DDDR or DDI mode. The numbers of episodes of syncope and presyncope, and quality‐of‐life (QOL), were assessed at the end of each period. During the 6 months before implant, the mean number of syncopal episodes per patient was 3.2 ± 9 . During pacing in the DDDR mode, 0.09 ± 0.29 syncope/presyncope per patient was observed, while during the DDI period 0.48 ± 0.73 episodes per patient were reported (P < 0.05) . QOL scores were77.40 ± 11.32in the DDDR mode versus74.45 ± 14.59in the DDI mode (NS). In patients with recurrent VVS, symptomatic recurrences were less frequent during contractility‐driven DDDR pacing, than during DDI pacing. QOL was similar in the two pacing modes. (PACE 2003; 26[Pt. II]:447–450)

Reducing operator radiation exposure during cardiac resynchronization therapy

AIMS To quantify the reduction in equivalent dose at operators hand that can be achieved by placement of a radiation-absorbing drape (RADPAD) during long-lasting cardiac resynchronization therapy (CRT) procedures. METHODS AND RESULTS This is a prospective observational study that included 22 consecutive patients with drug-refractory heart failure who underwent implantation of a CRT device. The cases were randomly assigned to Group A (11 cases), performed without RADPAD, and to Group B (11 cases), performed using RADPAD. Dose equivalent at the examiners hand was measured as H(p)(0.07) and as a time-adjusted H(p)(0.07) rate (mGy/min) with a direct reading dosimeter. The mean fluoroscopy time was 20.8 ± 7.7 min and the mean dose area product (DAP) was 118.6 ± 45.3 Gy cm(2). No significant differences were found between body mass index, fluoroscopy time, and DAP between patients examined with or without RADPAD. The correlation between the fluoroscopy time and the DAP was high (R(2) = 0.94, P < 0.001). Mean dose and dose rate measurement without the RADPAD at the finger and hand were H(p)(0.07) = 1.27 ± 0.47 mGy per procedure and H(p)(0.07) rate = 0.057 ± 0.011 mGy/min, respectively. The dosage was reduced with the RADPAD to H(p)(0.07) = 0.48 ± 0.20 (P < 0.05) and to H(p)(0.07) rate = 0.026 ± 0.008 (P < 0.001), respectively. CONCLUSION A mean reduction of 54% in the equivalent dose rate to the operators hand can be achieved with the use of RADPAD. The use of the RADPAD in CRT devices implantation will make unlikely the necessity of limiting the yearly number of implants for high volume operators.

Proportion of patients needing an implantable cardioverter defibrillator on the basis of current guidelines: impact on healthcare resources in Italy and the USA. Data from the ALPHA study registry

AIMS Implantable cardioverter defibrillators (ICD) improve survival in selected patients with left ventricular dysfunction or heart failure (HF). The objective is to estimate the number of ICD candidates and to assess the potential impact on public health expenditure in Italy and the USA. METHODS AND RESULTS Data from 3513 consecutive patients (ALPHA study registry) were screened. A model based on international guidelines inclusion criteria and epidemiological data was used to estimate the number of eligible patients. A comparison with current ICD implant rate was done to estimate the necessary incremental rate to treat eligible patients within 5 years. Up to 54% of HF patients are estimated to be eligible for ICD implantation. An implantation policy based on guidelines would significantly increase the ICD number to 2671 implants per million inhabitants in Italy and to 4261 in the USA. An annual increment of prophylactic ICD implants of 20% in the USA and 68% in Italy would be necessary to treat all indicated patients in a 5-year timeframe. CONCLUSION Implantable cardioverter defibrillator implantation policy based on current evidence may have significant impact on public health expenditure. Effective risk stratification may be useful in order to maximize benefit of ICD therapy and its cost-effectiveness in primary prevention.

Respiratory‐Dependent Atrial Pacing, Management of Sinus Node Disease

The effectiveness of respiratory‐dependent atrial pacing (AAI‐RD) was assessed in 23 patients (11 male, 12 female; 68 ± 10 years) with symptomatic isolated sinus node disease (SND). Follow‐up was performed at 3 month intervals and included history taking, physical examination, ECG recording and 24‐hour Holter monitoring. An incremental treadmill exercise test was performed in 21/23 patients before pacemaker implantation, in 23/23 patients after implantation (at least two tests with different programmed settings of respiratory rate/paced rate ratio); 21/23 patients underwent treadmill tests during both fixed rate 70 bpm and AAI‐RD pacing. Physiological sensitivity of AAI‐RD pacing was found excellent in 34 tests (85%) and fair in six (15%). Spontaneous heart rate was significantly higher after pacemaker implantation fbpm 115 ± 20 vs 98 ± 24, P < 0.001). In 10/21 patients paced rate was significantly higher during AAI‐RD vs AAI pacing (131 ±9 vs 106 ± 16, P < 0.001) with better total work time (min 9.9 ± 4 AAI‐RD vs 6.8 ± 2.6 AAI, P < 0.002), higher oxygen consumption at anaerobic threshold (ml/min 1137 ± 406 AAI‐RD vs 882 ± 268 AAI‐RD vs 5.5 ± 2.6 AAI, P ‐ 0.001). No significant difference was found in 7/21 patients (overlap between spontaneous and paced rate during both AAI‐RD and AAI programming); 4/21 patients did not reach anaerobic threshold owing to osteomuscular limitations. AV block was detected in 1/23 patients, Biorate circuital failure in 1/23, sporadic undersensing in 5/23, short and symptom‐free myopotential inhibitions in 10/23. We concluded that AAI‐RD pacing is a reliable, safe and useful modality in pacemaker management of isolated SNA, especially in patients with abnormal rate response to exercise.

Orthostatic hypotension as an unusual clinical manifestation of pheochromocytoma: a case report.

Pheochromocytoma is a rare endocrine tumor which can have a highly variable presentation related to increased catecholamine secretion. We report the case of a 74-year-old man in whom recurrent episodes of syncope due to orthostatic hypotension were the only clinical manifestations of this challenging entity. Diagnosis of pheochromocytoma was achieved by biochemical test samples and computed tomography scans. Surgical excision of the tumor resulted in clinical improvement with normalization of catecholamine concentrations and no more episodes of orthostatic hypotension during a follow-up of 24 months. Although rare, pheochromocytoma may frequently cause disorders of orthostatic tolerance; because of its meaningful implications, screening for this entity should be considered in case of recurrent syncopal episodes due to new-onset orthostatic hypotension.

Lack of Influence of Atrioventricular Delay on Stroke Volume at Rest in Patients with Complete Atrioventricular Block and Dual Chamber Pacing

Dual chamber pacing (DDD) maintains atrioventricular (AV) sequence; AV delay program mobility modifies the relationship between atrial and ventricular contraction. To evaluate the hemodynamic effects of such a modification, ten patients with a DDD unit for complete AV block were studied by time‐motion (M‐mode) and Doppler echocardiography during inhibited ventricular pacing (VVI), atrial‐triggered ventricular pacing (VDDJ and atrioventricular sequential pacing (DVI) at different AV delay (90, 140, 390, 240 msec). A significant improvement in stroke volume (SV) (15%–20%, P < 0.05) was seen during DDD versus VVI pacing; no changes, however, were observed in the same patient with different AV delay or during DVI versus VDD pacing. These data suggest that programming of AV delay does not affect systolic performance at rest; longer diastolic filling times recorded during DDD pacing with “short” AV delay (90–340 msec) do not seem to be a hemodynamically relevant epiphenomenon of PM programming.