Methods

Patients were deemed eligible for randomization if they were aged 18 to 80 years and had chronic class III systolic heart failure despite optimal medical therapy, LV dysfunction with ejection fraction ≤35%, and a QRS duration ≥130 ms. Patients were excluded if they had a body mass index >35 kg/m ² , underlying pulmonary disease that precluded single lung ventilation (see the following), or previous left-sided thoracotomy. A random number generator was used to randomize patients to either transvenous or epicardial LV lead placement. The protocol was approved by the local institutional review board, and all patients provided written informed consent.

The primary end point of the study was to compare the percentage decrease from baseline in LV end-systolic volume index (LVESVI) between the transvenous and epicardial groups 6 months after the CRT. Secondary end points included comparison of the following in the 2 patient cohorts: (1) 30-day procedural morbidity and mortality rates, (2) 1-year electrical performance of the LV lead, (3) effect of CRT as assessed by clinical criteria, and (4) survival rate 1 year after the CRT implantation.

All eligible patients underwent a thorough history and comprehensive physical examination. A baseline 12-lead electrocardiogram was recorded. Patients also completed a 6-minute hall walk (6MHW) test, a Minnesota Living with Heart Failure Questionnaire, and had an echocardiography performed.

All echocardiographic images were acquired using a Vivid-7 ultrasound system (GE Ultrasound, Horton, Norway), with a 3.5-MHz transducer. Standard views were used for conventional echocardiography. The echocardiographer was blinded to the patient’s demographics and clinical data. LV end-diastolic diameter, end-systolic diameter, and LV volumes with their indices were determined. LV ejection fraction was calculated using the modified Simpson biplane method off-line on a workstation (EchoPac BT05; GE Healthcare, Little Chalfont, United Kingdom).

Patients randomized to the transvenous arm underwent CRT implantation in the electrophysiology laboratory. The right ventricular pacing lead was placed into the apex or septum. The LV lead placement was guided by an intraoperative CS occlusive venogram. The left anterior oblique projection was used to assess whether the lead was positioned in a septal, anterior, anterolateral, lateral, posterolateral, or posterior location; the right anterior oblique projection was used to assess whether the lead was positioned at the base, mid, or apical portion of the LV. The operator aimed to place the lead in a branch vessel that most closely overlays the lateral or posterolateral wall of the LV.

Patients randomized to the surgical epicardial approach were brought to the operating room, placed under general anesthesia, and intubated with a double lumen endotracheal tube to allow for single (right) lung ventilation. Details of this procedure have been previously published. The 2 robotic arms were introduced through 5-mm ports in the posterior axillary line, typically in the fifth and ninth intercostal spaces. This port placement, in addition to a 5-mm working port placed posteriorly in the seventh intercostal space and a 7-mm working port placed anteriorly, allowed for access to all areas of the heart: the anterior, lateral, posterior, basal, and apical segments. Only the septal segments were not directly accessible using this technique. To access the posterior wall of the LV, electrocautery was used to open the pericardium posterior to the phrenic nerve. A screw-in epicardial LV lead was passed into the chest and secured in place. Once acceptable pacing and sensing thresholds were confirmed, an additional lead was placed as a backup. Both proximal ends of the leads were retrieved from the chest through the anterior working port site. These leads were then tunneled subcutaneously to a small skin counterincision anteriorly that provided easy access to the leads from the supine position. The patient was then placed in the supine position. The left subclavicular area was then freshly prepped and draped. An incision was made for the device pocket, and the right atrial and right ventricular leads were inserted under fluoroscopy in the standard fashion. The epicardial leads were tunneled subcutaneously into the pocket and were tested again for threshold and pacing. One epicardial LV lead was connected to the device; the other LV lead was capped and buried within the implantable cardioverter-defibrillator pocket. The device was tested for defibrillation threshold and programmed.

At each follow-up visit, patients had a history taken, physical examination performed, and their device interrogated. All patients were seen at 1, 3, 6, and 12 months after device implantation. At the 3- and 6-month visits, the 6MHW test was repeated, the Minnesota Living with Heart Failure Questionnaire administered, and a transthoracic echocardiography performed.

Continuous variables are reported as mean and SD or median and interquartile ranges. Categorical variables are reported as frequencies and their relative percentage. Characteristics of the 2 groups were respectively compared using Student t test and chi-square test for continuous and categorical variables, respectively. All tests were 2-tailed with a p value of <0.05 being considered statistically significant. The statistical analysis was performed using SPSS 16.0 (SPSS Inc., Chicago, Illinois).

Results

The demographics and clinical characteristics of the patients at baseline are listed in Table 1 . Patients in the transvenous and epicardial LV lead groups were similar with respect to age, gender, ejection fraction, body mass index, QRS duration, use of medications, co-morbidities, and origin of cardiomyopathy. More than 90% of each group were treated with angiotensin-converting enzyme inhibitor or angiotensin receptor blocker, and all patients in both arms were on β-blocker therapy.

All patients in the epicardial arm had successful LV lead implantation on the lateral wall, posterior to the phrenic nerve. In contrast, in 2 (17%) of the 12 patients who underwent transvenous lead implantation, the LV lead was placed septally into the anterior interventricular vein. One patient (8%) had a failed transvenous procedure and crossed over to the epicardial arm. There was no difference in LV performance at the conclusion of the implant procedures.

There were 2 procedure-related complications in each arm (17% vs 22%; p = NS): 2 diaphragmatic pacing (one requiring device reprogramming and the other requiring lead revision), in the transvenous arm and 2 pocket hematomas requiring evacuation in the epicardial arm. Patients in the transvenous arm had a shorter hospital stay than those in the epicardial arm, which was not statistically significant (3.4 ± 2.6 vs 5.4 ± 4.6 days, p = 0.22). There was no procedure-related mortality in either group.

Both groups demonstrated significant improvement in the primary study end point, LVESVI at 6 months ( Figure 1 ). The individual patient end point data (baseline and 6-month follow-up) are presented in Table 2 . The baseline LVESVI was similar for the transvenous and epicardial groups (72.5 ± 28 vs 77.5 ± 28 ml/m ² , respectively, p = 0.69), and the relative change at 6 months from baseline was similar for each group (−28.8% and −30.5%, respectively, p = 0.93).

Change in LVESVI during the study.

Table 2

Baseline and 6-month end point data

Patient ID	Randomization	Age (yrs)	NYHA, Baseline	NYHA, 6 Months	6MHW, Baseline	6MHW, 6 Months	LVEDVI, Baseline	LVEDVI, 6 Months	LVESVI, Baseline	LVESVI, 6 Months	LVEF, Baseline	LVEF, 6 Months
1	TV	52	3	2	183	380	125	65	107	48	16	26
2	EPI	54	3	2	274	481	103	89	81	62	20	30
3	TV	55	3	2	2	46	114	150	102	136	11	9
4	EPI	61	3	X	31	X	142	X	118	X	17	X
5	TV	62	3	2	305	335	43	64	35	30	21	45
6	EPI	63	3	R	122	R	112	R	95	R	14	R
7	TV	64	3	2	152	381	130	134	116	110	10	10
8	TV	65	3	2	198	229	84	61	57	42	32	30
9	EPI	65	3	2	290	451	120	118	98	93	18	20
10	EPI	66	3	2	125	220	109	146	82	117	24	20
11	EPI	67	3	3	91	H	97	104	77	86	14	18
12	TV	69	3	D	152	D	81	D	68	D	16	D
13	EPI	69	3	2	348	366	54	50	35	31	35	38
14	TV	70	3	2	76	131	72	32	45	24	38	26
15	EPI	71	3	2	61	R	98	73	79	56	18	21
16	TV	78	3	D	113	D	67	D	49	D	27	D
17	TV	78	3	2	230	183	101	63	76	49	26	23
18	TV	79	3	2	15	161	133	116	92	88	31	25
19	TV	80	3	R	61	R	112	81	84	72	12	15
20	TV	82	3	2	183	472	66	48	39	35	30	27
21	EPI	85	3	2	R	209	47	63	33	41	30	35

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